How spatial attention alters visual cortical representation during target anticipation.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Perception

Background:

• Attention is crucial for efficient environmental interaction by prioritizing visual features.
• Understanding how attention modulates neural processing before stimulus appearance is key.

Purpose of the Study:

• To investigate the effects of covert spatial attention on human visual cortex activity prior to target onset.
• To examine how spatial attention influences subsequent behavioral performance.

Main Methods:

• Concurrent psychophysics and functional Magnetic Resonance Imaging (fMRI) experiment.
• Measured behavioral performance and blood-oxygen-level-dependent (BOLD) responses in visual cortex.
• Compared effects of cued (attended) vs. uncued (unattended) locations with distributed attention.

Main Results:

• Behavioral performance improved at cued locations and worsened at uncued locations, indicating a selective processing tradeoff.
• Pre-target BOLD responses showed a stimulus-independent baseline shift: positive near the cued location, negative elsewhere.
• Population receptive field centers shifted towards the attended location, with effects amplifying in higher visual areas.

Conclusions:

• Spatial attention significantly impacts visual cortex activity even before a target appears.
• Attention alters neural response properties, including baseline activity and receptive field organization, across multiple visual areas.
• These neural changes directly correlate with observed behavioral performance shifts.