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The medial temporal lobe consists of the hippocampal formation (blue-green) superiorly and the parahippocampal gyrus inferiorly. The entorhinal (brown) and perirhinal (yellow) cortices form the medial and lateral components, respectively, of the anterior portion of the parahippocampal gyrus, while the parahippocampal cortex (off-white) forms the posterior portion. Adapted with permission from Purves D, Brannon E, Cabeza R, et al. Principles of Cognitive Neuroscience. Sunderland, MA: Sinauer Associates; 2008.
Source publication
The medial temporal lobe plays a central role in memory processing and is more than just the hippocampus.[1][1] The hippocampal formation, which forms the upper segment of the medial temporal lobe, is a heterogeneous structure consisting of the Ammon horn or Cornus Ammonis (Cornus Ammonis area 1 to
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There were studied behavioural and neurophysiological indices of image recognition of fragmented pictures. Two groups of recognition efficiency were found out. The first group was characterized by little number of mistakes and by recognition at fragmentation close to the whole image. The second group was characterized by a higher number of mistakes...
Citations
... As we shall see further on, the neurocontagion's toxic AβOs start AD by pruning synapses in the entorhinal cortex of the persisting ancient limbic core of the medial temporal lobe by being released into the local ISF from presynaptic vesicles and from EVs (extracellular vesicles, exosomes) produced by the autophagic intercellular signaling system [18,19,122]. Attracted by synaptic PrP C s, the infectious' AβOs spread through the medial temporal perirhinal and parahippocampal gyruses, for example, into the neocortical rich-club networks of the posterior cingulate gyrus and parietal associational cortices, destroying synapses and disconnecting the circuits as they go [112,[123][124][125][126][127][128][129][130]. ...
... This evolutionary neocortical 'Big Bang' happened without an equivalent expansion of the EC-hippocampus in the medial temporal cortex. This required the development of ways to manage the increased flow of messages converging on the memory system [130,[148][149][150][151][152][153][154][155]. This challenge was met with an internet-like [156] increase in the routing of messages through the perirhinal and parahippocampal cortices via the EC to the hippocampus, which rapidly induces the cortical rubbing of the abstracted original event-inducing networks into interacting ensembles for on-cue replay [144,152,[157][158][159]. ...
The enormous, 2–3-million-year evolutionary expansion of hominin neocortices to the current enormity enabled humans to take over the planet. However, there appears to have been a glitch, and it occurred without a compensatory expansion of the entorhinal cortical (EC) gateway to the hippocampal memory-encoding system needed to manage the processing of the increasing volume of neocortical data converging on it. The resulting age-dependent connectopathic glitch was unnoticed by the early short-lived populations. It has now surfaced as Alzheimer’s disease (AD) in today’s long-lived populations. With advancing age, processing of the converging neocortical data by the neurons of the relatively small lateral entorhinal cortex (LEC) inflicts persistent strain and high energy costs on these cells. This may result in their hyper-release of harmless Aβ1–42 monomers into the interstitial fluid, where they seed the formation of toxic amyloid-β oligomers (AβOs) that initiate AD. At the core of connectopathic AD are the postsynaptic cellular prion protein (PrPC). Electrostatic binding of the negatively charged AβOs to the positively charged N-terminus of PrPC induces hyperphosphorylation of tau that destroys synapses. The spread of these accumulating AβOs from ground zero is supported by Aβ’s own production mediated by target cells’ Ca2+-sensing receptors (CaSRs). These data suggest that an early administration of a strongly positively charged, AβOs-interacting peptide or protein, plus an inhibitor of CaSR, might be an effective AD-arresting therapeutic combination.
... Growing evidence points to forms of dementia like Alzheimer's disease as being related to brain connectivity issues that hinder communication between areas of the brain (38)(39)(40). The medial temporal lobe is one of the first networks in the brain to be impacted by neurodegenerative conditions like Alzheimer's disease (41). Sinha et al. tested cognitive flexibility and measured the functional activity within the medial temporal lobes of participants (ages 65+) engaged in moderate aerobic dance and analyzed participants' ability to acquire new information and correlate it to previous knowledge. ...
