There is a growing interest in the diagnosis and treatment of patients with dementia and cognitive impairment at an early stage. Recent imaging studies have explored neural mechanisms underlying cognitive dysfunction ...There is a growing interest in the diagnosis and treatment of patients with dementia and cognitive impairment at an early stage. Recent imaging studies have explored neural mechanisms underlying cognitive dysfunction based on brain network architecture and functioning. The dorsal anterior cingulate cortex (dACC) is thought to regulate large-scale intrinsic brain networks, and plays a primary role in cognitive processing with the anterior insular cortex (aIC), thus providing salience functions. Although neural mechanisms have been elucidated at the connectivity level by imaging studies, their understanding at the activity level still remains unclear because of limited time-based resolution of conventional imaging techniques. In this study, we investigated temporal activity of the dACC during word (verb) generation tasks based on our newly developed event-related deep brain activity (ER-DBA) method using occipital electroencephalogram (EEG) alpha-2 powers with a time resolution of a few hundred milliseconds. The dACC exhibited dip-like temporal waveforms indicating deactivation in an initial stage of each trial when appropriate verbs were successfully generated. By contrast, monotonous increase was observed for incorrect responses and a decrease was detected for no responses. The dip depth was correlated with the percentage of success. Additionally, the dip depth linearly increased with increasing slow component of the DBA index at rest across all subjects. These findings suggest that dACC deactivation is essential for cognitive processing, whereas its activation is required for goal-oriented behavioral outputs, such as cued speech. Such dACC functioning, represented by the dip depth, is supported by the activity of the upper brainstem region including monoaminergic neural systems.展开更多
Hyperthermia-induced decline in cognitive performance is a moderate complication that poses challenges to the maintenance of safety. Although the underlying mechanism can be attributed to the disruption of brain netwo...Hyperthermia-induced decline in cognitive performance is a moderate complication that poses challenges to the maintenance of safety. Although the underlying mechanism can be attributed to the disruption of brain networks, the propensity remains unclear. This study aimed to test the hypothesis that the extent of the alterations in cognitive performance is governed by the activity of deep brain structures, including monoaminergic neural systems. A decline in cognitive performance during mild hyperthermia and the beneficial effects of neck cooling were demonstrated using the Continuous Performance Test as a battery of cognitive tasks. Aspects of cognitive performance were characterized using the deep-brain activity (DBA) index as a neural activity parameter and the State-Trait Anxiety Inventory to assess the extent of alterations in cognitive performance as an individual measure. It was found that a higher average DBA index during tasks is essential for high cognitive performance in the heat. This beneficial effect of DBA is governed by the upper brainstem. This DBA benefit is more significant for individuals with higher average DBA indices at rest in a normal environment. Individual differences in cognitive performance in the heat are governed by differences in DBA. In addition, the beneficial effect of DBA on cognitive performance in heat only applies under conditions including neck cooling. This limited neck-cooling effect is attributed to anti-homeostatic thermoregulatory responses to cognitive tasks regulated by DBA.展开更多
The dorsal area of the anterior cingulate cortex (ACC) constructs the salience network associated with the anterior insular cortex. Conventional brain imaging studies, such as functional magnetic resonance imaging (fM...The dorsal area of the anterior cingulate cortex (ACC) constructs the salience network associated with the anterior insular cortex. Conventional brain imaging studies, such as functional magnetic resonance imaging (fMRI), have demonstrated that relational memory formation occurs in the ACC. However, how such memory is encoded and retrieved remains unknown due to limited time resolution of conventional fMRI. This study aimed to investigate temporal dynamics of the dorsal ACC (dACC) during word-pair tasks based on a newly developed event-related deep brain activity (ER-DBA) method using occipital electroencephalogram (EEG) signal powers. The method assesses dACC activity at a temporal resolution of approximately 0.3 s beyond the conventional resolution limit. We found that transient