scholarly journals Neurophysiology of Prehension. III. Representation of Object Features in Posterior Parietal Cortex of the Macaque Monkey

2007 ◽  
Vol 98 (6) ◽  
pp. 3708-3730 ◽  
Author(s):  
Esther P. Gardner ◽  
K. Srinivasa Babu ◽  
Soumya Ghosh ◽  
Adam Sherwood ◽  
Jessie Chen
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Macaque Monkey ◽  
Firing Rates ◽  
Video Recordings ◽  
Object Properties ◽  
Area 5 ◽  
Somatosensory Input ◽  
Posterior Parietal ◽  
Object Features

Neurons in posterior parietal cortex (PPC) may serve both proprioceptive and exteroceptive functions during prehension, signaling hand actions and object properties. To assess these roles, we used digital video recordings to analyze responses of 83 hand-manipulation neurons in area 5 as monkeys grasped and lifted objects that differed in shape (round and rectangular), size (large and small spheres), and location (identical rectangular blocks placed lateral and medial to the shoulder). The task contained seven stages—approach, contact, grasp, lift, hold, lower, relax—plus a pretrial interval. The four test objects evoked similar spike trains and mean rate profiles that rose significantly above baseline from approach through lift, with peak activity at contact. Although representation by the spike train of specific hand actions was stronger than distinctions between grasped objects, 34% of these neurons showed statistically significant effects of object properties or hand postures on firing rates. Somatosensory input from the hand played an important role as firing rates diverged most prominently on contact as grasp was secured. The small sphere—grasped with the most flexed hand posture—evoked the highest firing rates in 43% of the population. Twenty-one percent distinguished spheres that differed in size and weight, and 14% discriminated spheres from rectangular blocks. Location in the workspace modulated response amplitude as objects placed across the midline evoked higher firing rates than positions lateral to the shoulder. We conclude that area 5 neurons, like those in area AIP, integrate object features, hand actions, and grasp postures during prehension.

scholarly journals Neural Representation of Hand Kinematics During Prehension in Posterior Parietal Cortex of the Macaque Monkey

2009 ◽  
Vol 102 (6) ◽  
pp. 3310-3328 ◽  
Author(s):  
Jessie Chen ◽  
Shari D. Reitzen ◽  
Jane B. Kohlenstein ◽  
Esther P. Gardner
Keyword(s):  
Parietal Cortex ◽  
Muscle Activation ◽  
Posterior Parietal Cortex ◽  
Macaque Monkey ◽  
Neural Representation ◽  
Firing Rates ◽  
Hand Kinematics ◽  
Object Properties ◽  
Area 5 ◽  
Posterior Parietal

Studies of hand manipulation neurons in posterior parietal cortex of monkeys suggest that their spike trains represent objects by the hand postures needed for grasping or by the underlying patterns of muscle activation. To analyze the role of hand kinematics and object properties in a trained prehension task, we correlated the firing rates of neurons in anterior area 5 with hand behaviors as monkeys grasped and lifted knobs of different shapes and locations in the workspace. Trials were divided into four classes depending on the approach trajectory: forward, lateral, and local approaches, and regrasps. The task factors controlled by the animal—how and when he used the hand—appeared to play the principal roles in modulating firing rates of area 5 neurons. In all, 77% of neurons studied (58/75) showed significant effects of approach style on firing rates; 80% of the population responded at higher rates and for longer durations on forward or lateral approaches that included reaching, wrist rotation, and hand preshaping prior to contact, but only 13% distinguished the direction of reach. The higher firing rates in reach trials reflected not only the arm movements needed to direct the hand to the target before contact, but persisted through the contact, grasp, and lift stages. Moreover, the approach style exerted a stronger effect on firing rates than object features, such as shape and location, which were distinguished by half of the population. Forty-three percent of the neurons signaled both the object properties and the hand actions used to acquire them. However, the spread in firing rates evoked by each knob on reach and no-reach trials was greater than distinctions between different objects grasped with the same approach style. Our data provide clear evidence for synergies between reaching and grasping that may facilitate smooth, coordinated actions of the arm and hand.

scholarly journals Neurophysiology of Prehension. I. Posterior Parietal Cortex and Object-Oriented Hand Behaviors

2007 ◽  
Vol 97 (1) ◽  
pp. 387-406 ◽  
Author(s):  
Esther P. Gardner ◽  
K. Srinivasa Babu ◽  
Shari D. Reitzen ◽  
Soumya Ghosh ◽  
Alice S. Brown ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Related Area ◽  
Firing Rates ◽  
Sensorimotor Transformations ◽  
Area 5 ◽  
On Line ◽  
Posterior Parietal ◽  
Neuronal Spike Trains ◽  
Task Goals

