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Updated: Jul 13, 2026
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Investigating Object Representations in the Macaque Dorsal Visual Stream Using Single-unit Recordings
Published on: August 1, 2018
Monotonic coding of numerosity in macaque lateral intraparietal area
Jamie D Roitman1, Elizabeth M Brannon, Michael L Platt
1Department of Neurobiology, Duke University, Durham, North Carolina, United States of America. jroitman@uic.edu
Plos Biology
|August 7, 2007
Summary
Researchers discovered neurons in the brain
Area of Science:
- Neuroscience
- Cognitive Science
- Computational Neuroscience
Background:
- The neural basis of basic number processing, such as summing elements, is not well understood.
- Parietal cortex damage in humans is often linked to visuospatial and numerical deficits.
Purpose of the Study:
- To investigate the brain mechanisms underlying the summation of individual elements into a total quantity.
- To identify specific neuronal populations involved in early number processing.
Main Methods:
- Electrophysiological recordings were performed in monkeys to measure neuronal activity.
- Neuronal responses were analyzed in relation to visual stimuli with varying quantities of elements.
Main Results:
- A population of neurons in the lateral intraparietal area (LIP) demonstrated graded encoding of total element counts (2-32).
- This numerical encoding was rapid (within 100 ms) and independent of attention or stimulus features.
- Neuronal activity resembled computational models of "accumulator neurons".
Conclusions:
- Neurons in the monkey lateral intraparietal area act as numerical accumulators, processing visual quantity.
- These findings provide a potential neural basis for number processing and may explain deficits after parietal cortex damage.
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