Neuroscience
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We studied eye and body movements in 16 healthy young adults who performed visual tasks in upright stance. Our objective was to investigate whether these movements could be functionally related to each other when performing a precise visual task requiring large ecological gaze shifts. We also questioned the influence of an additional counting task on these relations. ⋯ The subjective cognitive involvement (significantly higher in searching than in free-viewing and gaze-fixation) was significantly related to all (100%) and to half (50%) of these previous correlations in search-counting and searching, respectively. Complementarily, the participants rotated their segments and oscillated more in searching than free-viewing and more in both tasks than in gaze-fixation. This study confirmed that precise visual tasks may require the brain to control synergistic relations between eye and body movements instead of individual eye and body movements.
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Two-photon vision arises from the perception of pulsed infrared (IR) laser light as color corresponding to approximately half of the laser wavelength. The physical process responsible for two-photon vision in rods has been delineated and verified experimentally only recently. Here, we sought to determine whether IR light can also be perceived by mammalian cone photoreceptors via a similar activation mechanism. ⋯ In both cases, efficient detection of IR light was dependent on minimizing the dispersion of the ultrashort light pulses, indicating a non-linear two-photon activation process. Together, our studies demonstrate that mammalian cones can be activated by near IR light by a nonlinear two-photon excitation. Our results pave the way for the creation of a two-photon IR-based ophthalmoscope for the simultaneous imaging and functional testing of human retinas as a novel tool for the diagnosis and treatment of a wide range of visual disorders.
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L2 processing is shaped by L1 experience; however, it is not completely understood whether L1 reading experience also influences how the brain learns L2 under different learning conditions. In this study, we compare brain mechanisms of Spanish word learning in Chinese and English speakers using two learning conditions: speech-based learning and handwriting-based learning. The behavioral data suggest an advantage for learning that uses handwriting over speech-based learning across all participants. ⋯ Thus, the handwriting-based learning engaged visuo-orthographic regions to a greater degree in highly skilled Chinese speakers. In summary, the current findings suggest that handwriting facilitates lexical learning by enhancing orthographic involvement in Chinese speakers, while the handwriting condition enhanced phonological involvement in English speakers. This difference between Chinese and English speakers might be due to different L1 learning experience.
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Some models of motivation distinguish between intrinsic and extrinsic motivation. While past work has examined the neural and cognitive correlates of extrinsic motivation, research on intrinsic motivation has relied primarily on behavioral measures of performance and learning. In particular, no past work has examined the neural and cognitive correlates of social performance expectancy, which is linked to intrinsic motivation. ⋯ EEG was used to examine motor-action preparation as measured by suppression of beta band activity over the motor cortex and feedback processing as measured by the Reward Positivity (RewP). Results revealed expectancy of difficult (vs. easy) trials narrowed attentional scope, reduced beta activity over the motor cortex, and enhanced RewP amplitudes to win feedback. These findings suggest that enhancing intrinsic motivation through expectancies of positive social comparison engages similar neural and cognitive correlates as extrinsic motivators high in motivational intensity.
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Colivelin is a neuroprotective humanin family peptide with potent long-term capacity against Aβ deposition, neuronal apoptosis, and synaptic plasticity deficits in neurodegenerative disease. We seek to investigate whether this effect of Colivelin also govern ischemic brain injury, and potential mechanism underlying the Colivelin-mediated action on ischemic neurons. We adopted 60 min induction of transient focal cerebral ischemia and reperfusion in mice. ⋯ Moreover, Colivelin activated STAT3 signaling, which may partially contribute to its beneficial effect against neuronal death and axon growth. In conclusion, Colivelin induce anti-apoptotic genes up-regulation, and activate JAK/STAT3 signaling after ischemic stroke, which may contribute to its effects of rescuing ischemic neuronal death and axonal remodeling. This study may justify further works to examine Colivelin as a single or adjunct therapy in ischemic stroke.