Search results for "CORTEX"

2021

Background: Normal aging is associated with working memory decline. A decrease in working memory performance is associated with age-related changes in functional activation patterns in the dorsolateral prefrontal cortex (DLPFC). Cognitive training can improve cognitive performance in healthy older adults. We implemented a cognitive training study to assess determinants of generalization of training gains to untrained tasks, a key indicator for the effectiveness of cognitive training. We aimed to investigate the association of resting-state functional connectivity (FC) of DLPFC with working memory performance improvement and cognitive gains after the training.Method: A sample of 60 healthy o…

Tracking Changes in Frontal Lobe Hemodynamic Response in Individual Adults With Developmental Language Disorder Following HD tDCS Enhanced Phonologic…

2020

Background: Current research suggests a neurobiological marker of developmental language disorder (DLD) in adolescents and young adults may be an atypical neural profile coupled with behavioral performance that overlaps with that of normal controls. Although many imaging techniques are not suitable for the study of speech and language processing in DLD populations, fNIRS may be a viable option. In this study we asked if fNIRS can be used to identify atypical cortical activation patterns in individual adults with DLD and track potential changes in cortical activation patterns following a phonological working memory training protocol enhanced with anodal HD tDCS stimulation to the presuppleme…

Topical Review: Functional Anatomy of Human Hippocampal Formation and Related Structures

1996

Data on the internal organization, and neuronal connections of the human hippocampal formation and related structures of the limbic system are briefly reviewed. In the healthy brain, somatosensory, visual, and auditory input proceeds through neocortical core and belt fields to a variety of association areas, and from here the data is transported via long cortico-cortical pathways to the extended prefrontal association cortex. Tracts generated from this highest organizational level of the brain guide the data via the frontal belt (premotor cortex) to the frontal core (primary motor area). The striatal and cerebellar loops provide the major routes for this data transfer. The main components o…

Continuous Theta-Burst Stimulation Intensity Dependently Facilitates Motor-Evoked Potentials Following Focal Electrical Stimulation of the Rat Motor …

2020

Although theta-burst stimulation (TBS) is known to differentially modify motor cortical excitability according to stimulus conditions in humans, whether similar effects can be seen in animals, in particular rats, remains to be defined. Given the importance of experimental rat models for humans, this study explored this stimulation paradigm in rats. Specifically, this study aimed to explore corticospinal excitability after TBS in anesthetized animals to confirm its comparability with human results. Both inhibition-facilitation configurations using paired electrical stimulation protocols and the effects of the TBS paradigm on motor-evoked potentials (MEPs) in rat descending motor pathways wer…

Electrophysiological and morphological properties of Cajal–Retzius cells with different ontogenetic origins

2010

International audience; The different origins of Cajal-Retzius cells (CRc) as well as their diverse molecular profile suggest that this cell type may represent different neuronal subpopulations. In order to investigate whether CRc from different origins show distinct functional or morphological characteristics we used transgenic Dbx1(cre);ROSA26(YFP) mice in which two subpopulations of CRc, originating from the septum and ventral pallium (VP) at the pallial-subpallial border (PSB), were permanently labeled by yellow fluorescent protein (YFP) expression. Electrophysiological properties of YFP(+) and YFP(-) CRc were investigated by whole-cell patch-clamp recordings, while a thorough somatoden…

The multiple facets of Cajal-Retzius neurons.

2021

ABSTRACTCajal-Retzius neurons (CRs) are among the first-born neurons in the developing cortex of reptiles, birds and mammals, including humans. The peculiarity of CRs lies in the fact they are initially embedded into the immature neuronal network before being almost completely eliminated by cell death at the end of cortical development. CRs are best known for controlling the migration of glutamatergic neurons and the formation of cortical layers through the secretion of the glycoprotein reelin. However, they have been shown to play numerous additional key roles at many steps of cortical development, spanning from patterning and sizing functional areas to synaptogenesis. The use of genetic l…

Heat shock factor 2 is a stress-responsive mediator of neuronal migration defects in models of fetal alcohol syndrome

2014

Fetal alcohol spectrum disorder (FASD) is a frequent cause of mental retardation. However, the molecular mechanisms underlying brain development defects induced by maternal alcohol consumption during pregnancy are unclear. We used normal and Hsf2-deficient mice and cell systems to uncover a pivotal role for heat shock factor 2 (HSF2) in radial neuronal migration defects in the cortex, a hallmark of fetal alcohol exposure. Upon fetal alcohol exposure, HSF2 is essential for the triggering of HSF1 activation, which is accompanied by distinctive post-translational modifications, and HSF2 steers the formation of atypical alcohol-specific HSF1–HSF2 heterocomplexes. This perturbs the in vivo bindi…

Abnormal peripheral and central visual processing in migraine

2018

Sound induced flash illusion (SIFI) is an illusory cross modal (audio-visual) phenomenon critically dependent upon excitability of visual cortex. A recent study with SIFI confirmed hyperexcitability of visual cortex in migraine; patients with migraine show abnormality of chromatic perception. Here we explored the relationship between peripheral chromatic and central visual dysfunction in patients with migraine

Auditory cortical and hippocampal local-field potentials to frequency deviant tones in urethane-anesthetized rats: An unexpected role of the sound fr…

2015

The human brain can automatically detect auditory changes, as indexed by the mismatch negativity of event-related potentials. The mechanisms that underlie this response are poorly understood. We recorded primary auditory cortical and hippocampal (dentate gyrus, CA1) local-field potentials to serial tones in urethane-anesthetized rats. In an oddball condition, a rare (deviant) tone (p = 0.11) randomly replaced a repeated (standard) tone. The deviant tone was either lower (2200, 2700, 3200, 3700 Hz) or higher (4300, 4800, 5300, 5800 Hz) in frequency than the standard tone (4000 Hz). In an equiprobability control condition, all nine tones were presented at random (p = 0.11). Differential respo…

The Superficial Anastomosing Veins of the Human Brain Cortex: A Microneurosurgical Anatomical Study

2022

Introduction: In this microneurosurgical and anatomical study, we characterized the superficial anastomosing veins of the human brain cortex in human specimens.Material and Methods: We used 21 brain preparations fixed in formalin (5%) that showed no pathological changes and came from the autopsy sections. The superficial veins were dissected out of the arachnoid with the aid of a surgical microscope.Results: We dissected nine female and 12 male brain specimens, with an average age of 71 ± 11 years (range 51–88 years). We classified the superficial veins in five types: (I) the vein of Trolard as the dominat vein; (II) the vein of Labbé as the dominant vein; (III) a dominant sylvian vein grou…