Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model.
Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input-output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation.
Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut 06520; Department of Psychology, University of California Riverside, Riverside, California 92521.
Edward
E
Zagha
Department of Psychiatry, Yale School of Medicine , New Haven, Connecticut 06520.
John D
JD
Murray
Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut 06520; Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut 06520.
David A
DA
McCormick
D000200:Action Potentials; D000818:Animals; D003198:Computer Simulation; D005073:Evoked Potentials, Somatosensory; D056228:Feedback, Sensory / Q000502:physiology*; D051379:Mice; D008959:Models, Neurological; D009044:Motor Cortex / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology
cortical circuit; cortical feedback; inhibition; neuromodulation; sensorimotor; top-down