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Full-Text Articles in Psychology
Differential Effects And Rates Of Normal Aging In Cerebellum And Hippocampus, Michael R. Foy
Differential Effects And Rates Of Normal Aging In Cerebellum And Hippocampus, Michael R. Foy
Michael R. Foy
Cognitive functions show many alternative outcomes and great individual variation during normal aging. We examined learning over the adult life span in CBA mice, along with morphological and electrophysiological substrates. Our aim was to compare cerebellum-dependent delay eyeblink classical conditioning and hippocampus-dependent contextual fear conditioning in the same animals using the same conditioned and unconditioned stimuli for eyeblink and fear conditioning. In a subset of the behaviorally tested mice, we used unbiased stereology to estimate the total number of Purkinje neurons in cerebellar cortex and pyramidal neurons in the hippocampus. Several forms of synaptic plasticity were assessed at different ages …
Cyclic Changes In Estradiol Regulate Synaptic Plasticity Through The Map Kinase Pathway, Michael R. Foy
Cyclic Changes In Estradiol Regulate Synaptic Plasticity Through The Map Kinase Pathway, Michael R. Foy
Michael R. Foy
Hippocampal synaptic structure and function exhibit marked variations during the estrus cycle of female rats. Estradiol activates the mitogen-activated protein (MAP) kinase pathway in numerous cell types, and MAP kinase has been shown to play a critical role in the mechanisms underlying synaptic plasticity. Here, we report that endogenous estrogen produces a tonic phosphorylation/activation of extracellular signal-regulated kinase 2 (ERK2)/MAP kinase throughout the female rat brain and an increase in tyrosine phosphorylation of NR2 subunits of N-methyl-D-aspartate (NMDA) receptors. Moreover, cyclic changes in estrogen levels during the estrus cycle of female rats are associated with corresponding changes in the levels …
The Tyrosine Kinase And Mitogen-Activated Protein Kinase Pathways Mediate Multiple Effects Of Estrogen In Hippocampus, Michael R. Foy
The Tyrosine Kinase And Mitogen-Activated Protein Kinase Pathways Mediate Multiple Effects Of Estrogen In Hippocampus, Michael R. Foy
Michael R. Foy
Estrogen replacement therapy in women is associated with improvement of cognitive deficits and reduced incidence of Alzheimer's disease. The present study indicates that estrogen is neuroprotective against N-methyl-D-aspartate (NMDA)- and kainate-mediated neurotoxicity, an effect mediated by tyrosine kinase/mitogen-activated protein kinase (MAPK) pathways. Estrogen also stimulates tyrosine phosphorylation of NMDA receptors via an src tyrosine kinase/MAPK pathway. Finally, estrogen-mediated enhancement of long-term potentiation in hippocampal slices is mediated by activation of an src tyrosine kinase pathway. Thus, estrogen, by activating an src tyrosine kinase and the extracellular signal-related protein kinase/MAPK signaling pathway, both enhances NMDA receptor function and long-term potentiation and …
Behavioral Stress Modifies Hippocampal Plasticity Through N-Methyl-D-Aspartate Receptor Activation, Michael R. Foy
Behavioral Stress Modifies Hippocampal Plasticity Through N-Methyl-D-Aspartate Receptor Activation, Michael R. Foy
Michael R. Foy
Behavioral stress has detrimental effects on subsequent cognitive performance in many species, including humans. For example, humans exposed to stressful situations typically exhibit marked deficits in various learning and memory tasks. However, the underlying neural mechanisms by which stress exerts its effects on learning and memory are unknown. We now report that in adult male rats, stress (i.e., restraint plus tailshock) impairs long-term potentiation (LTP) but enhances long-term depression (LTD) in the CA1 area of the hippocampus, a structure implicated in learning and memory processes. These effects on LTP and LTD are prevented when the animals were given CGP39551 (the …