Emotional modulation of visual cortex activity: a functional near-infrared spectroscopy study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Affective Neuroscience

Background:

• Emotional stimuli are known to influence cognitive processes.
• Previous research suggests emotional effects extend to early sensory cortices, but the precise mechanisms remain unclear.

Purpose of the Study:

• To investigate the haemodynamic responses in the early visual cortex to emotional stimuli using functional near-infrared spectroscopy (fNIRS).
• To determine how stimulus valence (positive, negative, neutral) and arousal impact neural processing and peripheral autonomic reactions.

Main Methods:

• Used fNIRS to measure haemodynamic responses (oxy-, deoxy-, and total haemoglobin) to neutral, positive, and negative emotional pictures.
• Pictures were carefully matched for visual properties (brightness, contrast, hue, saturation, spatial frequency, entropy).
• Monitored peripheral autonomic reactions, including blood pressure changes.

Main Results:

• Emotion content significantly modulated the amplitude and latency of haemodynamic responses in the early visual cortex.
• Processing of both positive and negative emotional pictures increased haemodynamic response amplitude, correlating with blood pressure changes.
• Processing of positive emotional pictures specifically reduced the peak latency of the haemodynamic response.

Conclusions:

• The early visual cortex exhibits an amplitude-dependent representation of stimulus salience.
• Latency-dependent information regarding stimulus valence is encoded in the early visual cortex.
• These findings offer novel insights into the affective modulation of sensory processing and neural mechanisms of emotion perception.