Publications by authors named "D W Sweetnam"

Recovery from stroke is rarely complete as humans and experimental animals typically show lingering deficits in sensory function. One explanation for limited recovery could be that rewired cortical networks do not process sensory stimuli with the same temporal precision as they normally would. To examine how well peri-infarct and more distant cortical networks process successive vibro-tactile stimulations of the affected forepaw (a measure of temporal fidelity), we imaged cortical depolarizations with millisecond temporal resolution using voltage-sensitive dyes.

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Article Synopsis
  • Diabetic mice have an increased risk of stroke and show limited recovery compared to non-diabetic mice, with persistent deficits in forelimb sensorimotor function.
  • Changes in sensory evoked depolarizations occur in the primary forelimb somatosensory cortex (FLS1) post-stroke, but these responses are absent in diabetic mice, indicating impaired brain plasticity.
  • The secondary forelimb somatosensory cortex (FLS2) may aid recovery after stroke, but its function is diminished in diabetic mice, highlighting the complex interaction between diabetes and brain recovery mechanisms.
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The molecular mechanisms that mediate experience-based changes in the function of the cerebral cortex, particularly in the adult animal, are poorly understood. Here we show using in vivo voltage-sensitive dye imaging, that whisker trimming leads to depression of whisker-evoked sensory responses in primary, secondary and associative somatosensory cortical regions. Given the importance of cholinergic neurotransmission in cognitive and sensory functions, we examined whether α4-containing (α4*) nicotinic acetylcholine receptors (nAChRs) mediate cortical depression.

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The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna.

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