BACKGROUND The neural mechanisms underlying aggressive behavior in schizophrenia(SCZ)remain poorly understood.To date,no studies have reported on the event-related potential(ERP)characteristics of aggression in SCZ us...BACKGROUND The neural mechanisms underlying aggressive behavior in schizophrenia(SCZ)remain poorly understood.To date,no studies have reported on the event-related potential(ERP)characteristics of aggression in SCZ using the competitive reaction time task(CRTT).Further investigation into the ERP correlates of aggression in SCZ would provide valuable insights into the neural processes involved.AIM To explore the neural mechanism of aggressive behavior in SCZ.METHODS Participants of this study included 40 SCZ patients and 42 healthy controls(HCs).The Reactive Proactive Aggression Questionnaire was used to assess trait of aggression.The Barratt Impulsiveness Scale 11 was used to measure impulsiveness.The Positive and Negative Symptom Scale(PANSS)was used to evaluate psychopathological features and disease severity.All participants were measured with ERP while performing the CRTT.Data of behavior,ERP components(P2,N2,and P3),and feedback-related negativity(FRN)were analyzed.RESULTS Analysis of the behavioral data revealed that compared with HCs,SCZ patients exhibited higher punishment choices.Analysis of ERP components showed that compared with HCs,SCZ patients exhibited higher N2 amplitudes and P2 amplitudes during the decision phase of the CRTT;however,SCZ patients exhibited lower FRN amplitudes and lower P3 amplitudes during the outcome phase of the CRTT.The N2 amplitudes evoked by highintensity provocation were positively related to PANSS-P scores.And the P3 amplitudes evoked in the winning trials were negatively correlated with the PANSS-G scores.CONCLUSION SCZ patients exhibit abnormal ERP characteristics evoked by the CRTT,which suggests the neural correlates of aggressive behavior in SCZ.展开更多
BACKGROUND： According to observable behaviors, sleep and wakefulness are two fundamentally different behavioral states. Although electroencephalogram （EEG） is traditionally used to define sleep stage, it is difficu...BACKGROUND： According to observable behaviors, sleep and wakefulness are two fundamentally different behavioral states. Although electroencephalogram （EEG） is traditionally used to define sleep stage, it is difficult to detect or to quantify microarousals or disruptions during sleep. In addition initial sleep cannot be defined. It is thought that the wake-sleep transition cannot be defined by EEG patterns. OBJECTIVE： To observe the behavioral response magnitude during wake-sleep transition by EEG monitoring and to define the wake-sleep transition. DESIGN, TIME AND SETTING： A behavioral and neural network study was performed at the Key Lab of Human Being Development and Mental Health of Central China Normal University, and Lab of Brain and Cognitive Science of South Central University for Nationalities, China in July 2007. PARTICIPANTS： A total of 30 healthy volunteers, of equal gender and aged （19.7 ± 1.1 ） years, were recruited from the Central China Normal University, China for this study. None of the subjects had undergone EEG recording prior to this study or received any medication for sleep disturbances. METHODS： A novel adaptive approach was applied to detect wake-sleep transition, which avoided stimulus-induced waking. To test the difference between wake state and wake-sleep transition, the amount of self-information and mutual-information were effective parameters to analyze wake-sleep transition. MAIN OUTCOME MEASURES： The following parameters were measured： morphological changes in reaction time-magnitude, as well as correlation between phase changes and sleep, and wake and wake-sleep transition. RESULTS： There were three typical phases in morphological changes of reaction time-magnitude. With regard to the behavioral definition and criterion for sleep, the phase morphological characteristics displayed good correlation with behavioral states, such as sleep, wakefulness, and sleep onset. Entropy as an indicator of brain cognitive processes was introduced to test for differences between the wakefulness and sleep onset phase. Results indicated a cognitive declined transitional period different between sleep and wake. After staggered cognitive changes during the wake-sleep transition, the brain underwent marked alterations and transitioned into sleep quickly with no bi-directional EEG changes. CONCLUSION： Wake-sleep transition exists as an independent stage.展开更多
Objectives:This study aimed to evaluate the effects of a 16-week creative expression intervention program(CrExp)on the event-related potential(ERP)and task reaction time in older individuals with mild cognitive impair...Objectives:This study aimed to evaluate the effects of a 16-week creative expression intervention program(CrExp)on the event-related potential(ERP)and task reaction time in older individuals with mild cognitive impairment(MCI).Methods:This study is a randomized controlled clinical trial conducted in the Memory Center of Fujian Provincial hospital.Thirty-six MCI patients were randomly distributed into two groups.One group underwent a 16-week creative expression program(CrExp,n=18)and the other performed as a control group(CG,n=18)by general social activities.The amplitude and latency of ERP-P300 from the central(Cz),parietal(Pz),frontal(Fz)cortices and task reaction time(RT)were assessed at baseline,postinterventi on,and 24-week follow-up.Results:The CrExp group showed greater differences than CG of P300 latency in Cz(F=4.37,P=0.015),Pz(F=2.78,P=0.009),Fz(F=6.45,P=0.031)brain area after 16 weeks of intervention and in Fz(F=3.23,P=0.028),Cz(F=3.79,P=0.024),and Pz(F=5.60,P=0.036)at 24 weeks follow-up.Also,we analyzed the task reaction time between two groups and found that a shorten reaction time at postintervention(F=4.47,P=0.011)and 24 weeks follow-up(F=3.12,P=0.007)in the CrExp group.However,there was no difference in P300 amplitude in either brain area between the two groups.Conclusion:The electrophysiological results of the creative expression cognitive therapy group were more obvious than those of the general cognitive therapy group,and the latency and task reaction time may be considered as supported parameters in diagnosing the effects during non-drug therapy intervention in clinical practice.展开更多
Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral l...Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function （i.e., primary motor cortex, premotor area, posterior parietal cortex） showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.展开更多
The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It i...The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.展开更多