There is a growing appreciation for the ability of person-centered arts-based approaches to extend multiple domains of brain health of people living with dementia. Dance is a multi-modal artistic engagement which has positive impacts on cognition, mobility and the emotional and social aspects of brain health. Although research into multiple domains of brain health among older adults and people living with dementia is promising, several gaps remain, specifically in understanding the benefits of co-creative and improvisational dance practices. Collaborative research between dancers, researchers, people living with dementia and care partners is needed to design and evaluate future research on dance and to determine relevance and usability. Furthermore, the respective praxes and experience of researchers, dance artists and people living with dementia contribute distinctly and uniquely to the identification and the assignment of value to dance in the context of the lives of people living with dementia. In this manuscript the author, a community-based dance artist, creative aging advocate and Atlantic Fellow for Equity in Brain Health, discusses current challenges and gaps in the understanding of the value of dance for and with people living with dementia and how transdisciplinary collaboration between neuroscientists, dance artists and people living with dementia can advance collective comprehension and implementation of dance practice.
... Regional gray matter volumes were determined through the 3D-T1 weighted images using a segmentation process based on atlas propagation with the Learning Embeddings for Atlas Propagation (LEAP) framework [40]. The analysis focussed on the medial temporal lobe (MTL) as the main brain region regulating cognition and memory processing [41]. The MTL includes the hippocampus (right and left), parahippocampus (right and left), entorhinal cortex (right and left), and amygdala (right and left). ...
Background
The risk of dementia is higher in women than men. The metabolic consequences of estrogen decline during menopause accelerate neuropathology in women. The use of hormone replacement therapy (HRT) in the prevention of cognitive decline has shown conflicting results. Here we investigate the modulating role of APOE genotype and age at HRT initiation on the heterogeneity in cognitive response to HRT.
Methods
The analysis used baseline data from participants in the European Prevention of Alzheimer’s Dementia (EPAD) cohort (total n = 1906, women= 1178, 61.8%). Analysis of covariate (ANCOVA) models were employed to test the independent and interactive impact of APOE genotype and HRT on select cognitive tests, such as MMSE, RBANS, dot counting, Four Mountain Test (FMT), and the supermarket trolley test (SMT), together with volumes of the medial temporal lobe (MTL) regions by MRI. Multiple linear regression models were used to examine the impact of age of HRT initiation according to APOE4 carrier status on these cognitive and MRI outcomes.
Results
APOE4 HRT users had the highest RBANS delayed memory index score (P- APOE *HRT interaction = 0.009) compared to APOE4 non-users and to non- APOE4 carriers, with 6–10% larger entorhinal (left) and amygdala (right and left) volumes ( P -interaction= 0.002, 0.003, and 0.005 respectively). Earlier introduction of HRT was associated with larger right (standardized β = −0.555, p =0.035) and left hippocampal volumes (standardized β = −0.577, p =0.028) only in APOE4 carriers.
Conclusion
HRT introduction is associated with improved delayed memory and larger entorhinal and amygdala volumes in APOE4 carriers only. This may represent an effective targeted strategy to mitigate the higher life-time risk of AD in this large at-risk population subgroup. Confirmation of findings in a fit for purpose RCT with prospective recruitment based on APOE genotype is needed to establish causality.
... Novel object recognition (NOR) involves medial temporal lobe processing (50). The ventral stream from the occipital lobe (visual stimuli) processes information about object recognition with relays in the perirhinal cortex and the lateral entorhinal cortex (51). The ventral occipitotemporal region is known to be involved in reading processes (52). ...
