Electrocorticographic Activity Stimulating in Subicular Complex of the Left Hippocampus of Cats

2015 ◽  
pp. 199-208
Author(s):  
Yasunori Oana ◽  
Masazumi Shinozaki ◽  
Shinichiro Komatsu ◽  
Hiroshi Matsuda ◽  
Sho Kimura ◽  
...  
Keyword(s):  
Left Hippocampus

scholarly journals Effects of amnesia on processing in the hippocampus and default mode network during a naturalistic memory task: a case study

2018 ◽  
Author(s):  
Christiane Oedekoven ◽  
James L. Keidel ◽  
Stuart Anderson ◽  
Angus Nisbet ◽  
Chris Bird
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Structural Mri ◽  
Brain Regions ◽  
Left Hippocampus ◽  
Cortical Regions ◽  
The Right ◽  
Encoding And Retrieval

Despite their severely impaired episodic memory, individuals with amnesia are able to comprehend ongoing events. Online representations of a current event are thought to be supported by a network of regions centred on the posterior midline cortex (PMC). By contrast, episodic memory is widely believed to be supported by interactions between the hippocampus and these cortical regions. In this MRI study, we investigated the encoding and retrieval of lifelike events (video clips) in a patient with severe amnesia likely resulting from a stroke to the right thalamus, and a group of 20 age-matched controls. Structural MRI revealed grey matter reductions in left hippocampus and left thalamus in comparison to controls. We first characterised the regions activated in the controls while they watched and retrieved the videos. There were no differences in activation between the patient and controls in any of the regions. We then identified a widespread network of brain regions, including the hippocampus, that were functionally connected with the PMC in controls. However, in the patient there was a specific reduction in functional connectivity between the PMC and a region of left hippocampus when both watching and attempting to retrieve the videos. A follow up analysis revealed that in controls the functional connectivity between these regions when watching the videos was correlated with memory performance. Taken together, these findings support the view that the interactions between the PMC and the hippocampus enable the encoding and retrieval of multimodal representations of the contents of an event.

scholarly journals Corresponding erdosteine changes autophagy genes expression in hippocampus on Rhinitis medicamentosa model

Genetika ◽  
2015 ◽  
Vol 47 (3) ◽  
pp. 1091-1098
Author(s):  
Recep Dokuyucu ◽  
Bulent Gogebakan ◽  
Cengiz Cevik
Keyword(s):  
Control Group ◽  
Gene Expressions ◽  
Autophagy Gene ◽  
Genes Expression ◽  
Left Hippocampus ◽  
Antioxidant Agent ◽  
Group 3 ◽  
Group 2 ◽  
Rhinitis Medicamentosa

In our study, rats were subjected to Oxymetazoline hydrochloride treatment and Rhinitis medicamentosa (RM) was formed and then autophagy gene expression levels were determined after the application of an antioxidant agent erdosteine (ED). The rats were divided into three groups; Group 1 was the control group. Group 2 (RM) and group 3 (RM+ED) rats received two spray puffs of 0.05% oxymetazoline into the nasal cavities three times daily for eight weeks. After determination of RM in the rats, the RM group were killed. The ED+RM group received 10 mg/kg of an ED suspension. At the end of seven days, these rats were also killed. All groups? hippocampus tissues were obtained for the measurement of autophagy gene expressions. In rhinitis medicamentosa group Atg5, Atg7 and Atg10 gene expressions in the left hippocampus were reduced as compared to control group (p=0.01, p>0.05, p=0.01, respectively). Also, erdosteine treatments were restored mRNA expression of autophagy genes. In right hippocampus of rhinitis medicamentosa group, Atg5 and Atg10 gene expressions was found to be down-regulated as compared to control group (p>0.05, p<0.05, respectively). Both BECN1 and ULK genes expression were found to be reduced in left hippocampus of rhinitis medicamentosa group. Erdosteine applications was restored the expression of these genes (p=0.03, p=0.03, respectively). Additionally, in right hippocampus, Erdosteine application was restored the expression of ULK gene (p=0.01). This is the first report that evaluated the expression autophagy genes in RM rat models and the changes observed after erdosteine applications.

scholarly journals Progressive Volume Atrophy in Hippocampal Subfields and the Correlation with Cognition in Alzheimer’s Disease and Mild Cognitive Impairment

2021 ◽  
Author(s):  
Guixia Kang ◽  
Peiqi Luo ◽  
Xin Xu ◽  
Ying Han ◽  
Xuemei Li ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Reference Value ◽  
Structural Mri ◽  
Volume Changes ◽  
Brain Scans ◽  
Left Hippocampus ◽  
The Right

