Marked hippocampal changes in response to excitatory amino acid agonists occur during pregnancy (e.g. decreased frequency in spontaneous recurrent seizures in rats with KA lesions of the hippocampus) and lactation (e.g. reduced c-Fos expression in response to N-methyl-d,l-aspartic acid but not to kainic acid). In this study, the possibility that lactation protects against the excitotoxic damage induced by KA in hippocampal areas was explored. We compared cell damage induced 24 h after a single systemic administration of KA (5 or 7.5 mg/kg bw) in regions CA1, CA3, and CA4 of the dorsal hippocampus of rats in the final week of lactation to that in diestrus phase. To determine cellular damage in a rostro-caudal segment of the dorsal hippocampus, we used NISSL and Fluorojade staining, immunohistochemistry for active caspase-3 and TUNEL, and we observed that the KA treatment provoked a significant loss of neurons in diestrus rats, principally in the pyramidal cells of CA1 region. In contrast, in lactating rats, pyramidal neurons from CA1, CA3, and CA4 in the dorsal hippocampus were significantly protected against KA-induced neuronal damage, indicating that lactation may be a natural model of neuroprotection.
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http://dx.doi.org/10.1016/j.yhbeh.2007.09.004 | DOI Listing |
J Neurophysiol
January 2025
Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee WI, USA.
The hippocampus has a known role in learning and memory, with the ventral subregion supporting many learning tasks involving affective responding, including fear conditioning. Altered neuronal intrinsic excitability reflects experience-dependent plasticity that supports learning-related behavioral changes. Such changes have previously been observed in the dorsal hippocampus following fear conditioning, but little work has examined the effect of fear conditioning on ventral hippocampal intrinsic plasticity.
View Article and Find Full Text PDFJ Neurosci
January 2025
Laboratory of Systems Neuroscience, Department of Physiology, University of Bern, Bern, Switzerland.
The hippocampus supports a multiplicity of functions, with the dorsal region contributing to spatial representations and memory, and the ventral hippocampus (vH) being primarily involved in emotional processing. While spatial encoding has been extensively investigated, how the vH activity is tuned to emotional states, e.g.
View Article and Find Full Text PDFNeuroscience
January 2025
Laboratory of Epileptogenesis, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St, 02-093 Warsaw, Poland. Electronic address:
Our previous in silico data indicated an overrepresentation of the ZF5 motif in the promoters of genes in which circadian oscillations are altered in the ventral hippocampus in the pilocarpine model of temporal lobe epilepsy in mice. In this study, we test the hypothesis that the Zbtb14 protein oscillates in the hippocampus in a diurnal manner and that this oscillation is disrupted by epilepsy. We found that Zbtb14 immunostaining is present in the cytoplasm and cell nuclei.
View Article and Find Full Text PDFProg Neurobiol
January 2025
Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile; Millennium Nucleus of Neuroepigenetics and Plasticity (EpiNeuro), Santiago, Chile. Electronic address:
Ketamine administration during adolescence affects cognitive performance; however, its long-term impact on synaptic function and neuronal integration in the hippocampus a brain region critical for cognition remains unclear. Using functional and molecular analyses, we found that chronic ketamine administration during adolescence exerts long-term effects on synaptic integration, expanding the temporal window in an input-specific manner affecting the inner molecular layer but not the medial perforant path inputs in the adult mouse dorsal hippocampal dentate gyrus. Ketamine also alters the excitatory/inhibitory balance by reducing the efficacy of inhibitory inputs likely due to a reduction in parvalbumin-positive interneurons number and function.
View Article and Find Full Text PDFNeuropsychologia
January 2025
Neuroscience Area, SISSA, Trieste, Italy; Dipartimento di Medicina dei Sistemi, Università di Roma-Tor Vergata, Roma, Italy.
Although gesture observation tasks are believed to invariably activate the action-observation network (AON), we investigated whether the activation of different cognitive mechanisms when processing identical stimuli with different explicit instructions modulates AON activations. Accordingly, 24 healthy right-handed individuals observed gestures and they processed both the actor's moved hand (hand laterality judgment task, HT) and the meaning of the actor's gesture (meaning task, MT). The main brain-level result was that the HT (vs MT) differentially activated the left and right precuneus, the left inferior parietal lobe, the left and right superior parietal lobe, the middle frontal gyri bilaterally and the left precentral gyrus.
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