The Human 1.2-Mb AUTS2 locus on chromosome 7q11.22 encodes a 1259-aa full-length protein, and a 711-aa C-terminal isoform. Functions of these AUTS2 proteins are only partly known. The major traits found in patients displaying AUTS2 locus mutations are Intellectual Disabilities, microcephaly attention deficit hyperactivity disorder (ADHD) (54%), and autistic traits. Furthermore, AUTS2 common variants were recently found associated to alcohol consumption and dyslexia using GWAS approaches. Auts2 localizes mainly in cell nuclei. We evidenced by super-resolution that Auts2 is present in dendritic spines. Auts2 interacts with Ttc3, the Akt2 E3 ligase, and negatively regulates Akt2 ubiquitination. Auts2 haploinsufficiency affects Akt/mTorc1 pathway with a decrease in AMPA and NMDA receptor subunits and in synaptic currents. Akt2 injection in postsynaptic neurons is sufficient to reverse changes in synaptic currents generated by Auts2 haploinsufficiency. Using chromosome engineering based on targeted meiotic recombination, we generated two mouse models with Auts2 locus deletion and duplication. Deleted Auts2 locus mice display stereotypies (rearing), perseveration and abnormal recognition memory. Duplicated Auts2 locus mice display similar perseveration and abnormal recognition memory but also a decrease in cued and contextual fear memory. Gene dosage induce changes in brain sub-region neuronal networks. In the thalamo-lateral amygdala pathway linked to cued fear memory, we found synaptic impairments linked to AMPA receptors, with a specific decrease in pAKT/total AKT ratio in duplicated Auts2 mice. Altogether, our study thereby provides a novel mechanistic and potentially therapeutic understanding of synaptic AKT/mTORC1 deregulated signaling and its related behavioral and cognitive phenotypes.
... In their proposed system, each image with size 256*256 has been divided into four blocks which then encrypt each block with a key generated from a chaotic map and then encode blocks into DNA format. They have evaluated their system using entropy, NPCR, UACI, and histogram analysis [11]. ...
Background
The Internet of things (IoT) is the network of different objects or “things” containing sensors, software, and other technologies used to exchange data between devices and systems over the cloud. Such systems and networks should be provided with a proper cryptographic methodology to block unauthorized data transmission access. This issue is considered an essential challenge of resources that are shared on the data communication network, that is its security. So, in this study, a cryptosystem is proposed to maintain the security level of such systems with a new idea depending on DNA cryptography and DNA mixing.
Results
In this study, the proposed cryptosystem is based on the RSA algorithm and DNA cryptography concepts with a novel idea for mixing DNA strands obtained from encoding medical image and report to enhance the security level through the IoT networks. This system achieved a proper result in reconstructing images with high quality. The similarity between the original data and the restored one reached 92% through 18 s.
Conclusions
Such a proposed cryptosystem provided the feasibility of data security in network security, especially for E-health care through IoT system to help medical teamwork in handling medical data between hospitals safely. The result showed that RSA is a fast, efficient algorithm that can be utilized safely in cryptography schemes.
... The protocols used, quality controls and data transfer are described in details elsewhere (40). The analysis focussed on the medial temporal lobe (MTL) as the main brain region regulating cognition and memory processing (45).The MTL includes the hippocampus (right and left), parahippocampus (right and left), entorhinal cortex (right and left) and amygdala (right and left). A wider exploratory analysis for 20 different brain regions was carried out separately and presented in the supplemental document. ...
Background:
The risk of dementia is higher in women than men. The metabolic consequences of estrogen decline during menopause accelerates neuropathology in women. The use of hormone replacement therapy (HRT) in the prevention of cognitive decline has shown conflicting results. Here we investigate the modulating role of APOE genotype and age at HRT initiation on the heterogeneity in cognitive response to HRT.
Methods:
The analysis used baseline data from participants in the European Prevention of Alzheimer’s Dementia (EPAD) cohort (total n= 1906, women= 1178, 61.8%). Analysis of covariate (ANCOVA) models were employed to test the independent and interactive impact of APOE genotype and HRT on select cognitive tests, such as MMSE, RBANS, dot counting, Four Mountain Test (FMT) and the supermarket trolley test (SMT), together with volumes of the medial temporal lobe (MTL) regions by MRI. Multiple linear regression models were used to examine the impact of age of HRT initiation according to APOE4 carrier status on these cognitive and MRI outcomes.
Results:
APOE4 HRT users had the highest RBANS delayed memory index score (P-APOE*HRT interaction = 0.009) compared to APOE4 non-users and to non-APOE4 carriers, with 6-10% larger entorhinal (left) and amygdala (right and left) volumes (P-interaction= 0.002, 0.003, and 0.005 respectively). Earlier introduction of HRT was associated with larger right (standardized β= -0.555, p=0.035) and left hippocampal volumes (standardized β= -0.577, p=0.028) only in APOE4 carriers.
