We investigated whether the ventral and dorsal hippocampus were differentially involved in incidental spatial learning. Rats with ventral and dorsal hippocampal lesions were tested on an unreinforced test of spatial memory that takes advantage of their natural propensity to explore novelty. Rats were presented with two copies of an identical object in a large circular open field arena. Subsequently, the rats were placed back into the open field with one of the objects displaced to an adjacent quadrant of the arena. Sham-operated rats and rats with ventral hippocampal lesions spent more time in the quadrant that contained the displaced object than in the quadrant that contained the non-displaced object, and more time investigating the displaced object than the non-displaced object. Rats with dorsal hippocampal lesions were impaired on both measures. Both sham and ventral hippocampal lesioned rats subsequently learned to retrieve a food pellet in the ends of each arm of a radial maze. Rats with lesions to the dorsal hippocampus showed no significant improvement in the number of errors made across training sessions and made significantly more errors, overall, than rats with ventral hippocampal or sham lesions. The findings suggest that an intact dorsal but not ventral hippocampus is necessary for spatial learning in rats.
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http://dx.doi.org/10.1016/j.bbr.2009.03.016 | DOI Listing |
Int J Mol Sci
December 2024
Department of Animal and Human Physiology, Faculty of Biology, University of Gdansk, 59 Wita Stwosza Str., 80-308 Gdansk, Poland.
Amphetamine abuse is a global health epidemic that is difficult to treat due to individual differences in response to environmental factors, including stress reactivity and anxiety levels, as well as individual neuronal differences, which may result in increased/decreased vulnerability to addiction. In the present study, we investigated whether the Wistar rats behavioral traits of high (HR) and low (LR) locomotor activity to novelty influence motivational behavior (induced feeding model; iFR by electrical stimulation of the ventral tegmental area; Es-VTA) supported by amphetamine injection into the nucleus accumbens shell (AcbSh) (HR, n = 5; LR, n = 5). A correlation was found between the novelty test's locomotor activity score and the frequency threshold percentage change ( < 0.
View Article and Find Full Text PDFNeuropharmacology
January 2025
Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
Hypoactive sexual desire disorder (HSDD) is the most reported sexual dysfunction among premenopausal women worldwide. Bremelanotide, trade name Vyleesi, has been approved by the United States Food and Drug Administration to treat HSDD. However, despite approval, very little is known about its neurobiological mechanism of action.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.
The novelty, saliency, and valency of ongoing experiences potently influence the firing rate of the ventral tegmental area (VTA) and the locus coeruleus (LC). Associative experience, in turn, is recorded into memory by means of hippocampal synaptic plasticity that is regulated by noradrenaline sourced from the LC, and dopamine, sourced from both the VTA and LC. Two persistent forms of synaptic plasticity, long-term potentiation (LTP), and long-term depression (LTD) support the encoding of different kinds of spatial experience.
View Article and Find Full Text PDFSci Rep
January 2025
Neuroscience Graduate Program, The Ohio State University, Columbus, OH, 43210, USA.
Postpartum depression (PPD) affects up to 20% of new mothers and has adverse consequences for the well-being of both mother and child. Exposure to stress during pregnancy as well as dysregulation in the mesolimbic dopamine (DA) reward system and its upstream modulator oxytocin (OT) have been independently linked to PPD. However, no studies have directly examined DA or OT signaling in the postpartum brain after gestational stress.
View Article and Find Full Text PDFJ Neurosci
January 2025
Carleton University, Neuroscience Department, Ottawa, ON, Canada,
Ghrelin enhances feeding by activating the growth hormone secretagogue receptor (GHSR). In the brain, GHSRs are expressed in regions responsible for regulating food motivation including the ventral tegmental area (VTA). Endogenous cannabinoids also promote food seeking behaviors through the cannabinoid receptor 1 type (CB-1Rs) in brain regions including the VTA.
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