Responses of macaque STS neurons to optic flow components: a comparison of areas MT and MST

Lagae, Lieven; Maes, Hugo; Raiguel, Steven; Xiao, Dongping; Orban, Guy A.

doi:10.1152/jn.1994.71.5.1597

Cited by 264 publications

(288 citation statements)

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“…Another electrophysiological result that is consistent with our data is the inverse relationship between neuronal response latency and stimulus speed in MT (Movshon et al, 1990;Kawano et al, 1994;Lagae et al, 1994;Lisberger and Movshon, 1999; but see Raiguel et al, 1999). Although latency and integration time can, in principle, be independent, for many biological systems they are linked because simple low-pass filtering is associated with a delay.…”

Section: Tf and Temporal Integrationsupporting

confidence: 87%

Adaptive Temporal Integration of Motion in Direction-Selective Neurons in Macaque Visual Cortex

Bair¹,

Movshon²

2004

J. Neurosci.

122

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Direction-selective neurons in the primary visual cortex (V1) and the extrastriate motion area MT/V5 constitute a critical channel that links early cortical mechanisms of spatiotemporal integration to downstream signals that underlie motion perception. We studied how temporal integration in direction-selective cells depends on speed, spatial frequency (SF), and contrast using randomly moving sinusoidal gratings and spike-triggered average (STA) analysis. The window of temporal integration revealed by the STAs varied substantially with stimulus parameters, extending farther back in time for slow motion, high SF, and low contrast. At low speeds and high SF, STA peaks were larger, indicating that a single spike often conveyed more information about the stimulus under conditions in which the mean firing rate was very low. The observed trends were similar in V1 and MT and offer a physiological correlate for a large body of psychophysical data on temporal integration. We applied the same visual stimuli to a model of motion detection based on oriented linear filters (a motion energy model) that incorporated an integrate-and-fire mechanism and found that it did not account for the neuronal data. Our results show that cortical motion processing in V1 and in MT is highly nonlinear and stimulus dependent. They cast considerable doubt on the ability of simple oriented filter models to account for the output of direction-selective neurons in a general manner. Finally, they suggest that spike rate tuning functions may miss important aspects of the neural coding of motion for stimulus conditions that evoke low firing rates.

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Section: Tf and Temporal Integrationsupporting

confidence: 87%

Adaptive Temporal Integration of Motion in Direction-Selective Neurons in Macaque Visual Cortex

Bair¹,

Movshon²

2004

J. Neurosci.

122

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“…First, we outline the motion-responsive cortex in general and chart specific areas within this motion-sensitive cortex, using subtractions based on speed, optic flow selectivity, and receptive field (RF) sizes as documented by single-cell studies of the MT/V5 and MST areas (Maunsell and Van Essen, 1983;Desimone and Ungerleider, 1986;Mikami et al, 1986;Saito et al, 1986;Duffy and Wurtz, 1991;Lagae et al, 1994;Orban et al, 1995;Raiguel et al, 1997). Next, we characterize the charted regions by their fMRI adaptation for direction of motion, suggesting the presence of direction-selective neurons.…”

Section: Introductionmentioning

confidence: 99%

Charting the Lower Superior Temporal Region, a New Motion-Sensitive Region in Monkey Superior Temporal Sulcus

Nelissen¹,

Vanduffel²,

Orban³

2006

J. Neurosci.

155

163

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Although the role of the middle temporal (MT/V5) area and its medial superior temporal (MST) satellites in motion processing has been well explored, relatively little is known about motion regions located more rostrally in the superior temporal sulcus (STS), such as the fundus of the superior temporal (FST) area, the superior temporal polysensory (STP) region, or beyond. To fill this void, we used contrast-enhanced functional magnetic resonance imaging in awake macaques and a five-step testing procedure that allowed us to identify six motion-sensitive regions within the STS. Direction adaptation tests confirmed the motion sensitivity of these six regions. Five of them [MT/V5, its three satellites, and the middle part of the STP (STPm) region in the upper bank of the STS] have been documented by previous single-cell studies. A sixth, previously unknown motion-responsive region, which we termed the lower superior temporal (LST) region, was observed on the lower bank and fundus of the STS, 6 -8 mm anterior to the FST area. In contrast to the MST areas, the LST region responds to slow as well as fast speeds and is responsive to static and moving images of objects, to patterns defined by opponent motion, and to actions. These results, obtained in both group and single-subject analyses, suggest that motion information in the STS might follow a second path, in addition to the MT/V5-MST path. This ventral path including the LST region, FST area, and STPm region is likely involved in the visual analysis of actions and biological motion.