Conclusion:
HRT introduction is associated with improved delayed memory and larger entorhinal and amygdala volumes in APOE4 carriers only. This may represent an effective targeted strategy to mitigate the higher life-time risk of AD in this large at-risk population subgroup. Confirmation of findings in a fit for purpose RCT with prospective recruitment based on APOE genotype is needed to establish causality.
... The parahippocampal gyrus is an active region in the limbic system, and exercise intervention appears to strengthen their neuronal excitability, increase the volume of white matter/gray matter, and positively change the production of brain-derived neural factors (Li et al., 2017;Loprinzi, 2017;Muller et al., 2017;Ji et al., 2021). Previous research has validated the effect of exercise on the plasticity of the parahippocampal gyrus, which plays a crucial role in maintaining memory function and aids in spatial information processing and object recognition (Brown and Aggleton, 2001;Raslau et al., 2015). We guess that the parahippocampal gyrus of spatial information processing and object recognition functions are also likely the underlying reason(s) that exercise improves cognitive control function. ...
It is widely known that exercise improves inhibitory control; however, the mechanisms behind the cognitive improvement remain unclear. This study analyzes the extant literature on the neuronal effects of exercise on inhibitory control functions. We searched four online databases (Pubmed, Scopus, PsycINFO, and Web of Science) for relevant peer-reviewed studies to identify eligible studies published before September 1, 2021. Among the 4,090 candidate studies identified, 14 meet the inclusion criteria, and the results of 397 participants in these 14 studies are subsequently analyzed. We quantify the neural effects on the entire brain by using GingerALE software and identify 10 clusters of exercise-induced neuronal with either increases/decreases in the superior temporal gyrus (BA 22), precuneus (BA 7), superior frontal gyrus (BA 10), cuneus (BA 19), precuneus (BA 19), caudate, posterior cingulate (BA 19), middle temporal gyrus (B 37), parahippocampal gyrus (BA 30), precentral gyrus (BA 6). Meta-analytic coactivation map (MACM) showed that multiple functional networks overlap with brain regions with activation likelihood estimation (ALE) results. We propose the effect of exercise on neural activity is related to inhibitory control in the extended frontoparietal, default mode network (DMN), visual network, and other pathways. These results provide preliminary evidence of the neural effects of exercise on inhibitory control.
... One view purports that the ATL is the locus of processing of general domain representations as well as of basic semantic discriminations [115,116]. An alternative thesis proposes that exemplars are processed by a more mesial region within the basal temporal lobe, namely the perirhinal cortex [117][118][119], which would be the final locus of the ventral visual stream along which object representations are increasingly differentiated, and would enable a sharp distinction between objects that have several overlapping features. The mesial temporal locus of hypometabolism that we found to be linked with Superordinates comprises the perirhinal/entorhinal cortex, suggesting that this type of errors might be interpreted as the possibility to provide only the name of the general semantic category due to an inability to differentiate between confusable concepts belonging to that category. ...
Background:
Analysis of subtypes of picture naming errors produced by patients with Alzheimer's disease (AD) have seldom been investigated yet may clarify the cognitive and neural underpinnings of naming in the AD spectrum.
Objective:
To elucidate the neurocognitive bases of picture naming in AD through a qualitative analysis of errors.
Methods:
Over 1000 naming errors produced by 70 patients with amnestic, visuospatial, linguistic, or frontal AD were correlated with general cognitive tests and with distribution of hypometabolism on FDG-PET.
Results:
Principal component analysis identified 1) a Visual processing factor clustering visuospatial tests and unrecognized stimuli, pure visual errors and visual-semantic errors, associated with right parieto-occipital hypometabolism; 2) a Concept-Lemma factor grouping language tests and anomias, circumlocutions, superordinates, and coordinates, correlated with left basal temporal hypometabolism; 3) a Lemma-Phonology factor including the digit span and phonological errors, linked with left temporo-parietal hypometabolism. Regression of brain metabolism on individual errors showed that errors due to impairment of basic and higher-order processing of object visual attributes or of their interaction with semantics, were related with bilateral occipital and left occipito-temporal dysfunction. Omissions and superordinates were linked to degradation of broad and basic concepts in the left basal temporal cortex. Semantic-lexical errors derived from faulty semantically- and phonologically-driven lexical retrieval in the left superior and middle temporal gyri. Generation of nonwords was underpinned by of phonological impairment within the left inferior parietal cortex.
