Neural Foundations of Vision 
> 
J. Anthony Movshon, Ph.D. — Investigator 
Dr. Movshon is also Professor of Neural Science and Psychology at New York University and Adjunct Pro- 
fessor of Physiology and Biophysics at New York University Medical Center. He received his B.A. degree 
and his Ph.D. degree in experimental psychology from Cambridge University, where he worked with Colin 
Blakemore. After joining the faculty of NYU, Dr. Movshon has remained there except for a sabbatical year 
at Oxford University. He was founding director of the NYU Center for Neural Science. Among his honors 
is the Young Investigator Award from the Society for Neuroscience. 
MY research concerns the function and devel- 
opment of the visual system, especially the 
visual areas of the primate cerebral cortex. My 
main experimental tools are electrophysiological 
recording and quantitative analysis of the visually 
evoked activity of single neurons. We also draw 
importantly from related work in visual psycho- 
physics, computational modeling, and comple- 
mentary neuroanatomy. 
Presently we are involved in two broad groups 
of studies. The first concerns the functional prop- 
erties of single neurons in the extrastriate visual 
areas of the macaque monkey's cerebral cortex, 
with special emphasis on the processing of infor- 
mation about visual motion, space, form, and 
color. The second group of studies concerns the 
development of cortical visual function in mon- 
keys and the way that development is affected by 
abnormal early visual experience. 
An important organizing theme derives from 
the discovery of two functional streams in the 
monkey's geniculo-cortical visual pathway. One 
stream, the P system, originates in the dense and 
numerous PjS ganglion cells of the retina, contin- 
ues through the parvocellular layers of the lateral 
geniculate nucleus (LGN), and extends to layer 
4Ci8 of the striate (or primary visual) cortex, VI . 
A second stream, the M system, originates in the 
large, fast-conducting but relatively sparse Pa 
retinal ganglion cells, continues through the 
magnocellular layers of the LGN, and enters the 
striate cortex through layer 4Ca. 
Signals from the P system are passed preferen- 
tially into a set of cortical areas that seem to be of 
special importance for the processing of form and 
color, especially visual areas 2 and 4, and into the 
inferior temporal cortex. Signals from the M sys- 
tem pass rather selectively into another set of cor- 
tical areas that seem to be essential for the analy- 
sis of visual motion and visual space, especially 
the middle temporal area (MT, or V5), and into 
the posterior parietal cortex. Our working hy- 
pothesis is that these streams subserve different, 
albeit overlapping visual functions, and also that 
different forms of developmental visual disorder 
may reflect abnormalities primarily affecting one 
stream or the other. 
To study the functions of cortical visual areas, 
we analyze the responses evoked in single neu- 
rons by visual stimuli carefully selected to permit 
formal characterization of underlying neuronal 
mechanisms. The class of properties in which we 
are generally interested concerns the selectivity 
with which neurons respond to variations along 
one or another visual dimension. We also try to 
examine the neuroanatomical distribution and 
functional properties of neurons providing affer- 
ent signals to a particular area, so that we can 
attempt to understand the computational trans- 
formations of the visual signal executed by the 
circuits in each area. 
An important concern is to establish the partic- 
ular dimensions of the visual stimulus for which 
neurons in that area show an invariant selectivity 
— that is, for which their selectivity is unaffected 
by parametric variation in other, unrelated di- 
mensions. For example, neurons in VI have in- 
variant selectivity for the spatial, temporal, and 
chromatic structure of visual stimuli. Neurons in 
MT transform afferent spatiotemporal signals into 
invariant representations of an object's speed and 
direction. Neurons in V4, on the other hand, may 
transform simple afferent chromatic signals into 
invariant representations of the object's surface 
properties. 
A critical issue in cortical sensory physiology is 
to relate perceptual experience and judgment to 
the activity of neurons and neuron assemblies. In 
collaboration with William Newsome at Stanford 
University, we have used statistical methods 
based on the theory of signal detection to com- 
pare the performance of single neurons with psy- 
chophysical measures of performance obtained 
concurrently from an awake, behaving monkey. 
The goal is to deduce the associations between 
the computation of perceptual features and the 
activity of particular groups of neurons. The re- 
sults suggest that small groups of neurons in area 
MT may carry the signals upon which behaving 
monkeys make judgments of the motion content 
of visual targets. This approach allows us to form 
a common language in which to consider psycho- 
physical, computational, and neurobiological 
analyses of visual cortical function. 
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