Relationship Between Anterior Commissure and Corpus Callosum Size and Human Intelligence in Brain MRI of Healthy Volunteers

Background: The parieto-frontal integration theory of intelligence revealed a novel scope of investigation examining how performance networks are related to structural networks in the brain. Objectives: These investigations highlighted the role of brain commissures, but no evaluation has been performed examining the anterior commissure (AC) in determining the level of intelligence. Patients and Methods: A total of 100 healthy volunteers were selected, and their brain MRIs were acquired. Measurements were performed for the AC and the corpus callosum (CC) on MRI. Intelligence quotient (IQ) was calculated using the Wechsler Adult Intelligence Scale-R (WAIS-R). P < 0.05 was considered significant. Results: The average age of men was 32.58 ± 8.84 years, and the average age of women was 32.88 ± 7.83 years. The average IQ of volunteers in the study was 103.57 ± 4.178. Partitioning the subjects by gender did not lead to significant results. No significant correlation was determined between the dimensions of AC and IQ. The height of the CC had a positive correlation with IQ. However, the thickness of the genu, body, and splenium of the CC demonstrated no significant relation to IQ. Conclusion: The AC had no clear relationship with IQ, although it may have a role in women. The height parameter of the CC had a significant correlation with IQ, suggesting the interference between the anterior and posterior parts of the brain in the human intelligence process.