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Molecular and Cellular Neuroscience Commons™
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Full-Text Articles in Molecular and Cellular Neuroscience
Mechanisms Underlying Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Medial Prefrontal Cortex, Emily K. Stephens, Arielle L. Baker, Allan T. Gulledge
Mechanisms Underlying Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Medial Prefrontal Cortex, Emily K. Stephens, Arielle L. Baker, Allan T. Gulledge
Dartmouth Scholarship
Serotonin (5-HT) selectively excites subpopulations of pyramidal neurons in the neocortex via activation of 5-HT2A (2A) receptors coupled to Gq subtype G-protein alpha subunits. Gq-mediated excitatory responses have been attributed primarily to suppression of potassium conductances, including those mediated by KV7 potassium channels (i.e., the M-current), or activation of non-specific cation conductances that underlie calcium-dependent afterdepolarizations (ADPs). However, 2A-dependent excitation of cortical neurons has not been extensively studied, and no consensus exists regarding the underlying ionic effector(s) involved. In layer 5 of the mouse medial prefrontal cortex, we tested potential mechanisms of serotonergic excitation …
Neuron Morphology Influences Axon Initial Segment Plasticity, Allan T. Gulledge, Jaime J. Bravo
Neuron Morphology Influences Axon Initial Segment Plasticity, Allan T. Gulledge, Jaime J. Bravo
Dartmouth Scholarship
In most vertebrate neurons, action potentials are initiated in the axon initial segment (AIS), a specialized region of the axon containing a high density of voltage-gated sodium and potassium channels. It has recently been proposed that neurons use plasticity of AIS length and/or location to regulate their intrinsic excitability. Here we quantify the impact of neuron morphology on AIS plasticity using computational models of simplified and realistic somatodendritic morphologies. In small neurons (e.g., dentate granule neurons), excitability was highest when the AIS was of intermediate length and located adjacent to the soma. Conversely, neurons having larger dendritic trees (e.g., pyramidal …
Activity-Dependent Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Prefrontal Cortex, Emily K. Stephens, Daniel Avesar, Allan T. Gulledge
Activity-Dependent Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Prefrontal Cortex, Emily K. Stephens, Daniel Avesar, Allan T. Gulledge
Dartmouth Scholarship
Layer 5 pyramidal neurons (L5PNs) in the mouse prefrontal cortex respond to serotonin (5-HT) according to their long-distance axonal projections; 5-HT1A (1A) receptors mediate inhibitory responses in corticopontine (CPn) L5PNs, while 5-HT2A (2A) receptors can enhance action potential (AP) output in callosal/commissural (COM) L5PNs, either directly (in “COM-excited” neurons), or following brief 1A-mediated inhibition (in “COM-biphasic” neurons). Here we compare the impact of 5-HT on the excitability of CPn and COM L5PNs experiencing variable excitatory drive produced by current injection (DC current or simulated synaptic current) or with exogenous glutamate. 5-HT delivered at resting membrane potentials, or paired …
Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge
Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge
Dartmouth Scholarship
Serotonin (5-HT) acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs) in the mouse medial prefrontal cortex (mPFC), and found three distinct response types: long-lasting 5-HT1A (1A) receptor-dependent inhibitory responses (84% of L5PNs), 5-HT2A (2A) receptor-dependent excitatory responses (9%), and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%). Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM) neurons that project to the …