deactivation of dACC during the presentation of the second word of each pair was essential for encoding success regardless of whether the words were related or unrelated. We also found that memory accuracy was not affected by the intervention of inter-trials until the recall trial. Taken together, these findings suggest that dACC deactivation for encoding success is accompanied with short-term potentiation essential for durability of memory. We further found that false memory formation associated with the presentation of word pairs was occasionally committed. In such cases, dACC exhibited a similar transient deactivation although false memory commission was independent of related or unrelated conditions. Our findings suggest that encoding and retrieval of associates are paralleled and that simultaneous production of associates seems to be an essential strategy for successful relational memory formation. The study was limited to the assessment of dACC activity and did not account for other regional brain activities or receptor regulation related to short-term potentiation. We detected fast behavior of dACC during relational memory formation using the novel ER-DBA method. Such temporal dynamics will be important for eliciting underlying mechanisms of memory dysfunctions.展开更多
Aroma touch therapy is widely used in clinical fields for alleviating pain-related symptoms;however, few studies have reported the pain-relief mechanisms. The present study aimed to elucidate the analgesic effects of ...Aroma touch therapy is widely used in clinical fields for alleviating pain-related symptoms;however, few studies have reported the pain-relief mechanisms. The present study aimed to elucidate the analgesic effects of aroma touch therapy with Citrus junos oil based on the quantitative evaluation of deep brain network (DBN) activity using electroencephalogram (EEG) occipital alpha-2 rhythm (10-13 Hz) powers. Experimental investigations were performed with 13 healthy volunteers using the cold pressor task for simulating chronic pain in three different sessions: a baseline session with no therapies, a control session with a touch therapy, and an aroma touch therapy. We have found for the first time that the interviewed pain ratings represented by Numeric Rating Scale (NRS) scores were strongly correlated with a DBN activity index, which was derived from the slow fluctuation components of occipital EEG alpha-2 rhythm powers. The correlation was characterized by a V-shaped curve in the DBN activity index versus the pain rating, i.e., the NRS score, which provided the complete analgesic states (NRS = 0) for some subjects under aroma touch therapy at an appropriate DBN activity index. Such analgesic states were not so strongly correlated with emotional valence. In conclusion, aroma touch therapy may directly modulate DBN activity so that pain-induced outcomes are minimized.展开更多
Once people have a well-trained motor skill, their performance becomes stabilized and achieving substantial improvement is difficult. Recently, we have shown that even a plateaued hand motor skill can be upgraded with...Once people have a well-trained motor skill, their performance becomes stabilized and achieving substantial improvement is difficult. Recently, we have shown that even a plateaued hand motor skill can be upgraded with short-period electrical stimulation to the hand prior to the task. Here, we identify the neuronal substrates underlying the improvement of the plateaued skill by examining the enhanced functional connectivity in the sensory-motor regions that are associated with motor learning. We measured brain activity using functional magnetic resonance imaging and performed psychophysiological interaction analysis. We recruited seven right-handed very-well trained participants, whose motor performance of continuously rotating two balls with their right hands became stabilized at higher performance levels. We prepared two experiments, in each of which they repeated an experimental run 16 times. In each run, they performed this cyclic rotation as many times as possible in 16 s. In the thenar-stimulation experiment, we applied 60-s stimulation to the thenar muscle before each of the 5th - 12th runs, and the others were preceded by ineffective sham stimulation. In the control experiment, the sham was always provided. Thenar stimulation enabled the participants to perform the movements at higher cycles. In association with this performance improvement, we found enhanced activity couplings between the primary motor cortex and the sensorimotor territory of the putamen and between the cerebellum and the primary sensorimotor cortices, without any quantitative activity increase. Neither behavioral change nor these increased activity couplings were observed in the control.Thus, in contrast to the stable neuronal states in the cortico-subcortical motor circuits when the well-learned task is repeated at the later stages of motor skill learning, plastic changes in the motor circuits seem to be required when the plateaued skill is upgraded, and the stimulation may entail a state of readiness for the plastic change that allows subsequent performance improvement.展开更多
