The visual hyperstriatal region in the chick: potentials evoked by electrical stimuli.

The visual hyperstriatum of the 100-g chick has been investigated for responses evoked by electrical stimuli to the optic papilla. The visual hyperstriatum is not restricted to the anterior forebrain; posterior regions are also responsive, but for maximum response in amplitude the stimulating electrodes need to be re-positioned and, for reliable detection, a 10-fold gain in amplification is required.