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Abstract
Prefrontal cortex-related circuits are important to several executive functions, including serial organization of behavior. Serial organization of memory was investigated by means of a list discrimination task. During stimulus presentation, two lists of ten stimuli each (ten concrete word or ten line drawings of objects) were presented before and after a distracter task. In the testing phase, 20 pairs of stimuli were presented one by one. One of the stimuli in the pair was new and the other had already been presented. Participants should recognize the old stimulus and determine the list where it appeared before (temporal order judgment). We report on initial clinical investigations suggesting that the task may be useful to differentiate between young adults and older subjects, and these from patients with frontal lobe pathology, multiple sclerosis as well as psychiatric patients. All groups of patients, as well as aged subjects, showed performance dissociation with normal recognition and altered serial ordering in memory.