Predatory hunting is an important type of innate behavior evolutionarily conserved across the animal king-dom.It is typically composed of a set of sequential actions,including prey search,pursuit,attack,and consumptio...Predatory hunting is an important type of innate behavior evolutionarily conserved across the animal king-dom.It is typically composed of a set of sequential actions,including prey search,pursuit,attack,and consumption.This behavior is subject to control by the nervous system.Early studies used toads as a model to probe the neuroethology of hunting,which led to the proposal of a sensory-triggered release mechanism for hunting actions.More recent stud-ies have used genetically-trackable zebrafish and rodents and have made breakthrough discoveries in the neuroethol-ogy and neurocircuits underlying this behavior.Here,we review the sophisticated neurocircuitry involved in hunting and summarize the detailed mechanism for the circuitry to encode various aspects of hunting neuroethology,including sensory processing,sensorimotor transformation,motivation,and sequential encoding of hunting actions.We also discuss the overlapping brain circuits for hunting and feeding and point out the limitations of current studies.We propose that hunting is an ideal behavioral paradigm in which to study the neuroethology of motivated behaviors,which may shed new light on epidemic disorders,including bingeeating,obesity,and obsessive-compulsive disorders.展开更多
There is emerging evidence implicating glucagon-like peptide-1 (GLP-1) in reward, including palatable food reinforcement and alcohol-based reward circuitry. While recent findings suggest that mesolimbic structures, su...There is emerging evidence implicating glucagon-like peptide-1 (GLP-1) in reward, including palatable food reinforcement and alcohol-based reward circuitry. While recent findings suggest that mesolimbic structures, such as the ventral tegmental area (VTA) and the nucleus accumbens (NAc), are critical anatomical sites mediating the role of GLP-1’s inhibitory actions, the present study focused on the potential novel impact of GLP-1 within the habenula, a region of the forebrain expressing GLP-1 receptors. Given that the habenula has also been implicated in the neural control of reward and reinforcement, we hypothesized that this brain region, like the VTA and NAc, might mediate the anhedonic effects of GLP-1. Rats were stereotaxically implanted with guide cannula targeting the habenula and trained on a progressive ratio 3 (PR3) schedule of reinforcement. Separate rats were trained on an alcohol two-bottle choice paradigm with intermittent access. The GLP-1 agonist exendin-4 (Ex-4) was administered directly into the habenula to determine the effects on operant responding for palatable food as well as alcohol intake. Our results indicated that Ex-4 reliably suppressed PR3 responding and that this effect was dose-dependent. A similar suppressive effect on alcohol consumption was observed. These findings provide initial and compelling evidence that the habenula may mediate the inhibitory action of GLP-1 on reward, including operant and drug reward. Our findings further suggest that GLP-1 receptor mechanisms outside of the midbrain and ventral striatum are critically involved in brain reward neurotransmission.展开更多
文摘Predatory hunting is an important type of innate behavior evolutionarily conserved across the animal king-dom.It is typically composed of a set of sequential actions,including prey search,pursuit,attack,and consumption.This behavior is subject to control by the nervous system.Early studies used toads as a model to probe the neuroethology of hunting,which led to the proposal of a sensory-triggered release mechanism for hunting actions.More recent stud-ies have used genetically-trackable zebrafish and rodents and have made breakthrough discoveries in the neuroethol-ogy and neurocircuits underlying this behavior.Here,we review the sophisticated neurocircuitry involved in hunting and summarize the detailed mechanism for the circuitry to encode various aspects of hunting neuroethology,including sensory processing,sensorimotor transformation,motivation,and sequential encoding of hunting actions.We also discuss the overlapping brain circuits for hunting and feeding and point out the limitations of current studies.We propose that hunting is an ideal behavioral paradigm in which to study the neuroethology of motivated behaviors,which may shed new light on epidemic disorders,including bingeeating,obesity,and obsessive-compulsive disorders.
文摘There is emerging evidence implicating glucagon-like peptide-1 (GLP-1) in reward, including palatable food reinforcement and alcohol-based reward circuitry. While recent findings suggest that mesolimbic structures, such as the ventral tegmental area (VTA) and the nucleus accumbens (NAc), are critical anatomical sites mediating the role of GLP-1’s inhibitory actions, the present study focused on the potential novel impact of GLP-1 within the habenula, a region of the forebrain expressing GLP-1 receptors. Given that the habenula has also been implicated in the neural control of reward and reinforcement, we hypothesized that this brain region, like the VTA and NAc, might mediate the anhedonic effects of GLP-1. Rats were stereotaxically implanted with guide cannula targeting the habenula and trained on a progressive ratio 3 (PR3) schedule of reinforcement. Separate rats were trained on an alcohol two-bottle choice paradigm with intermittent access. The GLP-1 agonist exendin-4 (Ex-4) was administered directly into the habenula to determine the effects on operant responding for palatable food as well as alcohol intake. Our results indicated that Ex-4 reliably suppressed PR3 responding and that this effect was dose-dependent. A similar suppressive effect on alcohol consumption was observed. These findings provide initial and compelling evidence that the habenula may mediate the inhibitory action of GLP-1 on reward, including operant and drug reward. Our findings further suggest that GLP-1 receptor mechanisms outside of the midbrain and ventral striatum are critically involved in brain reward neurotransmission.
