The spatial summation characteristics of three categories of V1 neurons differing in non-classical receptive field modulation properties.

The spatial summation of excitation and inhibition determines the final output of neurons in the cat V1. To characterize the spatial extent of the excitatory classical receptive field (CRF) and inhibitory non-classical receptive field (nCRF) areas, we examined the spatial summation properties of 169 neurons in cat V1 at high (20-90%) and low (5-15%) stimulus contrasts. Three categories were classified based on the difference in the contrast dependency of the surround suppression.

A simple and effective method for obtaining stable in vivo whole-cell recordings from visual cortical neurons.

We describe a simple and effective method for obtaining stable in vivo whole-cell recordings in cat visual cortex. The core of the new approach is to prevent brain pulsation by retaining the dura mater. After being treated with an enzyme (collagenase), the dura became soft enough to allow easy penetration by a patch-clamp electrode with negligible damage to the tip.