Hippocampus is crucial for the formation of emotional memory. We found the relationship between hippocampal responses to emotional stimuli and the mental stabilities of people in our preliminary study. In this study, ...Hippocampus is crucial for the formation of emotional memory. We found the relationship between hippocampal responses to emotional stimuli and the mental stabilities of people in our preliminary study. In this study, we have also evaluated how the emotional stimuli would affect amygdala and thalamus in the brain, and how the personality stabilities could relate to the responses in the brain using functional magnetic resonance imaging (fMRI). We evaluated the subjects’ personality features with the Yatabe-Guilford Personality Test (Y-G test) and psychosomatic symptoms with the Cornell Medical Index (CMI). The subjects were categorized into the mentally stable group and the mentally unstable group according to the total scores of the Y-G test and the CMI. The brain functional responses under emotional stimuli were measured using fMRI. The region of interest (ROI) analysis was performed to abstract significant changes in order to compare responses among the different emotional stimuli. We conducted the regression analysis to abstract the relationship between the mean % signal change from fMRI and the personality stability. The fMRI results showed that the hippocampus, thalamus, and right amygdala activities under the human relationship stimuli increased with ascending value of mental instability. Our findings suggest that the memory process in the hippocampus and the threat alarm system in the thalamus under the human-related stimuli crucially influence the emotional reaction of mentally unstable people. These processes in the brain would affect the event that stresses on human relationships that often cause people to suffer from mental disorders.展开更多
Vibratory stimulation but also motor imagery and action observation can induce corticomotor modulation, as a bottom-up stimulus and top-down stimuli, respectively. However, it remains unknown whether the combination o...Vibratory stimulation but also motor imagery and action observation can induce corticomotor modulation, as a bottom-up stimulus and top-down stimuli, respectively. However, it remains unknown whether the combination of motor imagery, action observation, and vibratory stimulation can effectively increase corticomotor excitability. This study aimed to investigate the effect of motor imagery and/or action observation, in the presence or absence of vibratory stimulation, on the corticomotor excitability of healthy young adults. Vibratory stimulation was provided to the palm of the right hand. Action observation consisted in viewing a movie of someone else’s finger flexion and extension movements. The imagery condition required the participants to imagine they were moving their fingers while viewing the movie and attempting to move their fingers in accordance with the movie. Eleven right-handed healthy young adults were asked to perform six conditions randomly: 1) vibratory stimulation, imagery, and action observation, 2) vibratory stimulation and action observation, 3) vibratory stimulation and viewing of a blank screen, 4) imagery and action observation, 5) action observation, and 6) viewing of a blank screen. Single-pulse transcranial magnetic stimulation was conducted to assess corticomotor excitability and the peak-to-peak amplitude of the motor evoked potentials. The results showed that vibratory stimulation increases corticospinal excitability. The findings further revealed that performing motor imagery while viewing finger movement is more effective at inducing an augmentation of corticomotor excitability compared to action observation alone. Thus, the combination of motor imagery, action observation, and vibratory stimulation can effectively augment corticomotor excitability.展开更多
