scholarly journals Virtual Lesion of Angular Gyrus Disrupts the Relationship between Visuoproprioceptive Weighting and Realignment

2013 ◽  
Vol 25 (4) ◽  
pp. 636-648 ◽  
Author(s):  
Hannah Block ◽  
Amy Bastian ◽  
Pablo Celnik
Keyword(s):  
Posterior Parietal Cortex ◽  
Angular Gyrus ◽  
Hand Position ◽  
Proprioceptive Information ◽  
Neural Pathways ◽  
Virtual Lesion ◽  
Sensory Weighting ◽  
Posterior Parietal ◽  
Common Substrate ◽  
The Relationship

Posterior parietal cortex is thought to be involved in multisensory processes such as sensory weighting (how much different modalities are represented in sensory integration) and realignment (recalibrating the estimates given by unisensory inputs relative to each other, e.g., when viewing the hand through prisms). Sensory weighting and realignment are biologically independent but can be correlated such that the lowest-weighted modality realigns most. This is important for movement precision because it results in the brain's estimate of hand position favoring the more reliable (higher-weighted) modality. It is unknown if this interaction is an emergent property of separate neural pathways for weighting and realignment or if it is actively mediated by a common substrate. We applied disruptive TMS to the angular gyrus near the intraparietal sulcus (PGa) before participants performed a task with misaligned visual and proprioceptive information about hand position. Visuoproprioceptive weighting and realignment were unaffected. However, the relationship between weighting and realignment, found in control conditions, was absent after TMS in the angular gyrus location. This suggests that a specific region in the angular gyrus actively mediates the interaction between visuoproprioceptive weighting and realignment and may thus play a role in the decreased movement precision associated with posterior parietal lesions.

Transcranial Magnetic Stimulation Over Human Dorsal–Lateral Posterior Parietal Cortex Disrupts Integration of Hand Position Signals Into the Reach Plan

2008 ◽  
Vol 100 (4) ◽  
pp. 2005-2014 ◽  
Author(s):  
Michael Vesia ◽  
Xiaogang Yan ◽  
Denise Y. Henriques ◽  
Lauren E. Sergio ◽  
J. D. Crawford
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Visual Feedback ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Internal Representation ◽  
Hand Position ◽  
Proprioceptive Information ◽  
New Findings ◽  
Posterior Parietal

Posterior parietal cortex (PPC) has been implicated in the integration of visual and proprioceptive information for the planning of action. We previously reported that single-pulse transcranial magnetic stimulation (TMS) over dorsal–lateral PPC perturbs the early stages of spatial processing for memory-guided reaching. However, our data did not distinguish whether TMS disrupted the reach goal or the internal estimate of initial hand position needed to calculate the reach vector. To test between these hypotheses, we investigated reaching in six healthy humans during left and right parietal TMS while varying visual feedback of the movement. We reasoned that if TMS were disrupting the internal representation of hand position, visual feedback from the hand might still recalibrate this signal. We tested four viewing conditions: 1) final vision of hand position; 2) full vision of hand position; 3) initial and final vision of hand position; and 4) middle and final vision of hand position. During the final vision condition, left parietal stimulation significantly increased endpoint variability, whereas right parietal stimulation produced a significant leftward shift in both visual fields. However, these errors significantly decreased with visual feedback of the hand during both planning and control stages of the reach movement. These new findings demonstrate that 1) visual feedback of hand position during the planning and early execution of the reach can recalibrate the perturbed signal and, importantly, and 2) TMS over dorsal–lateral PPC does not disrupt the internal representation of the visual goal, but rather the reach vector, or more likely the sense of initial hand position that is used to calculate this vector.

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.

Reaching-related Neurons in Superior Parietal Area 5: Influence of the Target Visibility

2016 ◽  
Vol 28 (11) ◽  
pp. 1828-1837 ◽  
Author(s):  
Emiliano Brunamonti ◽  
Aldo Genovesio ◽  
Pierpaolo Pani ◽  
Roberto Caminiti ◽  
Stefano Ferraina
Keyword(s):  
Visual Information ◽  
Posterior Parietal Cortex ◽  
Hand Movement ◽  
Visual Signals ◽  
Hand Position ◽  
Movement Initiation ◽  
Starting Position ◽  
Area 5 ◽  
Posterior Parietal ◽  
Target Visibility

