Biomedical subjects

Natalie Foong

Publications and source records attributed to Natalie Foong.

3 recordsLinked to original sources

PubMed2005

Implicit memory, age, and time of day: paradoxical priming effects.

Memory retrieval can occur by at least two routes: a deliberate one, as when one attempts to retrieve an event or fact, and an unintentional one, as when one's behavior is triggered by the past without one's knowledge or awareness. We assessed the efficacy of these retrieval systems as a function of circadian arousal and time of day. Evening-type younger adults and morning-type older adults were tested at either peak (morning for old; evening for young) or off-peak times on implicit and explicit stem completion (Experiment 1) or on implicit category generation (Experiment 2). Results for explicit stem-cued recall replicated better performance for each age group at its peak time. In stark contrast, implicit performance was better at off-peak than at peak times of day, raising the possibility that the processes that serve explicit and implicit retrieval are on different circadian schedules, and highlighting the need to consider individual differences in circadian arousal when assessing either memory system.

Adolescent↗

PubMed2004

Incidental information acquired by the amygdala during acquisition of a stimulus-response habit task.

In the present paper we tested the hypothesis that the amygdala incidentally acquires information during the acquisition of a task sensitive to damage to the dorso-lateral striatum. Two groups of rats were trained on a stimulus-response (S-R) habit task on the eight-arm radial maze. Prior to initial acquisition, one group received NMDA lesions of the amygdala and the other received sham surgeries. After reaching a strict learning criterion, both groups underwent reversal training in either the same or different context from original training. Consistent with our previous work, the sham group showed enhanced reversal learning in a context different from original training. The rats with amygdala damage showed a deficit in reversal learning in both contexts, although the deficit was more apparent in the different context. Both groups of rats that underwent reversal training in the context different from original training showed a normal competition effect for this task (chance performance) when they were returned to the initial training context. This data supports the idea that the second S-R association, acquired during reversal training, and the context-specific inhibitory association, acquired during original training, were unaffected by the amygdala damage. Taken together, this pattern of data suggests that the amygdala incidentally acquired information during the acquisition of the S-R habit task. The nature of the association acquired in this learning paradigm, and the implications of this finding for theories dealing with the organization and functions of mammalian learning and memory are discussed.

Amygdala↗

PubMed2002

Age, time of testing, and proactive interference.

A four-list version of a release from proactive interference paradigm was used to assess the degree to which older and younger adults tested at optimal and nonoptimal times of day are vulnerable to interference effects in memory, effects that may increase at nonoptimal times. Morning type older adults and Evening type younger adults were tested either early in the morning or late in the afternoon. Standard buildup and release effects were shown for all age groups except for older adults tested in the afternoon; they failed to show release. Recall and intrusion data suggested that older adults are more vulnerable to proactive interference than younger adults and that for older adults at least, interference effects are heightened at nonoptimal times of day. The data are discussed in terms of an inhibitory model of control over the contents of working memory (Hasher, Zacks, & May, 1999).

Adolescent↗