Search results for "Cortex"

Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety

2004

Abstract To image the possible alterations in brain regional GABAA receptor subtype properties in a genetic animal model of human anxiety, mice heterozygous for the deletion of GABAA receptor γ2 subunit (γ2+/−) were studied using ligand autoradiographic assays on brain cryostat sections. The [ 35 S ]TBPS binding assay was designed to reveal impaired GABA and channel site coupling shown to be more prominent in recombinant α1/6β3 than in α1/2β3γ2 or β2 subunit-containing GABAA receptors expressed in HEK 293 cells. Increased GABA-insensitive [ 35 S ]TBPS binding in the γ2+/− mouse brains was evident in the cerebral cortex and in subcortical regions, the alterations being regionally similar to …

Normative vs. patient-specific brain connectivity in Deep Brain Stimulation

2020

AbstractBrain connectivity profiles seeding from deep brain stimulation (DBS) electrodes have emerged as informative tools to estimate outcome variability across DBS patients. Given the limitations of acquiring and processing patient-specific diffusion-weighted imaging data, most studies have employed normative atlases of the human connectome. To date, it remains unclear whether patient-specific connectivity information would strengthen the accuracy of such analyses. Here, we compared similarities and differences between patient-specific, disease-matched and normative structural connectivity data and retrospective estimation of clinical improvement that they may generate.Data from 33 patien…

Mapping effective connectivity between the frontal and contralateral primary motor cortex using dual-coil transcranial magnetic stimulation

2019

AbstractCytoarchitectonic, anatomical and electrophysiological studies have divided the frontal cortex into distinct functional subdivisions. Many of these subdivisions are anatomically connected with the contralateral primary motor cortex (M1); however, effective neurophysiological connectivity between these regions is not well defined in humans. Therefore, we aimed to use dual-coil transcranial magnetic stimulation (TMS) to map, with high spatial resolution, the effective connectivity between different frontal regions of the right hemisphere and contralateral M1 (cM1). TMS was applied over the left M1 alone (test pulse) or after a conditioning pulse was applied to different grid points co…

The cholinergic system in Down's syndrome

2006

The cholinergic system is one of the most important modulatory neurotransmitter systems in the brain. Alterations of the transmission communicators are accompanied by reduction of the cortical activity, which is associated with a learning and memory deficit. Down's syndrome is a pathological condition characterized by a high number of abnormalities that involve the brain.The cholinergic system is involved in alterations of the neurological system such as severe learning difficulties.To explain these alterations, important results are obtained from studies about murine trisomy 16 (animal model of Down's syndrome).The results obtained provide useful elements in the improvement of knowledge ab…

2016

The negative interpretation of body sensations (e.g., as sign of a severe illness) is a crucial cognitive process in pathological health anxiety (HA). However, little is known about the nature and the degree of automaticity of this interpretation bias. We applied an implicit association test (IAT) in 20 subjects during functional magnetic resonance imaging (fMRI) to investigate behavioral and neural correlates of implicit attitudes towards symptom words. On the behavioral level, body symptom words elicited strong negative implicit association effects, as indexed by slowed reaction times when symptom words were paired with the attribute “harmless” (incongruent condition) relative to a contro…

The Course of COVID-19 in Inflammatory Bowel Disease: Protective Role of TNF Antagonists

2021

Layer-Specific Refinement of Sensory Coding in Developing Mouse Barrel Cortex

2017

Rodent rhythmic whisking behavior matures during a critical period around 2 weeks after birth. The functional adaptations of neocortical circuitry during this developmental period remain poorly understood. Here, we characterized stimulus-evoked neuronal activity across all layers of mouse barrel cortex before, during, and after the onset of whisking behavior. Employing multi-electrode recordings and 2-photon calcium imaging in anesthetized mice, we tested responses to rostro-caudal whisker deflections, axial "tapping" stimuli, and their combination from postnatal day 10 (P10) to P28. Within this period, whisker-evoked activity of neurons displayed a general decrease in layer 2/3 (L2/3) and …

Meta-analysis of real-time fMRI neurofeedback studies using individual participant data: How is brain regulation mediated?

2015

An increasing number of studies using real-time fMRI neurofeedback have demonstrated that successful regulation of neural activity is possible in various brain regions. Since these studies focused on the regulated region(s), little is known about the target-independent mechanisms associated with neurofeedback-guided control of brain activation, i.e. the regulating network. While the specificity of the activation during self-regulation is an important factor, no study has effectively determined the network involved in self-regulation in general. In an effort to detect regions that are responsible for the act of brain regulation, we performed a post-hoc analysis of data involving different ta…

Focal Cortical Lesions Induce Bidirectional Changes in the Excitability of Fast Spiking and Non Fast Spiking Cortical Interneurons

2014

A physiological brain function requires neuronal networks to operate within a well-defined range of activity. Indeed, alterations in neuronal excitability have been associated with several pathological conditions, ranging from epilepsy to neuropsychiatric disorders. Changes in inhibitory transmission are known to play a key role in the development of hyperexcitability. However it is largely unknown whether specific interneuronal subpopulations contribute differentially to such pathological condition. In the present study we investigated functional alterations of inhibitory interneurons embedded in a hyperexcitable cortical circuit at the border of chronically induced focal lesions in mouse …

Action in Perception: Prominent Visuo-Motor Functional Symmetry in Musicians during Music Listening.

2015

Musical training leads to sensory and motor neuroplastic changes in the human brain. Motivated by findings on enlarged corpus callosum in musicians and asymmetric somatomotor representation in string players, we investigated the relationship between musical training, callosal anatomy, and interhemispheric functional symmetry during music listening. Functional symmetry was increased in musicians compared to nonmusicians, and in keyboardists compared to string players. This increased functional symmetry was prominent in visual and motor brain networks. Callosal size did not significantly differ between groups except for the posterior callosum in musicians compared to nonmusicians. We conclude…