Morphometry Difference of the Hippocampal Formation Between Blind and Sighted Individuals

Area of Science:

• Neuroscience
• Neuroimaging
• Human Anatomy

Background:

• The human hippocampal formation (HF) morphometry in blind individuals remains understudied.
• Understanding these alterations is crucial for comprehending brain plasticity and sensory compensation mechanisms.

Purpose of the Study:

• To investigate detailed morphometric alterations in the human hippocampal formation (HF) of blind individuals.
• To compare HF volume and shape differences between congenital blindness, late blindness, and sighted controls.

Main Methods:

• Recruited 50 subjects: 16 congenital blindness, 14 late blindness, 20 sighted controls.
• Conducted volume and shape analyses of the hippocampal formation.
• Utilized FDR correction for statistical significance.

Main Results:

• No significant difference in overall hippocampal volume between blind and sighted groups.
• Blind individuals exhibited rightward hippocampal volume asymmetry, unlike sighted controls.
• Shape analysis revealed expansion in superior/inferior HF parts and constriction in medial/lateral parts in blind individuals.
• Significant expansion of the superior hippocampal tail was observed in the left hippocampi of both congenital and late blind groups.

Conclusions:

• Morphometric alterations in the HF of blind individuals are similar for congenital and late blindness.
• Cross-modal plasticity in both HF hemispheres may enhance navigation abilities in the absence of visual cues.
• The observed alterations are more prominent in the left hemisphere, suggesting its crucial role in compensatory navigation.