Binocular rivalry from luminance and contrast.

Binocular rivalry is the phenomenon that when two incompatible images are simultaneously presented, one to each eye, the two images compete with each other to be the dominant percept. Studying the underlying neural mechanisms of binocular rivalry is useful for understanding the mechanisms of interocular inhibition. Levelt's Propositions, a set of four propositions that were originally published over fifty years ago, are not only useful for characterizing the perceptual dynamics of binocular rivalry, but can also provide a metric for assessing the common or differential neural mechanisms of binocular rivalry when diverse stimulus types are used. In the present study, we conducted a series of psychophysics experiments, where we compared the rivalry dynamics of two quite different types of stimuli. Orthogonal gratings, a classic type of rivalry stimulus, were contrasted with luminance patches, a type of rivalry stimulus that is relatively less studied. Our results showed that, similar to the orthogonal gratings, the alternate percepts in luminance-only rivalry were described by the modified Levelt's Propositions, despite the clearly slower alternation rates for luminance patches. However, unlike the mixed percepts observed during transitions between oriented gratings, fusion percepts during luminance rivalry were common, could be lustrous, and obeyed the same Propositions, suggesting a regime of tri-stability. Overall, both types of rivalry are consistent with recent models that posit separate binocular and monocular channels embedded within neural circuits that also accomplish contrast normalization. Finally, luminance rivalry is discussed in the contexts of binocular summation and suppression, as well as Fechner's paradox.

Pattern integrations in young depressed women: Part II.

Using Hildegard Peplau's theoretical model and focusing on the concept of pattern integrations, clinical data from a pilot intervention program for depressed women were analyzed. The program consisted of a collaborative relationship between primary-care providers and two Psychiatric-Mental Health Clinical Nurse Specialists in which women experiencing symptoms of depression were identified and referred to the research program. Data derived from clinical intervention done over a 4-month period with 6 women (42 hours of clinical tapes) was used for analysis. Clusters of behaviors constituting pattern integrations were analyzed for the reciprocal interactions of the nurses and the clients. Four pattern integrations common to the women in the sample were identified. Clinical examples and a framework for intervention using the patterns integrations is presented.

Reduced natural killer cell cytotoxicity in depression but not in schizophrenia.

A reduction of natural killer (NK) cell activity has been found in hospitalized patients with major depressive disorder. To examine whether a reduction of NK activity is found in other psychiatric patients or related to the nonspecific effects of hospitalization, NK cell cytotoxicity was compared in hospitalized depressed patients, schizophrenic inpatients, and two groups of controls separately age matched to each patient group. NK activity was significantly (p less than 0.01) lower in depressed inpatients than control subjects. However, in the hospitalized schizophrenic patients values of natural cytotoxicity did not differ from controls. These findings suggest that reduced NK cytotoxicity in depression is independent of the effects of hospitalization.

Small cell neuroendocrine carcinoma of Bartholin's gland.

A small cell neuroendocrine carcinoma that arose in Bartholin's gland in a 30-year-old woman is reported. The tumor had light, electron microscopic, and immunohistochemical features typical of pulmonary small cell carcinoma and was metastatic to inguinal lymph nodes at presentation. This is the first reported example of this tumor occurring in Bartholin's gland.