A compressed hierarchy for visual form processing in the tree shrew

Area of Science:

• Neuroscience
• Comparative Vision Research
• Mammalian Visual Processing

Background:

• Primate visual system studies inform deep neural network architecture.
• The universality of primate-like visual hierarchies remains under investigation.
• Tree shrews, close primate relatives, offer a model for comparative studies.

Purpose of the Study:

• To investigate the large-scale functional organization of the tree shrew visual system.
• To determine if visual processing in tree shrews mirrors primate hierarchical structures.
• To explore the capabilities of early visual areas in object representation.

Main Methods:

• Neuropixels recordings across cortical and thalamic visual areas in awake tree shrews.
• Presentation of diverse visual stimuli, including naturalistic textures and spectrally matched noise.
• Analysis of receptive field properties, response latency, and selectivity.

Main Results:

• Visual processing showed a primate-like hierarchical organization with increasing receptive field size and latency anteriorly.
• Tree shrew area V2 demonstrated high-level object representation, surpassing other visual areas in decoding accuracy.
• Face-selective cells, similar to those in macaque inferotemporal cortex, were identified in V2.

Conclusions:

• Core computational principles of primate visual form processing are conserved in tree shrews.
• The tree shrew visual system exhibits a hierarchically compressed organization.
• Early visual areas like V2 play a crucial role in complex object recognition in mammals.