Binocular interaction at cat's lateral geniculate body.

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Abstract
The geniculate field response evoked by a test volley in one optic nerve was depressed for several tenths of a second by a conditioning volley applied to the opposite optic nerve. This prolonged suppressive state of the geniculate neurons was studied in anesthetized cats. Unit activity of the geniculate relay cells was recorded extracellulary and it was found that a conditioning volley in one optic nerve suppressed spike generation of the cell produced by a test volley in the opposite optic nerve. The conditioning volley itself evoked not spikes, indicating that the suppression is due to inhibition. Intracellular recording of IPSPs [inhibitory post-synaptic potential] from the geniculate relay cells revealed that the suppression present in the cells was due to a postsynaptic inhibition. In most of the relay cells, a volley in either one of the two optic nerves produced an action spike which was followed by a prolonged hyperpolarization, while a volley in the opposite optic nerve evoked a pure IPSP without spike.