Reduced neuronal plasticity in the striatum, hippocampus, and neocortex is a common feature of transgenic mouse models of Huntington's disease (HD). Doublecortin (DCX) and polysialylated neural cell adhesion molecule (PSA-NCAM) are associated with structural plasticity in the adult mammalian brain, are markers of newly formed neurons in the dentate gyrus of the adult hippocampus, and are highly expressed in primary olfactory (piriform) cortex. Animal studies have demonstrated that a reduction in plasticity in the piriform cortex is associated with a selective impairment in odour discrimination. Therefore, the number of DCX and PSA-NCAM immunoreactive cells in the piriform cortex were quantified as measures of plasticity in early stage (fifteen week old) R6/1 transgenic HD mice. The transgenic mice had a large reduction in the number of DCX and PSA-NCAM immunoreactive cells in the piriform cortex, similar to that previously reported in the R6/2 mice. We also tested whether odour discrimination, as well as identification and detection, were impaired in HD patients and found that patients (at a similar disease stage as the mice) had an impairment in odour discrimination and identification, but not odour detection. These results suggest that olfactory impairments observed in HD patients may be the result of reduced plasticity in the primary olfactory cortex.
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http://dx.doi.org/10.1016/j.brainres.2007.03.018 | DOI Listing |
Alzheimers Dement
December 2024
Byrd Alzheimer's Center & Research Institute, Tampa, FL, USA.
Background: BIN1, the second strongest GWAS risk factor for late-onset Alzheimer's disease (AD), encodes a nucleocytoplasmic adaptor protein that plays many roles in multiple tissue and cell types. It is known that BIN1 can directly bind to tau in vitro, and neuronal BIN1 expression decreases in patients with AD. Accumulation of intracellular hyperphosphorylated tau is a hallmark pathogenic feature of AD and related tauopathies.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Stanford University School of Medicine, Stanford, CA, USA.
Background: Olfactory deficiency can be present in preclinical Alzheimer's (AD) and Parkinson's disease (PD), predicting their subsequent manifestation, including mild cognitive impairment (MCI). Analyzing key regions within the olfactory circuit could reveal important insights into the neuropathological progression. Dysfunction in the olfactory circuit has been shown in the olfactory nerve in limited postmortem studies, including involvement of a key region, the piriform cortex.
View Article and Find Full Text PDFNat Commun
January 2025
Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, Jiangsu, China.
Norepinephrine (NE) released from locus coeruleus (LC) noradrenergic (NAergic) neurons plays a pivotal role in the regulation of olfactory behaviors. However, the precise circuits and receptor mechanisms underlying this function are not well understood. Here, in DBH-Cre mice model, we show that LC NAergic neurons project directly to both anterior piriform cortex (aPC) and the olfactory bulb (OB).
View Article and Find Full Text PDFNeurosci Lett
December 2024
Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain. Electronic address:
Neuronal structural plasticity gives the adult brain the capacity to adapt to internal or external factors by structural and molecular changes. These plastic processes seem to be mediated, among others, by the action of the neurotransmitter serotonin through specific receptors (5-HTRs). Previous studies have shown that the maturation of granule cells in the hippocampus is mediated by 5-HT3.
View Article and Find Full Text PDFEur J Neurosci
January 2025
Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
The locus coeruleus (LC) plays a vital role in cognitive function through norepinephrine release. Impaired LC neuronal health and function is linked to cognitive decline during ageing and Alzheimer's disease. This study investigates age-related alterations in olfactory detection and discrimination learning, along with its reversal, in Long-Evans rats, and examines the effects of atomoxetine (ATM), a norepinephrine uptake inhibitor, on these processes.
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