Search results for "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…

The Significance of Low O2-Tensi0ns in the Brain Cortex for Occurrence of Metabolic Alterations under Critical Flow Conditions

1985

A reduction in the 02 supply to the brain cortex leads to O2 deficiency and curtailment of neuronal metabolism and function as soon as a minimal cellular O2 tension of 0.1 – 1 mmHG (13 – 133 Pa) can no longer be maintained (Chance et al., 1964; Grote 1967). The hypoxia-induced metabolic alterations are characterized by decreased tissue levels of the energy-rich phosphate compounds PCr and ATP. In addition, elevated concentrations of lactate, pyruvate and NADH and an increase in the lactate/pyruvate ratio and in the NADH/NAD+ ratio are to be expected (Duffy et al., 1972; Granholm and Siesjo 1969; Granholm et al., 1969; Granholm and Siesjo 1971; Grote 1978; Grote and Schubert 1982; Norberg an…

Differential antiepileptic effects of the organic calcium antagonists verapamil and flunarizine in neurons of organotypic neocortical explants from n…

1988

Effects of the organic calcium antagonists verapamil and flunarizine on pentylenetetrazol induced paroxysmal depolarizations were tested in organotypic neocortical explants taken from neonatal rats. In these in vitro experiments the papaverin derivative verapamil depressed, and finally abolished, epileptic discharges in all cases. The piperazine derivative flunarizine, however, which is known to suppress epileptic discharges in hippocampal CA3 neurons (Bingmann and Speckmann 1986), showed no significant antiepileptic effects in the explanted neocortical neurons. Thus, the present findings may indicate that the suppressive action of flunarizine on the generation of paroxysmal depolarizations…

Neuronal Growth and Behavioral Alterations in Mice Deficient for the Psychiatric Disease-Associated Negr1 Gene

2018

Neuronal growth regulator 1 (NEGR1), a member of the immunoglobulin superfamily cell adhesion molecule subgroup IgLON, has been implicated in neuronal growth and connectivity. In addition, genetic variants in or near the NEGR1 locus have been associated with obesity and more recently with learning difficulties, intellectual disability and psychiatric disorders. However, experimental evidence is lacking to support a possible link between NEGR1, neuronal growth and behavioral abnormalities. Initial expression analysis of NEGR1 mRNA in C57Bl/6 wildtype (WT) mice by in situ hybridization demonstrated marked expression in the entorhinal cortex (EC) and dentate granule cells. In co-cultures of co…

Neuronal Growth and Behavioral Alterations in Mice Deficient for the Psychiatric Disease-Associated

2017

Neuronal growth regulator 1 (NEGR1), a member of the immunoglobulin superfamily cell adhesion molecule subgroup IgLON, has been implicated in neuronal growth and connectivity. In addition, genetic variants in or near the NEGR1 locus have been associated with obesity and more recently with learning difficulties, intellectual disability and psychiatric disorders. However, experimental evidence is lacking to support a possible link between NEGR1, neuronal growth and behavioral abnormalities. Initial expression analysis of NEGR1 mRNA in C57Bl/6 wildtype (WT) mice by in situ hybridization demonstrated marked expression in the entorhinal cortex (EC) and dentate granule cells. In co-cultures of co…