Publications by authors named "Nicole A Donlan"

Stroke enhances proliferation of neural precursor cells within the subventricular zone (SVZ) and induces ectopic migration of newborn cells towards the site of injury. Here, we characterize the identity of cells arising from the SVZ after stroke and uncover a mechanism through which they facilitate neural repair and functional recovery. With genetic lineage tracing, we show that SVZ-derived cells that migrate towards cortical photothrombotic stroke in mice are predominantly undifferentiated precursors.

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Background: Electrical and magnetic brain stimulation can improve motor function following stroke in humans, rats, and nonhuman primates, especially when paired with rehabilitative training (RT). Previously, we found in rodent stroke models that epidural electrical cortical stimulation (CS) of the ipsilesional motor cortex (MC) combined with motor RT enhances motor function and motor cortical plasticity. It was unknown whether CS following experimental traumatic brain injury (TBI) would have similar effects.

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Following unilateral stroke, the contralateral (paretic) body side is often severely impaired, and individuals naturally learn to rely more on the nonparetic body side, which involves learning new skills with it. Such compensatory hyper-reliance on the "good" body side, however, can limit functional improvements of the paretic side. In rats, motor skill training with the nonparetic forelimb (NPT) following a unilateral infarct lessens the efficacy of rehabilitative training, and reduces neuronal activation in perilesion motor cortex.

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Article Synopsis
  • Motor cortex representations adapt during motor skill learning in young adults, but the impact of aging on these changes is not well understood.
  • In young mice, short-term training altered forelimb movement areas, but after long training, these changes reverted despite continuous practice, though some improvements in responsiveness were noted.
  • Aged mice showed no significant changes in movement representation despite learning skilled tasks effectively, indicating that while they maintain some learning capacity, their cortical plasticity and overall sensorimotor functions decline with age.
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The organization of forelimb representation areas of the monkey, cat, and rat motor cortices has been studied in depth, but its characterization in the mouse lags far behind. We used intracortical microstimulation (ICMS) and cytoarchitectonics to characterize the general organization of the C57BL/6 mouse motor cortex, and the forelimb representation in more detail. We found that the forelimb region spans a large area of frontal cortex, bordered primarily by vibrissa, neck, shoulder, and hindlimb representations.

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Adult workers of some social insect species show dramatic behavioral changes as they pass through a sequence of task specializations. In the paper wasp, Polybia aequatorialis, female workers begin adult life within the nest tending brood, progress to maintaining and defending the nest exterior, and ultimately leave the nest to forage. The mushroom body (MB) calyx neuropil increases in volume as workers progress from in-nest to foraging tasks.

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Highly eusocial insect workers exhibit age-related division of labor. Adults begin working inside the nest, moving to the nest periphery and later to foraging. Passage through this task sequence is associated with neuroanatomical changes in the mushroom bodies (MB) of honey bee (Apis) and ant (Camponotus) workers.

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Recommendations from experts and recently established guidelines on how to improve the face and predictive validity of animal models of stroke have stressed the importance of using older animals and long-term behavioral-functional endpoints rather than relying almost exclusively on acute measures of infarct volume in young animals. The objective of the present study was to determine whether we could produce occlusions in older rats with an acceptable mortality rate and then detect reliable, long-lasting functional deficits. A reversible intraluminar suture middle cerebral artery occlusion (MCAO) procedure was used to produce small infarcts in middle-aged rats.

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