Abstract Objective: To assess the progression of volume changes in hippocampus and its subfields of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI), and to explore the association of the hippocampus and its subfields volumes with cognitive function.Methods: Five groups of participants including 35 normal controls (NC) persons, 30 MCI patients, 30 Mild AD patients, 30 Moderate AD patients and 8 Severe AD patients received structural MRI brain scans. Freesurfer6.0 was used for automatically segmentation of MRI, and the left and right hippocampus were respectively divided into 12 subfields. By statistical analysis, the volumes of hippocampus and its subfields were compared between the five groups, and the correlation of the volumes with Mini-mental State Examination (MMSE) score was analyzed.Result & Conclusion: In the disease, each hippocampal subfield shows an uneven atrophy trajectory; The volumes of the subiculum and presubiculum are significantly different between Mild AD and MCI, which can contribute to the early diagnosis of AD; Parasubiculum is the least sensitive subfield for volume atrophy of AD, while subiculum, presubiculum, CA1, molecular_layer_HP and fimbria show much more significant volume changes. Meanwhile the volumes of these five subfields are positively correlated with MMSE, which may help in stage division of AD; Compared with the right hippocampus, the volume atrophy on the left side is more significantly, and the volumes are more significantly correlated with MMSE, So the left hippocampus and its subfields may provide a higher reference value for the clinical evaluation of AD than the right side.

scholarly journals Effect of electroconvulsive therapy on hippocampal and amygdala volumes: systematic review and meta-analysis

2018 ◽  
Vol 212 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Akihiro Takamiya ◽  
Jun Ku Chung ◽  
Kuo-ching Liang ◽  
Ariel Graff-Guerrero ◽  
Masaru Mimura ◽  
...  
Keyword(s):  
Systematic Review ◽  
Electroconvulsive Therapy ◽  
Animal Studies ◽  
Brain Volume ◽  
Meta Analysis ◽  
Brain Structures ◽  
Volume Increase ◽  
Left Hippocampus ◽  
Before And After ◽  
Underlying Mechanisms

BackgroundElectroconvulsive therapy (ECT) is one of the most effective treatments for depression, although the underlying mechanisms remain unclear. Animal studies have shown that electroconvulsive shock induced neuroplastic changes in the hippocampus.AimsTo summarise volumetric magnetic resonance imaging studies investigating the effects of ECT on limbic brain structures.MethodA systematic review and meta-analysis was conducted to assess volumetric changes of each side of the hippocampus and amygdala before and after ECT. Standardised mean difference (SMD) was calculated.ResultsA total of 8 studies (n = 193) were selected for our analyses. Both right and left hippocampal and amygdala volumes increased after ECT. Meta-regression analyses revealed that age, percentage of those responding and percentage of those in remission were negatively associated with volume increases in the left hippocampus.ConclusionsECT increased brain volume in the limbic structures. The clinical relevance of volume increase needs further investigation.Declaration of interestNone.

scholarly journals Coding of episodic memory in the human hippocampus

2018 ◽  
Vol 115 (5) ◽  
pp. 1093-1098 ◽  
Author(s):  
John T. Wixted ◽  
Stephen D. Goldinger ◽  
Larry R. Squire ◽  
Joel R. Kuhn ◽  
Megan H. Papesh ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Single Neuron ◽  
Large Fraction ◽  
Memory Task ◽  
Neuron Activity ◽  
Distributed Coding ◽  
Repeated Word ◽  
Human Hippocampus ◽  
Left Hippocampus ◽  
Episodic Memories

Neurocomputational models have long posited that episodic memories in the human hippocampus are represented by sparse, stimulus-specific neural codes. A concomitant proposal is that when sparse-distributed neural assemblies become active, they suppress the activity of competing neurons (neural sharpening). We investigated episodic memory coding in the hippocampus and amygdala by measuring single-neuron responses from 20 epilepsy patients (12 female) undergoing intracranial monitoring while they completed a continuous recognition memory task. In the left hippocampus, the distribution of single-neuron activity indicated that only a small fraction of neurons exhibited strong responding to a given repeated word and that each repeated word elicited strong responding in a different small fraction of neurons. This finding reflects sparse distributed coding. The remaining large fraction of neurons exhibited a concurrent reduction in firing rates relative to novel words. The observed pattern accords with longstanding predictions that have previously received scant support from single-cell recordings from human hippocampus.

Altered hippocampal functional connectivity in primary Sjögren syndrome: a resting-state fMRI study

Lupus ◽  
2020 ◽  
Vol 29 (5) ◽  
pp. 446-454 ◽  
Author(s):  
X-D Zhang ◽  
L-R Zhao ◽  
J-M Zhou ◽  
Y-Y Su ◽  
J Ke ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Connectivity ◽  
Resting State ◽  
Neuropsychological Tests ◽  
Sjogren Syndrome ◽  
Resonance Imaging ◽  
Primary Sjögren Syndrome ◽  
Left Hippocampus ◽  
The Right

