Search results for "Corte"

Lesions to the posterior insular cortex cause dysarthria

2011

Background:  Up to now, there are few systematic studies in a sufficient number of patients with lesions involving the insular cortex (IC) examining whether damage of the IC is directly related to dysarthria. Thus, this is the first study applying modern voxel-lesion behaviour mapping (VLBM) aimed to examine whether the IC is involved in dysarthria – and if so – which part of the IC is involved. Methods:  Twenty-five patients with acute stroke lesions affecting the IC and peri-insular region were investigated employing VLBM analysis. Results:  Present data indicated that dysarthria is associated with stroke lesions affecting the right- and left-sided posterior IC. Conclusions:  Owing to the…

Visual Cortex Performs a Sort of Non-linear ICA

2010

Here, the standard V1 cortex model optimized to reproduce image distortion psychophysics is shown to have nice statistical properties, e.g. approximate factorization of the PDF of natural images. These results confirm the efficient encoding hypothesis that aims to explain the organization of biological sensors by information theory arguments.

Tissue Oxygenation in Normal and Edematous Brain Cortex During Arterial Hypocapnia

1984

Since arterial hypocapnia causes a cerebral blood flow decrease, hypocapnic conditions are induced in patients with severe traumatic brain injury by controlled hyperventilation in order to reduce the intracranial pressure (Gordon, 1971). Beneficial effects on the clinical course of patients, however, can be observed only under conditions of moderate hypocapnia. As shown by animal experiments severe arterial hypocapnia results in insufficient oxygen supply conditions in brain tissue (Grote et al., 1981), which subsequently influences the brain metabolism (Granholm et al., 1969, 1971) and counteracts the influence of hypocapnia on cerebral blood flow regulation (Grote et al., 1981). The prese…

Cellular Acetylcholine Receptor Expression in the Brain of Patients with Alzheimer’s and Parkinson’s Dementia

1995

Binding studies and receptor autoradiography reveal the overall changes of acetylcholine receptors (AChR) in Alzheimer’s and Parkinson’s dementia cortices.2,5 A detailed account of these changes requires a study of neurochemical phenotype of individual neurons as basic elements of networks constituting the substrate of cortical functions.4 Examples will be given for cell-type specific AChR localization in normal and diseased human cerebral cortex.

Multifocal TMS for temporo-spatial description of cortico-cortical connectivity patterns

2016

Pheromone-induced odor learning modifies Fos expression in the newborn rabbit brain.

2013

Research report; International audience; Associative learning contributes crucially to adjust the behavior of neonates to the permanently changing environment. In the European rabbit, the mammary pheromone (MP) excreted in milk triggers sucking behavior in newborns, and additionally promotes very rapid learning of initially neutral odor cues. Such stimuli become then as active as the MP itself to elicit the orocephalic motor responses involved in suckling. In this context, the rabbit is an interesting model to address the question of brain circuits early engaged by learning and memory. Here, we evaluated the brain activation (olfactory bulb and central regions) induced in 4-day-old pups by …

Prenatal exposure to cannabinoids evokes long-lasting functional alterations by targeting CB 1 receptors on developing cortical neurons

2015

The CB1 cannabinoid receptor, the main target of Δ(9)-tetrahydrocannabinol (THC), the most prominent psychoactive compound of marijuana, plays a crucial regulatory role in brain development as evidenced by the neurodevelopmental consequences of its manipulation in animal models. Likewise, recreational cannabis use during pregnancy affects brain structure and function of the progeny. However, the precise neurobiological substrates underlying the consequences of prenatal THC exposure remain unknown. As CB1 signaling is known to modulate long-range corticofugal connectivity, we analyzed the impact of THC exposure on cortical projection neuron development. THC administration to pregnant mice in…

Sex Differences in the Behavioral and Synaptic Consequences of a Single in vivo Exposure to the Synthetic Cannabimimetic WIN55,212-2 at Puberty and A…

2019

Heavy cannabis consumption among adolescents is associated with significant and lasting neurobiological, psychological and health consequences that depend on the age of first use. Chronic exposure to cannabinoid agonists during the perinatal period or adolescence alters social behavior and prefrontal cortex (PFC) activity in adult rats. However, sex differences on social behavior as well as PFC synaptic plasticity after acute cannabinoid activation remain poorly explored. Here, we determined that the consequences of a single in vivo exposure to the synthetic cannabimimetic WIN55,212-2 differently affected PFC neuronal and synaptic functions after 24 h in male and female rats during the pube…

Identification of Novel Principles of Keratin Filament Network Turnover in Living Cells

2004

It is generally assumed that turnover of the keratin filament system occurs by exchange of subunits along its entire length throughout the cytoplasm. We now present evidence that a circumscribed submembranous compartment is actually the main site for network replenishment. This conclusion is based on the following observations in living cells synthesizing fluorescent keratin polypeptides: 1) Small keratin granules originate in close proximity to the plasma membrane and move toward the cell center in a continuous motion while elongating into flexible rod-like fragments that fuse with each other and integrate into the peripheral KF network. 2) Recurrence of fluorescence after photobleaching i…

Molecular Evolution of Lactate Dehydrogenase in the Developing Nervous Tissue*

1964

Publisher Summary This chapter describes both electrophoretic and catalytic studies on lactate dehydrogenase (LDH) in the developing brain. It has been found that the enzyme exhibits at birth a composition that gradually changes to attain the final pattern observed in the adult. The neurochemical findings on LDH isozymes parallel the rapid growth in the first days after birth. Isozyme E, which is not present in detectable amounts 2 days after birth, represents 15% of the enzyme on the 22nd day. Similarly, the percentage decrease of isozyme B is quite steep at the beginning. Nevertheless, the final pattern is attained only at the end of the 2nd month that is, when the cerebral cortex is full…