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Functional streams in occipito-frontal connections in the monkey
J Bullier1, J D Schall, A Morel
1Cerveau et Vision INSERM 371, Bron/Lyon, France. bullier@lyon 151.inserm.fr
Behavioural Brain Research
|April 1, 1996
Summary
Visual information streams from the occipital cortex to the frontal eye fields (FEF) show convergence. Parietal and temporal pathways meet in lateral FEF, forming distinct visual processing networks.
Area of Science:
- Neuroscience
- Visual Neuroscience
- Primate Neuroanatomy
Background:
- Two distinct visual information streams originate from the occipital cortex.
- These streams project to the parietal cortex (area LIP) and temporal cortex (areas TEO and TE).
Purpose of the Study:
- To investigate whether these parietal and temporal visual streams remain segregated in their projections to the frontal cortex.
- To identify the convergence patterns within the frontal eye field (FEF).
Main Methods:
- Paired injections of retrograde fluorescent tracers into parietal and temporal cortex, or into lateral and medial FEF.
- Reconstruction of retrogradely labeled cortical regions using two-dimensional maps.
Main Results:
- Temporal cortex primarily projects to lateral FEF (area 45).
- Parietal cortex projects to medial FEF (area 8a), lateral FEF, and area 46.
- Convergence of parietal and temporal streams occurs in lateral FEF.
- Distinct occipital inputs to medial and lateral FEF correlate with parietal and temporal stream origins, respectively.
Conclusions:
- Two interconnected visual processing networks are identified.
- One network, linked to inferotemporal cortex, involves lateral FEF and emphasizes central vision and form recognition.
- The other network, linked to intraparietal sulcus cortex, involves medial FEF and processes peripheral vision and large saccades.