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A Comprehensive Protocol for Manual Segmentation of the Medial Temporal Lobe Structures
Published on: July 2, 2014
Human posterior parietal cortex plans where to reach and what to avoid
Axel Lindner1, Asha Iyer, Igor Kagan
1California Institute of Technology, Division of Biology, Pasadena, California 91125, USA. a.lindner@medizin.uni-tuebingen.de
Summary
Human posterior parietal cortex exhibits prospective planning activity for visually guided actions. This brain region differentiates between planning to acquire and avoid targets, distinct from memory and attention functions.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Motor Control
Background:
- Human posterior parietal cortex is implicated in visual working memory and attention.
- Electrophysiological studies in monkeys suggest parietal neurons are involved in motor planning.
- Human imaging studies have provided limited evidence for prospective motor planning in the posterior parietal cortex.
Purpose of the Study:
- To investigate the neuronal correlates of covert planning processes preceding visually guided motor behavior.
- To determine if human posterior parietal cortex exhibits prospective planning activity separable from visual memory and attention.
- To differentiate motor planning functions from mnemonic and attentional roles within the posterior parietal cortex.
Main Methods:
- Time-resolved functional magnetic resonance imaging (fMRI) was employed.
- Subjects performed delayed-response tasks with varying degrees of motor planning.
- Tasks involved memorizing target locations and distinguishing between desired and undesired goals for finger reaches.
Main Results:
- Both desired and undesired goal conditions showed increased preparatory fMRI activity in the posterior parietal and dorsal premotor cortex.
- This preparatory activity was specific to conditions involving motor planning, compared to memory/attention-only conditions.
- Posterior parietal cortex demonstrated prospective planning activity for upcoming behaviors.
Conclusions:
- The posterior parietal cortex plays a role in prospective motor planning, not solely visual memory and attention.
- This region integrates information about both desired and undesired targets for action planning.
- Findings clarify the distinct functions of the posterior parietal cortex in motor control and cognitive processes.
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