All Chinese born in the 1960's know the famous movie script "the function of a horse tail". Indeed, there is another famous "horse tail" in the field of basic biology, the premeiotic nucleus in...All Chinese born in the 1960's know the famous movie script "the function of a horse tail". Indeed, there is another famous "horse tail" in the field of basic biology, the premeiotic nucleus in the fission yeast Schizosaccharomyces pombe. It is not only because of its characteristic shape which looks like a horse tail, but also its dramatic oscillatory movement called "the horsetail movement". In the horsetail nucleus, all of the ends of chromosomes, the telomeres, are tightly clustering under spindle pole body (a centrosome equivalent in yeasts). Actually, this horsetail chromosome arrangement is an extreme form of so called "bouquet arrangement", a polarized chromosome arrangement with all the telomeres clustered in a confined area on the nuclear envelope. Bouquet arrangement is widely conserved meiotic prophase chromosomal phenomenon among eukaryotes. From study of the horsetail nucleus in fission yeast, many progresses have been made in the field of meiosis.展开更多
In 2007, superconducting nanowire single photon detectors （SSPD or SNSPD） [ 1 ] made an outstanding impact in the field of quantum information technology by demonstrating quan- tum key distribution （QKD） over a 20...In 2007, superconducting nanowire single photon detectors （SSPD or SNSPD） [ 1 ] made an outstanding impact in the field of quantum information technology by demonstrating quan- tum key distribution （QKD） over a 200-kin optical fiber with a 42-dB optical loss using a practical SNSPD system [2]. This successful demonstration was realized thanks to its extremely low dark count rate （DCR） of a few Hz and short timing jitter of 60 ps, while the system detection efficiency （SDE） showed a poor value of 0.7% at a wavelength of 1550 nm.展开更多
文摘There is a growing interest in the diagnosis and treatment of patients with dementia and cognitive impairment at an early stage. Recent imaging studies have explored neural mechanisms underlying cognitive dysfunction based on brain network architecture and functioning. The dorsal anterior cingulate cortex (dACC) is thought to regulate large-scale intrinsic brain networks, and plays a primary role in cognitive processing with the anterior insular cortex (aIC), thus providing salience functions. Although neural mechanisms have been elucidated at the connectivity level by imaging studies, their understanding at the activity level still remains unclear because of limited time-based resolution of conventional imaging techniques. In this study, we investigated temporal activity of the dACC during word (verb) generation tasks based on our newly developed event-related deep brain activity (ER-DBA) method using occipital electroencephalogram (EEG) alpha-2 powers with a time resolution of a few hundred milliseconds. The dACC exhibited dip-like temporal waveforms indicating deactivation in an initial stage of each trial when appropriate verbs were successfully generated. By contrast, monotonous increase was observed for incorrect responses and a decrease was detected for no responses. The dip depth was correlated with the percentage of success. Additionally, the dip depth linearly increased with increasing slow component of the DBA index at rest across all subjects. These findings suggest that dACC deactivation is essential for cognitive processing, whereas its activation is required for goal-oriented behavioral outputs, such as cued speech. Such dACC functioning, represented by the dip depth, is supported by the activity of the upper brainstem region including monoaminergic neural systems.
文摘Hyperthermia-induced decline in cognitive performance is a moderate complication that poses challenges to the maintenance of safety. Although the underlying mechanism can be attributed to the disruption of brain networks, the propensity remains unclear. This study aimed to test the hypothesis that the extent of the alterations in cognitive performance is governed by the activity of deep brain structures, including monoaminergic neural systems. A decline in cognitive performance during mild hyperthermia and the beneficial effects of neck cooling were demonstrated using the Continuous Performance Test as a battery of cognitive tasks. Aspects of cognitive performance were characterized using the deep-brain activity (DBA) index as a neural activity parameter and the State-Trait Anxiety Inventory to assess the extent of alterations in cognitive performance as an individual measure. It was found that a higher average DBA index during tasks is essential for high cognitive performance in the heat. This beneficial effect of DBA is governed by the upper brainstem. This DBA benefit is more significant for individuals with higher average DBA indices at rest in a normal environment. Individual differences in cognitive performance in the heat are governed by differences in DBA. In addition, the beneficial effect of DBA on cognitive performance in heat only applies under conditions including neck cooling. This limited neck-cooling effect is attributed to anti-homeostatic thermoregulatory responses to cognitive tasks regulated by DBA.