We consider the psychophysical experiments in which the test subject’s binary reaction is determined by the prescribed exposure duration to a stimulus and a random variable subjective threshold. For example, when a s...We consider the psychophysical experiments in which the test subject’s binary reaction is determined by the prescribed exposure duration to a stimulus and a random variable subjective threshold. For example, when a subject is exposed to a millimeter wave beam for a prescribed duration, the occurrence of flight action is binary (yes or no). In experiments, in addition to the binary outcome, the actuation time of flight action is also recorded if it occurs;the delay from the initiation time to the actuation time of flight action is the human reaction time, which is not measurable. In this study, we model the random subjective threshold as a Weibull distribution and formulate an inference method for estimating the human reaction time, from data of prescribed exposure durations, binary outcomes and actuation times of flight action collected in a sequence of tests. Numerical simulations demonstrate that the inference of human reaction time based on the Weibull distribution converges to the correct value even when the underlying true model deviates from the inference model. This robustness of the inference method makes it applicable to real experimental data where the underlying true model is unknown.展开更多
Background:The concept of stochastic facilitation suggests that the addition of precise amounts of white noise can improve the perceptibility of a stimulus of weak amplitude.We know from previous research that tactile...Background:The concept of stochastic facilitation suggests that the addition of precise amounts of white noise can improve the perceptibility of a stimulus of weak amplitude.We know from previous research that tactile and auditory noise can facilitate visual perception,respectively.Here we wanted to see if the effects of stochastic facilitation generalise to a reaction time paradigm,and if reaction times are correlated with tactile thresholds.We know that when multiple sensory systems are stimulated simultaneously,reaction times are faster than either stimulus alone,and also faster than the sum of reaction times(known as the race model).Methods:Five participants were re-tested in five blocks each of which contained a different background noise levels,randomly ordered across sessions.At each noise level,they performed a tactile threshold detection task and a tactile reaction time task.Results:Both tactile threshold and tactile reaction times were significantly affected by the background white noise.While the preferred amplitude for the white noise was different for every participant,the average lowest threshold was obtained with white noise presented binaurally at 70 db.The reaction times were analysed by fitting an ex-Gaussian,the sum of a Gaussian function and an exponential decay function.The white noise significantly affected the exponential parameter(tau)in a way that is compatible with the facilitation of thresholds.Conclusions:We therefore conclude that multisensory reaction time facilitation can,at least in part,be explained by stochastic facilitation of the neural signals.展开更多
Municipal solid wastes from industrial plants were pyrolyzed in a fixed bed reactor to evaluate the influence of paper/plastic ratio and reaction time both on product quantity and quality. Raw materials have been pyro...Municipal solid wastes from industrial plants were pyrolyzed in a fixed bed reactor to evaluate the influence of paper/plastic ratio and reaction time both on product quantity and quality. Raw materials have been pyrolyzed under nitrogen in a 3.0 dm^3 autoclave. Results show considerable differences in yields and quality of products obtained by pyrolysis of wastes with different paper content. Light and heavy oils were mixtures of organic compounds containing valuable hydrocarbons and oxygenated chemicals, while chars were rather composed of inorganic compounds from the raw materials. Longer reaction time of pyrolysis had produced higher non-condensable gas, water and light oil. Gases contained CO, CO2 and hydrocarbons, but the concentrations were very function of reaction time and paper/plastic ratio. Light and heavy oils showed similarities with middle distillates and heavy oils in refinery, the high paper content of the raw materials was unfavourable for longer storage of waste derived oils.展开更多
Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron m...Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron microscopy(SEM)observation and electrochemical tests.The results showed that the crystallinity of LDH film was increased with reaction time.When the reaction time was more than 12 h,the LDH film had complete crystal layered structure.The anodic oxide film was sealed basically by the growth of LDH nanosheets after 6 h reaction.The corrosion resistance of the films became better with the increasing of reaction time.However,after 12 h reaction,the corrosion resistance of the film decreased.The formation behavior of the Mg-Al LDH film was proposed.That the competitive growth of LDH grains,which contains dissolution and recrystallization,was proposed to explain the change of the growth and corrosion resistance of the Mg-Al LDH film.展开更多
We evaluated whole body reaction time and one leg with eye closed balance in elderly Japanese. A total of 2059 elderly Japanese (730 men and 1329 women), aged 60 - 79 years, were enrolled in the cross-sectional invest...We evaluated whole body reaction time and one leg with eye closed balance in elderly Japanese. A total of 2059 elderly Japanese (730 men and 1329 women), aged 60 - 79 years, were enrolled in the cross-sectional investigation study. Anthropometric parameters, whole body reaction time and one leg with eye closed balance were measured. Whole body reaction time was significantly higher and one leg with eye closed balance was significantly lower in 70’s than those in 60’s in both sexes. Two hundred twenty seven men (31.1%) and 533 women (40.1%) were having no medications. In men, whole body reaction time was significantly higher and one leg with eye closed balance was significantly lower in subjects with medications than those in subjects without in 60’s. However, significant differences of whole body reaction time and one leg with eye closed balance between subjects with and without medications in men with 70’s and women with 60’s and 70’s were not noted. This standard mean value may provide a useful reference database for evaluating whole body reaction time and one leg with eye closed balance in Japanese elderly subjects.展开更多
