Receptive fields of neurons in the cats visual cortex after a change of alertness level.

Exact and reliable changes in receptive fields (RF) of neurons in the primary visual cortex were revealed after the action of extravisual stimuli such as air-puff to the corner of a closed eye which leads to an enhancement of alertness level. Such stimulus evoked a change in the configuration and size of RFs in most investigated units. This lasted from 15 to 30 min and in most cases the size of RFs excitatory zones decreased, while the size of inhibitory surround increased.

Single-unit activity in cat's isolated midbrain.

The midbrain was isolated by two brainstem transections, pretrigeminal and premesencephalic. In the isolated midbrain, particularly within the reticular formation, EEG activity was greatly depressed. On the other hand, single-unit spike activity remained at a high level.

Proprioceptive effects on evoked responses to sounds in the cat auditory cortex.

With a view to analyse the influence of neck proprioceptors on directional hearing, evoked potentials (EPs) to dichotically or monaurally presented clicks were recorded from the auditory cortex of cats under deep Nembutal anaesthesia with their head pointing to the front, and then to the right or to the left side at 45 degrees. The change in the head position produced considerable changes in the amplitude of the two primary EP components and in their thresholds. The changes were of two kinds: either decrease or increase of the amplitude.