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Updated: Jul 14, 2026
07:08
Investigating Object Representations in the Macaque Dorsal Visual Stream Using Single-unit Recordings
Published on: August 1, 2018
A fast, reciprocal pathway between the lateral geniculate nucleus and visual cortex in the macaque monkey.
Farran Briggs1, W Martin Usrey
1Center for Neuroscience, University of California, Davis, Davis, California 95618, USA.
Summary
Visual signals rapidly travel between the lateral geniculate nucleus (LGN) and visual cortex (V1). This study reveals fast feedback pathways, showing the cortex can influence LGN activity within milliseconds.
Area of Science:
- Neuroscience
- Visual Processing
Background:
- The lateral geniculate nucleus (LGN) receives input from the retina and projects to the primary visual cortex (V1).
- Visual processing in the LGN is influenced by feedback from the cortex, indicating dynamic interactions.
Purpose of the Study:
- To investigate the temporal dynamics of feedforward and feedback pathways between the LGN and V1 in macaque monkeys.
- To establish a lower bound for the speed at which cortical feedback influences the LGN.
Main Methods:
- Electrophysiological recordings in macaque monkeys.
- Analysis of neuronal response latencies in corticogeniculate pathways.
Main Results:
- Identified a subclass of corticogeniculate neurons receiving direct LGN input with short latency (4.2 +/- 0.4 ms).
- These neurons provide feedback to the LGN with significantly shorter latency (5.1 +/- 1.3 ms) compared to those without direct LGN input (11.1 +/- 2.3 ms).
- The combined latency for visual signal transmission and feedback was as short as 37 ms (mean 52.5 +/- 3.8 ms).
Conclusions:
- Cortical feedback to the LGN can occur very rapidly.
- These findings demonstrate a fast loop for visual information processing between the LGN and V1.
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