Ventral intraparietal area of the macaque: anatomic location and visual response properties

1993 ◽  
Vol 69 (3) ◽  
pp. 902-914 ◽  
Author(s):  
C. L. Colby ◽  
J. R. Duhamel ◽  
M. E. Goldberg

1. The middle temporal area (MT) projects to the intraparietal sulcus in the macaque monkey. We describe here a discrete area in the depths of the intraparietal sulcus containing neurons with response properties similar to those reported for area MT. We call this area the physiologically defined ventral intraparietal area, or VIP. In the present study we recorded from single neurons in VIP of alert monkeys and studied their visual and oculomotor response properties. 2. Area VIP has a high degree of selectivity for the direction of a moving stimulus. In our sample 72/88 (80%) neurons responded at least twice as well to a stimulus moving in the preferred direction compared with a stimulus moving in the null direction. The average response to stimuli moving in the preferred direction was 9.5 times as strong as the response to stimuli moving in the opposite direction, as compared with 10.9 times as strong for neurons in area MT. 3. Many neurons were also selective for speed of stimulus motion. Quantitative data from 25 neurons indicated that the distribution of preferred speeds ranged from 10 to 320 degrees/s. The degree of speed tuning was on average twice as broad as that reported for area MT. 4. Some neurons (22/41) were selective for the distance at which a stimulus was presented, preferring a stimulus of equivalent visual angle and luminance presented near (within 20 cm) or very near (within 5 cm) the face. These neurons maintained their preference for near stimuli when tested monocularly, suggesting that visual cues other than disparity can support this response. These neurons typically could not be driven by small spots presented on the tangent screen (at 57 cm). 5. Some VIP neurons responded best to a stimulus moving toward the animal. The absolute direction of visual motion was not as important for these cells as the trajectory of the stimulus: the best stimulus was one moving toward a particular point on the face from any direction. 6. VIP neurons were not active in relation to saccadic eye movements. Some neurons (10/17) were active during smooth pursuit of a small target. 7. The predominance of direction and speed selectivity in area VIP suggests that it, like other visual areas in the dorsal stream, may be involved in the analysis of visual motion.

2016 ◽  
Author(s):  
Liu D. Liu ◽  
Christopher C. Pack

SummaryPerceptual decisions require the transformation of raw sensory inputs into cortical representations suitable for stimulus discrimination. One of the best-known examples of this transformation involves the middle temporal area (MT) of the primate visual cortex. Area MT provides a robust representation of stimulus motion, and previous work has shown that it contributes causally to performance on motion discrimination tasks. Here we report that the strength of this contribution can be highly plastic: Depending on the recent training history, pharmacological inactivation of MT can severely impair motion discrimination, or it can have little detectable influence. Similarly, depending on training, microstimulation can bias motion perception or simply introduce noise. Further analysis of neural and behavioral data suggests that training shifts the readout of motion information between MT and lower-level cortical areas. These results show that the contribution of individual brain regions to conscious perception can shift flexibly depending on sensory experience.


2001 ◽  
Vol 85 (1) ◽  
pp. 187-196 ◽  
Author(s):  
James W. Bisley ◽  
Daniel Zaksas ◽  
Tatiana Pasternak

We applied electrical stimulation to physiologically identified sites in macaque middle temporal area (MT) to examine its role in short-term storage of recently encoded information about stimulus motion. We used a behavioral task in which monkeys compared the directions of two moving random-dot stimuli, sample and test, separated by a 1.5-s delay. Four sample directions were used for each site, and the animals had to indicate whether the direction of motion in the sample was the same as or different to the direction of motion in the test. We found that the effect of stimulation of the same directional column in MT depended on the behavioral state of the animal. Although stimulation had strong effects when applied during the encoding and the storage components of the task, these effects were not equivalent. Stimulation applied during the presentation of the sample produced signals interpreted by the monkeys as directional motion. However, the same stimulation introduced during the period of storage no longer produced signals interpreted as unambiguous directional information. We conclude that the directional information used by the monkeys in the working memory task is likely to be provided by neurons in MT, and the use of this information appears to be dependent on the portion of the task during which stimulation was delivered. Finally, the disruptive effects of stimulation during the delay suggest that MT neurons not only participate in the encoding of visual motion information but also in its storage by either maintaining an active connection with the circuitry involved in storage or being an integral component of that circuitry.


