Brain research bulletin
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Functional brain-imaging studies of house-face binocular rivalry and Rubin's vase-faces illusion have consistently reported face perception-dependent activity in the right fusiform gyrus. Here we use Rubin's illusion and report that activation of the left hemisphere by caloric vestibular stimulation increases the predominance of the faces percept in a substantial number of test subjects. While partially supporting the brain-imaging lateralization reports, our findings also challenge these studies by suggesting that neural mechanisms of Rubin's illusion cannot be limited to extrastriate perception-dependent processing. In accordance with our previously proposed interhemispheric switch model, the present findings support the notion that perceptual rivalry engages high-level cortical structures that mediate unihemispheric attentional selection.
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Brain research bulletin · Mar 2008
Chronic buspirone treatment normalizes open field behavior in olfactory bulbectomized rats: assessment with a quantitative autoradiographic evaluation of the 5-HT1A binding sites.
The olfactory bulbectomized (OBX) rat model of depression has been widely used in studies on the behavioral and neurochemical aspects of human depression. The objective of the present investigation was to assess open field (OF) activity and the brain regional 5-HT(1A) receptor densities of the sham operated (SHX) and OBX rats treated with saline (SHX-SAL, OBX-SAL), and either 10 mg/(kg day) (SHX-B10, OBX-B10) or 20 mg/(kg day) (SHX-B20, OBX-B20) of buspirone for 14 days, delivered by a subcutaneous osmotic minipump. Adult Sprague-Dawley rats were used for this experiment. ⋯ A dose dependent reduction in the density of 5-HT(1A) sites was observed in the sham rats, but the buspirone treatment had very little effect on the density of the 5-HT(1A) receptors in the OBX rats. From these observations, we conclude that the antidepressant effects of buspirone in the OBX rat model of depression are likely mediated through the fine tuning of the regional imbalance of 5-HT(1A) receptors with even increases of about 20% in some limbic regions. The data suggest that the neurochemical effects of antidepressants should be studied in animal models of depression rather than in normal rats.