Visual instrumental learning in blindsight monkeys.

Area of Science:

• Neuroscience
• Visual Neuroscience
• Cognitive Neuroscience

Background:

• Blindsight demonstrates residual visuo-motor function after primary visual cortex (V1) lesions, but its role in instrumental learning is unclear.
• Investigating instrumental visual associative learning is crucial for understanding blindsight.
• The potential role of V1-bypassing visual pathways in reinforcement learning needs examination.

Purpose of the Study:

• To investigate the secondary reinforcing properties of visual cues in the hemianopic field of macaque monkeys with unilateral V1 lesions.
• To test if visual pathways bypassing V1 can reinforce instrumental learning.
• To understand the impact of V1 lesions on visual associative learning and reinforcement.

Main Methods:

• Monkeys with unilateral V1 lesions performed an oculomotor search task.
• Conditioned visual cues were presented to the lesion-affected hemifield.
• The study assessed the effect of these cues as secondary reinforcers on learning and behavior.

Main Results:

• Visual cues presented to the V1-lesioned hemifield acted as effective secondary reinforcers for learning hidden area location and saccade vectors.
• Monkeys continued searching when reinforcement cues were in the affected field, unlike when cues were in the intact field, suggesting reduced confidence.
• Residual visual pathways after V1 lesions can access reinforcement mechanisms.

Conclusions:

• Visual signals mediated by residual pathways post-V1 lesions can engage fundamental reinforcement mechanisms.
• Despite retaining some learning capabilities, visual awareness remains impaired in V1-lesioned individuals.
• These findings highlight the complex interplay between residual vision, reinforcement, and awareness after V1 damage.