Hand manipulation neurons in areas 5 and 7b/anterior intraparietal area (AIP) of posterior parietal cortex were analyzed in three macaque monkeys during a trained prehension task. Digital video recordings of hand kinematics synchronized to neuronal spike trains were used to correlate firing rates of 128 neurons with hand actions as the animals grasped and lifted rectangular and round objects. We distinguished seven task stages: approach, contact, grasp, lift, hold, lower, and relax. Posterior parietal cortex (PPC) firing rates were highest during object acquisition; 88% of task-related area 5 neurons and 77% in AIP/7b fired maximally during stages 1, 2, or 3. Firing rates rose 200–500 ms before contact, peaked at contact, and declined after grasp was secured. 83% of area 5 neurons and 72% in AIP/7b showed significant increases in mean rates during approach as the fingers were preshaped for grasp. Somatosensory signals at contact provided feedback concerning the accuracy of reach and helped guide the hand to grasp sites. In error trials, tactile information was used to abort grasp, or to initiate corrective actions to achieve task goals. Firing rates declined as lift began. 41% of area 5 neurons and 38% in AIP/7b were inhibited during holding, and returned to baseline when grasp was relaxed. Anatomical connections suggest that area 5 provides somesthetic information to circuits linking AIP/7b to frontal motor areas involved in grasping. Area 5 may also participate in sensorimotor transformations coordinating reach and grasp behaviors and provide on-line feedback needed for goal-directed hand movements.

scholarly journals Change in Motor Plan, Without a Change in the Spatial Locus of Attention, Modulates Activity in Posterior Parietal Cortex

1998 ◽  
Vol 79 (5) ◽  
pp. 2814-2819 ◽  
Author(s):  
Lawrence H. Snyder ◽  
Aaron P. Batista ◽  
Richard A. Andersen
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Macaque Monkey ◽  
Case Control ◽  
Visually Guided ◽  
Lateral Intraparietal Area ◽  
Central Target ◽  
Motor Plan ◽  
Motor Intention ◽  
Posterior Parietal

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.

scholarly journals Functional organization of human posterior parietal cortex: grasping- and reaching-related activations relative to topographically organized cortex

2013 ◽  
Vol 109 (12) ◽  
pp. 2897-2908 ◽  
Author(s):  
Christina S. Konen ◽  
Ryan E. B. Mruczek ◽  
Jessica L. Montoya ◽  
Sabine Kastner
Keyword(s):  
Neural Networks ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Functional Organization ◽  
Macaque Monkey ◽  
Superior Parietal Lobule ◽  
Movement Type ◽  
The Neural Networks ◽  
Posterior Parietal ◽  
The Relationship

The act of reaching to grasp an object requires the coordination between transporting the arm and shaping the hand. Neurophysiological, neuroimaging, neuroanatomic, and neuropsychological studies in macaque monkeys and humans suggest that the neural networks underlying grasping and reaching acts are at least partially separable within the posterior parietal cortex (PPC). To better understand how these neural networks have evolved in primates, we characterized the relationship between grasping- and reaching-related responses and topographically organized areas of the human intraparietal sulcus (IPS) using functional MRI. Grasping-specific activation was localized to the left anterior IPS, partially overlapping with the most anterior topographic regions and extending into the postcentral sulcus. Reaching-specific activation was localized to the left precuneus and superior parietal lobule, partially overlapping with the medial aspects of the more posterior topographic regions. Although the majority of activity within the topographic regions of the IPS was nonspecific with respect to movement type, we found evidence for a functional gradient of specificity for reaching and grasping movements spanning posterior-medial to anterior-lateral PPC. In contrast to the macaque monkey, grasp- and reach-specific activations were largely located outside of the human IPS.

Comparison of neuronal firing rates in somatosensory and posterior parietal cortex during prehension

2001 ◽  
Vol 137 (3-4) ◽  
pp. 269-291 ◽  
Author(s):  
Daniel J. Debowy ◽  
Soumya Ghosh ◽  
Esther P. Gardner ◽  
Jin Y. Ro
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Neuronal Firing ◽  
Firing Rates ◽  
Posterior Parietal

Lesions of Area 5 of the Posterior Parietal Cortex in the Cat Produce Errors in the Accuracy of Paw Placement During Visually Guided Locomotion

2007 ◽  
Vol 97 (3) ◽  
pp. 2339-2354 ◽  
Author(s):  
Kim Lajoie ◽  
Trevor Drew
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Major Change ◽  
Single Step ◽  
Visually Guided ◽  
Double Step ◽  
Area 5 ◽  
Posterior Parietal ◽  
Step Over ◽  
Standard Strategy

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.

A Contribution of Area 5 of the Posterior Parietal Cortex to the Planning of Visually Guided Locomotion: Limb-Specific and Limb-Independent Effects

2010 ◽  
Vol 103 (2) ◽  
pp. 986-1006 ◽  
Author(s):  
Jacques-Étienne Andujar ◽  
Kim Lajoie ◽  
Trevor Drew
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Rhythmic Activity ◽  
Progressive Increase ◽  
Visually Guided ◽  
Step Cycle ◽  
Area 5 ◽  
Posterior Parietal ◽  
Gait Modification ◽  
Step Over

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.

Supragranular pyramidal neurones in the medial posterior parietal cortex of the macaque monkey

Neuroreport ◽  
1999 ◽  
Vol 10 (9) ◽  
pp. 1925-1929 ◽  
Author(s):  
Guy N. Elston ◽  
Rowan Tweedale ◽  
Marcello G.P. Rosa
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Macaque Monkey ◽  
Posterior Parietal
Sign in / Sign up

Export Citation Format

Share Document