Response to movement of neurons in areas 17 and 18 of the cat: velocity sensitivity.

Orban, Guy A.; Kennedy, Henry; Maes, Hugo

doi:10.1152/jn.1981.45.6.1043

Cited by 159 publications

(83 citation statements)

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“…By itself, however, invariance does not reveal the fundamental nature of the three-dimensional shape coding, and more detailed tests were necessary to assess the three-dimensional shape representation in AIP. Accordingly we have shown that AIP neurons provide detailed information about the degree of curvedness in the stimuli, not by virtue of a collection of neurons tuned to different values of this continuous quantity (Tudusciuc and Nieder, 2007), but rather through a mostly monotonic relationship between spike rate and curvedness (Orban et al, 1981). Conversely, many AIP neurons do not signal the presence of disparity discontinuities in reduced versions of the smoothly curved surfaces, at least in the initial part of their response.…”

Section: Discussionmentioning

confidence: 80%

A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse

Srivastava

Orban²,

Mazière³

et al. 2009

J. Neurosci.

113

166

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Differences in the horizontal positions of retinal images-binocular disparity-provide important cues for three-dimensional object recognition and manipulation. We investigated the neural coding of three-dimensional shape defined by disparity in anterior intraparietal (AIP) area. Robust selectivity for disparity-defined slanted and curved surfaces was observed in a high proportion of AIP neurons, emerging at relatively short latencies. The large majority of AIP neurons preserved their three-dimensional shape preference over different positions in depth, a hallmark of higher-order disparity selectivity. Yet both stimulus type (concave-convex) and position in depth could be reliably decoded from the AIP responses. The neural coding of three-dimensional shape was based on first-order (slanted surfaces) and second-order (curved surfaces) disparity selectivity. Many AIP neurons tolerated the presence of disparity discontinuities in the stimulus, but the population of AIP neurons provided reliable information on the degree of curvedness of the stimulus. Finally, AIP neurons preserved their three-dimensional shape preference over different positions in the frontoparallel plane. Thus, AIP neurons extract or have access to three-dimensional object information defined by binocular disparity, consistent with previous functional magnetic resonance imaging data. Unlike the known representation of three-dimensional shape in inferior temporal cortex, the neural representation in AIP appears to emphasize object parameters required for the planning of grasping movements.

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Section: Discussionmentioning

confidence: 80%

A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse

Srivastava

Orban²,

Mazière³

et al. 2009

J. Neurosci.

113

166

View full text Add to dashboard Cite

show abstract

“…For moving bars, the response metric was the average firing rate over a time window equal to the duration of the sweep of the bar through the receptive field. The duration of this window varied inversely, therefore, with the speed of the bar (Movshon, 1975;Orban et al, 1981). The best speed was defined as the stimulus speed that elicited the greatest response.…”

Section: Methodsmentioning

confidence: 99%

How Is a Sensory Map Read Out? Effects of Microstimulation in Visual Area MT on Saccades and Smooth Pursuit Eye Movements

1997

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To generate behavioral responses based on sensory input, motor areas of the brain must interpret, or "read out," signals from sensory maps. Our experiments tested several algorithms for how the motor systems for smooth pursuit and saccadic eye movements might extract a usable signal of target velocity from the distributed representation of velocity in the middle temporal visual area (MT or V5). Using microstimulation, we attempted to manipulate the velocity information within MT while monkeys tracked a moving visual stimulus. We examined the effects of the microstimulation on smooth pursuit and on the compensation for target velocity shown by saccadic eye movements. Microstimulation could alter both the speed and direction of the motion estimates of both types of eye movements and could also cause monkeys to generate pursuit even when the visual target was actually stationary. The pattern of alterations suggests that microstimulation can introduce an additional velocity signal into MT and that the pursuit and saccadic systems usually compute a vector average of the visually evoked and microstimulation-induced velocity signals (pursuit, 55 of 122 experiments; saccades, 70 of 122). Microstimulation effects in a few experiments were consistent with vector summation of these two signals (pursuit, 6 of 122; saccades, 2 of 122). In the remainder of the experiments, microstimulation caused either an apparent impairment in motion processing (pursuit, 47 of 122; saccades, 41 of 122) or had no effect (pursuit, 14 of 122; saccades, 9 of 122). Within individual experiments, the effects on pursuit and saccades were usually similar, but the occasional striking exception suggests that the two eye movement systems may perform motion computations somewhat independently.

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“…(4) Velocity sensitivity was determined using moving stimuli of optimal orientation and direction. Units were categorized as low-pass, broadband, tuned or high-pass, according to the criteria de®ned by Orban et al (1981). (5) Precise limits of the receptive ®elds (RFs) were mapped as the`minimum response ®elds'.…”

Section: Analysis Of Visual Responses Propertiesmentioning

confidence: 99%

Visual interhemispheric transfer to areas 17 and 18 in cats with convergent strabismus

Milleret¹,

Houzel²

2001

Eur J Neurosci

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Commissural connections between primary visual cortical maps of the two hemispheres are essential to unify the split representation of the visual ®eld. In normal adult cats, callosal connections are essentially restricted to the border between areas A17 and A18, where the central vertical meridian is projected. In contrast, early convergent strabismus leads to an expanded callosal-receiving zone, as repeatedly indicated by anatomical experiments. We investigated here the functional correlates of this widespread distribution of callosal terminals by analysing transcallosal visual responses in ®ve anaesthetized and paralysed 4± 10-month-old cats whose right eye had been surgically deviated on postnatal day 6. After acute section of the optic chiasm, single-unit activity was recorded from A17 and A18 of the right hemisphere while the left eye was visually stimulated. A total of 108/406 units were transcallosally activated. While they were more frequent at the 17/18 border (46% of the units recorded within this region), numerous transcallosally activated units were located throughout A17 (16%), A18 (27%) or within the white matter (17%). In all regions, transcallosally driven units displayed functional de®cits usually associated with strabismus, such as decreased binocularity and ability to respond to fast-moving stimuli, and increased receptive ®eld size. Many units also displayed reduced orientation selectivity and increased position disparity. In addition, transcallosal receptive ®elds were manifestly located within the hemi®eld ipsilateral to the explored cortex, with almost no contact with the central vertical meridian. Comparison with data from normal adults revealed that strabismus induced a considerable expansion of the callosal receiving zone, both in terms of the cortical region and of the extent of the visual ®eld involved in interhemispheric transfer, with implications in the integration of visual information across the hemispheres.

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Response to movement of neurons in areas 17 and 18 of the cat: velocity sensitivity.

Cited by 159 publications

References 0 publications

A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse

A Distinct Representation of Three-Dimensional Shape in Macaque Anterior Intraparietal Area: Fast, Metric, and Coarse

How Is a Sensory Map Read Out? Effects of Microstimulation in Visual Area MT on Saccades and Smooth Pursuit Eye Movements

Visual interhemispheric transfer to areas 17 and 18 in cats with convergent strabismus

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