Search results for "Prefrontal Cortex"
showing 10 items of 323 documents
Amygdala pathology in Parkinson's disease.
1994
The amygdala undergoes severe pathological changes during the course of Parkinson's disease (PD). Lewy bodies and Lewy neurites are distributed in a specific manner throughout the nuclear complex. The lesional pattern displays only minor interindividual variation. The most prominent changes occur in the accessory cortical and central nuclei. The cortical, accessory basal and granular nuclei show less severe alterations, while the basal and lateral nuclei, as well as the intercalated cell masses, generally remain uninvolved. The amygdala receives a broad range of afferents, allowing integration of exteroceptive information with interoceptive data. It generates major projections to the isocor…
Different brain oxidative and neuroinflammation status in rats during prolonged abstinence depending on their ethanol relapse-like drinking behavior:…
2022
Rationale: Accumulating evidence suggests that chronic alcohol consumption is associated with excessive oxidative damage and neuroinflammatory processes and these events have been associated to early alcohol withdrawal. In the present research we wonder if brain oxidative stress and neuroinflammation remains altered during prolonged withdrawal situations and whether these alterations can be correlated with relapse behavior in alcohol consumption. The effects of alcohol reintroduction were also evaluated Methods: We have used a model based on the alcohol deprivation effect (ADE) within a cohort of wild-type male Wistar rats. Two subpopulations were identified according to the alcohol relapse…
Effect of cholinergic stimulation in early Alzheimer's disease - functional imaging during a recognition memory task.
2011
Treatment of Alzheimer's disease (AD) with acetylcholinesterase inhibitors (AChEI) enhances cholinergic activity and alleviates clinical symptoms. In the present functional magnetic resonance imaging (fMRI) study, we investigated the effect of the AChEI rivastigmine on cognitive function and brain activation patterns during a face recognition memory task. Twenty patients with newly-diagnosed mild AD were administered a single oral dose of placebo, a single dose of rivastigmine (acute), and twice-daily treatment with rivastigmine for 4 weeks (chronic). After each treatment, the patients underwent a facial recognition task during fMRI. The prefrontal areas known to be involved in face recogni…
Auditory cortex reflects goal-directed movement but is not necessary for behavioral adaptation in sound-cued reward tracking
2020
Mounting evidence suggests that the role of sensory cortices in perceptual decision making goes beyond the mere representation of the discriminative stimuli and additionally involves the representation of nonsensory variables such as reward expectation. However, the relevance of these representations for behavior is not clear. To address this issue, we trained rats to discriminate sounds in a single-interval forced-choice task and then confronted the animals with unsignaled blockwise changes of reward probabilities. We found that unequal reward probabilities for the two choice options led to substantial shifts in response bias without concomitant reduction in stimulus discrimination. Althou…
Cognitive estimation: Performance of patients with focal frontal and posterior lesions
2018
The Cognitive Estimation Test (CET) is a widely used test to investigate estimation abilities requiring complex processes such as reasoning, the development and application of appropriate strategies, response plausibility checking as well as general knowledge and numeracy (e.g., Shallice and Evans, 1978; MacPherson et al., 2014). Thus far, it remains unknown whether the CET is both sensitive and specific to frontal lobe dysfunction. Neuroimaging techniques may not represent a useful methodology for answering this question since the complex processes involved are likely to be associated with a large network of brain regions, some of which are not functionally necessary to successfully carry …
Chronic restraint stress and chronic corticosterone treatment modulate differentially the expression of molecules related to structural plasticity in…
2004
Stress and stress-related hormones induce structural changes in neurons of the adult CNS. Neurons in the hippocampus, the amygdala and the prefrontal cortex undergo neurite remodeling after chronic stress. In the hippocampus some of these effects can be mimicked with chronic administration of adrenal steroids. These changes in neuronal structure may be mediated by certain molecules related to plastic events such as the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). The expression of PSA-NCAM persists in the adult hippocampus and it is up-regulated after chronic stress. The piriform cortex also displays considerable levels of PSA-NCAM during adulthood and indirect evide…
Cortical networks of procedural learning: Evidence from cerebellar damage
2007
The lateral cerebellum plays a critical role in procedural learning that goes beyond the strict motor control functions attributed to it. Patients with cerebellar damage show marked impairment in the acquisition of procedures, as revealed by their performance on the serial reaction time task (SRTT). Here we present the case of a patient affected by ischemic damage involving the left cerebellum who showed a selective deficit in procedural learning while performing the SRTT with the left hand. The deficit recovered when the cortical excitability of an extensive network involving both cerebellar hemispheres and the dorsolateral prefrontal cortex (DLPFC) was decreased by low-frequency repetitiv…
Serotonin, the Prefrontal Cortex, and the Antidepressant-Like Effect of Cannabinoids
2007
Preclinical and clinical studies show that cannabis modulates mood and possesses antidepressant-like properties, mediated by the agonistic activity of cannabinoids on central CB1 receptors (CB1Rs). The action of CB1R agonists on the serotonin (5-HT) system, the major transmitter system involved in mood control and implicated in the mechanism of action of antidepressants, remains however poorly understood. In this study, we demonstrated that, at low doses, the CB1R agonist WIN55,212-2 [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)]pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl) methanone mesylate] exerts potent antidepressant-like properties in the rat forced-swim test (FST). This effect …
Behavioral deficits induced by lead exposure are accompanied by serotonergic and cholinergic alterations in the prefrontal cortex
2013
The effects of long-term lead (Pb) exposure producing a blood Pb concentration of lower than 20 μg/dL, i.e. below that associated with overt neurological deficits in occupationally exposed individuals, was studied in adult rats. In order to assess gender differences, we performed parallel behavioral experiments in male and female rats. Exposure to Pb acetate (50 ppm in drinking water) for 6 months induced motor and cognitive alterations, however these effects were gender- and task-dependent. Chronic lead exposure impaired spatial learning assessed in the Morris water maze test (MWM) in both genders, whereas it only induced hyperactivity in the open field and impaired motor coordination in t…
Feeling addressed! The neural processing of social communicative cues in patients with major depression
2020
Abstract The feeling of being addressed is the first step in a complex processing stream enabling successful social communication. Social impairments are a relevant characteristic of patients with major depressive disorder (MDD). Here, we investigated a mechanism which—if impaired—might contribute to withdrawal or isolation in MDD, namely, the neural processing of social cues such as body orientation and gesture. During funtional magnetic resonance imaging (fMRI) data acquisition, 33 patients with MDD and 43 healthy control subjects watched video clips of a speaking actor: one version with a gesture accompanying the speech and one without gesture. Videos were filmed simultaneously from two …