文摘The dorsal area of the anterior cingulate cortex (ACC) constructs the salience network associated with the anterior insular cortex. Conventional brain imaging studies, such as functional magnetic resonance imaging (fMRI), have demonstrated that relational memory formation occurs in the ACC. However, how such memory is encoded and retrieved remains unknown due to limited time resolution of conventional fMRI. This study aimed to investigate temporal dynamics of the dorsal ACC (dACC) during word-pair tasks based on a newly developed event-related deep brain activity (ER-DBA) method using occipital electroencephalogram (EEG) signal powers. The method assesses dACC activity at a temporal resolution of approximately 0.3 s beyond the conventional resolution limit. We found that transient deactivation of dACC during the presentation of the second word of each pair was essential for encoding success regardless of whether the words were related or unrelated. We also found that memory accuracy was not affected by the intervention of inter-trials until the recall trial. Taken together, these findings suggest that dACC deactivation for encoding success is accompanied with short-term potentiation essential for durability of memory. We further found that false memory formation associated with the presentation of word pairs was occasionally committed. In such cases, dACC exhibited a similar transient deactivation although false memory commission was independent of related or unrelated conditions. Our findings suggest that encoding and retrieval of associates are paralleled and that simultaneous production of associates seems to be an essential strategy for successful relational memory formation. The study was limited to the assessment of dACC activity and did not account for other regional brain activities or receptor regulation related to short-term potentiation. We detected fast behavior of dACC during relational memory formation using the novel ER-DBA method. Such temporal dynamics will be important for eliciting underlying mechanisms of memory dysfunctions.
文摘Aroma touch therapy is widely used in clinical fields for alleviating pain-related symptoms;however, few studies have reported the pain-relief mechanisms. The present study aimed to elucidate the analgesic effects of aroma touch therapy with Citrus junos oil based on the quantitative evaluation of deep brain network (DBN) activity using electroencephalogram (EEG) occipital alpha-2 rhythm (10-13 Hz) powers. Experimental investigations were performed with 13 healthy volunteers using the cold pressor task for simulating chronic pain in three different sessions: a baseline session with no therapies, a control session with a touch therapy, and an aroma touch therapy. We have found for the first time that the interviewed pain ratings represented by Numeric Rating Scale (NRS) scores were strongly correlated with a DBN activity index, which was derived from the slow fluctuation components of occipital EEG alpha-2 rhythm powers. The correlation was characterized by a V-shaped curve in the DBN activity index versus the pain rating, i.e., the NRS score, which provided the complete analgesic states (NRS = 0) for some subjects under aroma touch therapy at an appropriate DBN activity index. Such analgesic states were not so strongly correlated with emotional valence. In conclusion, aroma touch therapy may directly modulate DBN activity so that pain-induced outcomes are minimized.
文摘Once people have a well-trained motor skill, their performance becomes stabilized and achieving substantial improvement is difficult. Recently, we have shown that even a plateaued hand motor skill can be upgraded with short-period electrical stimulation to the hand prior to the task. Here, we identify the neuronal substrates underlying the improvement of the plateaued skill by examining the enhanced functional connectivity in the sensory-motor regions that are associated with motor learning. We measured brain activity using functional magnetic resonance imaging and performed psychophysiological interaction analysis. We recruited seven right-handed very-well trained participants, whose motor performance of continuously rotating two balls with their right hands became stabilized at higher performance levels. We prepared two experiments, in each of which they repeated an experimental run 16 times. In each run, they performed this cyclic rotation as many times as possible in 16 s. In the thenar-stimulation experiment, we applied 60-s stimulation to the thenar muscle before each of the 5th - 12th runs, and the others were preceded by ineffective sham stimulation. In the control experiment, the sham was always provided. Thenar stimulation enabled the participants to perform the movements at higher cycles. In association with this performance improvement, we found enhanced activity couplings between the primary motor cortex and the sensorimotor territory of the putamen and between the cerebellum and the primary sensorimotor cortices, without any quantitative activity increase. Neither behavioral change nor these increased activity couplings were observed in the control.Thus, in contrast to the stable neuronal states in the cortico-subcortical motor circuits when the well-learned task is repeated at the later stages of motor skill learning, plastic changes in the motor circuits seem to be required when the plateaued skill is upgraded, and the stimulation may entail a state of readiness for the plastic change that allows subsequent performance improvement.
