Projections to the posterior visual hyperstriatal region in the chick: an HRP study.

The thalamic nuclei in birds are known to receive afferents from the retina and project to the hyperstriatum. However, the efferent connections of one of these, the anterior lateral nucleus (LA) have been a subject of controversy for some time. Using horseradish peroxidase tracing techniques we have shown that, in the chick, the efferents of the thalamus (including the LA) project to the visual hyperstriatum. In the case of the LA this is to the right hyperstriatum only and to posterior regions not previously regarded as having a visual function.