Biomedical subjects

P A T M Eling

Publications and source records attributed to P A T M Eling.

3 recordsLinked to original sources

PubMed2006

Learned irrelevance and response perseveration in a total change dimensional shift task.

Thirty-six healthy participants received a discrimination learning task requiring the identification of a relevant stimulus dimension. After successful learning, the relevant dimension was shifted unannounced. All exemplars of the two dimensions presented after the shift were novel, implying a 'total change' design. In three experimental conditions, participants could either make only errors reflecting perseveration of responding to the former relevant dimension, continued ignoring of the former irrelevant dimension, or both. After the shift, the participants in the perseveration condition made fewer errors than did those in the other two conditions, which did not differ. These results imply a predominance of the learned irrelevance mechanism even when any direct transfer of learning about exemplars in the pre-shift phase is precluded.

Adult↗

PubMed2006

Processing of emotionally toned pictures in dementia.

BACKGROUND: Apathy is a common symptom in dementia and is often associated with reduced emotional reactivity. This study examined whether reduced emotional reactivity can be demonstrated in dementia patients using a picture viewing task. METHODS: The viewing time of three different types of visual stimuli was measured in 24 elderly participants, half of which suffered from dementia. The participants had to make a target response to an emotionally neutral target stimulus that was intermixed with a frequently occurring non-target or 'background' stimulus and infrequently presented emotional stimuli. All participants could control the presentation time of each stimulus, but one half of the participants were explicitly instructed to perform the task quickly. RESULTS: The main measure was a ratio score in which the viewing time for emotional stimuli was expressed relative to the viewing time for the neutral non-target stimulus. Using this measure, the instigation of a time-pressure condition proved to significantly reduce the viewing time for emotional stimuli in the healthy subjects. Irrespective of time-pressure condition, the dementia patients showed a similar short viewing time for emotional stimuli as did the healthy subjects in the time-pressure condition. However, both dementia patients and healthy controls displayed longer viewing times for unpleasant than for pleasant stimuli. CONCLUSION: These results suggest the ability of the present task to reveal the simultaneous occurrence of an overall reduced interest for novel stimuli and an intact differential emotional reactivity to stimuli with a negative versus positive valence in the dementia patients.

Aged↗

PubMed2004

More learned irrelevance than perseveration errors in rule shifting in healthy subjects.

The present experiments examined the extent to which two possible sources of error affect healthy subjects' performance in a rule-shift task. All 115 participants first received a discrimination learning task, in which a pair of different visual stimuli was presented on each trial, one of which had to be identified as 'correct.' Each stimulus varied in two dimensions: a task-relevant and a task-irrelevant dimension. Feedback on correctness was given after each choice. After eight successive correct choices, the nature of the task-relevant dimension changed: the post-shift learning phase. Two types of error can occur in this phase: continued responding to the former relevant, but now irrelevant, dimension, a perseverative error, and non-responding to the former irrelevant, but now relevant, dimension, an error due to learned irrelevance. Different groups received a post-shift task in which none, one, or both of these two types of error could affect performance. The number of incorrect choices in the post-shift phase was significantly affected by learned-irrelevance errors but not by perseverative errors. An associative-learning model incorporating feedback-induced changes in both associative strength and saliency of the elements comprising the stimuli can explain these results.

Adolescent↗