Altered Regional Gray Matter Volume in Obese Men: A Structural MRI Study

Area of Science:

• Neuroscience
• Endocrinology
• Medical Imaging

Background:

• Obesity is linked to insulin resistance and Type 2 diabetes.
• Previous research indicated altered neural activity in obese males' orbital frontal cortex (OFC) and left putamen.
• These changes suggest altered eating behaviors due to striatal hyperactivity and impaired inhibitory control.

Purpose of the Study:

• To investigate structural brain alterations in obese individuals within the OFC and putamen.
• To determine correlations between brain structure, body mass index, and insulin resistance markers.

Main Methods:

• Structural MRI and voxel-based morphometry (VBM) were used.
• Twenty obese men and 20 lean controls (aged 20-28) participated.
• Plasma glucose and insulin levels were measured to calculate HOMA-IR.

Main Results:

• Obese men exhibited significantly increased gray matter volume (GMV) in the left putamen.
• Left putamen GMV positively correlated with BMI, plasma insulin, and HOMA-IR.
• Orbital frontal cortex (OFC) GMV negatively correlated with hunger rating, with no significant group difference.

Conclusions:

• Altered gray matter volume in the putamen is a key structural change in obesity and aberrant insulin regulation.
• The putamen's structural changes may play a significant role in the pathophysiology of obesity and insulin resistance.