The Journal of Neuroscience, January 1, 2003, 23(1):339-348
The Receptive Fields of Inferior Temporal Cortex Neurons in
Natural Scenes
Edmund T.
Rolls,
Nicholas C.
Aggelopoulos, and
Fashan
Zheng
University of Oxford, Department of Experimental Psychology, South
Parks Road, Oxford OX1 3UD, United Kingdom
Inferior temporal cortex neurons have generally been found to have
large visual receptive fields that typically include the fovea and
extend throughout much of the visual field. However, a problem of such
a large receptive field is that it does not easily support object
selection by subsequent processing areas, in that all objects within
such a large receptive field might activate inferior temporal cortex
cells. To clarify this, we recorded from inferior temporal cortex
neurons while macaques searched for objects in complex natural scenes
or in plain backgrounds, as normally used. Inferior temporal cortex
neuron receptive fields were much smaller in natural scenes (mean
radius, 11°) than in plain backgrounds (39°). With two objects in a
scene, one of which was a target for action (a touch), the firing rates
were equally high during foveation of the effective stimulus when it
was the target and when it was the distractor in both the plain and the complex scenes. With a plain background and two objects present, the
receptive fields were much larger (24°) for the stimulus when it was
the target than when it was the distractor (9°). This effect of
object-based attention was much less evident in the complex scene, when
the receptive fields were small both when the stimulus was a distractor
and when it was a target. The results show that the temporal visual
cortex provides an unambiguous representation in natural scenes by
responding to the object shown at or close to the fixation point.
Key words:
visual search; translation invariance; attention; object recognition; rhesus monkey; active vision
Copyright © 2003 Society for Neuroscience 0270-6474/03/231339-10$05.00/0