Layer-specificity in the effects of attention and working memory on activity in primary visual cortex

Area of Science:

• Neuroscience
• Visual Cortex Research
• Cognitive Neuroscience

Background:

• Neuronal activity in the early visual cortex is known to be influenced by attention shifts.
• However, its specific contribution to working memory processes remains incompletely understood.

Purpose of the Study:

• To investigate neuronal activity patterns within the distinct layers of the primary visual cortex (V1).
• To differentiate the roles of these layers in attention-demanding tasks versus working memory tasks.

Main Methods:

• Utilized current-source density analysis to map neuronal activity.
• Examined neuronal firing rates across different layers of V1 during attention and working memory tasks.

Main Results:

• Identified top-down inputs primarily in superficial layers and layer 5.
• Observed increased neuronal firing rates, most prominent in superficial and deep layers, with weaker effects in layer 4.
• Found heightened activity during attention tasks, with significant reliability during working memory delays.
• Demonstrated that a visual mask temporarily erases V1 memory activity, which then reappears.

Conclusions:

• Provides novel insights into the laminar circuit mechanisms underlying top-down modulation of V1 activity.
• Highlights the involvement of V1 in both the presence and absence of visual stimuli for cognitive functions.