Ventral midbrain stimulation induces perceptual learning and cortical plasticity in primates

Area of Science:

• Neuroscience
• Cognitive Science
• Perception

Background:

• Visual perceptual learning (VPL) enhances perception and neural representations of trained stimuli.
• Attention is crucial for VPL, but reinforcement associations can also drive learning subconsciously.
• The role of neuromodulatory centers, like the ventral tegmental area (VTA), in VPL is proposed but unconfirmed in primates.

Purpose of the Study:

• To causally investigate the role of the ventral tegmental area (VTA) in VPL in primates.
• To determine if pairing VTA microstimulation with visual stimuli can induce VPL.

Main Methods:

• Task-irrelevant visual stimuli were paired with microstimulation of the VTA in macaque monkeys.
• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Stimulus discrimination capacity was assessed.

Main Results:

• Pairing VTA microstimulation with a visual stimulus increased fMRI activity.
• fMRI activity patterns were more accurately classified for the microstimulation-paired stimulus.
• Subjects showed improved discrimination of the paired visual stimulus.

Conclusions:

• This study provides the first causal evidence for the role of neuromodulatory centers (VTA) in VPL in primates.
• Reinforcement via VTA activation can drive VPL, even for task-irrelevant stimuli.