Fatigue is a common sense caused by crushing labor, stressful social events and various illnesses. It is usually judged by their subjective symptoms, but it should be evaluated in an objective perspective. Here we sho...Fatigue is a common sense caused by crushing labor, stressful social events and various illnesses. It is usually judged by their subjective symptoms, but it should be evaluated in an objective perspective. Here we show that the decrease of working efficiency and sympathetic hyperactivity are associated with mental fatigue state caused by prolonged mental workload. Recently we made a new mental fatigue model of healthy volunteers caused by long-term computerized Kraepelin test (CKT) workload. CKT is our new software for automatically checking the calculation capability, with which it is easy to determine the reaction time (RT), coefficient of variance of reaction time (CV), and accuracy of the answers (AC) during tasks. We put 24 healthy volunteers into the fatigue state by subjecting them to 120 minutes’ CKT workload, and then studied the changes in fatigue sensation, RT, CV, and AC before and after the CKT workload. The fatigue sensation, RT, and CV were clearly increased by the fatigue-inducing task and recovered during the resting period. We also studied the changes in autonomic nerve activity by using heart rate variability analysis. The low/high frequency component ratio (LF/HF) was signifi-cantly increased by the fatigue-inducing task and decreased by resting, suggesting that mental stress causes a relatively sympathetic nerve activity-dominant state. Therefore, our new fatigue model involving a long-term CKT workload is a good mental fatigue model to provide much information about the fatigue state simultane-ously, and the increase of RT, CV, and proportion of sympathetic activity (LF/HF) are associated with mental fatigue state. These might be useful objective biomarkers or evaluating a mental fatigue state.展开更多
Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 1...Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.展开更多
The results of visual event-related potential(ERP)examinations and reactiontime(RT)tests were reported in 30 elders and compared with their performanceintellegence quotient(PIQ)scores.The subjects consisted of 18 male...The results of visual event-related potential(ERP)examinations and reactiontime(RT)tests were reported in 30 elders and compared with their performanceintellegence quotient(PIQ)scores.The subjects consisted of 18 males and 12 femalesaged 50-71(mean 61.4)years old.No history of central nervous system disease wasfound.The visual stimuli were randomly presented to the subject,including three sym-bols:E as target stimulus with 0.15 probability,and H and E as nontarget stimuliwith 0.15 and 0.70 probability respectively.The recording electrodes were placed on Fzand Pz.The duration from the subject seeing the target to touching a button immediatelywas considered as reaction time(RT).It was shown that the P3 latency at Pz was longer than that at Fz and the P3amplitude at Pz was larger than that at Fz,and that the RT was longer than P3 latencywith obvious effect of distribution(P【0.05 at Fz and P】0.05 at Pz)as well .The higherthe PIQ scores,the longer the RT and the P3 latency.It is suggested that the ERPmight reflect the differences of PIQ scores,and the P3 is an objective index.We considerthat the research of ERP is of great interest in the neuropsychological and neurological sci-ences.展开更多
Stimulus-Response Compatibility (SRC) refers to the fact that some tasks are performed easier and better than others because of the way stimuli and responses are paired with each other. To assess the brain responses t...Stimulus-Response Compatibility (SRC) refers to the fact that some tasks are performed easier and better than others because of the way stimuli and responses are paired with each other. To assess the brain responses to stimulus-response conflicts, we investigated the behavioral (accuracy and Reaction Times: RTs) as well as the physiological response (Lateralized Readiness Potentials: LRP) modulations in a positional blocked and a conditional mixed design in twelve university students. Results revealed that the performance was less accurate and the RTs, as well as the LRP onset, were delayed under the mixed conditional design. A greater compatibility effect was also noted on accuracy, RTs and LRP onset latency in the mixed design. Consistent with these findings, smaller peak activation at fronto-central areas suggests that more selective inhibition is needed in a mixed design context. Despite a smaller activation, the topographical distribution is similar in both designs. These results indicate that the translation time between stimulus- and response codes are greater under the mixed instruction, while the similar LRP topography suggests that common neural structures underlie LRPs in response to both type of designs.展开更多
This study was conducted to evaluate and compare simple and choice reaction times for the comparison of perceptual-motor development levels found in children with and without autism. The participants of the study cons...This study was conducted to evaluate and compare simple and choice reaction times for the comparison of perceptual-motor development levels found in children with and without autism. The participants of the study consisted of 24 children with autism and 10 typically developing (TD) children. Within the group of children with autism, only 10 were able to offer a full set data and four offered partial data. Data were collected through a computer-based procedure of reaction time test software, where the participant reacted by pressing a key on a laptop upon the appearance of one of the boxes turning yellow. Simple and choice reaction times appeared on the screen and were then recorded. The means and standard deviations were calculated for comparison and the data were evaluated from the results of a t-test. Significant differences were found among all reaction time tasks, whereas the group consisting of children with autism demonstrated slower reaction times and greater standard deviations compared with the typically developing/control group.展开更多
Background: Obstacle crossing is the common reason of falling in older adults. Anticipatory postural adjustments phase (APAP) and reaction time phase (RTP) are two important factors in falling prediction. According to...Background: Obstacle crossing is the common reason of falling in older adults. Anticipatory postural adjustments phase (APAP) and reaction time phase (RTP) are two important factors in falling prediction. According to previous studies, these parameters increase in older adults at high risk falling. This study explored the effect of aging on APAP and RTP in obstacle negotiation. Method: Nineteen older adults (mean age: 66.73 ± 3.38 years) and twelve young adults (mean age: 26.5 ± 4.37 years), participated in this study. Participants take part in gait initiation task from a starting position on a force platform under two conditions, unobstructed and obstructed (obstacle placed at 1 m from the initial position). RTP and APAP were measured and Timed “Up” & “Go” test (TUG) as a functional test, recorded for all participants. Results: There was no significant difference between healthy young and older adults in RTP and APAP in the unobstructed and obstructed conditions. TUG test was the most sensitive indicator of falling between two groups. Conclusion: Information processing capacity for motor planning and proper strategy selection in pre crossing phase of obstacle negotiation did not have significant difference in healthy old and young groups. Maybe in respect to select healthy older adults without any neurological disorders and cognitive impairments, low attention demand of well learned walking and obstacle negotiation tasks, lead to perform both postural task more automatically and without any significant difference detection.展开更多
