Serotonin increases population coding of behaviorally relevant stimuli by enhancing responses of ON but not OFF-type sensory neurons.

How neural populations encode sensory input to generate behavioral responses remains a central problem in systems neuroscience. Here we investigated how neuromodulation influences population coding of behaviorally relevant stimuli to give rise to behavior in the electrosensory system of the weakly electric fish . We performed multi-unit recordings from ON and OFF sensory pyramidal cells in response to stimuli whose amplitude (i.

Serotonergic Modulation of Sensory Neuron Activity and Behavior in .

Organisms must constantly adapt to changes in their environment to survive. It is thought that neuromodulators such as serotonin enable sensory neurons to better process input encountered during different behavioral contexts. Here, we investigated how serotonergic innervation affects neural and behavioral responses to behaviorally relevant envelope stimuli in the weakly electric fish species .

Serotonin modulates optimized coding of natural stimuli through increased neural and behavioural responses via enhanced burst firing.

Key Points: The function of serotonergic fibres onto sensory areas remains poorly understood We show that serotonin application enhances sensory neural and behavioural responses to second order stimuli Enhanced neural responses most likely occurred because of increased burst firing Changes in neural sensitivity due to burst firing were the best predictor of changes in behavioural sensitivity Our results suggest that serotonin optimizes coding of stimuli encountered during aggression.

Abstract: Understanding how the processing of sensory information leads to behavioural responses remains a central problem in systems neuroscience. Here, we investigated how the neuromodulator serotonin affects neural and behavioural responses to second-order envelope stimuli within the electrosensory system of the weakly electric fish Apteronotus leptorhynchus.

Serotonin Selectively Increases Detectability of Motion Stimuli in the Electrosensory System.

Serotonergic innervation of sensory areas is found ubiquitously across the central nervous system of vertebrates. Here, we used a system's level approach to investigate the role of serotonin on processing motion stimuli in the electrosensory system of the weakly electric fish . We found that exogenous serotonin application increased the firing activity of pyramidal neural responses to both looming and receding motion.

Extra-neurohypophyseal axonal projections from individual vasopressin-containing magnocellular neurons in rat hypothalamus.

Conventional neuroanatomical, immunohistochemical techniques, and electrophysiological recording, as well as in vitro labeling methods may fail to detect long range extra-neurohypophyseal-projecting axons from vasopressin (AVP)-containing magnocellular neurons (magnocells) in the hypothalamic paraventricular nucleus (PVN). Here, we used in vivo extracellular recording, juxtacellular labeling, post-hoc anatomo-immunohistochemical analysis and camera lucida reconstruction to address this question. We demonstrate that all well-labeled AVP immunopositive neurons inside the PVN possess main axons joining the tract of Greving and multi-axon-like processes, as well as axonal collaterals branching very near to the somata, which project to extra-neurohypophyseal regions.