Conclusion:
Analysis of individual naming errors allowed to outline a comprehensive anatomo-functional model of picture naming in classical and atypical AD.
... The neural factors of BV likely involve a complex interplay between hyperarousal, fear conditioning, and memory processing (i.e., learning and executive functions). Memory processing can be mapped onto the anterior cerebral network between the PFC, amygdala, hippocampus, and its adjacent cortex, the parahippocampal gyrus with peri-and ento-rhinal cortical areas (e.g., Raslau et al., 2014Raslau et al., , 2015. In this anatomical network, the stress-response of the ventral hippocampus is distressed by the amygdala's projections that are linked to fear conditioning and affective processes (e.g., Anagnostaras et al., 2002;Cenquizca and Swanson, 2007). ...
Bullying victimization is a form of psychological stress that is associated with poor outcomes in the areas of mental health and learning. Although the emotional maladjustment and memory impairment following interpersonal stress are well documented, the mechanisms of complex cerebral dysfunctions have neither been outlined nor studied in depth in the context of childhood bullying victimization. As a contribution to the cross-disciplinary field of developmental psychology and neuroscience, we review the neuropathophysiology of early life stress, as well as general psychological stress to synthesize the data and clarify the versatile dynamics within neuronal networks linked to bullying victimization. The stress-induced neuropsychological cascade and associated cerebral networks with a focus on cognitive and emotional convergence are described. The main findings are that stress-evoked neuroendocrine reactivity relates to neuromodulation and limbic dysregulation that hinder emotion processing and executive functioning such as semantic cognition, cognitive flexibility, and learning. Developmental aspects and interacting neural mechanisms linked to distressed cognitive and emotional processing are pinpointed and potential theory-of-mind nuances in targets of bullying are presented. The results show that childhood stress psychopathology is associated with a complex interplay where the major role belongs to, but is not limited to, the amygdala, fusiform gyrus, insula, striatum, and prefrontal cortex. This interplay contributes to the sensitivity toward facial expressions, poor cognitive reasoning, and distress that affect behavioral modulation and emotion regulation. We integrate the data on major brain dynamics in stress neuroactivity that can be associated with childhood psychopathology to help inform future studies that are focused on the treatment and prevention of psychiatric disorders and learning problems in bullied children and adolescents.
... The latter finding suggests a role of the MTG in cognitive dysfunction in AD. Indeed, the middle temporal lobe is heavily connected with the hippocampus and parahippocampus in the memory circuit [98][99][100]. Memory dysfunction is a defining feature of AD [101] and MTG atrophy may lead to apathy in conjunction with cognitive deficits. ...
Background:
Affecting nearly half of the patients with Alzheimer's disease (AD), apathy is associated with higher morbidity and reduced quality of life. Basal ganglia and cortical atrophy have been implicated in apathy. However, the findings have varied across studies and left unclear whether subdomains of apathy may involve distinct neuroanatomical correlates.
Objective:
To identify neuroanatomical correlates of AD-associated apathy.
Methods:
We performed a meta-analysis and label-based review of the literature. Further, following published routines of voxel-based morphometry, we aimed to confirm the findings in an independent cohort of 19 patients with AD/mild cognitive impairment and 25 healthy controls evaluated with the Apathy Evaluation Scale.
Results:
Meta-analysis of 167 AD and 56 healthy controls showed convergence toward smaller basal ganglia gray matter volume (GMV) in apathy. Label-based review showed anterior cingulate, putamen, insula, inferior frontal gyrus (IFG) and middle temporal gyrus (MTG) atrophy in AD apathy. In independent cohort, with small-volume-correction, right putamen and MTG showed GMVs in negative correlation with Apathy Evaluation Scale total, behavioral, and emotional scores, and right IFG with emotional score (p < 0.05 family-wise error (FWE)-corrected), controlling for age, education, intracranial volume, and depression. With the Mini-Mental State Examination scores included as an additional covariate, the correlation of right putamen GMV with behavioral and emotional score, right MTG GMV with total and emotional score, and right IFG GMV with emotional score were significant.
Conclusion:
The findings implicate putamen, MTG and IFG atrophy in AD associated apathy, potentially independent of cognitive impairment and depression, and suggest potentially distinct volumetric correlates of apathy.