A tactile system to support severe visually-impaired or blind people in the world for their orientation and navigation had been developed. To optimize the design, some parameters of tactile display device were evaluat...A tactile system to support severe visually-impaired or blind people in the world for their orientation and navigation had been developed. To optimize the design, some parameters of tactile display device were evaluated. In the present paper,we focused on the reaction time to tactile stimuli. In the test, the stimuli were produced through a vibration belt that was worn around the participants’ waist. In the choice reaction time task, the participants had to click corresponding arrow keys according to the location of a tactile signal. The findings of this study provided a reference of the reaction time range, so as to design a more effective and safe tactile navigation system.展开更多
Background:Multiple Sclerosis(MS)is a neurological disease,related to different factors and systems.It causes fatigue,anxiety and depression.Virtual reality is used during rehabilitation.To evaluate the reaction time ...Background:Multiple Sclerosis(MS)is a neurological disease,related to different factors and systems.It causes fatigue,anxiety and depression.Virtual reality is used during rehabilitation.To evaluate the reaction time in MS patients and the interference of fatigue,anxiety and depression in performing a virtual task(VT).Methods:A cross-sectional study comparing MS patients(GMS)with people without MS(GC),by evaluating the Beck Inventory(BDI depression,BAI anxiety)and VT Simple Reaction Time(RTs)in GMS and GC and Modified Fatigue Impact Scale(MFIS)in GMS.The study period was January-June 2018.GMS sample 57,minimum age 23,maximum 77 years old(M=45.86,SD-12.24),GC sample 27,minimum age 23,maximum 57 years old(M=45.00,SD=12.09),both genders.Results:A positive correlation between MFIS,anxiety,and depression;between BDI and RTs.GMS had a lower performance(M=406.76)in RTs and all fatigue measurements.Conclusion:GMS showed an increase in RT indices,which may be related to neuronal impulse delay or depression.A fatigue scored on the MFIS did not interfere with VT.展开更多
Background Brain injury had an effect on reaction time （RT） and brain-injured patients were normally significantly slower than normal controls. The RT of the paretic upper limb （UL） in patients with stroke was slo...Background Brain injury had an effect on reaction time （RT） and brain-injured patients were normally significantly slower than normal controls. The RT of the paretic upper limb （UL） in patients with stroke was slower than in a control group. The present study was designed to compare the RTs of the unaffected and affected sides in stroke survivors and those of normal subjects. This study also explores the relationships among wrist flexion and extension RTs in the affected side and the motor deficits of the UL as measured by clinical Composite Spasticity Index （CSI）, Associated Reaction Rating Score （ARRS）, and Wolf Motor Function Test （WMFT） scores. Methods Ninety-eight hemiparetic stroke survivors and 20 normal subjects participated in the study. Abnormal muscle tone was measured by CSI. Associated reaction was measured by ARRS. Motor function was measured by WMFT. The subject was asked to flex or extend the affected and non-affected wrists as fast as possible, following an auditory ＂go＂ signal. An electrogoniometer attached to the wrist measured wrist flexion and extension angle. RT was defined as the time from the ＂go＂ signal to a change in wrist angle denoting movement onset. Clinical assessments and RT were conducted within one day. Differences in the variables between normal subjects and the unaffected sides of the stroke patients were analyzed using analysis of variance. Correlations were assessed by computing Spearman＇s correlation coefficient. The significance level was set at 5%. Results RTs of wrist flexion and extension in the stroke survivors＇ affected hands were significantly longer than those in normal subjects and their unaffected hands （P 〈0.01 for both）. The wrist flexion RT moderately correlated with CSI （p=0.412, P 〈0.001） and ARRS （p=0.341, P 〈0.001） and with WMFT functional ability （negatively; p=-0.531, P 〈0.001） and time score （p=0.504, P 〈0.001 ）. Similarly, the wrist extension RT moderately correlated with CSI （p=0.429, P 〈0.001）, ARRS （p=0.374, P 〈0.001）, and with WMFT functional ability （negatively; p=-0.531, P 〈0.001） and time score （p=0.486, P 〈0.001 ）. Conclusions RTs of wrist flexion and extension on the stroke survivors＇ affected sides were significantly longer than those on the unaffected sides and those of normal subjects. The wrist flexion and extension RTs moderately correlated with CSI and ARRS and inversely with motor functional performance of the UL in patients with stroke.展开更多
Multiclass Lighthill-Whitham-Richards trafficmodels[Benzoni-Gavage and Colombo,Euro.J.Appl.Math.,14(2003),pp.587–612;Wong and Wong,Transp.Res.A,36(2002),pp.827–841]give rise to first-order systems of conservation la...Multiclass Lighthill-Whitham-Richards trafficmodels[Benzoni-Gavage and Colombo,Euro.J.Appl.Math.,14(2003),pp.587–612;Wong and Wong,Transp.Res.A,36(2002),pp.827–841]give rise to first-order systems of conservation laws that are hyperbolic under usual conditions,so that their associated Cauchy problems are wellposed.Anticipation lengths and reaction times can be incorporated into these models by adding certain conservative second-order terms to these first-order conservation laws.These terms can be diffusive under certain circumstances,thus,in principle,ensuring the stability of the solutions.The purpose of this paper is to analyze the stability of these diffusively correctedmodels under varying reaction times and anticipation lengths.It is demonstrated that instabilities may develop for high reaction times and short anticipation lengths,and that these instabilities may have controlled frequencies and amplitudes due to their nonlinear nature.展开更多
基金Supported by Wuxi Municipal Health Commission Major Project,No.Z202107Wuxi Taihu Talent Project,No.WXTTP 2021.
