title: Changes in visual responses in the feline dLGN: selective thalamic suppression induced by transcranial magnetic stimulation of V1.
abstract: Transcranial magnetic stimulation (TMS) of the cortex can modify activity noninvasively and produce either excitatory or inhibitory effects, depending on stimulus parameters. Here we demonstrate controlled inhibitory effects on the large corticogeniculate feedback pathway from primary visual cortex to cells of the dorsal lateral geniculate nucleus (dLGN) that are focal and reversible-induced by either single pulses or trains of pulses of TMS. These effects selectively suppress the sustained component of responses to flashed spots or moving grating stimuli and are the result of loss of spikes fired in tonic mode, whereas the number of spikes fired in bursts remain the same. We conclude that acute inactivation of the corticogeniculate downflow selectively affects the tonic mode. We found no evidence to suggest that cortical inactivation increased burst frequency.
authors.affiliation: Neuroscience and Motor Control Group, Department of Medicine, Universidad de A Coruña, Campus de Oza, 15006 A Coruña, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: de Labra
authors.forename: Casto
authors.initials: C
authors.lastname: Rivadulla
authors.forename: Kenneth
authors.initials: K
authors.lastname: Grieve
authors.forename: Jorge
authors.initials: J
authors.lastname: Mariño
authors.forename: Nelson
authors.initials: N
authors.lastname: Espinosa
authors.forename: Javier
authors.initials: J
authors.lastname: Cudeiro
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002415:Cats; D005260:Female; D005829:Geniculate Bodies / Q000166:cytology / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D012160:Retina / Q000166:cytology / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*