Optical imaging of visually guided reaching in macaque posterior parietal cortex

2013 ◽  
Vol 219 (2) ◽  
pp. 495-509 ◽  
Author(s):  
Barbara Heider ◽  
Ralph M. Siegel
2020 ◽  
Vol 31 (1) ◽  
pp. 267-280
Author(s):  
Rossella Breveglieri ◽  
Annalisa Bosco ◽  
Sara Borgomaneri ◽  
Alessia Tessari ◽  
Claudio Galletti ◽  
...  

Abstract Accumulating evidence supports the view that the medial part of the posterior parietal cortex (mPPC) is involved in the planning of reaching, but while plenty of studies investigated reaching performed toward different directions, only a few studied different depths. Here, we investigated the causal role of mPPC (putatively, human area V6A–hV6A) in encoding depth and direction of reaching. Specifically, we applied single-pulse transcranial magnetic stimulation (TMS) over the left hV6A at different time points while 15 participants were planning immediate, visually guided reaching by using different eye-hand configurations. We found that TMS delivered over hV6A 200 ms after the Go signal affected the encoding of the depth of reaching by decreasing the accuracy of movements toward targets located farther with respect to the gazed position, but only when they were also far from the body. The effectiveness of both retinotopic (farther with respect to the gaze) and spatial position (far from the body) is in agreement with the presence in the monkey V6A of neurons employing either retinotopic, spatial, or mixed reference frames during reach plan. This work provides the first causal evidence of the critical role of hV6A in the planning of visually guided reaching movements in depth.


2010 ◽  
Vol 104 (6) ◽  
pp. 3494-3509 ◽  
Author(s):  
Barbara Heider ◽  
Anushree Karnik ◽  
Nirmala Ramalingam ◽  
Ralph M. Siegel

Visually guided hand movements in primates require an interconnected network of various cortical areas. Single unit firing rate from area 7a and dorsal prelunate (DP) neurons of macaque posterior parietal cortex (PPC) was recorded during reaching movements to targets at variable locations and under different eye position conditions. In the eye position–varied task, the reach target was always foveated; thus eye position varied with reach target location. In the retinal-varied task, the monkey reached to targets at variable retinotopic locations while eye position was kept constant in the center. Spatial tuning was examined with respect to temporal (task epoch) and contextual (task condition) aspects, and response fields were compared. The analysis showed distinct tuning types. The majority of neurons changed their gain field tuning and retinotopic tuning between different phases of the task. Between the onset of visual stimulation and the preparatory phase (before the go signal), about one half the neurons altered their firing rate significantly. Spatial response fields during preparation and initiation epochs were strongly influenced by the task condition (eye position varied vs. retinal varied), supporting a strong role of eye position during visually guided reaching. DP neurons, classically considered visual, showed reach related modulation similar to 7a neurons. This study shows that both area 7a and DP are modulated during reaching behavior in primates. The various tuning types in both areas suggest distinct populations recruiting different circuits during visually guided reaching.


Nature ◽  
1996 ◽  
Vol 383 (6601) ◽  
pp. 618-621 ◽  
Author(s):  
Dottie M. Clower ◽  
John M. Hoffman ◽  
John R. Votaw ◽  
Tracy L. Faber ◽  
Roger P. Woods ◽  
...  

2009 ◽  
Vol 102 (6) ◽  
pp. 3433-3446 ◽  
Author(s):  
Leighton B. N. Hinkley ◽  
Leah A. Krubitzer ◽  
Jeff Padberg ◽  
Elizabeth A. Disbrow

Areas of human posterior parietal cortex (PPC) specialized for processing sensorimotor information associated with visually locating an object, reaching to grasp, and manually exploring that object were examined using functional MRI. Cortical activation was observed in response to three tasks: 1) saccadic eye movements, 2) visually guided reaching to grasp, and 3) manual shape discrimination. During saccadic eye movements, cortical fields within the lateral and rostral superior parietal lobe (SPL) and the caudal SPL and parieto-occipital boundary were active. During visually guided reaching to grasp, regions of cortex within the postcentral sulcus (PoCS) and rostral intraparietal sulcus (IPS) were active, as well as the caudal SPL of the left hemisphere and the medial and caudal IPS of the right hemisphere. Cortical regions at the junction of the IPS and PoCS and an area in the medial SPL were active bilaterally during shape manipulation. Only a few regions were most active during a single motor behavior, whereas several areas were highly active during two or more tasks. Hemispheric asymmetries in activation patterns were observed during visually guided reaching to grasp. The gross areal organization of human PPC is likely similar to the pattern previously described in nonhuman primates, including multifunctional regions and asymmetric processing of some manual abilities.


