scholarly journals Preparatory neuronal activity for reaching: movement planning, target location, and attentional signals converge in macaque medial posterior parietal cortex

2013 ◽  
Vol 13 (9) ◽  
pp. 351-351
Author(s):  
P. Fattori ◽  
R. Breveglieri ◽  
G. Dal Bo' ◽  
K. Hadjidimitrakis ◽  
F. Bertozzi ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Target Location ◽  
Movement Planning ◽  
Reaching Movement ◽  
Posterior Parietal

scholarly journals Dynamical Latent State Computation in the Posterior Parietal Cortex

2022 ◽  
Author(s):  
Kaushik J Lakshminarasimhan ◽  
Eric Avila ◽  
Xaq Pitkow ◽  
Dora E Angelaki
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Target Location ◽  
Neural Representation ◽  
World Model ◽  
Population Activity ◽  
The World ◽  
Neural Interactions ◽  
Posterior Parietal ◽  
Hidden States

Success in many real-world tasks depends on our ability to dynamically track hidden states of the world. To understand the underlying neural computations, we recorded brain activity in posterior parietal cortex (PPC) of monkeys navigating by optic flow to a hidden target location within a virtual environment, without explicit position cues. In addition to sequential neural dynamics and strong interneuronal interactions, we found that the hidden state -- monkey's displacement from the goal -- was encoded in single neurons, and could be dynamically decoded from population activity. The decoded estimates predicted navigation performance on individual trials. Task manipulations that perturbed the world model induced substantial changes in neural interactions, and modified the neural representation of the hidden state, while representations of sensory and motor variables remained stable. The findings were recapitulated by a task-optimized recurrent neural network model, suggesting that neural interactions in PPC embody the world model to consolidate information and track task-relevant hidden states.

scholarly journals Topographic Organization for Delayed Saccades in Human Posterior Parietal Cortex

2005 ◽  
Vol 94 (2) ◽  
pp. 1372-1384 ◽  
Author(s):  
Denis Schluppeck ◽  
Paul Glimcher ◽  
David J. Heeger
Keyword(s):  
Visual Field ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Target Location ◽  
Critical Role ◽  
Topographic Maps ◽  
Field Orientation ◽  
Topographic Organization ◽  
Motor Intention ◽  
Posterior Parietal

Posterior parietal cortex (PPC) is thought to play a critical role in decision making, sensory attention, motor intention, and/or working memory. Research on the PPC in non-human primates has focused on the lateral intraparietal area (LIP) in the intraparietal sulcus (IPS). Neurons in LIP respond after the onset of visual targets, just before saccades to those targets, and during the delay period in between. To study the function of posterior parietal cortex in humans, it will be crucial to have a routine and reliable method for localizing specific parietal areas in individual subjects. Here, we show that human PPC contains at least two topographically organized regions, which are candidates for the human homologue of LIP. We mapped the topographic organization of human PPC for delayed (memory guided) saccades using fMRI. Subjects were instructed to fixate centrally while a peripheral target was briefly presented. After a further 3-s delay, subjects made a saccade to the remembered target location followed by a saccade back to fixation and a 1-s inter-trial interval. Targets appeared at successive locations “around the clock” (same eccentricity, ≈30° angular steps), to produce a traveling wave of activity in areas that are topographically organized. PPC exhibited topographic organization for delayed saccades. We defined two areas in each hemisphere that contained topographic maps of the contra-lateral visual field. These two areas were immediately rostral to V7 as defined by standard retinotopic mapping. The two areas were separated from each other and from V7 by reversals in visual field orientation. However, we leave open the possibility that these two areas will be further subdivided in future studies. Our results demonstrate that topographic maps tile the cortex continuously from V1 well into PPC.

Directional Selectivity of BOLD Activity in Human Posterior Parietal Cortex for Memory-Guided Double-Step Saccades

2006 ◽  
Vol 95 (3) ◽  
pp. 1645-1655 ◽  
Author(s):  
W. Pieter Medendorp ◽  
Herbert C. Goltz ◽  
Tutis Vilis
Keyword(s):  
Visual Field ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Target Location ◽  
Double Step ◽  
Fmri Signal ◽  
Posterior Parietal ◽  
Visual Hemifields ◽  
Target Locations

We used functional magnetic resonance imaging (fMRI) to investigate the role of the human posterior parietal cortex (PPC) in storing target locations for delayed double-step saccades. To do so, we exploited the laterality of a subregion of PPC that preferentially responds to the memory of a target location presented in the contralateral visual field. Using an event-related design, we tracked fMRI signal changes in this region while subjects remembered the locations of two sequentially flashed targets, presented in either the same or different visual hemifields, and then saccaded to them in sequence. After presentation of the first target, the fMRI signal was always related to the side of the visual field in which it had been presented. When the second target was added, the cortical activity depended on the respective locations of both targets but was still significantly selective for the target of the first saccade. We conclude that this region within the human posterior parietal cortex not only acts as spatial storage center by retaining target locations for subsequent saccades but is also involved in selecting the target for the first intended saccade.

scholarly journals Neural encoding of actual and imagined touch within human posterior parietal cortex

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Srinivas Chivukula ◽  
Carey Y Zhang ◽  
Tyson Aflalo ◽  
Matiar Jafari ◽  
Kelsie Pejsa ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Semantic Processing ◽  
Posterior Parietal Cortex ◽  
Receptive Fields ◽  
Body Part ◽  
Neuronal Population ◽  
Movement Planning ◽  
Trial Participant ◽  
Imagery Task ◽  
Posterior Parietal

In the human posterior parietal cortex (PPC), single units encode high-dimensional information with partially mixed representations that enable small populations of neurons to encode many variables relevant to movement planning, execution, cognition, and perception. Here, we test whether a PPC neuronal population previously demonstrated to encode visual and motor information is similarly engaged in the somatosensory domain. We recorded neurons within the PPC of a human clinical trial participant during actual touch presentation and during a tactile imagery task. Neurons encoded actual touch at short latency with bilateral receptive fields, organized by body part, and covered all tested regions. The tactile imagery task evoked body part-specific responses that shared a neural substrate with actual touch. Our results are the first neuron-level evidence of touch encoding in human PPC and its cognitive engagement during a tactile imagery task, which may reflect semantic processing, attention, sensory anticipation, or imagined touch.

