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Cortical Regulation of the Mesolimbic Dopamine System: Implications for Schizophrenia
Published in Peter W. Kalivas, Charles D. Barnes, Limbic Motor Circuits and Neuropsychiatry, 2019
Barbara K. Lipska, Daniel R. Weinberger
Although the hippocampus has also been implicated in stress, it does not seem to directly regulate mechanisms of coping with stress. The hippocampus does, however, influence the mesolimbic dopaminergic system, and it does affect dopaminergic transmission in the prefrontal cortex. These effects have been shown to be primarily dependent on the ventral hippocampal formation. The destruction of the ventral hippocampal formation early in life, supposedly before maturation of cortical connections and/or before puberty, induces still different effects. In contrast to the lesion induced in an adult animal, excitotoxic hippocampal damage remains silent with respect to mesolimbic DA for a prolonged period of time, whereupon profound mesolimbic dopaminergic dysregulation accompanied by the hyperresponsiveness to stressful stimuli emerges. The emergence of abnormal behaviors after a relatively prolonged period of normalcy seems to be a unique and crucial aspect of this animal model that is particularly relevant to schizophrenia, because it involves both the developmental pathology in the hippocampus and a unique profile of changes strongly suggestive of hyperresponsiveness of the mesolimbic DA system that are all features of this illness.
Surgical outcomes, cognitive frailty and delirium
Published in Shibley Rahman, Living with frailty, 2018
The cellular mechanisms underlying resilience, in relation to cognitive frailty and reserve, are actually quite fascinating. There is converging evidence that degenerative processes of the entorhinal–hippocampal formation occur at very early stages of Alzheimer’s disease (Braak and Braak, 1991, 1997). Atrophy of the medial temporal lobe, particularly the parahippocampal and hippocampal regions, seems associated with memory loss (Laakso et al., 2000; Pennanen et al., 2004). Thus, reduction in hippocampal volume represents one of the structural hallmarks of incipient AD (Chetelat and Baron, 2003; Kantarci and Jack, 2003; Wolf et al., 2004). From a clinical standpoint, the amnestic type of mild cognitive impairment (Petersen et al., 1999, 2001) is at present the most valid concept indicative of incipient or early AD (Morris et al., 2001; Grundman et al., 2003; Crocco and Loewenstein, 2005).
Non-Synonyms (Similar-Sounding)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Hippocampal formation (B&K, p. 264): Usually includes not only the “hippocampus” (see below), but also the dentate gyrus and a small part (subiculum) of the “parahippocampal gyrus” (see below). See, also, D: Hippocampal formation.
Short-term consumption of alcohol (vodka) mixed with energy drink (AMED) attenuated alcohol-induced cerebral capillary disturbances and neuroinflammation in adult wild-type mice
Published in Nutritional Neuroscience, 2022
Ryusuke Takechi, John Mamo, Sukanya Das, Liam Graneri, Zachary D’Alonzo, Michael Nesbit, Edwin Junaldi, Virginie Lam
Hippocampal formation of the brain plays a critical role in retrieving the sequence of events that forms episodic memory [30]. Parts of the cerebral cortex play critical role in performance monitoring, other cognitive control and task switching [31, 32]. Increasing evidence indicates that the disruption of BBB in those particular brain regions are causally associated with the onset of cognitive impairment. Montagne et al. found that the breakdown of BBB and cerebral capillary pericyte degeneration accurately predicts cognitive decline in clinically healthy participants and subjects with cognitive decline [33]. Furthermore, in animal models of cognitive deficits, disruption of the BBB was shown to precede neurodegeneration and cognitive decline, suggesting causality [3]. Thus, the present study offers valuable insight on the potential effects of alcohol and ED consumption on brain capillary integrity and risk of cognitive impairment.
Effect of sodium selenite on synaptic plasticity and neurogenesis impaired by hypothyroidism
Published in International Journal of Neuroscience, 2022
Ercan Babur, Özlem Canöz, Burak Tan, Cem Süer, Nurcan Dursun
It is usually assumed that synaptic plasticity within the hippocampal formation contributes to the acquisition and retention of memories. A considerable body of evidence has accumulated indicating that the dentate gyrus (DG) of the adult hippocampus produces new neurons in substantial numbers. Synaptic plasticity and neurogenesis are inter-related phenomena, and considered to provide substrate for specific aspects of learning and memory function [10]. Previous studies have shown that long-term potentiation (LTP) evoked by train stimulation of the perforant pathway are significantly depressed [11] and that the number of newborn neuroblasts is decreased in adult hypothyroid animals [12]. It is well-known that fetal neurogenesis requires thyroid hormone signaling [13]. Thyroid hormone also regulates hippocampal subgranular zone () progenitor survival and neuronal cell fate acquisition in adulthood [14,15]. Moreover, decreased hippocampal neurogenesis as shown by decreases in survival and neuronal differentiation of hippocampal progenitors [16] and impaired LTP [17] could be rescued by restored euthyroid status.
Sectorization of the hippocampal formation: Cytoarchitectonics, topography, or vulnerability to hypoxia?
Published in Journal of the History of the Neurosciences, 2022
But the terminology related to these structures also shows some discrepancies: for example, the term hippocampal formation designates either the hippocampal complex to which is added the subiculum (Nieuwenhuys, Voogd, and van Huijzen 2008, 372) or all of these structures plus the entorhinal cortex (Standring 2016, 387). The Terminologia Anatomica, which is supposed to simplify the nomenclature and to clarify once and for all the meaning of terms used in morphological sciences, is unfortunately of very little help. It includes under the term “Hippocampus” the hippocampus proper (or Ammon’s horn, formed by regions I–IV or sectors CA1-C4), the subiculum and its subdivisions (why apart from the prosubiculum?), the fimbria, the layers of hippocampus, and the dentate gyrus with its layers (Federative Committee on Anatomical Terminology, 1998, 128).