Change in the receptive fields of the visual cortex of the cat in relation to the level of wakefulness

Conclusions

• 1. Clear and reliable changes in the dimensions, area and form of the RFs in 94% of the neurons investigated were detected within 10–30 minutes after a puff of air.

• 2. With respect to neurons possessing RFs with an excitatory center (79%), in two-thirds of the cases a contraction of this zone was observed and in 25–30% an expansion. The inhibitory periphery of such RFs in three-quarters of the neurons expanded after a puff of air and more rarely (19%) contracted. The inhibitory centers of the RFs in off-central neurons changed in the same way (21%)

• 3. The change in the inhibitory zone of the RF after a puff of air is expressed more sharply with regard to its magnitude and duration as well as the probability of its manifestation.

• 4. The reorganizations of the RFs appears clearly at different levels of adaptation of the visual system, although their expression is diminished to an insignificant extent with diurnal background illumination.

• 5. The contraction of the excitatory centers of the RFs with transition from calm alertness to a state of strained attention, owing to an expansion of their inhibitory peripheral zone, may apparently provide the animal with a more precise identification of the form of objects

• 6. The data obtained reinforce our hypothesis concerning the leading role of cortical inhibition in the formation of the RFs of the neurons of the visual cortex and their modification in relation to a change in the state of the organism.