Journal of Neuroscience, Vol 9, 347-357, Copyright © 1989 by Society for Neuroscience
Visual receptive fields in the striate-recipient zone of the lateral posterior-pulvinar complex
LM Chalupa and BP Abramson
Department of Psychology, University of California, Davis 95616.
The lateral posterior (LP)-pulvinar complex of the cat is known to contain
multiple visual areas. In the present study, we examined the receptive
field properties of single neurons isolated in the lateral division of this
complex (the LPI). The LPI is designated the striate- recipient zone
because it is the only region of the LP-pulvinar receiving cortical
projections from areas 17 and 18. The recordings revealed that the
striate-recipient zone of LP comprises 2 subareas, which we have termed
LPI-1 and LPI-2. In the main segment (LPI-1), virtually all cells responded
securely to visual stimuli. The vast majority of these neurons were
binocular, with relatively small and well-defined receptive fields. More
than half of the cells were found to be directionally selective, and almost
this many were orientation specific. The orientation tuning of these cells
was found to be quite precise, comparable to complex cells in area 17. In
contrast, in the small dorsolateral segment of the striate-recipient zone
(the LPI-2), a substantial proportion of cells could not be visually
activated. Here, the visual cells had very large receptive fields, and
relatively few were direction or orientation selective. The LPI-2 receives
subcortical inputs from the superficial layers of the superior colliculus,
the hypothalamus, and cerebellum, while the LPI-1 is innervated only by
cortical axons. It is suggested that the subcortical connections of the
LPI-2 account for the differences in the response properties of the 2
striate-recipient areas. The present results, in conjunction with our
previous findings on the principal tectorecipient zone (Chalupa et al.,
1983), permit 2 generalizations regarding the functional organization of
the cat's LP-pulvinar complex. First, there are clear differences among the
visual areas of the LP-pulvinar in the cellular processing of visual
information. Second, these functional differences can be related to the
principal sources of visual input to the various divisions of the
LP-pulvinar.