Brain functional connectivity network breakdown and restoration in blindness.

Area of Science:

• Neuroscience
• Ophthalmology
• Biophysics

Background:

• Prechiasmatic visual system damage can lead to significant vision loss.
• Understanding the neural mechanisms underlying vision loss is crucial for developing effective treatments.

Purpose of the Study:

• To characterize brain functional connectivity in individuals with prechiasmatic visual system damage.
• To investigate the relationship between functional connectivity patterns and the extent of vision loss.
• To explore the effects of repetitive transorbital alternating current stimulation (rtACS) on brain connectivity and visual perception.

Main Methods:

• Resting-state electroencephalography (EEG) was used to record brain activity in patients with optic nerve damage and healthy controls.
• Analysis included power density and functional connectivity metrics such as coherence and Granger causality.
• Noninvasive rtACS was applied to modulate brain connectivity and assess its impact on visual perception and processing speed.

Main Results:

• Patients with optic nerve damage showed reduced spectral power and decreased short- and long-range coherence in the high-alpha frequency band.
• rtACS significantly strengthened alpha band coherence, both short- and long-range.
• Improvements in alpha coherence were correlated with enhanced visual detection abilities and processing speed.

Conclusions:

• Vision loss is associated not only with primary tissue damage but also with disrupted synchronization in brain networks.
• Restoration of alpha band coherence through brain stimulation is linked to improvements in visual field.
• Brain connectivity is a critical factor in partial blindness and holds potential for vision restoration strategies.