Neuroscience
-
Alzheimer's disease (AD) is a neurodegenerative disease characterised by progressive cognitive decline and the accumulation of two hallmark proteins, amyloid-beta (Aβ) and tau. Traditionally, transgenic mouse models for AD have generally focused on Aβ pathology, however, in recent years a number of tauopathy transgenic mouse models have been developed, including the TAU58/2 mouse model. These mice develop tau pathology and neurofibrillary tangles from 2 months of age and show motor impairments and alterations in the behavioural response to elevated plus maze (EPM) testing. ⋯ Aggressive and socio-positive behaviours were not affected except a reduction in the occurrence of nosing and anogenital sniffing. Our study identified new phenotypic characteristics of young adult male TAU58/2 transgenic mice and clarified the nature of changes detected in the behavioural response of these mice to EPM testing. Social withdrawal and inappropriate social behaviours are common symptoms in both AD and FTD patients and impaired sensorimotor gating is seen in moderate-late stage AD, emphasising the relevance of the TAU58/2 model to these diseases.
-
Activity-regulated cytoskeleton-associated (Arc) gene is one of the effector neuronal immediate early genes (IEG) that is rapidly upregulated after neuronal activation and is involved in synaptic long-term potentiation and depression. In recent years, it has been implicated in several cognitive disorders, viz. Angelman syndrome, Alzheimer's disease, fragile-X syndrome, etc. ⋯ We studied the involvement of Arc in these changes by inhibiting Arc protein expression via stereotaxic infusions of Arc antisense oligodeoxynucleotides in the hippocampus of mice. We found that both temporal order and object recognition memories are dependent on the inter-familiarization phase interval. Strikingly, we also found that Arc accelerated the memory decay of an object when mice were re-exposed to the environment without that object.
-
Tuning of the cardiovascular response is crucial to maintain performance during high-intensity exercise. It is well known that the nucleus of the solitary tract (NTS) in the brainstem medulla plays a central role in cardiovascular regulation; however, where and how upper brain regions form circuits with NTS and coordinately control cardiovascular responses during high-intensity exercise remain unclear. Here focusing on the amygdala and claustrum, we investigated part of the mechanism for regulation of the cardiovascular system during exercise. ⋯ Simultaneous stimulation of the central nucleus of the amygdala and pCL showed a greater pressor response compared with the stimulation of the amygdala alone. These results suggest the amygdala and pCL are involved in different phases of exercise. More speculatively, these areas might coordinately tune cardiovascular responses that help maintain performance during high-intensity exercise.