Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory...

Area of Science:

• Neuroscience
• Primate research
• Sensory processing

Background:

• Cross-modal plasticity in early-onset blindness is not well understood.
• Investigating visual cortex reorganization in binocularly blind primates is crucial.

Purpose of the Study:

• To examine cross-modal plasticity in the visual and auditory cortices of early binocularly blind macaques.
• To compare neural activation patterns between control and visually deprived macaques.

Main Methods:

• Utilized blood oxygenation level-dependent functional imaging (BOLD-fMRI) in neonatal macaques.
• Auditory stimuli (pure tones) were used to assess cortical activation.
• Correlated BOLD-fMRI findings with immunofluorescence staining for c-Fos positive cells.

Main Results:

• Binocularly blind macaques showed significantly greater BOLD activity in bilateral visual cortices compared to controls.
• Enhanced activation was particularly noted in the right visual cortex of the blind group.
• Increased activation volumes were observed in bilateral auditory cortices, especially the right, in blind macaques.
• Higher counts of c-Fos positive cells in visual and auditory cortices of blind macaques confirmed increased neural activity.

Conclusions:

• The visual cortex in binocularly blind macaques undergoes reorganization to process auditory information.
• This cross-modal plasticity is more pronounced in the right visual cortex.
• Findings confirm the establishment of cross-modal plasticity within visual and auditory cortices following visual deprivation.