Structural and metabolic abnormalities in the hippocampus have been associated with the pathophysiological mechanism of central nervous system involvement in primary Sjögren syndrome (pSS). Nevertheless, how hippocampal function is altered in pSS remains unknown. The purpose of our study is to investigate the alterations in hippocampal functional connectivity (FC) in pSS by using resting-state functional magnetic resonance imaging (rs-fMRI). Thirty-eight patients with pSS and 38 age- and education level-matched healthy controls (HCs) underwent magnetic resonance imaging examination. Prior to each MRI examination, neuropsychological tests were performed. Left and right hippocampal FCs were analyzed by using seed-based whole-brain correlation and compared between pSS and HCs. Spearman correlation analysis was performed between the z-value of hippocampal FC in brain regions with significant difference between the two groups and neuropsychological tests/clinical data in pSS. Compared with the controls, the patients with pSS showed decreased hippocampal FC between the left hippocampus and the right inferior occipital gray (IOG)/inferior temporal gray (ITG), as well as between the right hippocampus and right IOG/middle occipital gray (MOG), left MOG, and left middle temporal gray. In addition, increased hippocampal FCs were detected between the left hippocampus and left putamen, as well as between the right hippocampus and right cerebellum posterior lobe. Moreover, the visual reproduction score positively correlated with the FC between right hippocampus and right IOG/MOG. The white matter hyperintensity score negatively correlated with the FC between left hippocampus and right IOG/ITG. In conclusion, patients with pSS suffered decreased hippocampal FC mainly sited in the occipital and temporal cortex with right hippocampal laterality. Altered hippocampal FC might be a potential biomarker in detecting brain function changes and guiding neuroprotection in pSS.

scholarly journals Increased hippocampal engagement during learning as a marker of sensitivity to psychotomimetic effects of δ-9-THC

2018 ◽  
Vol 48 (16) ◽  
pp. 2748-2756 ◽  
Author(s):  
Sagnik Bhattacharyya ◽  
Thomas Sainsbury ◽  
Paul Allen ◽  
Chiara Nosarti ◽  
Zerrin Atakan ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Verbal Learning ◽  
Learning Task ◽  
Psychotic Symptoms ◽  
Neural Basis ◽  
Experimental Conditions ◽  
Double Blind ◽  
Left Hippocampus ◽  
Leave One Out ◽  
Psychotomimetic Effects

AbstractBackgroundCannabis and its main psychoactive ingredient δ-9-tetrahydrocannibidiol (THC) can induce transient psychotic symptoms in healthy individuals and exacerbate them in those with established psychosis. However, not everyone experience these effects, suggesting that certain individuals are particularly susceptible. The neural basis of this sensitivity to the psychotomimetic effects of THC is unclear.MethodsWe investigated whether individuals who are sensitive to the psychotomimetic effects of THC (TP) under experimental conditions would show differential hippocampal activation compared with those who are not (NP). We studied 36 healthy males under identical conditions under the influence of placebo or THC (10 mg) given orally, on two separate occasions, in a pseudo-randomized, double-blind, repeated measures, within-subject, cross-over design, using psychopathological assessments and functional MRI while they performed a verbal learning task. They were classified into those who experienced transient psychotic symptoms (TP; n = 14) following THC administration and those who did not (NP; n = 22).ResultsUnder placebo conditions, there was significantly greater engagement of the left hippocampus (p < 0.001) in the TP group compared with the NP group during verbal encoding, which survived leave-one-out analysis. The level of hippocampal activation was directly correlated (Spearman's ρ = 0.44, p = 0.008) with the severity of transient psychotic symptoms induced by THC. This difference was not present when we compared two subgroups from the same sample that were defined by sensitivity to anxiogenic effects of THC.ConclusionsThese results suggest that altered hippocampal activation during verbal encoding may serve as a marker of sensitivity to the acute psychotomimetic effects of THC.

scholarly journals Temporal pole signal abnormality on MR imaging in temporal lobe epilepsy with hippocampal sclerosis: a fluid-attenuated inversion-recovery study

2007 ◽  
Vol 65 (3a) ◽  
pp. 553-560 ◽  
Author(s):  
Henrique Carrete Junior ◽  
Nitamar Abdala ◽  
Kátia Lin ◽  
Luís Otávio Caboclo ◽  
Ricardo Silva Centeno ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Hippocampal Sclerosis ◽  
Normal Subjects ◽  
Inversion Recovery ◽  
Signal Abnormality ◽  
Lateral Zone ◽  
Left Hippocampus ◽  
Temporal Pole ◽  
Fluid Attenuated Inversion Recovery ◽  
Recovery Study

OBJECTIVE: To determine the frequency and regional involvement of temporal pole signal abnormality (TPA) in patients with hippocampal sclerosis (HS) using fluid-attenuated inversion-recovery (FLAIR) MR imaging, and to correlate this feature with history. METHOD: Coronal FLAIR images of the temporal pole were assessed in 120 patients with HS and in 30 normal subjects, to evaluate gray-white matter demarcation. RESULTS: Ninety (75%) of 120 patients had associated TPA. The HS side made difference regarding the presence of TPA, with a left side prevalence (p=0.04, chi2 test). The anteromedial zone of temporal pole was affected in 27 (30%) out of 90 patients. In 63 (70%) patients the lateral zone were also affected. Patients with TPA were younger at seizure onset (p=0.018), but without association with duration of epilepsy. CONCLUSION: Our FLAIR study show temporal pole signal abnormality in 3/4 of patients with HS, mainly seen on the anteromedial region, with a larger prevalence when the left hippocampus was involved.

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