Biomedical subjects

Denise Park

Publications and source records attributed to Denise Park.

3 recordsLinked to original sources

PubMed2006

Age-related changes in object processing and contextual binding revealed using fMR adaptation.

Using fMR adaptation, we studied the effects of aging on the neural processing of passively viewed naturalistic pictures composed of a prominent object against a background scene. Spatially distinct neural regions showing specific patterns of adaptation to objects, background scenes, and contextual integration (binding) were identified in young adults. Older adults did not show adaptation responses corresponding to binding in the medial-temporal areas. They also showed an adaptation deficit for objects whereby their lateral occipital complex (LOC) did not adapt to repeated objects in the context of a changing background. The LOC could be activated, however, when objects were presented without a background. Moreover, the adaptation deficit for objects viewed against backgrounds was reversed when elderly subjects were asked to attend to objects while viewing these complex pictures. These findings suggest that the elderly have difficulty with simultaneous processing of objects and backgrounds that, in turn, could contribute to deficient contextual binding.

Adult↗

PubMed2004

Cortical areas involved in object, background, and object-background processing revealed with functional magnetic resonance adaptation.

Previous work has suggested that object and place processing are neuroanatomically dissociated in ventral visual areas under conditions of passive viewing. It has also been shown that the hippocampus and parahippocampal gyrus mediate the integration of objects with background scenes in functional imaging studies, but only when encoding or retrieval processes have been directed toward the relevant stimuli. Using functional magnetic resonance adaptation, we demonstrated that object, background scene, and contextual integration of selectively repeated objects and background scenes could be dissociated during the passive viewing of naturalistic pictures involving object-scene pairings. Specifically, bilateral fusiform areas showed adaptation to object repetition, regardless of whether the associated scene was novel or repeated, suggesting sensitivity to object processing. Bilateral parahippocampal regions showed adaptation to background scene repetition, regardless of whether the focal object was novel or repeated, suggesting selectivity for background scene processing. Finally, bilateral parahippocampal regions distinct from those involved in scene processing and the right hippocampus showed adaptation only when the unique pairing of object with background scene was repeated, suggesting that these regions perform binding operations.

Adult↗

PubMedDate not supplied

Phytoestrogens as cardioprotective agents.

Epidemiologic studies have shown that women with a higher dietary intake of phytoestrogens, plant-derived compounds with partial estrogen agonist properties, have a lower incidence of cardiovascular disease and breast and uterine cancer than women with a lower dietary intake of these substances. The most-studied category of phytoestrogens is the isoflavones found in soybeans, chick peas, and other legumes. Genistein and daidzein are the 2 major forms of isoflavones and have demonstrated lipid-lowering properties, especially in hypercholesterolemic subjects. The mechanism for the hypocholesterolemic effects is unclear, but may involve altered hepatic metabolism, antioxidant properties, tyrosine kinase inhibition, and improved vascular reactivity. Other phytoestrogens, including coumestans and lignans, have shown unfavorable results with regard to their role in the prevention of coronary artery disease. Food and food supplements containing phytoestrogens are often advocated as an alternative to hormone replacement therapy (HRT) in women with contraindications to the use of conventional estrogen replacement or those wanting a natural alternative. In light of the recent trial results with HRT (estrogen plus progesterone), it would be prudent not to recommend phytoestrogens as cardioprotective substances until adequate safety and efficacy studies are completed.

Cardiotonic Agents↗