文摘Hippocampus is crucial for the formation of emotional memory. We found the relationship between hippocampal responses to emotional stimuli and the mental stabilities of people in our preliminary study. In this study, we have also evaluated how the emotional stimuli would affect amygdala and thalamus in the brain, and how the personality stabilities could relate to the responses in the brain using functional magnetic resonance imaging (fMRI). We evaluated the subjects’ personality features with the Yatabe-Guilford Personality Test (Y-G test) and psychosomatic symptoms with the Cornell Medical Index (CMI). The subjects were categorized into the mentally stable group and the mentally unstable group according to the total scores of the Y-G test and the CMI. The brain functional responses under emotional stimuli were measured using fMRI. The region of interest (ROI) analysis was performed to abstract significant changes in order to compare responses among the different emotional stimuli. We conducted the regression analysis to abstract the relationship between the mean % signal change from fMRI and the personality stability. The fMRI results showed that the hippocampus, thalamus, and right amygdala activities under the human relationship stimuli increased with ascending value of mental instability. Our findings suggest that the memory process in the hippocampus and the threat alarm system in the thalamus under the human-related stimuli crucially influence the emotional reaction of mentally unstable people. These processes in the brain would affect the event that stresses on human relationships that often cause people to suffer from mental disorders.
文摘Vibratory stimulation but also motor imagery and action observation can induce corticomotor modulation, as a bottom-up stimulus and top-down stimuli, respectively. However, it remains unknown whether the combination of motor imagery, action observation, and vibratory stimulation can effectively increase corticomotor excitability. This study aimed to investigate the effect of motor imagery and/or action observation, in the presence or absence of vibratory stimulation, on the corticomotor excitability of healthy young adults. Vibratory stimulation was provided to the palm of the right hand. Action observation consisted in viewing a movie of someone else’s finger flexion and extension movements. The imagery condition required the participants to imagine they were moving their fingers while viewing the movie and attempting to move their fingers in accordance with the movie. Eleven right-handed healthy young adults were asked to perform six conditions randomly: 1) vibratory stimulation, imagery, and action observation, 2) vibratory stimulation and action observation, 3) vibratory stimulation and viewing of a blank screen, 4) imagery and action observation, 5) action observation, and 6) viewing of a blank screen. Single-pulse transcranial magnetic stimulation was conducted to assess corticomotor excitability and the peak-to-peak amplitude of the motor evoked potentials. The results showed that vibratory stimulation increases corticospinal excitability. The findings further revealed that performing motor imagery while viewing finger movement is more effective at inducing an augmentation of corticomotor excitability compared to action observation alone. Thus, the combination of motor imagery, action observation, and vibratory stimulation can effectively augment corticomotor excitability.
文摘All Chinese born in the 1960's know the famous movie script "the function of a horse tail". Indeed, there is another famous "horse tail" in the field of basic biology, the premeiotic nucleus in the fission yeast Schizosaccharomyces pombe. It is not only because of its characteristic shape which looks like a horse tail, but also its dramatic oscillatory movement called "the horsetail movement". In the horsetail nucleus, all of the ends of chromosomes, the telomeres, are tightly clustering under spindle pole body (a centrosome equivalent in yeasts). Actually, this horsetail chromosome arrangement is an extreme form of so called "bouquet arrangement", a polarized chromosome arrangement with all the telomeres clustered in a confined area on the nuclear envelope. Bouquet arrangement is widely conserved meiotic prophase chromosomal phenomenon among eukaryotes. From study of the horsetail nucleus in fission yeast, many progresses have been made in the field of meiosis.
文摘In 2007, superconducting nanowire single photon detectors （SSPD or SNSPD） [ 1 ] made an outstanding impact in the field of quantum information technology by demonstrating quan- tum key distribution （QKD） over a 200-kin optical fiber with a 42-dB optical loss using a practical SNSPD system [2]. This successful demonstration was realized thanks to its extremely low dark count rate （DCR） of a few Hz and short timing jitter of 60 ps, while the system detection efficiency （SDE） showed a poor value of 0.7% at a wavelength of 1550 nm.
