The Journal of Neuroscience, February 1, 2000, 20(3):1157-1169
Specificity of Projections from Wide-Field and Local
Motion-Processing Regions within the Middle Temporal Visual
Area of the Owl Monkey
Vladimir K.
Berezovskii and
Richard
T.
Born
Department of Neurobiology, Harvard Medical School, Boston,
Massachusetts 02115-5701
The middle temporal visual area (MT) of the owl monkey is
anatomically organized with respect to both preferred direction of
motion and different types of center-surround interaction. The latter
organization consists of clusters of neurons whose receptive fields
have antagonistic surrounds that render them unresponsive to wide-field
motion (local motion columns) interdigitated with groups of neurons
whose receptive fields have additive surrounds and thus respond best to
wide-field motion (wide-field motion columns).
To learn whether the information in these regions remained segregated
further along the visual pathways, we made injections of retrograde
tracers into two visual areas to which MT projects [the medial
superior temporal area (MST) and fundus of the superior temporal sulcus
(FST)] and then labeled the wide-field and local organization using
2-deoxyglucose. In complementary experiments, we injected anterograde
tracers into regions of MT that we had mapped using microelectrode recordings.
Injections into both dorsal FST and ventral MST labeled clusters of
cell bodies in MT that were concentrated within wide-field motion
columns, whereas injections into dorsal MST labeled neurons predominantly within local motion columns. Results from the anterograde tracer experiments corroborated these findings. The high degree of
specificity in the connections reinforces a model of functional organization for wide-field versus local motion processing within MT.
Our data support the previously reported division of FST into separate
dorsal and ventral areas, and they also suggest that MST of the owl
monkey is, like MST of the macaque, functionally organized with respect
to local versus wide-field motion processing.
Key words:
functional neuroanatomy; functional organization; parallel processing; modularity; center-surround; figure ground
Copyright © 2000 Society for Neuroscience 0270-6474/00/2031157-13$05.00/0