Task difficulty in a simultaneous face matching task modulates activity in face fusiform area

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Task difficulty influences neural activation patterns.
• Previous research indicated increased frontal lobe activation but unclear effects in extrastriate visual areas.
• The role of the face fusiform area (FFA) in response to varying task difficulty remained to be elucidated.

Purpose of the Study:

• To investigate how increasing task difficulty affects neural activation, specifically in the face fusiform area (FFA).
• To examine the relationship between task difficulty, performance, and brain activation using functional magnetic resonance imaging (fMRI).
• To explore the modulation of extrastriate visual areas during face matching tasks of varying difficulty.

Main Methods:

• Participants performed a face matching task with image quality degraded at 10%, 20%, 40%, and 60% levels.
• Brain activation was measured using functional magnetic resonance imaging (fMRI).
• Data were categorized into baseline (0-10% degradation) and difficult (20-60% degradation) levels based on performance.

Main Results:

• Task difficulty did not linearly correlate with image degradation levels.
• The face fusiform area (FFA) showed increased activation modulated by task difficulty, with performance linearly correlated to FFA activation.
• Activation in the dorsolateral prefrontal cortex (DLPFC) increased with difficulty but was not significant when response time was a covariate.
• Extrastriate visual areas exhibited decreased activation as task difficulty increased.

Conclusions:

• The face fusiform area (FFA) is crucial for face processing and its activation is modulated by task difficulty.
• Increased task difficulty enhances FFA response for focused face processing while suppressing less relevant visual extrastriate areas.
• Neural mechanisms adapt to task demands, prioritizing specific processing regions like the FFA over general visual areas.