Search results for "Gyrus"
showing 10 items of 277 documents
Diaschisis-Like Association of Hippocampal Atrophy and Posterior Cingulate Cortex Hypometabolism in Cognitively Normal Elderly Depends on Impaired In…
2017
Hippocampal atrophy and hypometabolism of the posterior cingulate cortex (PCC), early markers of Alzheimer's disease (AD), have been shown to be associated in late mild cognitive impairment and early AD via atrophy of connecting cingulum fibers. Recently, a direct association of hippocampal atrophy and PCC hypometabolism has been shown in cognitively normal elderly. We aimed to investigate if this association might be modulated by partly non-hippocampogenic alterations of parahippocampal cingulum (PHC) integrity. 45 cognitively healthy elderly aged 59 to 89 years were included from the Alzheimer's Disease Neuroimaging Initiative. Hippocampal volumes and PCC glucose metabolism were measured …
High dose of 8-OH-DPAT decreases maximal dentate gyrus activation and facilitates granular cell plasticity in vivo.
2013
Although several studies have emphasized a crucial role for the serotonergic system in the control of hippocampal excitability, the role of serotonin (5-HT) and its receptors in normal and pathologic conditions, such as temporal lobe epilepsy (TLE), is still unclear. The present study was therefore designed firstly to investigate the acute effect of 8-OH-DPAT, a mixed 5-HT1A/7 receptor agonist, at a high dose (1 mg/kg, i.p.) known to have antiepileptic properties, in a model of acute partial epilepsy in rats. For this purpose, a maximal dentate activation (MDA) protocol was used to measure electrographic seizure onset and duration. In addition, the effect of 8-OH-DPAT on in vivo dentate gyr…
Moderate drinking? Alcohol consumption significantly decreases neurogenesis in the adult hippocampus
2012
Drinking alcohol in moderation is often considered a health-conscious behavior, associated with improved cardiovascular and brain health. However, “moderate” amounts of alcohol include drinking 3-4 alcohol beverages in a day, which is closer to binge drinking and may do more harm than good. Here we examined how daily drinking of moderate-high alcohol alters the production of new neurons in the adult hippocampus. Male and female adult Sprague-Dawley rats were provided free access to a liquid replacement diet that was supplemented with either 4 % ethanol or Maltodextrin for a period of two weeks. Proliferating cells were labeled with 5-bromo-2-deoxyuridine (BrdU) and the number of BrdU-positi…
Different electrophysiological actions of 24- and 72-hour aggregated amyloid-beta oligomers on hippocampal field population spike in both anesthetize…
2010
Diffusible oligomeric assemblies of the amyloid beta-protein (Abeta) could be the primary factor in the pathogenic pathway leading to Alzheimer's disease (AD). Converging lines of evidence support the notion that AD begins with subtle alterations in synaptic efficacy, prior to the occurrence of extensive neuronal degeneration. Recently, however, a shared or overlapping pathogenesis for AD and epileptic seizures occurred as aberrant neuronal hyperexcitability, as well as nonconvulsive seizure activity were found in several different APP transgenic mouse lines. This generated a renewed attention to the well-known comorbidity of AD and epilepsy and interest in how Abeta oligomers influence neu…
Recollection and familiarity in dense hippocampal amnesia: A case study
2004
In the amnesia literature, disagreement exists over whether anterograde amnesia involves recollective-based recognition processes and/or familiarity-based ones depending on whether the anatomical damage is restricted to the hippocampus or also involves adjacent areas, particularly the entorhinal and perirhinal cortices. So far, few patients with well documented anatomical lesions and detailed assessment of recollective and recognition performance have been described. We report a comprehensive neuroanatomical assessment and detailed investigation of the anterograde memory functions of a previously described severe amnesic patient (VC). The results of four previously published neuroradiologic…
Neurochemical correlates of rapid treatment response to electroconvulsive therapy in patients with major depression
2016
Background: Electroconvulsive therapy (ECT) is a highly effective brain stimulation treatment for severe depression. Identifying neurochemical changes linked with ECT may point to biomarkers and predictors of successful treatment response. Methods: We used proton magnetic resonance spectroscopy (1H-MRS) to measure longitudinal changes in glutamate/glutamine (Glx), creatine (Cre), choline (Cho) and N-acetylaspartate (NAA) in the dorsal (dACC) and subgenual anterior cingulate cortex (sgACC) and bilateral hippocampus in patients receiving ECT scanned at baseline, after the second ECT session and after the ECT treatment series. Patients were compared with demographically similar controls at bas…
Hidden sources of joy, fear, and sadness: Explicit versus implicit neural processing of musical emotions.
2016
Music is often used to regulate emotions and mood. Typically, music conveys and induces emotions even when one does not attend to them. Studies on the neural substrates of musical emotions have, however, only examined brain activity when subjects have focused on the emotional content of the music. Here we address with functional magnetic resonance imaging (fMRI) the neural processing of happy, sad, and fearful music with a paradigm in which 56 subjects were instructed to either classify the emotions (explicit condition) or pay attention to the number of instruments playing (implicit condition) in 4-s music clips. In the implicit vs. explicit condition, stimuli activated bilaterally the infe…
Chronic social stress inhibits cell proliferation in the adult medial prefrontal cortex: hemispheric asymmetry and reversal by fluoxetine treatment.
2006
Profound neuroplastic changes have been demonstrated in various limbic structures after chronic stress exposure and antidepressant treatment in animal models of mood disorders. Here, we examined in rats the effect of chronic social stress and concomitant antidepressant treatment on cell proliferation in the medial prefrontal cortex (mPFC). We also examined possible hemispheric differences. Animals were subjected to 5 weeks of daily social defeat by an aggressive conspecific and received concomitant, daily, oral fluoxetine (10 mg/kg) during the last 4 weeks. Bromodeoxyuridine (BrdU) labeling and quantitative stereological techniques were used to evaluate the treatment effects on proliferatio…
Transient topographical amnesia and cingulate cortex damage: A case report
1996
Transient topographical amnesia (TTA) is the temporary inability to find one's way in familiar or unfamiliar surroundings due to the inability to use well known environmental landmarks for route finding. The syndrome has not been described as having any obvious aetiology and has been thought to be caused by a vascular deficit in right hemispheric structures which are crucial for topographic recognition, i.e. parietal association and parahippocampal cortex. The patient described in the present study complained of several critical episodes of TTA and tonic rigidity of the left limbs. Neuropsychological assessment was normal except for a deficit in spatial memory tasks. Magnetic resonance (MR)…
The hippocampal dentate gyrus is essential for generating contextual memories of fear and drug-induced reward
2008
The hippocampus is believed to play a role in processing information relative to the context in which emotionally salient experiences occur but evidence on the specific contribution of the hippocampal dentate gyrus (DG) to these processes is limited. Here, we have used two classical behavioral paradigms to study the participation of the dorsal DG in context-conditioned reward and context-conditioned fear. Rats received intra-hippocampal vehicle or colchicine injections (4 μg/μl solution; 0.2 μl injections at 10 sites) that damaged the DG but spared other hippocampal subfields. In the first experiment, we used a place conditioning procedure pairing cocaine exposure (20 mg/kg, i.p.) with a sp…