Sensitive period for a multimodal response in human visual motion area MT/MST.
The middle temporal complex (MT/MST) is a brain region specialized for the perception of motion in the visual modality. However, this specialization is modified by visual experience: after long-standing blindness, MT/MST responds to sound. Recent evidence also suggests that the auditory response of MT/MST is selective for motion. The developmental time course of this plasticity is not known. To test for a sensitive period in MT/MST development, we used fMRI to compare MT/MST function in congenitally blind, late-blind, and sighted adults. MT/MST responded to sound in congenitally blind adults, but not in late-blind or sighted adults, and not in an individual who lost his vision between ages of 2 and 3 years. All blind adults had reduced functional connectivity between MT/MST and other visual regions. Functional connectivity was increased between MT/MST and lateral prefrontal areas in congenitally blind relative to sighted and late-blind adults. These data suggest that early blindness affects the function of feedback projections from prefrontal cortex to MT/MST. We conclude that there is a sensitive period for visual specialization in MT/MST. During typical development, early visual experience either maintains or creates a vision-dominated response. Once established, this response profile is not altered by long-standing blindness.
Bedny
Marina
M
Brain and Cognitive Sciences Department, Massachusetts Institute of Technology, Room 46-4021, 43 Vassar Street, room 46-4021, Cambridge, MA 02139, USA. mbedny@mit.edu
Konkle
Talia
T
Pelphrey
Kevin
K
Saxe
Rebecca
R
Pascual-Leone
Alvaro
A
D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D001766:Blindness / Q000503:physiopathology; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception; D014793:Visual Cortex / Q000502:physiology* / Q000503:physiopathology