Induced sensorimotor cortex plasticity remediates chronic treatment-resistant visual neglect

• DOI: 10.7554/elife.26602
• Publication Date: 2017-09-12T00:00:28Z
• Authors: Jacinta O'Shea; Patrice Revol; Helena Cousijn; Jamie Near; Pierre Petitet; Sophie Jacquin-Co...; Heidi Johansen-Berg; Gilles Rode; Yves Rossetti
• Keywords: Adult; Male; QH301-705.5; Science; motor memory consolidation; Neuropsychological Tests; Perceptual Disorders; 03 medical and health sciences; 0302 clinical medicine; Humans; Attention; Biology (General); prism adaptation; Brain Mapping; Neuronal Plasticity; Q; R; Motor Cortex; Recovery of Function; neglect rehabilitation; Middle Aged; Adaptation, Physiological; Brain Injuries; Visual Perception; Medicine; Female; Sensorimotor Cortex; Nerve Net; Neuroscience

Right brain injury causes visual neglect - lost awareness of left space. During prism adaptation therapy, patients adapt to a rightward optical shift by recalibrating right arm movements leftward. This can improve left neglect, but the benefit of a single session is transient (~1 day). Here we show that tonic disinhibition of left motor cortex during prism adaptation enhances consolidation, stabilizing both sensorimotor and cognitive prism after-effects. In three longitudinal patient case series, just 20 min of combined stimulation/adaptation caused persistent cognitive after-effects (neglect improvement) that lasted throughout follow-up (18–46 days). Moreover, adaptation without stimulation was ineffective. Thus stimulation reversed treatment resistance in chronic visual neglect. These findings challenge consensus that because the left hemisphere in neglect is pathologically over-excited it ought to be suppressed. Excitation of left sensorimotor circuits, during an adaptive cognitive state, can unmask latent plastic potential that durably improves resistant visual attention deficits after brain injury.