1996 ◽  
Vol 13 (1) ◽  
pp. 87-100 ◽  
Author(s):  
K. H. Britten ◽  
W. T. Newsome ◽  
M. N. Shadlen ◽  
S. Celebrini ◽  
J. A. Movshon

AbstractWe have previously documented the exquisite motion sensitivity of neurons in extrastriate area MT by studying the relationship between their responses and the direction and strength of visual motion signals delivered to their receptive fields. These results suggested that MT neurons might provide the signals supporting behavioral choice in visual discrimination tasks. To approach this question from another direction, we have now studied the relationship between the discharge of MT neurons and behavioral choice, independently of the effects of visual stimulation. We found that trial-to-trial variability in neuronal signals was correlated with the choices the monkey made. Therefore, when a directionally selective neuron in area MT fires more vigorously, the monkey is more likely to make a decision in favor of the preferred direction of the cell. The magnitude of the relationship was modest, on average, but was highly significant across a sample of 299 cells from four monkeys. The relationship was present for all stimuli (including those without a net motion signal), and for all but the weakest responses. The relationship was reduced or eliminated when the demands of the task were changed so that the directional signal carried by the cell was less informative. The relationship was evident within 50 ms of response onset, and persisted throughout the stimulus presentation. On average, neurons that were more sensitive to weak motion signals had a stronger relationship to behavior than those that were less sensitive. These observations are consistent with the idea that neuronal signals in MT are used by the monkey to determine the direction of stimulus motion. The modest relationship between behavioral choice and the discharge of any one neuron, and the prevalence of the relationship across the population, make it likely that signals from many neurons are pooled to form the data on which behavioral choices are based.


2011 ◽  
Vol 31 (10) ◽  
pp. 3894-3903 ◽  
Author(s):  
C. R. Ponce ◽  
J. N. Hunter ◽  
C. C. Pack ◽  
S. G. Lomber ◽  
R. T. Born

2002 ◽  
Vol 88 (6) ◽  
pp. 3469-3476 ◽  
Author(s):  
Richard J. A. Van Wezel ◽  
Kenneth H. Britten

In many sensory systems, exposure to a prolonged stimulus causes adaptation, which tends to reduce neural responses to subsequent stimuli. Such effects are usually stimulus-specific, making adaptation a powerful probe into information processing. We used dynamic random dot kinematograms to test the magnitude and selectivity of adaptation effects in the middle temporal area (MT) and to compare them to effects on human motion discrimination. After 3 s of adaptation to a random dot pattern moving in the preferred direction, MT neuronal responses to subsequent test patterns were reduced by 26% on average compared with adaptation to a static pattern. This reduction in response magnitude was largely independent of what test stimulus was presented. However, adaptation in the opposite direction changed responses less often and very inconsistently. Therefore motion adaptation systematically and profoundly affects the neurons in MT representing the adapted direction, but much less those representing the opposite direction. In human psychophysical experiments, such adapting stimuli affected direction discrimination, biasing choices away from the adaptation direction. The magnitude of this perceptual shift was consistent with the magnitude of the changes seen in area MT, if one assumes that a motion comparison step occurs after MT.


1999 ◽  
Vol 81 (6) ◽  
pp. 2764-2786 ◽  
Author(s):  
Krishna V. Shenoy ◽  
David C. Bradley ◽  
Richard A. Andersen

Influence of gaze rotation on the visual response of primate MSTd neurons. When we move forward, the visual image on our retina expands. Humans rely on the focus, or center, of this expansion to estimate their direction of heading and, as long as the eyes are still, the retinal focus corresponds to the heading. However, smooth rotation of the eyes adds nearly uniform visual motion to the expanding retinal image and causes a displacement of the retinal focus. In spite of this, humans accurately judge their heading during pursuit eye movements and during active, smooth head rotations even though the retinal focus no longer corresponds to the heading. Recent studies in macaque suggest that correction for pursuit may occur in the dorsal aspect of the medial superior temporal area (MSTd) because these neurons are tuned to the retinal position of the focus and they modify their tuning during pursuit to compensate partially for the focus shift. However, the question remains whether these neurons also shift focus tuning to compensate for smooth head rotations that commonly occur during gaze tracking. To investigate this question, we recorded from 80 MSTd neurons while monkeys tracked a visual target either by pursuing with their eyes or by vestibulo-ocular reflex cancellation (VORC; whole-body rotation with eyes fixed in head and head fixed on body). VORC is a passive, smooth head rotation condition that selectively activates the vestibular canals. We found that neurons shift their focus tuning in a similar way whether focus displacement is caused by pursuit or by VORC. Across the population, compensation averaged 88 and 77% during pursuit and VORC, respectively (tuning shift divided by the retinal focus to true heading difference). Moreover the degree of compensation during pursuit and VORC was correlated in individual cells ( P< 0.001). Finally neurons that did not compensate appreciably tended to be gain-modulated during pursuit and VORC and may constitute an intermediate stage in the compensation process. These results indicate that many MSTd cells compensate for general gaze rotation, whether produced by eye-in-head or head-in-world rotation, and further implicate MSTd as a critical stage in the computation of heading. Interestingly vestibular cues present during VORC allow many cells to compensate even though humans do not accurately judge their heading in this condition. This suggests that MSTd may use vestibular information to create a compensated heading representation within at least a subpopulation of cells, which is accessed perceptually only when additional cues related to active head rotations are also present.


