Neural manifestations of memory with and without awareness.
Neurophysiological events responsible for different types of human memory tend to occur concurrently and are therefore difficult to measure independently. To surmount this problem, we produced perceptual priming (indicated by speeded responses) in the absence of conscious remembering. At encoding, faces appeared briefly while subjects' attention was diverted to other stimuli. Faces appeared again in either an implicit or explicit memory test. Neural correlates of priming were identified as brain potentials beginning 270 ms after face onset with more negative amplitudes for repeated than for new faces. Remembered faces, in contrast, activated a different configuration of intracranial sources producing positive potentials maximal at 600-700 ms. We thus disentangled and characterized distinct neural events associated with memory with and without awareness.
Department of Psychology and Institute for Neuroscience, Northwestern University, Evanston, IL 60208, USA. kap@northwestern.edu
Ken A
KA
Paller
Craig A
CA
Hutson
Brennan B
BB
Miller
Stephan G
SG
Boehm
D000293:Adolescent; D000328:Adult; D001364:Awareness / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005145:Face; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology