China
Africa
Explore chapters and articles related to this topic
Anterograde memory in frontotemporal dementia
Published in Lars-Göran Nilsson, Nobuo Ohta, Dementia and Memory, 2013
John R. Hodges, Michael Hornberger, Oliver Piguet
The perirhinal cortex occupies part of the anterior fusiform gyrus and is anatomically identical to the temporal pole emerges as the critical neuroanatomical region for such complex perceptual processing. The perirhinal cortex is damaged in SD from an early disease stage (Davies, Graham, Xuereb, Williams, & Hodges, 2004; Graham et al., 2000; Mion et al., 2010). The critical role of perirhinal cortex in object recognition was established in monkeys with experimentally-induced lesions of this region (e.g., Buckley & Gaffan, 1997). Recent evidence, however, suggests that perirhinal cortex damage causes a higher perceptual deficit, rather than a memory deficit per se (Bussey & Saksida, 2007). This brain region appears critically involved in analysing and representing complex conjunctions of the features that comprise an individual object. This role could explain the change in pattern of recognition memory performance observed in SD. Simple object recognition, where identical examples of the object are presented at study and test, do not require perirhinal cortex input (Graham et al., 2000; Simons, Graham, Galton, Patterson, & Hodges, 2001), whereas those with a change of example, viewpoint, or colour do. This hypothesis is supported by recent work showing that patients with SD fail perceptual tasks with virtually no memory load that use concurrent visual discrimination or object oddity judgements (Barense et al., 2005; Lee, Barense, & Graham, 2005; Lee et al., 2005; though see Levy, Shrager, & Squire, 2005; Shrager, Gold, Hopkins, & Squire, 2006).
A Potential Natural Product Combination Targeting Memory Disorders
Published in Vikas Kumar, Addepalli Veeranjaneyulu, Herbs for Diabetes and Neurological Disease Management, 2018
Manju Bhaskar, Meena Chintamaneni, Addepalli Veeranjaneyulu
Hippocampus: The hippocampal memory system consists of the hippocampus and its underlying cortices, the perihippocampal cortices (entorhinal, perirhinal, and parahippocampal), which are situated in the medial temporal lobe. Spatial learning and memory in rodents depends on hippocampus. Damage to the hippocampus or to some of its connections such as the fornix in monkeys produces deficits in learning about the places of objects and about the places where responses should be made. For example, macaques and humans with damage to the hippocampus or fornix are impaired in object-place memory tasks in which not only the objects seen, but where they were seen, must be remembered. Damage to the perirhinal cortex (PRC), which receives information from high order association cortex and has connections to the hippocampus, accounts for the deficits in recognition memory (i.e., for stimuli seen recently) produced by damage to this brain region.22 Some of the studies suggest that primates and mammals depend on medial temporal structures such as the hippocampus and parahippocampal gyrus to encode and consolidate memories of events and objects in time and space, just as humans use the same brain regions for the initial encoding and consolidation of declarative memory.23Cerebral cortex: Human cerebral cortex is a thin sheet of tissue that is extensively convoluted in order for a large surface area to fit within a restricted cranial volume. Specific types of sensory, motor, and integrative signals are processed in certain regions of the cerebral cortex. Generally, sensory areas receive sensory information and are involved in perception, the conscious awareness of a sensation; motor areas control the execution of voluntary movements; and association areas deal with more complex integrative functions such as memory, emotions, reasoning, will, judgment, personality traits, and intelligence.24 PRC, parahippocampal cortex (PHC), and retrosplenial cortex (RSC) have an essential role in memory. These networks not only support different types of memory but also appear to support different aspects of cognition. PRC is related to recognition and associative memory. PRC lesions in monkeys severely impair visual object recognition memory, and this deficit is much more severe than that produced by lesions at PHC. Humans with damage to PRC, amygdala and anterior hippocampal formation show substantial deficits in recognition memory for many types of stimuli, including words and faces. PRC activation during memory encoding predicts the extent to which the item will subsequently be experienced as familiar. Functional magnetic resonance imaging (fMRI) studies in humans suggest that PRC contributes to learning of associations between words and objects. PRC may also contribute to perceptual processing of objects.25
Nutritional stress timing differentially programs cognitive abilities in young adult male mice
Published in Nutritional Neuroscience, 2022
Bruno G. Berardino, Fabricio Ballarini, Mariela Chertoff, Lionel M. Igaz, Eduardo T. Cánepa
Although still controversial, there is compelling evidence of the involvement of the hippocampus, along with the perirhinal cortex, in aspects of recognition memory [44,45]. In rodents, hippocampal growth takes place mainly during late gestation and the first two weeks after birth, with the addition of new neurons throughout life. Accordingly, the hippocampus has been shown to be particularly susceptible to early-life environmental alterations [10]. Thus, the impaired learning observed in this task could be the result of the effects of perinatal stress on hippocampal function. In this regard, it has been reported that protein malnutrition during the embryonic and lactation periods results in long-lasting structural abnormalities in the hippocampus of the offspring, including decreased number of neurons and spines and decreased dendritic arborization [20,25,28]. Our results demonstrating the integrity of this type of recognition memory after mice were exposed to nutritional stress during adolescence are consistent with the fact that the hippocampus is almost completely organized by the time mice reach this period [10].
Prenatal dietary choline supplementation modulates long-term memory development in rat offspring
Published in Nutritional Neuroscience, 2021
Hayarelis Moreno, Isabel de Brugada
Previous studies in rodents support a well established role of the perirhinal cortex and the parahippocampal cortex in object recognition memory [51]. Hence, a plausible explanation for the worse performance of the younger group is the delayed developmental course of these areas. Accordinly, a late development of the parahippocampal areas has been reported in relation with visual memory functions in spatial cognition [52,53]. The implication of the cholinergic system in the NOR task is supported by the findings of previous studies showing that NOR acquisition and memory performance depend on the activity of the brain cholinergic system (see [54] for a review). Consistent with this, perirhinal cortex cholinergic depletion induces deficit in NOR tasks [19] and perirhinal microinjections of the cholinergic muscarinic receptor blocker scopolamine impair visual recognition memory in monkeys [55] and rats [21]. Moreover, systemic [22] and perirhinal [23] injections of the cholinergic agonist nicotine improve performance in NOR tasks. And given that prenatal choline supplementation increases the synthesis of acetylcholine from the stores in the phospholipidic membrane components [56], this could explain the enhancement of long-term memory in the early stages of development found in this study.
Agmatine-attenuated cognitive and social deficits in subchronic MK-801 model of schizophrenia in rats
Published in Psychiatry and Clinical Psychopharmacology, 2018
Gokhan Unal, Alpay Ates, Feyza Aricioglu
In our study, NORT was performed to assess visual recognition memory in rats. NORT is considered as a well-validated translational test in schizophrenia research and poor cognitive performance in NORT is a common finding in animal models of schizophrenia. It has been thought that perirhinal cortex and hippocampus have primer roles for mediating cognitive functions in NORT [37]. Therefore, the decreased discrimination ratio of novel and familiar objects in NORT due to the subchronic administration of MK-801 and PCP is one of the repeatable data to assess visual recognition memory in schizophrenia models [38,39]. In this study, we showed that subchronic MK-801 impaired visual recognition memory even after seven days of the washout period and both agmatine and risperidone attenuated this effect of MK-801 in NORT. To our current knowledge, there is no study investigating the effect of agmatine on schizophrenia-related visual memory deficits, though several studies have shown pro-cognitive effects of agmatine in different animal models [40–43]. This is the first time that the beneficial effect of agmatine has shown on MK-801-induced visual recognition memory deficit in NORT.