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Biomedical subjects

L A Cooper

Publications and source records attributed to L A Cooper.

42 records · Page 3Linked to original sources
PubMed1976

Mental transformations and visual comparison processes: effects of complexity and similarity.

Subjects were required to discriminate previously learned "standard" versions of angular shapes from randomly perturbed "distractor" versions that varied in similarity to the standard. Advance information concerning the identity and the orientation of the test form was provided. Subjects were instructed to prepare for the presentation of the test form by mentally rotating an internal representation of the designated standard form (identity cue) into the designated orientation. The time needed to prepare for the presentation of the test form increased linearly with the angular departure of the indicated orientation from a previously learned position. This finding suggests that, in accordance with instructions, subjects performed a mental rotation in preparing for the upcoming test shape. Rate of preparation was not affected by the complexity of the standard form presented as the identity cue. DIscriminative departure of the test form presented as the identity cue. Discriminative reaction time was not affected by either test-form complexity or angular departure of the test form from the learned orientation. In addition, striking individual differences in the pattern of discriminative reaction times were found. The implications of these results for (a) the nature of the processes and representations underlying the mental rotation task and (b) the nature of visual comparison processes are discussed.

Cognition↗
PubMed1975

Mental transformations in the identification of left and right hands.

Subjects determined as rapidly as possible whether each line drawing portrayed a left or a right hand when the drawings were presented in any of four versions (palm or back of either hand) and in any of six orientations in the picture plane. Reaction time varied systematically with orientation and, in the absence of advance information, was over 400 msec longer for the fingers-down orientation. However, when subjects were instructed to imagine a specified (palm or back) view of a specified (left or right) hand in a specified orientation, reaction times to test hands that were consistent with these instructions were short (about 500 msec), independent of orientation, and unacompanied by errors. It is proposed that subjects determine whether a visually presented hand is left or right by moving a mental "phantom" of one of their own hands into the portrayed position and by then comparing its imagined appearance against the appearance of the externally presented hand.

Cues↗
PubMedDate not supplied

Primary care patients' opinions regarding the importance of various aspects of care for depression.

The objectives of this study were to 1) ascertain the importance of various aspects of depression care from the patient's perspective and 2) select items and scales for inclusion in a new instrument to measure primary care patients' attitudes toward and ratings of depression care. We used a cross-sectional survey at a university-based urban primary care clinic; the subjects were adult patients being recruited for a study of minor depression. To help prioritize attitudinal domains, including 126 items identified previously in focus groups, we asked patients to rate the importance of each aspect of depression care on a five-point scale. Items were ranked according to mean scores and the percentage of patients ranking the items as extremely important. The items were selected for inclusion in an instrument to measure patients' attitudes toward depression care based on their importance ratings. We performed reliability and validity testing of scales comprising the 30 most important items and a shortened version that includes 16 items. The sample included 76 patients (mean age 34.8 years; mean CES-D score, 22.2; 72% women; 36% African-American; 32% college graduates). Forty-six percent had visited a mental health professional in the past. The top 30 items for the overall sample came from the following domains: 1) health care providers' interpersonal skills, 2) primary care provider recognition of depression, 3) treatment effectiveness, 4) treatment problems, 5) patient understanding about treatment, 6) intrinsic spirituality, and 7) financial access to services. Scales comprising items from these domains show adequate internal consistency (Cronbach's alpha >0.70) as well as convergent and discriminant validity. We have designed a brief patient-centered instrument for measuring attitudes toward depression care that has evidence for internal item consistency reliability and discriminant validity.

Adult↗
PubMedDate not supplied

Neuroanatomical correlates of implicit and explicit memory for structurally possible and impossible visual objects.

Implicit memory refers to nonconscious retrieval of past experience demonstrated by facilitation in test performance on tasks that do not require intentional recollection of previous experiences. Explicit memory, in contrast, refers to the conscious retrieval of prior information, as demonstrated during standard recall and recognition tasks. In this experiment, positron emission tomographic (PET) measurements of regional cerebral blood flow (CBF), a marker of local neuronal activity, were used to identify and contrast brain regions that participate in the perception, implicit memory, and explicit memory for structurally possible and impossible visual objects. Ten CBF images were acquired in 16 normal women as they made possible/impossible and old/new recognition decisions about previously studied (old) and nonstudied (new) structurally possible and impossible objects. As reported previously, object decisions for familiar possible objects were associated with increased CBF in the vicinity of the left inferior temporal and fusiform gyri and recognition memory for familiar possible objects was associated with increased CBF in the vicinity of the right hippocampus. In this report, we provide more extensive analyses of the roles of the inferior temporal cortex, the hippocampus, the parahippocampus, and the pulvinar in encoding and retrieval operations. Additionally, patterns of CBF increases and decreases provide information regarding the neural structures involved in implicit and explicit memory.

Adult↗