1993 ◽  
Vol 69 (4) ◽  
pp. 1314-1322 ◽  
Author(s):  
T. X. Fan ◽  
A. F. Rosenberg ◽  
M. Ariel

1. Single units were recorded extracellularly in the turtle's cerebellar cortex from an isolated brain preparation during visual stimulation. Only a small fraction of the isolated units responded to visual stimuli. For these visually responsive units, the most effective visual stimulus was a moving check pattern that covered the entire surface of the retinal eyecup. The visually responsive units had little or no spontaneous spike activity, nor were they driven by flashes of diffuse light or stationary patterns. 2. All the visually responsive units were direction sensitive and were driven exclusively by the contralateral eye. This direction tuning was well fit by a limacon model (mean correlation coefficient, 0.89). The distribution of the entire sample indicates a slight preponderance of upward preferred directions. 3. The direction tuning of these cerebellar units was independent of stimulus contrast or the pattern's configuration (such as checkerboards or random check or dot patterns). In the preferred direction, a unit's spike frequency increased monotonically as a function of stimulus velocity until approximately 10 degrees/s, but remained direction sensitive (relative to the opposite direction) at speeds as fast as 100 degrees/s. 4. In some experiments the ventrocaudal brain stem was transected in the frontal plane just caudal to the cerebellar peduncles. Although this lesion presumably removes climbing fiber input from the inferior olivary nuclei, the visual-response properties in the cerebellar cortex were unaffected. 5. The response properties of these units indicate that they encode retinal slip information in the cerebellum.(ABSTRACT TRUNCATED AT 250 WORDS)


1998 ◽  
Vol 80 (1) ◽  
pp. 282-296 ◽  
Author(s):  
Satoshi Eifuku ◽  
Robert H. Wurtz

Eifuku, Satoshi and Robert H. Wurtz. Response to motion in extrastriate area MSTl: center-surround interactions. J. Neurophysiol. 80: 282–296, 1998. The medial superior temporal area of the macaque monkey extrastriate visual cortex can be divided into a dorsal medial (MSTd) and a lateral ventral (MSTl) region. The functions of the two regions may not be identical: MSTd may process optic flow information that results from the movement of the observer, whereas MSTl may be related more closely to processing visual motion related specifically to the motion of objects. If MSTl were related to such object motion, one would expect to see mechanisms for the segregation of objects from their surround. We investigated one of these mechanisms in MSTl neurons: the effect of stimuli falling in the region surrounding the receptive field center on the response to stimuli falling in the field center. We found the effects of the surround stimulation to be modulatory with little response to the surround stimulus itself but a clear effect on the response to the stimulus falling on the receptive field center. The response to motion in the center in the direction preferred for the neuron usually increased when the surround motion was in the opposite direction to that in the center and decreased when surround motion was in the same direction as that in the center. Fifty-seven percent of the neurons showed a ratio of response for center motion with a surround moving in the opposite direction to that in the center for center motion alone that was >1. The response to motion in the center also increased when the surround stimulus was stationary, and this increase was sometimes larger than that with a moving surround. Nearly 70% of the neurons showed a ratio of response to center motion with a stationary surround to center motion alone that was >1. This is in contrast to the minimal effect of stationary surrounds in middle temporal area neurons. When the stimulus presentation was reversed so that the stimulus in the center was stationary and the surround moved, some MSTl neurons responded when the direction of motion in the surround was in the direction opposite to the preferred direction of motion in the center of the receptive field. Stimulation of the surround thus had a profound effect on the response of MSTl neurons, and this pronounced effect of the surround is consistent with a role in the segmentation of objects using motion.


2016 ◽  
Vol 116 (1) ◽  
pp. 210-217 ◽  
Author(s):  
Seiji Ono ◽  
Michael J. Mustari

Visual motion neurons in the posterior parietal cortex play a critical role in the guidance of smooth pursuit eye movements. Initial pursuit (open-loop period) is driven, in part, by visual motion signals from cortical areas, such as the medial superior temporal area (MST). The purpose of this study was to determine whether adaptation of initial pursuit gain arises because of altered visual sensitivity of neurons at the cortical level. It is well known that the visual motion response in MST is suppressed after exposure to a large-field visual motion stimulus, showing visual motion adaptation. One hypothesis is that foveal motion responses in MST are associated with smooth pursuit adaptation using a small target spot. We used a step-ramp tracking task with two steps of target velocity (double-step paradigm), which induces gain-down or gain-up adaptation. We found that after gain-down adaptation 58% of our MST visual neurons showed a significant decrease in firing rate. This was the case even though visual motion input (before the pursuit onset) from target motion was constant. Therefore, repetitive visual stimulation during the gain-down paradigm could lead to adaptive changes in the visual response. However, the time course of adaptation did not show a correlation between the visual response and pursuit behavior. These results indicate that the visual response in MST may not directly contribute to the adaptive change in pursuit initiation.


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