TY  - JOUR
T1  - Brain functional connectivity network breakdown and restoration in blindness
A1  - Bola, Michał
A1  - Gall, Carolin
A1  - Moewes, Christian
A1  - Fedorov, Anton
A1  - Hinrichs, Hermann
A1  - Sabel, Bernhard A.
JA  - Neurology
Y1  - 2014
VL  - 83
IS  - 6
SP  - 542
EP  - -441
UR  - http://www.neurology.org/content/83/6/542
M2  - doi: 10.1212/WNL.0000000000000672
KW  - blindness
KW  - functional connectivity
N2  - Objective: To characterize brain functional connectivity in subjects with prechiasmatic visual system damage and relate functional connectivity features to extent of vision loss.

Methods: In this case-control study, resting-state, eyes-closed EEG activity was recorded in patients with partial optic nerve damage (n = 15) and uninjured controls (n = 13). We analyzed power density and functional connectivity (coherence, Granger causality), the latter as (1) between-areal coupling strength and (2) individually thresholded binary graphs. Functional connectivity was then modulated by noninvasive repetitive transorbital alternating current stimulation (rtACS; 10 days, 40 minutes daily; n = 7; sham, n = 8) to study how this would affect connectivity networks and perception.

Results: Patients exhibited lower spectral power (p = 0.005), decreased short- (p = 0.015) and long-range (p = 0.033) coherence, and less densely clustered coherence networks (p = 0.025) in the high-alpha frequency band (11–13 Hz). rtACS strengthened short- (p = 0.003) and long-range (p = 0.032) alpha coherence and this was correlated with improved detection abilities (r = 0.57, p = 0.035) and processing speed (r = 0.56, p = 0.049), respectively.

Conclusion: Vision loss in the blind is caused not only by primary tissue damage but also by a breakdown of synchronization in brain networks. Because visual field improvements are associated with resynchronization of alpha band coherence, brain connectivity is a key component in partial blindness and in restoration of vision.
ER  -