The head-direction (HD) signal is believed to originate in the dorsal tegmental nucleus (DTN) and lesions to this structure have been shown to disrupt HD cell firing in other areas along the HD cell circuit. To investigate the role of the DTN in spatial navigation, rats with bilateral, electrolytic (Experiment 1), or neurotoxic (Experiment 2) lesions to the DTN were compared with sham controls on two tasks that differed in difficulty and could be solved using directional heading. Rats were first trained on a direction problem in a water T maze where they learned to travel either east or west from two locations in the experimental room. DTN-lesioned rats were impaired relative to sham controls, both early in training, on the first block of eight trials, and on the total trials taken to reach criterion. In the food-foraging task, rats were trained to leave a home cage at the periphery of a circular table, find food in the center of the table and return to the home cage. Again, DTN-lesioned rats were impaired relative to sham rats, making more errors on the return component of the foraging trip. These data extend previous cell-recording studies and behavioral tests in which rats with electrolytic DTN lesions were used, and they demonstrate the importance of the direction system to spatial learning.
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http://dx.doi.org/10.1037/a0034931 | DOI Listing |
Neuropharmacology
January 2025
Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
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December 2024
Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548 Coimbra, Portugal; Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal; Faculty of Medicine, Institute of Physiology, University of Coimbra, 3004-531 Coimbra, Portugal. Electronic address:
Dysfunctional response inhibition, mediated by the striatum and its connections, is thought to underly the clinical manifestations of obsessive-compulsive disorder (OCD). However, the exact neural mechanisms remain controversial. In this study, we undertook a novel approach by positing that a) inhibition is a dynamic construct inherently susceptible to numerous failures, which require error-processing, and b) the actor-critic framework of reinforcement learning can integrate neural patterns of inhibition and error-processing in OCD with their behavioural correlates.
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December 2024
Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
Rapid adaptation to novel environments is crucial for survival, and this ability is impaired in many neuropsychiatric disorders. Understanding neural adaptation to novelty exposure therefore has therapeutic implications. Here, I found that novelty induces time-dependent theta (4-12Hz) oscillatory dynamics in brain circuits including the medial prefrontal cortex (mPFC), ventral hippocampus (vHPC), and ventral tegmental area (VTA), but not dorsal hippocampus (dHPC), as mice adapt to a novel environment.
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December 2024
Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
Exercise activates the dorsal hippocampus that triggers synaptic and cellar plasticity and ultimately promotes memory formation. For decades, these benefits have been explored using demanding and stress-response-inducing exercise at moderate-to-vigorous intensities. In contrast, our translational research with animals and humans has focused on light-intensity exercise (light exercise) below the lactate threshold (LT), which almost anyone can safely perform with minimal stress.
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Fetal Medicine Unit, Ontario Fetal Center, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada.
Mesencephalosynapsis is characterized by a failure of the dorsal brainstem colliculi to separate into distinct lateral masses (non-cleavage, a.k.a.
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