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“…However, the fact that we did not find a decrease in sensitivity for the straight discontinuity at larger eccentricities indicates that this phase effect cannot be an explanation for our results. Orban (1992) and Lagae, Maes, Raiguel, Xiao, and Orban (1994) reported center surround cells in MST of the monkey that are dominated by either zero-or first-order optical flow fields in the annular surround. The cells' response would be similar for stimuli with or without the central part.…”

Section: Discussionmentioning

confidence: 99%

Detection of spatial discontinuities in first-order optical flow fields

Pas

Kappers

Koenderink

1997

Perception & Psychophysics

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We investigated the extent to which the human visual system can detect discontinuities in firstorder optical flow fields. Weconstructed two types of spatial discontinuities: a circular split field with a straight edge and a disk with annular surround. Weused two different first-order optical flow components: an expansion and a rotation. Wefound an intriguing difference in the detection thresholds for straight and circular discontinuities. Whereas straight discontinuities yielded thresholds of 10%-500!6 difference in expansion or rotation, circular discontinuities could, at first, only be detected at extreme differences (» 100%). After a learning period, thresholds for such stimuli decreased, but they remained significantly higher than thresholds for the straight edge. Thresholds rose for stimuli that formed a gradual transition between a circular and a straight edge, and they decreased with increasing eccentricity of the circular discontinuity. Results suggest that symmetry in the stimulus, defined by the coincidence of the center of expansion or rotation and the center of the circular discontinuity, was responsible for the difference in thresholds for circular and straight discontinuities.When we move around in the world, the optical flow field provides much information about the world around us and our movement relative to it (Gibson, 1950). In everyday life, we often come across spatial discontinuities in this optical flow. These discontinuities are caused by objects that move separate from their background or by movement relative to transitions between noncoplanar surfaces (such as between a wall and the floor).Mathematically, one can extract information about the slant and tilt of objects and about the movement of the observer relative to these objects from the first-order structure ofthe flow field (Koenderink & van Doom, 1975;Longuet-Higgins & Prazdny, 1980). Information can also be extracted about the difference between first-order optical flow components in two different planes (e.g., a floor and a wall; Koenderink & van Doom, 1976) or at two different times. Ofcourse, this does not mean that the human visual system uses all the information that can be extracted mathematicaIly from the first-order flow field. To investigate whether the visual system is able to detect discontinuities in first-order flow fields, we constructed 2-D first-order optical flow stimuli with discontinuities that were step functions in the spatial domain.To investigate spatial discontinuities, we implemented two different stimuli: one with a circular discontinuity and one with a straight discontinuity. The stimulus with a straight discontinuity consisted ofa split field with the division along a diameter of the circular aperture. The stimulus with a circular discontinuity was a split field consisting of a circular center with an annular surround. As a first-order flow field, we chose either an expanding field or a rotating field. The center of expansion or rotaCorrespondence should be addressed to S. F. te Pas. Helmholtz Institu...

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Responses of macaque STS neurons to optic flow components: a comparison of areas MT and MST

Cited by 264 publications

References 0 publications

Adaptive Temporal Integration of Motion in Direction-Selective Neurons in Macaque Visual Cortex

Adaptive Temporal Integration of Motion in Direction-Selective Neurons in Macaque Visual Cortex

Charting the Lower Superior Temporal Region, a New Motion-Sensitive Region in Monkey Superior Temporal Sulcus

Detection of spatial discontinuities in first-order optical flow fields

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