Nov 23

Implicit learning of a serial interception sequence by cognitively healthy elderly participants

Eric W. Gobel1,2, Kelsey M. Blomeke2, Sandra Weintraub3,4, and Paul J. Reber2
1Interdepartmental Neuroscience Program, 2Department of Psychology, 3Cognitive Neurology and Alzheimer’s Disease Center, and 4Departments of Psychiatry and Neurology
Northwestern University, Evanston, IL, and Northwestern Feinberg School Of Medicine, Chicago, IL

Cognitive Neuroscience Society Annual Meeting 2011

Skilled performance of complex motor skills requires learning a specific order of movements with precise timing. The Serial Interception Sequence Learning (SISL) task has been used to study this type of perceptual-motor sequence learning. During SISL, participants make keypress responses to coincide with the passage of a moving spatial cue though a target zone. Participants are not told that the cues follow a repeating sequence, but implicit sequence knowledge is observed through sequence-specific performance enhancement. Implicit learning with little concomitant explicit knowledge of the sequence has been demonstrated in undergraduate populations. This implicit-explicit memory dissociation is likely enhanced by the continuous performance demands and video-game-like interface. However, it is not known if SISL will be an effective tool for examining sequence learning in older adults given the overall task difficulty. Cognitively healthy elderly participants (mean age 70.0 years, range 63 – 76) performed a modified SISL task designed to provide an appropriate level of difficulty. The number of possible responses was reduced to three (making the task unimanual) and an initial performance pre-assessment identified an appropriate cue velocity for each participant. As in prior research, cues followed a 12-item repeating sequence during 80% of training trials. On a subsequent test phase, participants exhibited implicit sequence knowledge but no ability to recognize or recall the trained sequence. This cognitively healthy elderly sample demonstrated reliable implicit learning and would serve as a suitable comparison group for patient populations with impaired memory function, such as those with MCI, Alzheimer’s disease, and Parkinson’s disease.

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