文摘BACKGROUND The neural mechanisms underlying aggressive behavior in schizophrenia(SCZ)remain poorly understood.To date,no studies have reported on the event-related potential(ERP)characteristics of aggression in SCZ using the competitive reaction time task(CRTT).Further investigation into the ERP correlates of aggression in SCZ would provide valuable insights into the neural processes involved.AIM To explore the neural mechanism of aggressive behavior in SCZ.METHODS Participants of this study included 40 SCZ patients and 42 healthy controls(HCs).The Reactive Proactive Aggression Questionnaire was used to assess trait of aggression.The Barratt Impulsiveness Scale 11 was used to measure impulsiveness.The Positive and Negative Symptom Scale(PANSS)was used to evaluate psychopathological features and disease severity.All participants were measured with ERP while performing the CRTT.Data of behavior,ERP components(P2,N2,and P3),and feedback-related negativity(FRN)were analyzed.RESULTS Analysis of the behavioral data revealed that compared with HCs,SCZ patients exhibited higher punishment choices.Analysis of ERP components showed that compared with HCs,SCZ patients exhibited higher N2 amplitudes and P2 amplitudes during the decision phase of the CRTT;however,SCZ patients exhibited lower FRN amplitudes and lower P3 amplitudes during the outcome phase of the CRTT.The N2 amplitudes evoked by highintensity provocation were positively related to PANSS-P scores.And the P3 amplitudes evoked in the winning trials were negatively correlated with the PANSS-G scores.CONCLUSION SCZ patients exhibit abnormal ERP characteristics evoked by the CRTT,which suggests the neural correlates of aggressive behavior in SCZ.
文摘BACKGROUND： According to observable behaviors, sleep and wakefulness are two fundamentally different behavioral states. Although electroencephalogram （EEG） is traditionally used to define sleep stage, it is difficult to detect or to quantify microarousals or disruptions during sleep. In addition initial sleep cannot be defined. It is thought that the wake-sleep transition cannot be defined by EEG patterns. OBJECTIVE： To observe the behavioral response magnitude during wake-sleep transition by EEG monitoring and to define the wake-sleep transition. DESIGN, TIME AND SETTING： A behavioral and neural network study was performed at the Key Lab of Human Being Development and Mental Health of Central China Normal University, and Lab of Brain and Cognitive Science of South Central University for Nationalities, China in July 2007. PARTICIPANTS： A total of 30 healthy volunteers, of equal gender and aged （19.7 ± 1.1 ） years, were recruited from the Central China Normal University, China for this study. None of the subjects had undergone EEG recording prior to this study or received any medication for sleep disturbances. METHODS： A novel adaptive approach was applied to detect wake-sleep transition, which avoided stimulus-induced waking. To test the difference between wake state and wake-sleep transition, the amount of self-information and mutual-information were effective parameters to analyze wake-sleep transition. MAIN OUTCOME MEASURES： The following parameters were measured： morphological changes in reaction time-magnitude, as well as correlation between phase changes and sleep, and wake and wake-sleep transition. RESULTS： There were three typical phases in morphological changes of reaction time-magnitude. With regard to the behavioral definition and criterion for sleep, the phase morphological characteristics displayed good correlation with behavioral states, such as sleep, wakefulness, and sleep onset. Entropy as an indicator of brain cognitive processes was introduced to test for differences between the wakefulness and sleep onset phase. Results indicated a cognitive declined transitional period different between sleep and wake. After staggered cognitive changes during the wake-sleep transition, the brain underwent marked alterations and transitioned into sleep quickly with no bi-directional EEG changes. CONCLUSION： Wake-sleep transition exists as an independent stage.
基金supported by the Youth research project of Fujian Provincial Health Commission(No.2018-1-75)Joint Fund of Fujian Province Scientific and Technological Department(No.2018Y9102)+1 种基金Soft Science Project of Fujian Science and Technology Department(No.2019R0055)National Science Foundation of China(No.81571379).
文摘Objectives:This study aimed to evaluate the effects of a 16-week creative expression intervention program(CrExp)on the event-related potential(ERP)and task reaction time in older individuals with mild cognitive impairment(MCI).Methods:This study is a randomized controlled clinical trial conducted in the Memory Center of Fujian Provincial hospital.Thirty-six MCI patients were randomly distributed into two groups.One group underwent a 16-week creative expression program(CrExp,n=18)and the other performed as a control group(CG,n=18)by general social activities.The amplitude and latency of ERP-P300 from the central(Cz),parietal(Pz),frontal(Fz)cortices and task reaction time(RT)were assessed at baseline,postinterventi on,and 24-week follow-up.Results:The CrExp group showed greater differences than CG of P300 latency in Cz(F=4.37,P=0.015),Pz(F=2.78,P=0.009),Fz(F=6.45,P=0.031)brain area after 16 weeks of intervention and in Fz(F=3.23,P=0.028),Cz(F=3.79,P=0.024),and Pz(F=5.60,P=0.036)at 24 weeks follow-up.Also,we analyzed the task reaction time between two groups and found that a shorten reaction time at postintervention(F=4.47,P=0.011)and 24 weeks follow-up(F=3.12,P=0.007)in the CrExp group.However,there was no difference in P300 amplitude in either brain area between the two groups.Conclusion:The electrophysiological results of the creative expression cognitive therapy group were more obvious than those of the general cognitive therapy group,and the latency and task reaction time may be considered as supported parameters in diagnosing the effects during non-drug therapy intervention in clinical practice.
基金supported by the Yeungnam College of Science & Technology Research Grants in 2012
文摘Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function （i.e., primary motor cortex, premotor area, posterior parietal cortex） showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.
基金Projects(10805069,10405034) supported by the National Natural Science Foundation of China
文摘The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.
文摘We consider the psychophysical experiments in which the test subject’s binary reaction is determined by the prescribed exposure duration to a stimulus and a random variable subjective threshold. For example, when a subject is exposed to a millimeter wave beam for a prescribed duration, the occurrence of flight action is binary (yes or no). In experiments, in addition to the binary outcome, the actuation time of flight action is also recorded if it occurs;the delay from the initiation time to the actuation time of flight action is the human reaction time, which is not measurable. In this study, we model the random subjective threshold as a Weibull distribution and formulate an inference method for estimating the human reaction time, from data of prescribed exposure durations, binary outcomes and actuation times of flight action collected in a sequence of tests. Numerical simulations demonstrate that the inference of human reaction time based on the Weibull distribution converges to the correct value even when the underlying true model deviates from the inference model. This robustness of the inference method makes it applicable to real experimental data where the underlying true model is unknown.
文摘Background:The concept of stochastic facilitation suggests that the addition of precise amounts of white noise can improve the perceptibility of a stimulus of weak amplitude.We know from previous research that tactile and auditory noise can facilitate visual perception,respectively.Here we wanted to see if the effects of stochastic facilitation generalise to a reaction time paradigm,and if reaction times are correlated with tactile thresholds.We know that when multiple sensory systems are stimulated simultaneously,reaction times are faster than either stimulus alone,and also faster than the sum of reaction times(known as the race model).Methods:Five participants were re-tested in five blocks each of which contained a different background noise levels,randomly ordered across sessions.At each noise level,they performed a tactile threshold detection task and a tactile reaction time task.Results:Both tactile threshold and tactile reaction times were significantly affected by the background white noise.While the preferred amplitude for the white noise was different for every participant,the average lowest threshold was obtained with white noise presented binaurally at 70 db.The reaction times were analysed by fitting an ex-Gaussian,the sum of a Gaussian function and an exponential decay function.The white noise significantly affected the exponential parameter(tau)in a way that is compatible with the facilitation of thresholds.Conclusions:We therefore conclude that multisensory reaction time facilitation can,at least in part,be explained by stochastic facilitation of the neural signals.
文摘Municipal solid wastes from industrial plants were pyrolyzed in a fixed bed reactor to evaluate the influence of paper/plastic ratio and reaction time both on product quantity and quality. Raw materials have been pyrolyzed under nitrogen in a 3.0 dm^3 autoclave. Results show considerable differences in yields and quality of products obtained by pyrolysis of wastes with different paper content. Light and heavy oils were mixtures of organic compounds containing valuable hydrocarbons and oxygenated chemicals, while chars were rather composed of inorganic compounds from the raw materials. Longer reaction time of pyrolysis had produced higher non-condensable gas, water and light oil. Gases contained CO, CO2 and hydrocarbons, but the concentrations were very function of reaction time and paper/plastic ratio. Light and heavy oils showed similarities with middle distillates and heavy oils in refinery, the high paper content of the raw materials was unfavourable for longer storage of waste derived oils.
基金Supported by the National Natural Science Foundation of China (51701029, 51531002, 51474043)the National Key Research and Development Program of China (2016YFB0301100)+3 种基金the Chongqing Research Program of Basic Research and Frontier Technology (cstc2016jcyjA0388, cstc2017jcyjBX0040)China Postdoctoral Science Foundation Funded Project (2017M620410, 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation (Xm2017010)the Fundamental Research Funds for the Central Universities (2018CDGFCL005)~~
文摘Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron microscopy(SEM)observation and electrochemical tests.The results showed that the crystallinity of LDH film was increased with reaction time.When the reaction time was more than 12 h,the LDH film had complete crystal layered structure.The anodic oxide film was sealed basically by the growth of LDH nanosheets after 6 h reaction.The corrosion resistance of the films became better with the increasing of reaction time.However,after 12 h reaction,the corrosion resistance of the film decreased.The formation behavior of the Mg-Al LDH film was proposed.That the competitive growth of LDH grains,which contains dissolution and recrystallization,was proposed to explain the change of the growth and corrosion resistance of the Mg-Al LDH film.
