The role of the posterior parietal cortex in coordinate transformations for visual–motor integration

1988 ◽  
Vol 66 (4) ◽  
pp. 488-501 ◽  
Author(s):  
Richard A. Andersen ◽  
David Zipser
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Visual Stimuli ◽  
Back Propagation ◽  
Spatial Location ◽  
Eye Position ◽  
Area 7A ◽  
Posterior Parietal ◽  
Visual Motor

Lesion to the posterior parietal cortex in monkeys and humans produces spatial deficits in movement and perception. In recording experiments from area 7a, a cortical subdivision in the posterior parietal cortex in monkeys, we have found neurons whose responses are a function of both the retinal location of visual stimuli and the position of the eyes in the orbits. By combining these signals area 7a neurons code the location of visual stimuli with respect to the head. However, these cells respond over only limited ranges of eye positions (eye-position-dependent coding). To code location in craniotopic space at all eye positions (eye-position-independent coding) an additional step in neural processing is required that uses information distributed across populations of area 7a neurons. We describe here a neural network model, based on back-propagation learning, that both demonstrates how spatial location could be derived from the population response of area 7a neurons and accurately accounts for the observed response properties of these neurons.

scholarly journals Neural Representation During Visually Guided Reaching in Macaque Posterior Parietal Cortex

2010 ◽  
Vol 104 (6) ◽  
pp. 3494-3509 ◽  
Author(s):  
Barbara Heider ◽  
Anushree Karnik ◽  
Nirmala Ramalingam ◽  
Ralph M. Siegel
Keyword(s):  
Firing Rate ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Neural Representation ◽  
Eye Position ◽  
Visually Guided ◽  
Task Condition ◽  
Visually Guided Reaching ◽  
Area 7A ◽  
Posterior Parietal

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.

Covert attention suppresses neuronal responses in area 7a of the posterior parietal cortex

1994 ◽  
Vol 72 (2) ◽  
pp. 1020-1023 ◽  
Author(s):  
M. A. Steinmetz ◽  
C. E. Connor ◽  
C. Constantinidis ◽  
J. R. McLaughlin
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Potential Role ◽  
Visual Stimuli ◽  
Covert Attention ◽  
Neuronal Responses ◽  
Central Target ◽  
Match To Sample ◽  
Area 7A ◽  
Posterior Parietal

1. The effect of covert attention was studied in area 7a of the posterior parietal cortex of rhesus monkeys performing a spatial match-to-sample task. The task required the animals to fixate a central target light, to detect and remember the location of a transient spatial cue, and to respond when one of a series of stimuli appeared at the cued location. Neuronal responses evoked by the visual stimuli were recorded during each behavioral trial. 2. Thirty-eight percent of the neurons isolated and studied in these experiments responded to visual stimuli. The responses of 55% of the neurons tested were suppressed, and 5% enhanced for stimuli presented at the attended location. Responses in the remaining neurons (40%) were unaffected by shifts in attention. 3. Activity in 57% of the suppressed neurons was reduced to rates not significantly different from spontaneous activity. 4. The extent of suppression for individual neurons was often restricted to the attended portion of the receptive field. 5. These data suggest a potential role for these neurons in the redirection of visual attention.

Transcranial Magnetic Stimulation Disrupts Eye-Hand Interactions in the Posterior Parietal Cortex

2000 ◽  
Vol 84 (3) ◽  
pp. 1677-1680 ◽  
Author(s):  
Paul Van Donkelaar ◽  
Ji-Hang Lee ◽  
Anthony S. Drew
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Hand Movement ◽  
Open Loop ◽  
Neurophysiological Studies ◽  
Posterior Parietal ◽  
Hand Coordination

Recent neurophysiological studies have started to shed some light on the cortical areas that contribute to eye-hand coordination. In the present study we investigated the role of the posterior parietal cortex (PPC) in this process in normal, healthy subjects. This was accomplished by delivering single pulses of transcranial magnetic stimulation (TMS) over the PPC to transiently disrupt the putative contribution of this area to the processing of information related to eye-hand coordination. Subjects made open-loop pointing movements accompanied by saccades of the same required amplitude or by saccades that were substantially larger. Without TMS the hand movement amplitude was influenced by the amplitude of the corresponding saccade; hand movements accompanied by larger saccades were larger than those accompanied by smaller saccades. When TMS was applied over the left PPC just prior to the onset of the saccade, a marked reduction in the saccadic influence on manual motor output was observed. TMS delivered at earlier or later periods during the response had no effect. Taken together, these data suggest that the PPC integrates signals related to saccade amplitude with limb movement information just prior to the onset of the saccade.

Role of the posterior parietal cortex in updating reaching movements to a visual target

10.1038/9219 ◽  
1999 ◽  
Vol 2 (6) ◽  
pp. 563-567 ◽  
Author(s):  
M. Desmurget ◽  
C. M. Epstein ◽  
R. S. Turner ◽  
C. Prablanc ◽  
G. E. Alexander ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Visual Target ◽  
Reaching Movements ◽  
Posterior Parietal

scholarly journals Transcranial Magnetic Stimulation Over the Human Medial Posterior Parietal Cortex Disrupts Depth Encoding During Reach Planning

2020 ◽  
Vol 31 (1) ◽  
pp. 267-280
Author(s):  
Rossella Breveglieri ◽  
Annalisa Bosco ◽  
Sara Borgomaneri ◽  
Alessia Tessari ◽  
Claudio Galletti ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Critical Role ◽  
The Body ◽  
Visually Guided ◽  
Visually Guided Reaching ◽  
Posterior Parietal

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.

Sign in / Sign up

Export Citation Format

Share Document