Remapping the Remembered Target Location for Anti-Saccades in Human Posterior Parietal Cortex

2005 ◽  
Vol 94 (1) ◽  
pp. 734-740 ◽  
Author(s):  
W. Pieter Medendorp ◽  
Herbert C. Goltz ◽  
Tutis Vilis
Keyword(s):  
Visual Field ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Target Location ◽  
Functional Magnetic Resonance ◽  
Posterior Parietal ◽  
Saccade Task ◽  
Anti Saccades ◽  
Do So

We used functional magnetic resonance imaging (fMRI) to investigate the role of the human posterior parietal cortex (PPC) in anti-saccades. To do so, we exploited the laterality of a subregion of the PPC for remembered target location. Using an event-related design, we tracked fMRI signal changes in this region while subjects remembered the location of a flashed target, then were instructed to plan either an anti- or pro-saccade to that location, and finally were instructed to execute the movement. At first, the region responded preferentially to the memory of a target location presented in the contralateral visual field. However, when an anti-cue specified a saccadic response into the opposite visual field, we observed a dynamic shift in cortical activity from one hemisphere to the other. This shows that this region within the human posterior parietal cortex codes the target location for an upcoming saccade, rather than the location of the remembered visual stimulus in an anti-saccade task.

scholarly journals Integration of target and hand position signals in the posterior parietal cortex: effects of workspace and hand vision

2012 ◽  
Vol 108 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Christopher A. Buneo ◽  
Richard A. Andersen
Keyword(s):  
Parietal Cortex ◽  
Visual Cues ◽  
Posterior Parietal Cortex ◽  
Single Cells ◽  
Arm Movement ◽  
Movement Planning ◽  
Hand Position ◽  
Position Information ◽  
Limb Position ◽  
Posterior Parietal

Previous findings suggest the posterior parietal cortex (PPC) contributes to arm movement planning by transforming target and limb position signals into a desired reach vector. However, the neural mechanisms underlying this transformation remain unclear. In the present study we examined the responses of 109 PPC neurons as movements were planned and executed to visual targets presented over a large portion of the reaching workspace. In contrast to previous studies, movements were made without concurrent visual and somatic cues about the starting position of the hand. For comparison, a subset of neurons was also examined with concurrent visual and somatic hand position cues. We found that single cells integrated target and limb position information in a very consistent manner across the reaching workspace. Approximately two-thirds of the neurons with significantly tuned activity (42/61 and 30/46 for left and right workspaces, respectively) coded targets and initial hand positions separably, indicating no hand-centered encoding, whereas the remaining one-third coded targets and hand positions inseparably, in a manner more consistent with the influence of hand-centered coordinates. The responses of both types of neurons were largely invariant with respect to the presence or absence of visual hand position cues, suggesting their corresponding coordinate frames and gain effects were unaffected by cue integration. The results suggest that the PPC uses a consistent scheme for computing reach vectors in different parts of the workspace that is robust to changes in the availability of somatic and visual cues about hand position.

Facilitation of neuronal activity in somatosensory and posterior parietal cortex during prehension

1999 ◽  
Vol 127 (4) ◽  
pp. 329-354 ◽  
Author(s):  
E. P. Gardner ◽  
Jin Y. Ro ◽  
Daniel Debowy ◽  
Soumya Ghosh
Keyword(s):  
Neuronal Activity ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Posterior Parietal

scholarly journals NEURAL ENCODING OF FELT AND IMAGINED TOUCH WITHIN HUMAN POSTERIOR PARIETAL CORTEX

2020 ◽  
Author(s):  
Srinivas Chivukula ◽  
Carey Zhang ◽  
Tyson Aflalo ◽  
Matiar Jafari ◽  
Kelsie Pejsa ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Semantic Processing ◽  
Posterior Parietal Cortex ◽  
Receptive Fields ◽  
Body Part ◽  
Neuronal Population ◽  
Movement Planning ◽  
Trial Participant ◽  
Motor Information ◽  
Posterior Parietal

ABSTRACTIn the human posterior parietal cortex (PPC), single units encode high-dimensional information with partially mixed representations that enable small populations of neurons to encode many variables relevant to movement planning, execution, cognition, and perception. Here we test whether a PPC neuronal population previously demonstrated to encode visual and motor information is similarly selective in the somatosensory domain. We recorded from 1423 neurons within the PPC of a human clinical trial participant during objective touch presentation and during tactile imagery. Neurons encoded experienced touch with bilateral receptive fields, organized by body part, and covered all tested regions. Tactile imagery evoked body part specific responses that shared a neural substrate with experienced touch. Our results are the first neuron level evidence of touch encoding in human PPC and its cognitive engagement during tactile imagery which may reflect semantic processing, sensory anticipation, and imagined touch.

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