文摘We evaluated whole body reaction time and one leg with eye closed balance in elderly Japanese. A total of 2059 elderly Japanese (730 men and 1329 women), aged 60 - 79 years, were enrolled in the cross-sectional investigation study. Anthropometric parameters, whole body reaction time and one leg with eye closed balance were measured. Whole body reaction time was significantly higher and one leg with eye closed balance was significantly lower in 70’s than those in 60’s in both sexes. Two hundred twenty seven men (31.1%) and 533 women (40.1%) were having no medications. In men, whole body reaction time was significantly higher and one leg with eye closed balance was significantly lower in subjects with medications than those in subjects without in 60’s. However, significant differences of whole body reaction time and one leg with eye closed balance between subjects with and without medications in men with 70’s and women with 60’s and 70’s were not noted. This standard mean value may provide a useful reference database for evaluating whole body reaction time and one leg with eye closed balance in Japanese elderly subjects.
文摘Fatigue is a common sense caused by crushing labor, stressful social events and various illnesses. It is usually judged by their subjective symptoms, but it should be evaluated in an objective perspective. Here we show that the decrease of working efficiency and sympathetic hyperactivity are associated with mental fatigue state caused by prolonged mental workload. Recently we made a new mental fatigue model of healthy volunteers caused by long-term computerized Kraepelin test (CKT) workload. CKT is our new software for automatically checking the calculation capability, with which it is easy to determine the reaction time (RT), coefficient of variance of reaction time (CV), and accuracy of the answers (AC) during tasks. We put 24 healthy volunteers into the fatigue state by subjecting them to 120 minutes’ CKT workload, and then studied the changes in fatigue sensation, RT, CV, and AC before and after the CKT workload. The fatigue sensation, RT, and CV were clearly increased by the fatigue-inducing task and recovered during the resting period. We also studied the changes in autonomic nerve activity by using heart rate variability analysis. The low/high frequency component ratio (LF/HF) was signifi-cantly increased by the fatigue-inducing task and decreased by resting, suggesting that mental stress causes a relatively sympathetic nerve activity-dominant state. Therefore, our new fatigue model involving a long-term CKT workload is a good mental fatigue model to provide much information about the fatigue state simultane-ously, and the increase of RT, CV, and proportion of sympathetic activity (LF/HF) are associated with mental fatigue state. These might be useful objective biomarkers or evaluating a mental fatigue state.
文摘Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.
文摘The results of visual event-related potential(ERP)examinations and reactiontime(RT)tests were reported in 30 elders and compared with their performanceintellegence quotient(PIQ)scores.The subjects consisted of 18 males and 12 femalesaged 50-71(mean 61.4)years old.No history of central nervous system disease wasfound.The visual stimuli were randomly presented to the subject,including three sym-bols:E as target stimulus with 0.15 probability,and H and E as nontarget stimuliwith 0.15 and 0.70 probability respectively.The recording electrodes were placed on Fzand Pz.The duration from the subject seeing the target to touching a button immediatelywas considered as reaction time(RT).It was shown that the P3 latency at Pz was longer than that at Fz and the P3amplitude at Pz was larger than that at Fz,and that the RT was longer than P3 latencywith obvious effect of distribution(P【0.05 at Fz and P】0.05 at Pz)as well .The higherthe PIQ scores,the longer the RT and the P3 latency.It is suggested that the ERPmight reflect the differences of PIQ scores,and the P3 is an objective index.We considerthat the research of ERP is of great interest in the neuropsychological and neurological sci-ences.
文摘Stimulus-Response Compatibility (SRC) refers to the fact that some tasks are performed easier and better than others because of the way stimuli and responses are paired with each other. To assess the brain responses to stimulus-response conflicts, we investigated the behavioral (accuracy and Reaction Times: RTs) as well as the physiological response (Lateralized Readiness Potentials: LRP) modulations in a positional blocked and a conditional mixed design in twelve university students. Results revealed that the performance was less accurate and the RTs, as well as the LRP onset, were delayed under the mixed conditional design. A greater compatibility effect was also noted on accuracy, RTs and LRP onset latency in the mixed design. Consistent with these findings, smaller peak activation at fronto-central areas suggests that more selective inhibition is needed in a mixed design context. Despite a smaller activation, the topographical distribution is similar in both designs. These results indicate that the translation time between stimulus- and response codes are greater under the mixed instruction, while the similar LRP topography suggests that common neural structures underlie LRPs in response to both type of designs.
文摘This study was conducted to evaluate and compare simple and choice reaction times for the comparison of perceptual-motor development levels found in children with and without autism. The participants of the study consisted of 24 children with autism and 10 typically developing (TD) children. Within the group of children with autism, only 10 were able to offer a full set data and four offered partial data. Data were collected through a computer-based procedure of reaction time test software, where the participant reacted by pressing a key on a laptop upon the appearance of one of the boxes turning yellow. Simple and choice reaction times appeared on the screen and were then recorded. The means and standard deviations were calculated for comparison and the data were evaluated from the results of a t-test. Significant differences were found among all reaction time tasks, whereas the group consisting of children with autism demonstrated slower reaction times and greater standard deviations compared with the typically developing/control group.
文摘Background: Obstacle crossing is the common reason of falling in older adults. Anticipatory postural adjustments phase (APAP) and reaction time phase (RTP) are two important factors in falling prediction. According to previous studies, these parameters increase in older adults at high risk falling. This study explored the effect of aging on APAP and RTP in obstacle negotiation. Method: Nineteen older adults (mean age: 66.73 ± 3.38 years) and twelve young adults (mean age: 26.5 ± 4.37 years), participated in this study. Participants take part in gait initiation task from a starting position on a force platform under two conditions, unobstructed and obstructed (obstacle placed at 1 m from the initial position). RTP and APAP were measured and Timed “Up” & “Go” test (TUG) as a functional test, recorded for all participants. Results: There was no significant difference between healthy young and older adults in RTP and APAP in the unobstructed and obstructed conditions. TUG test was the most sensitive indicator of falling between two groups. Conclusion: Information processing capacity for motor planning and proper strategy selection in pre crossing phase of obstacle negotiation did not have significant difference in healthy old and young groups. Maybe in respect to select healthy older adults without any neurological disorders and cognitive impairments, low attention demand of well learned walking and obstacle negotiation tasks, lead to perform both postural task more automatically and without any significant difference detection.