Reaching movements require the integration of both somatic and visual information. These signals can have different relevance, depending on whether reaches are performed toward visual or memorized targets. We tested the hypothesis that under such conditions, therefore depending on target visibility, posterior parietal neurons integrate differently somatic and visual signals. Monkeys were trained to execute both types of reaches from different hand resting positions and in total darkness. Neural activity was recorded in Area 5 (PE) and analyzed by focusing on the preparatory epoch, that is, before movement initiation. Many neurons were influenced by the initial hand position, and most of them were further modulated by the target visibility. For the same starting position, we found a prevalence of neurons with activity that differed depending on whether hand movement was performed toward memorized or visual targets. This result suggests that posterior parietal cortex integrates available signals in a flexible way based on contextual demands.

rTMS-induced virtual lesion of the posterior parietal cortex (PPC) alters the control of reflexive shifts of social attention triggered by pointing hands

2014 ◽  
Vol 59 ◽  
pp. 148-156 ◽  
Author(s):  
Giuseppina Porciello ◽  
Filippo Crostella ◽  
Marco Tullio Liuzza ◽  
Elia Valentini ◽  
Salvatore Maria Aglioti
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Social Attention ◽  
Virtual Lesion ◽  
Posterior Parietal

The time course for visual extinction after a ‘virtual’ lesion of right posterior parietal cortex

2015 ◽  
Vol 98 ◽  
pp. 27-34 ◽  
Author(s):  
Michael Vesia ◽  
Matthias Niemeier ◽  
Sandra E. Black ◽  
W. Richard Staines
Keyword(s):  
Parietal Cortex ◽  
Time Course ◽  
Posterior Parietal Cortex ◽  
Visual Extinction ◽  
Virtual Lesion ◽  
Posterior Parietal

scholarly journals TMS over posterior parietal cortex disrupts the integration of initial hand position information into the reach plan

2010 ◽  
Vol 7 (9) ◽  
pp. 293-293
Author(s):  
M. Vesia ◽  
D. Henriques ◽  
X. Yan ◽  
L. Sergio ◽  
J. D. Crawford
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Hand Position ◽  
Position Information ◽  
Posterior Parietal

Somatosensory processes subserving perception and action

2007 ◽  
Vol 30 (2) ◽  
pp. 189-201 ◽  
Author(s):  
H. Chris Dijkerman ◽  
Edward H. F. de Haan
Keyword(s):  
Information Processing ◽  
Object Recognition ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Perception And Action ◽  
Somatosensory System ◽  
The Body ◽  
Proprioceptive Information ◽  
Tactile Information ◽  
Posterior Parietal

AbstractThe functions of the somatosensory system are multiple. We use tactile input to localize and experience the various qualities of touch, and proprioceptive information to determine the position of different parts of the body with respect to each other, which provides fundamental information for action. Further, tactile exploration of the characteristics of external objects can result in conscious perceptual experience and stimulus or object recognition. Neuroanatomical studies suggest parallel processing as well as serial processing within the cerebral somatosensory system that reflect these separate functions, with one processing stream terminating in the posterior parietal cortex (PPC), and the other terminating in the insula. We suggest that, analogously to the organisation of the visual system, somatosensory processing for the guidance of action can be dissociated from the processing that leads to perception and memory. In addition, we find a second division between tactile information processing about external targets in service of object recognition and tactile information processing related to the body itself. We suggest the posterior parietal cortex subserves both perception and action, whereas the insula principally subserves perceptual recognition and learning.

Observing Others Speak or Sing Activates Spt and Neighboring Parietal Cortex

2017 ◽  
Vol 29 (6) ◽  
pp. 1002-1021 ◽  
Author(s):  
Daniele Corbo ◽  
Guy A. Orban
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Vocal Communication ◽  
Action Observation ◽  
Angular Gyrus ◽  
Ventral Part ◽  
Parietal Region ◽  
Action Execution ◽  
Localize Area ◽  
Posterior Parietal

To obtain further evidence that action observation can serve as a proxy for action execution and planning in posterior parietal cortex, we scanned participants while they were (1) observing two classes of action: vocal communication and oral manipulation, which share the same effector but differ in nature, and (2) rehearsing and listening to nonsense sentences to localize area Spt, thought to be involved in audio-motor transformation during speech. Using this localizer, we found that Spt is specifically activated by vocal communication, indicating that Spt is not only involved in planning speech but also in observing vocal communication actions. In addition, we observed that Spt is distinct from the parietal region most specialized for observing vocal communication, revealed by an interaction contrast and located in PFm. The latter region, unlike Spt, processes the visual and auditory signals related to other's vocal communication independently. Our findings are consistent with the view that several small regions in the temporoparietal cortex near the ventral part of the supramarginal/angular gyrus border are involved in the planning of vocal communication actions and are also concerned with observation of these actions, though involvements in those two aspects are unequal.

Sign in / Sign up

Export Citation Format

Share Document