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Published on: August 25, 2020
Target selection signals for arm reaching in the posterior parietal cortex
Hansjörg Scherberger1, Richard A Andersen
1Division of Biology, California Institute of Technology, Pasadena, California 91125, USA. hjs@ini.phys.ethz.ch
Summary
Neurons in the parietal reach region (PRR) help monkeys decide which visual target to reach for. This brain area
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Motor Control
Background:
- The posterior parietal cortex, specifically the parietal reach region (PRR), is crucial for translating visual information into motor plans for reaching.
- Selecting a visual target for a motor action involves complex decision-making influenced by both external stimuli and internal states.
Purpose of the Study:
- To investigate how neurons in the PRR encode the decision-making process when selecting between two visual targets for a reach movement.
- To determine the role of PRR in action-specific target selection and its timing relative to movement initiation.
Main Methods:
- Recorded spiking activity from individual neurons in the PRR of macaque monkeys during a free-choice reach task.
- Manipulated stimulus-onset asynchrony (SOA) to equalize target selection probability while keeping reward constant.
- Analyzed neural activity in relation to target choice, movement execution, and fixation position.
Main Results:
- PRR neural activity was action-specific for arm reaching and reflected both SOA timing and target selection.
- A majority of PRR cells showed activity patterns that predicted target selection before the movement began.
- Fixation position modulated neural gain but did not directly influence the target selection process.
Conclusions:
- The PRR plays a significant role in the decision-making processes underlying reach movements.
- Findings suggest the existence of distinct cortical networks for target selection in different types of actions, such as reaching versus saccades.
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