Neurostructural correlates of two subtypes of specific phobia: a voxel-based morphometry study

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Specific phobias, like animal (e.g., snake phobia - SP) and blood-injection-injury (BII) subtypes (e.g., dental phobia - DP), involve fear but differ in autonomic responses.
• Previous research identified shared and distinct neural correlates using functional neuroimaging, but comparative structural data were lacking.

Purpose of the Study:

• To investigate and compare the structural brain differences between dental phobia (DP) subjects, snake phobia (SP) subjects, and healthy control (HC) individuals.
• To identify specific neuroanatomical variations associated with different subtypes of specific phobia.

Main Methods:

• Voxel-based morphometry (VBM) was employed to analyze gray and white matter volumes.
• Structural data were collected from 33 SP subjects, 26 DP subjects, and 37 HC subjects.

Main Results:

• Dental phobia (DP) subjects showed significantly increased gray matter volumes in regions including the right subgenual anterior cingulate gyrus, left insula, left orbitofrontal cortex, and left prefrontal cortex (PFC) compared to both HC and SP groups.
• Increased white matter volume in the left PFC was observed in DP subjects relative to SP subjects.

Conclusions:

• The observed structural brain differences in DP align with known functional alterations in dental phobia, implicating specific brain circuits in emotional processing and regulation.
• These findings contribute to understanding the neurobiological basis of specific phobia subtypes and suggest avenues for future research into functional and structural connectivity.