[The relationship between the second zone of the auditory cortex and the medial geniculate body and first auditory zone].
Extracellular and intracellular responses of the second auditory (AII) cortical neurons to stimulation of geniculocortical fibres and first auditory cortex (AI) were studied in experiments carried out on cats immobilized with d-tubocurarine. It is shown that in these neurons there appear antidromic, mono-, di- and polysynaptic spike potentials to geniculate and AI stimulation. The number of antidromic reactions was about twice as low as in AI under the same conditions. Di- and polysynaptic responses predominated among orthodromic reactions. Intracellular recording revealed EPSP, EPSP-IPSP and primary IPSP in AII neurons. Response latencies in AII neurons to AI stimulation were in the range of 0.75-6.0, 6.1-16.0, 18.0-23.0 and 60.100 ms. After the medial geniculate body was removed, the number of responses with a latency of 6.1-16.0 ms decreased considerably. In some neurons spike pontentials appeared both to geniculate and AI stimulation. Comparison of the response latencies at both types of stimulation showed that impulses from AI come in AII not only to the neurons that are inputs for MGB impulses but also to neurons in the sebsequent link of intracortical neuronal chain. In most AII neurons disynaptic IPSP appeared at AI stimulation. Only in one case IPSP with a latency of 1.0 ms was recorded being probably monosynaptic.
D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology; D001931:Brain Mapping; D002415:Cats; D004558:Electric Stimulation; D005071:Evoked Potentials; D005829:Geniculate Bodies / Q000502:physiology*; D008564:Membrane Potentials; D009431:Neural Conduction; D009433:Neural Inhibition; D011930:Reaction Time; D013570:Synaptic Membranes
Sviazi vtoroĭ zony slukhovoĭ kory s medial'nym kolenchatym telom i pervoĭ slukhovoĭ zonoĭ