Increased spreading activation in depression

The dopaminergic system is implicated in depressive disorders and research has also shown that dopamine constricts lexical/semantic networks by reducing spreading activation. Hence, depression, which is linked to reductions of dopamine, may be associated with increased spreading activation. However, research has generally found no effects of depression on spreading activation, using semantic priming paradigms. We used a different paradigm to investigate the relationship between depression and spreading activation, one based on word frequencies. Our sample included 97 undergraduates who completed the BDI-II and the Controlled Oral Word Association test as well as the Animal Naming test. The results indicated that the group scoring within the depressed ranged evidenced greater spreading activation as compared to those who scored within the normal range on the BDI-II. The implications of these results as they relate to creativity in depression is discussed.     

Transfer of motor learning engages specific neural substrates during motor memory consolidation dependent on the practice structure

The authors investigated how brain activity during motor-memory consolidation contributes to transfer of learning to novel versions of a motor skill following distinct practice structures. They used 1 Hz repetitive Transcranial Magnetic Stimulation (rTMS) immediately after constant or variable practice of an arm movement skill to interfere with primary motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC). The effect of interference was assessed through skill performance on two transfer targets: one within and one outside the range of practiced movement parameters for the variable practice group. For the control (no rTMS) group, variable practice benefited delayed transfer performance more than constant practice. The rTMS effect on delayed transfer performance differed for the two transfer targets. For the within-range target, rTMS interference had no significant affect on the delayed transfer after either practice structure. However, for the outside-range target, rTMS interference to DLPFC but not M1 attenuated delayed transfer benefit following variable practice. Additionally, for the outside-range target, rTMS interference to M1 but not DLPFC attenuated delayed transfer following constant practice. This suggests that variable practice may promote reliance on DLPFC for memory consolidation associated with outside-range transfer of learning, whereas constant practice may promote reliance on M1 for consolidation and long-term transfer.     

Aberrant first fixations when looking at inverted faces in various poses: The result of the centre‐of‐gravity effect?

Face recognition is essential in everyday human life, and all faces are encountered in different poses. However, when a face is inverted, difficulties arise for recognition and eye movements may (Barton, Radcliffe, Cherkasova, Edleman, & Intriligator, 2006) or may not be disrupted (Williams & Henderson, 2007). The present study explored the effects of orientation and pose on recognition and eye movements during a standard old/new recognition task in order to resolve whether inversion disrupts eye movements. Eye‐tracking data looked at the first fixations, the number of fixations, and the duration of fixations over a face. A standard inversion effect was observed, but the three‐quarter view advantage was not observed. Eye‐movement data revealed that the eyes were the most sampled feature (in terms of first fixation, number of fixations, and duration of fixation) for all upright faces, however, other features were sampled first for inverted faces. These results are consistent with Barton et al.'s (2006) but not Williams and Henderson's (2007) findings: possible explanations for this are discussed with the caveat that the same images were used from learning to test.     

Absent Qualia and Categorical Properties

Qualia have proved difficult to integrate into a broadly physicalistic worldview. In this paper, I argue that despite popular wisdom in the philosophy of mind, qualia’s intrinsicality is not sufficient for their non-reducibility. Second, I diagnose why philosophers mistakenly focused on intrinsicality. I then proceed to argue that qualia are categorical and end with some reflections on how the conceptual territory looks when we keep our focus on categoricity.     

Bingo! Externally supported performance intervention for deficient visual search in normal aging, Parkinson's disease, and Alzheimer's disease

External support may improve task performance regardless of an individual's ability to compensate for cognitive deficits through internally generated mechanisms. We investigated if performance of a complex, familiar visual search task (the game of bingo) could be enhanced in groups with suboptimal vision by providing external support through manipulation of task stimuli. Participants were 19 younger adults, 14 individuals with probable Alzheimer's disease (AD), 13 AD-matched healthy adults, 17 non-demented individuals with Parkinson's disease (PD), and 20 PD-matched healthy adults. We varied stimulus contrast, size, and visual complexity during game play. The externally supported performance interventions of increased stimulus size and decreased complexity resulted in improvements in performance by all groups. AD also obtained benefit from increasing contrast, presumably by compensating for their contrast sensitivity deficit. The general finding of improved performance across healthy and afflicted groups suggests the value of visual support as an easy-to-apply intervention to enhance cognitive performance.