Biomedical subjects

Melissa J Guynn

Publications and source records attributed to Melissa J Guynn.

6 recordsLinked to original sources

PubMed2006

Brain regions and their dynamics in prospective memory retrieval: a MEG study.

We measured brain activity using magnetoencephalography in five participants during ongoing tasks that included prospective memory, retrospective memory, and oddball trials. Sources were identified in the hippocampal formation and posterior parietal and frontal lobes. Posterior parietal cortex activation had an earlier onset in the prospective memory condition than retrospective memory or oddball conditions, a higher level of theta activity in the retrospective condition, and higher levels of upper alpha in the prospective and oddball conditions. Activation of the hippocampal formation had a longer duration in the retrospective memory and prospective memory conditions than the oddball condition, but prominent alpha and theta band activity was present in all three conditions. We interpret the early (87 ms) onset of activity in parietal cortex as evidence for an initial noticing of appropriate conditions for a PM response. Hippocampal activity may reflect a subsequent memory search for the intended action.

Adult↗

PubMed2006

The role of noticing in prospective memory forgetting.

Two experiments used autonomic reactions (i.e., skin conductance responses; SCRs) in conjunction with behavioral responses to study retrieval processes in prospective memory. SCRs were recorded while participants performed a prospective memory task embedded in an ongoing task. Stimuli that received the same behavioral response (i.e., no prospective memory response) evoked different autonomic reactions as a function of whether they were versus were not prospective cues (Experiments 1 and 2) and as a function of whether they did versus did not share perceptual or conceptual features with prospective cues (Experiment 2). To the extent that SCRs provide an index of noticing a stimulus, increased SCRs for prospective cues and for stimuli that shared features with prospective cues (even though they were not responded to as prospective cues) provided evidence that noticing a stimulus is not invariably accompanied by recognizing the stimulus as a cue to perform an intended action. The results are consistent with the general 2-stages cue-focused view of prospective memory retrieval, which proposes that noticing a prospective cue prompts a directed memory search, which can result in recognizing the stimulus as a cue to perform an intended action and retrieving the intended action.

Adult↗

PubMed2005

Apolipoprotein E and prospective memory in normally aging adults.

The epsilon4 allele of apolipoprotein E (APOE) is an established risk factor for Alzheimer's disease, despite uncertainty as to its effect on cognitive function in normal aging. Some evidence suggests poor episodic memory and executive functioning in epsilon4 allele carriers. Prospective memory has been overlooked in investigations of the relationship between APOE and cognition. The authors used a laboratory paradigm to examine the relationship between prospective memory and APOE status in healthy elderly adults, and they varied the association (high vs. low) between a target word and a response word. The authors found a significant deficit in prospective memory for epsilon4 allele carriers but no effect of association in either group. The results suggest the deficit was due to failure of the prospective component of the task.

Aged↗

PubMed2005

Disentangling encoding versus retrieval explanations of the bizarreness effect: implications for distinctiveness.

Recall effects attributed to distinctiveness have been explained by both encoding and retrieval accounts. Resolution of this theoretical controversy has been clouded because the typical methodology confounds the encoding and retrieval contexts. Using bizarre and common sentences as materials, we introduce a paradigm that decouples the nature of the encoding context (mixed vs. unmixed lists of items) from the retrieval set (mixed vs. unmixed retrieval sets). Experiment 1 presented unmixed lists for study, and Experiment 2 presented mixed lists for study. In both experiments, significant bizarreness effects were obtained in free recall when the retrieval set intermixed items but not when the retrieval set consisted of only one item type. Also, Experiment 1, using a repeated testing procedure, did not reveal evidence for more extensive encoding of bizarre sentences than of common sentences. The results support the idea that retrieval dynamics primarily mediate the bizarreness effect, and perhaps more generally, distinctiveness effects.

Affect↗

PubMed2004

Cue-focused and reflexive-associative processes in prospective memory retrieval.

Several theories of event-based prospective memory were evaluated in 3 experiments. The results depended on the association between the target event and the intended action. For associated target-action pairs (a) preexposure of nontargets did not reduce prospective memory, (b) divided attention did not reduce prospective memory, (c) prospective memory was better than when the target event and intended action were not associated, and (d) prospective memory was characterized by retrieval of the precise intended action. These results converge on the view that retrieval is mediated by a reflexive-associative process. In contrast, for unassociated pairs (a) preexposure of nontargets reduced prospective memory, and (b) divided attention reduced prospective memory. These results implicate cue-focused retrieval processes and are most consistent with a discrepancy-plus-search model. The entire pattern implicates both cue-focused and reflexive-associative processes and more generally supports a multiprocess framework of prospective memory (M. A. McDaniel & G. O. Einstein, 2000).

Association↗

PubMed2004

Goal specificity and knowledge acquisition in statistics problem solving: evidence for attentional focus.

Solving training problems with nonspecific goals (NG; i.e., solving for all possible unknown values) often results in better transfer than solving training problems with standard goals (SG; i.e., solving for one particular unknown value). In this study, we evaluated an attentional focus explanation of the goal specificity effect. According to the attentional focus view, solving NG problems causes attention to be directed to local relations among successive problem states, whereas solving SG problems causes attention to be directed to relations between the various problem states and the goal state. Attention to the former is thought to enhance structural knowledge about the problem domain and thus promote transfer. Results supported this view because structurally different transfer problems were solved faster following NG training than following SG training. Moreover, structural knowledge representations revealed more links depicting local relations following NG training and more links to the training goal following SG training. As predicted, these effects were obtained only by domain novices.

Attention↗