Anticipatory anxiety-induced changes in human lateral prefrontal cortex activity

Area of Science:

• Neuroscience
• Psychophysiology

Background:

• Frontal brain asymmetry is hypothesized to relate to emotional processing, particularly avoidance behaviors.
• Previous research suggests links between brain asymmetry and emotional dimensions.

Purpose of the Study:

• To investigate regional cerebral oxygenated hemoglobin (O2Hb) levels in the medial prefrontal cortex (MPFC) using near-infrared spectroscopy (NIRS).
• To determine if NIRS can detect anxiety-related changes in frontal brain activity.
• To explore the association between frontal brain asymmetry and anticipatory anxiety.

Main Methods:

• Near-infrared reflection spectroscopy (NIRS) was used to measure O2Hb levels in left and right frontal regions.
• Transient anxiety was induced in 56 volunteers via anticipation of a painful shock.
• Affective status was assessed using the State-Trait Anxiety Inventory (STAI) and Temperature Character Inventory (TCI).

Main Results:

• A significant increase in O2Hb was observed in the right MPFC compared to the left MPFC during anxiety anticipation.
• These right-sided O2Hb increases showed a significant positive correlation with the Harm Avoidance subscale of the TCI.
• NIRS successfully detected anxiety-related changes in regional cerebral O2Hb levels.

Conclusions:

• The findings support the hypothesis linking O2Hb levels in the right frontal region to anxiety and heightened negative affect.
• This study demonstrates the utility of NIRS in measuring brain activity associated with emotional states.
• Right frontal asymmetry in O2Hb may be a neural correlate of avoidance-withdrawal behavior.