文摘A tactile system to support severe visually-impaired or blind people in the world for their orientation and navigation had been developed. To optimize the design, some parameters of tactile display device were evaluated. In the present paper,we focused on the reaction time to tactile stimuli. In the test, the stimuli were produced through a vibration belt that was worn around the participants’ waist. In the choice reaction time task, the participants had to click corresponding arrow keys according to the location of a tactile signal. The findings of this study provided a reference of the reaction time range, so as to design a more effective and safe tactile navigation system.
文摘Background:Multiple Sclerosis(MS)is a neurological disease,related to different factors and systems.It causes fatigue,anxiety and depression.Virtual reality is used during rehabilitation.To evaluate the reaction time in MS patients and the interference of fatigue,anxiety and depression in performing a virtual task(VT).Methods:A cross-sectional study comparing MS patients(GMS)with people without MS(GC),by evaluating the Beck Inventory(BDI depression,BAI anxiety)and VT Simple Reaction Time(RTs)in GMS and GC and Modified Fatigue Impact Scale(MFIS)in GMS.The study period was January-June 2018.GMS sample 57,minimum age 23,maximum 77 years old(M=45.86,SD-12.24),GC sample 27,minimum age 23,maximum 57 years old(M=45.00,SD=12.09),both genders.Results:A positive correlation between MFIS,anxiety,and depression;between BDI and RTs.GMS had a lower performance(M=406.76)in RTs and all fatigue measurements.Conclusion:GMS showed an increase in RT indices,which may be related to neuronal impulse delay or depression.A fatigue scored on the MFIS did not interfere with VT.
文摘Background Brain injury had an effect on reaction time （RT） and brain-injured patients were normally significantly slower than normal controls. The RT of the paretic upper limb （UL） in patients with stroke was slower than in a control group. The present study was designed to compare the RTs of the unaffected and affected sides in stroke survivors and those of normal subjects. This study also explores the relationships among wrist flexion and extension RTs in the affected side and the motor deficits of the UL as measured by clinical Composite Spasticity Index （CSI）, Associated Reaction Rating Score （ARRS）, and Wolf Motor Function Test （WMFT） scores. Methods Ninety-eight hemiparetic stroke survivors and 20 normal subjects participated in the study. Abnormal muscle tone was measured by CSI. Associated reaction was measured by ARRS. Motor function was measured by WMFT. The subject was asked to flex or extend the affected and non-affected wrists as fast as possible, following an auditory ＂go＂ signal. An electrogoniometer attached to the wrist measured wrist flexion and extension angle. RT was defined as the time from the ＂go＂ signal to a change in wrist angle denoting movement onset. Clinical assessments and RT were conducted within one day. Differences in the variables between normal subjects and the unaffected sides of the stroke patients were analyzed using analysis of variance. Correlations were assessed by computing Spearman＇s correlation coefficient. The significance level was set at 5%. Results RTs of wrist flexion and extension in the stroke survivors＇ affected hands were significantly longer than those in normal subjects and their unaffected hands （P 〈0.01 for both）. The wrist flexion RT moderately correlated with CSI （p=0.412, P 〈0.001） and ARRS （p=0.341, P 〈0.001） and with WMFT functional ability （negatively; p=-0.531, P 〈0.001） and time score （p=0.504, P 〈0.001 ）. Similarly, the wrist extension RT moderately correlated with CSI （p=0.429, P 〈0.001）, ARRS （p=0.374, P 〈0.001）, and with WMFT functional ability （negatively; p=-0.531, P 〈0.001） and time score （p=0.486, P 〈0.001 ）. Conclusions RTs of wrist flexion and extension on the stroke survivors＇ affected sides were significantly longer than those on the unaffected sides and those of normal subjects. The wrist flexion and extension RTs moderately correlated with CSI and ARRS and inversely with motor functional performance of the UL in patients with stroke.
基金R.Burger acknowledges partial support by Fondecyt project 1130154BASAL project CMM,U.de Chile and Centro de Investigacion en Ingenierıa Matematica(CI2MA),U.de Concepcion+1 种基金Conicyt project Anillo ACT1118(ANANUM)and Red Doctoral REDOC.CTA,MINEDUC project UCO1202 at U.de Concepcion.P.Mulet is partially supported by Spanish MCINN MTM2011-22741.L.M.Villada is supported by MECESUP project UCO0713.
文摘Multiclass Lighthill-Whitham-Richards trafficmodels[Benzoni-Gavage and Colombo,Euro.J.Appl.Math.,14(2003),pp.587–612;Wong and Wong,Transp.Res.A,36(2002),pp.827–841]give rise to first-order systems of conservation laws that are hyperbolic under usual conditions,so that their associated Cauchy problems are wellposed.Anticipation lengths and reaction times can be incorporated into these models by adding certain conservative second-order terms to these first-order conservation laws.These terms can be diffusive under certain circumstances,thus,in principle,ensuring the stability of the solutions.The purpose of this paper is to analyze the stability of these diffusively correctedmodels under varying reaction times and anticipation lengths.It is demonstrated that instabilities may develop for high reaction times and short anticipation lengths,and that these instabilities may have controlled frequencies and amplitudes due to their nonlinear nature.
