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Nonconscious memory for motion activates MT+

Thakral, Preston P.a; Slotnick, Scott D.b

doi: 10.1097/WNR.0000000000000270
Integrative Systems

Extrastriate region MT+ is widely thought to reflect conscious motion processing. The primary aim of the present functional MRI study was to assess whether MT+ is activated during nonconscious memory for motion. During the encoding phase, moving and stationary abstract shapes were presented to the left or right of fixation. During the retrieval phase, the same shapes were presented at fixation and participants classified each shape as ‘moving-left’, ‘moving-right’, ‘stationary-left’, or ‘stationary-right’. The contrast of moving>stationary shapes at encoding was used to identify the location of MT+. Event-related activity was then extracted from MT+ within each hemisphere. MT+ activity was significantly greater for moving-misses than for stationary-misses, which indicates that nonconscious memory for motion activates MT+. Furthermore, nonconscious memory activity (moving-misses) had an earlier temporal onset than conscious memory activity (moving-hits). The present results are the first, to our knowledge, to demonstrate that MT+ is associated with nonconscious motion processing. Therefore, activity in this region or in other visual-sensory regions should not be assumed to reflect conscious processing.

aCenter for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas

bDepartment of Psychology, Boston College, Boston, Massachusetts, USA

Correspondence to Preston P. Thakral, PhD, Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX 75235, USA Tel: +1 972 883 3737; fax: +1 972 883 3250; e-mail: preston6667@gmail.com

Received August 17, 2014

Accepted August 26, 2014

© 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins