Detecting visual features in the environment such as motion direction is crucial for survival. The circuit mechanisms that give rise to direction selectivity in a major visual center, the superior colliculus (SC), are entirely unknown. Here, we optogenetically isolate the retinal inputs that individual direction-selective SC neurons receive and find that they are already selective as a result of precisely converging inputs from similarly-tuned retinal ganglion cells. The direction selective retinal input is linearly amplified by the intracollicular circuits without changing its preferred direction or level of selectivity. Finally, using 2-photon calcium imaging, we show that SC direction selectivity is dramatically reduced in transgenic mice that have decreased retinal selectivity. Together, our studies demonstrate a retinal origin of direction selectivity in the SC, and reveal a central visual deficit as a consequence of altered feature selectivity in the retina.

Purpose: The present study clarified the effects of repetitive transcranial magnetic stimulation (rTMS) in rats with vascular dementia (VaD) and explored the underlying mechanisms. Methods: Two-vessel occlusion was used as a VaD model. Two weeks after carotid artery occlusion, high (5 Hz) or low (1 Hz) frequency rTMS were applied for 10 days. Spatial learning and memory abilities were tested with a Morris water maze. Hippocampal CA1 neurons were histologically examined. The expressions of mammalian target of rapamycin (mTOR) and eukaryotic initiation factor 4E (eIF-4E) in CA1 were detected by western blot, and immunohistochemistry. Results: Unlike unlesioned control animals, VaD rats had an impaired morphology of CA1 neurons and a reduced ability of spatial memory. rTMS significantly improved both, the morphology and the learning and memory abilities of VaD rats compared to untreated lesioned rats. Protein expressions of mTOR and eIF-4E in CA1 of VaD rats were lower than in control rats but rTMS significantly increased the expression compared to untreated VaD rats. Conclusions: rTMS promotes recovery of learning and memory abilities of VaD rats. Molecular analysis suggests that the beneficial effect of rTMS may be partly induced by upregulation of protein expressions of mTOR and eIF-4E in CA1.Keywords: Vascular dementia (VaD), repetitive transcranial magnetic stimulation (rTMS), learning and memory, mammalian target of rapamycin (mTOR), eukaryotic translation initiation factor 4 (eIF-4E), Morris Water Maze, 2-vessel occlusion 1 These authors contributed equally to this work.

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

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