Motor modulation of afferent somatosensory circuits.
A prominent feature of thalamocortical circuitry in sensory systems is the extensive and highly organized feedback projection from the cortex to the thalamic neurons that provide stimulus-specific input to the cortex. In lightly sedated rats, we found that focal enhancement of motor cortex activity facilitated sensory-evoked responses of topographically aligned neurons in primary somatosensory cortex, including antidromically identified corticothalamic cells; similar effects were observed in ventral posterior medial thalamus (VPm). In behaving rats, thalamic responses were normally smaller during whisking but larger when signal transmission in brainstem trigeminal nuclei was bypassed or altered. During voluntary movement, sensory activity may be globally suppressed in the brainstem, whereas signaling by cortically facilitated VPm neurons is simultaneously enhanced relative to other VPm neurons receiving no such facilitation.
Lee
SooHyun
S
Department of Neurobiology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, Pennsylvania 15261, USA.
Carvell
George E
GE
Simons
Daniel J
DJ
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D001931:Brain Mapping; D002045:Bupivacaine / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D011597:Psychomotor Performance; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000502:physiology*; D013788:Thalamus / Q000166:cytology / Q000502:physiology; D013997:Time Factors; D014738:Vibrissae
D000779:Anesthetics, Local; D018756:GABA Antagonists; C017069:bicuculline methiodide; D001640:Bicuculline; D002045:Bupivacaine