1998 ◽  
Vol 79 (5) ◽  
pp. 2814-2819 ◽  
Author(s):  
Lawrence H. Snyder ◽  
Aaron P. Batista ◽  
Richard A. Andersen

Snyder, Lawrence H., Aaron P. Batista, and Richard A. Andersen. Change in motor plan, without a change in the spatial locus of attention, modulates activity in posterior parietal cortex. J. Neurophysiol. 79: 2814–2819, 1998. The lateral intraparietal area (LIP) of macaque monkey, and a parietal reach region (PRR) medial and posterior to LIP, code the intention to make visually guided eye and arm movements, respectively. We studied the effect of changing the motor plan, without changing the locus of attention, on single neurons in these two areas. A central target was fixated while one or two sequential flashes occurred in the periphery. The first appeared either within the response field of the neuron being recorded or else on the opposite side of the fixation point. Animals planned a saccade (red flash) or reach (green flash) to the flash location. In some trials, a second flash 750 ms later could change the motor plan but never shifted attention: second flashes always occurred at the same location as the preceding first flash. Responses in LIP were larger when a saccade was instructed ( n = 20 cells), whereas responses in PRR were larger when a reach was instructed ( n = 17). This motor preference was observed for both first flashes and second flashes. In addition, the response to a second flash depended on whether it affirmed or countermanded the first flash; second flash responses were diminished only in the former case. Control experiments indicated that this differential effect was not due to stimulus novelty. These findings support a role for posterior parietal cortex in coding specific motor intention and are consistent with a possible role in the nonspatial shifting of motor intention.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Michael Krumin ◽  
Julie J Lee ◽  
Kenneth D Harris ◽  
Matteo Carandini

Posterior parietal cortex (PPC) has been implicated in navigation, in the control of movement, and in visually-guided decisions. To relate these views, we measured activity in PPC while mice performed a virtual navigation task driven by visual decisions. PPC neurons were selective for specific combinations of the animal's spatial position and heading angle. This selectivity closely predicted both the activity of individual PPC neurons, and the arrangement of their collective firing patterns in choice-selective sequences. These sequences reflected PPC encoding of the animal’s navigation trajectory. Using decision as a predictor instead of heading yielded worse fits, and using it in addition to heading only slightly improved the fits. Alternative models based on visual or motor variables were inferior. We conclude that when mice use vision to choose their trajectories, a large fraction of parietal cortex activity can be predicted from simple attributes such as spatial position and heading.


2007 ◽  
Vol 97 (3) ◽  
pp. 2339-2354 ◽  
Author(s):  
Kim Lajoie ◽  
Trevor Drew

We developed a novel locomotor task in which cats step over obstacles that move at a different speed from that of the treadmill on which the cat is walking: we refer to this as a visual dissociation locomotion task. Slowing the speed of the obstacle with respect to that of the treadmill sometimes led to a major change in strategy so that cats made two steps with the hindlimbs before stepping over the obstacle (double step strategy) instead of the single step (standard strategy) observed when the obstacle was at the same speed as the treadmill. In addition, in the step preceding the step over the obstacle, the paws were placed significantly closer to the obstacle in the visual dissociation task than when the treadmill and the obstacle were at the same speed. After unilateral lesion of area 5 of the posterior parietal cortex (PPC), the cats frequently hit the obstacle as they stepped over it, especially in the visual dissociation task. This locomotor deficit was linked to significant differences in the location in which the forelimbs were placed in the step preceding that over the obstacle compared with the prelesion control. Cats also frequently hit the obstacle with their hindlimbs even when the forelimbs negotiated the obstacle successfully; this suggests an important role for the posterior parietal cortex in the coordination of the forelimbs and hindlimbs. Together, these results suggest an important contribution of the PPC to the planning of visually guided gait modifications.


2010 ◽  
Vol 103 (2) ◽  
pp. 986-1006 ◽  
Author(s):  
Jacques-Étienne Andujar ◽  
Kim Lajoie ◽  
Trevor Drew

We tested the hypothesis that area 5 of the posterior parietal cortex (PPC) contributes to the planning of visually guided gait modifications. We recorded 121 neurons from the PPC of two cats during a task in which cats needed to process visual input to step over obstacles attached to a moving treadmill belt. During unobstructed locomotion, 64/121 (53%) of cells showed rhythmic activity. During steps over the obstacles, 102/121 (84%) of cells showed a significant change of their activity. Of these, 46/102 were unmodulated during the control task. We divided the 102 task-related cells into two groups on the basis of their discharge when the limb contralateral to the recording site was the first to pass over the obstacle. One group (41/102) was characterized by a brief, phasic discharge as the lead forelimb passed over the obstacle (Step-related cells). These cells were recorded primarily from area 5a. The other group (61/102) showed a progressive increase in activity prior to the onset of the swing phase in the modified limb and frequently diverged from control at least one step cycle before the gait modification (Step-advanced cells). Most of these cells were recorded in area 5b. In both groups, some cells maintained a fixed relationship to the activity of the contralateral forelimb regardless of which limb was the first to pass over the obstacle (limb-specific cells), whereas others changed their phase of activity so that they were always related to activity of the first limb to pass over the obstacle, either contralateral or ipsilateral (limb-independent cells). Limb-independent cells were more common among the Step-advanced cell population. We suggest that both populations of cells contribute to the gait modification and that the discharge characteristics of the Step-advanced cells are compatible with a contribution to the planning of the gait modification.


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