Immediate thalamic sensory plasticity depends on corticothalamic feedback.
Multiple neuron ensemble recordings were obtained simultaneously from both the primary somatosensory (SI) cortex and the ventroposterior medial thalamus (VPM) before and during the combined administration of reversible inactivation of the SI cortex and a reversible subcutaneous block of peripheral trigeminal nerve fibers. This procedure was performed to quantify the contribution of descending corticofugal projections on (i) the normal organization of thalamic somatosensory receptive fields and (ii) the thalamic somatosensory plastic reorganization that immediately follows a peripheral deafferentation. Reversible inactivation of SI cortex resulted in immediate changes in receptive field properties throughout the VPM. Cortical inactivation also significantly reduced but did not completely eliminate the occurrence of VPM receptive field reorganization resulting from the reversible peripheral deafferentation. This result suggests that the thalamic plasticity that is seen immediately after a peripheral deafferentation is dependent upon both descending corticofugal projections and ascending trigeminothalamic projections.
Krupa
D J
DJ
Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA. krupad@neuro.duke.edu
Ghazanfar
A A
AA
Nicolelis
M A
MA
D000818:Animals; D001931:Brain Mapping; D004558:Electric Stimulation; D005260:Female; D007263:Infusions, Parenteral; D008012:Lidocaine / Q000494:pharmacology; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity; D009474:Neurons / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology*; D013788:Thalamus / Q000502:physiology*; D013997:Time Factors; D014276:Trigeminal Nerve / Q000502:physiology*; D014738:Vibrissae / Q000294:innervation
D009118:Muscimol; D008012:Lidocaine