Search results for "CORTEX"
showing 10 items of 1827 documents
Reduced presynaptic efficiency of excitatory synaptic transmission impairs LTP in the visual cortex of BDNF-heterozygous mice
2006
The neurotrophin brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival, axonal and dendritic growth and synapse formation. BDNF has also been reported to mediate visual cortex plasticity. Here we studied the cellular mechanisms of BDNF-mediated changes in synaptic plasticity, excitatory synaptic transmission and long-term potentiation (LTP) in the visual cortex of heterozygous BDNF-knockout mice (BDNF(+/-)). Patch-clamp recordings in slices showed an approximately 50% reduction in the frequency of miniature excitatory postsynaptic currents (mEPSCs) compared to wild-type animals, in the absence of changes in mEPSC amplitudes. A presynaptic impairment of excita…
Beta-amyloid monomers are neuroprotective
2009
The 42-aa-long β-amyloid protein—Aβ1-42—is thought to play a central role in the pathogenesis of Alzheimer's disease (AD) (Walsh and Selkoe, 2007). Data from AD brain (Shankar et al., 2008), transgenic APP (amyloid precursor protein)-overexpressing mice (Lesné et al., 2006), and neuronal cultures treated with synthetic Aβ peptides (Lambert et al., 1998) indicate that self-association of Aβ1-42monomers into soluble oligomers is required for neurotoxicity. The function of monomeric Aβ1-42is unknown. The evidence that Aβ1-42is present in the brain and CSF of normal individuals suggests that the peptide is physiologically active (Shoji, 2002). Here we show that synthetic Aβ1-42monomers support …
The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia: Further evidence and meta-analysis
2013
NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our stron…
Estimation of ambient GABA levels in layer I of the mouse neonatal cortex in brain slices
2010
GABAergic synapses on Cajal–Retzius neurons in layer I of the murine neocortex experience GABAB receptor (GABABR)-mediated tonic inhibition. Extracellular GABA concentration ([GABA]o) that determines the strength of GABABR-mediated inhibition is controlled by GABA transporters (GATs). In this study, we hypothesized that the strength ofpresynaptic GABABR activation reflects [GABA]o in the vicinity of synaptic contacts. Slices obtained from two age groups were used, namely postnatal days (P)2–3 and P5–7. GABAergic postsynaptic currents (IPSCs) were recorded using the whole-cell patch-clamp technique. Minimal electrical stimulation in layer I was applied to elicit evoked IPSCs (eIPSCs) using a…
Resonance properties of different neuronal populations in the immature mouse neocortex
2012
In vivo recordings in the immature neocortex revealed spontaneous and sensory-driven oscillatory activity from delta (0.5-4 Hz) to gamma (30-100 Hz) frequencies. In order to investigate whether the resonance properties of distinct neuronal populations in the immature neocortex contribute to these network oscillations, we performed whole-cell patch-clamp recordings from visually identified neurons in tangential and coronal neocortical slices from postnatal day (P)0-P7 C57Bl/6 mice. Subthreshold resonance was analysed by sinusoidal current injection of varying frequency. All Cajal-Retzius cells showed subthreshold resonance, with an average frequency of 2.6 ± 0.1 Hz (n = 60), which was massiv…
Disruption of Slc4a10 augments neuronal excitability and modulates synaptic short-term plasticity
2015
Slc4a10 is a Na(+)-coupled Cl(-)-HCO3 (-) exchanger, which is expressed in principal and inhibitory neurons as well as in choroid plexus epithelial cells of the brain. Slc4a10 knockout (KO) mice have collapsed brain ventricles and display an increased seizure threshold, while heterozygous deletions in man have been associated with idiopathic epilepsy and other neurological symptoms. To further characterize the role of Slc4a10 for network excitability, we compared input-output relations as well as short and long term changes of evoked field potentials in Slc4a10 KO and wildtype (WT) mice. While responses of CA1 pyramidal neurons to stimulation of Schaffer collaterals were increased in Slc4a1…
Does dark chocolate have an ergogenic impact on emotional state, vegetative nervous system and strength performance?
2021
International audience; The aim of this research is to assess the acute effect of consuming a dark chocolate with lemon (DCL) bar on the emotional state, the vegetative nervous system, and strength performance. This protocol was carried out by eleven male trained cyclists and trail runners (age: 27 ± 12 years old), who tested, in random order, either DCL bar containing flavonoids or a white chocolate bar (placebo) before a simulated competition of knee extension force. Their precompetitive state anxiety (SA), blood pressure, heart rate variability (HRV), and electroencephalography (EEG) responses were measured before and after eating the bars. The maximal voluntary force (MVC) of the knee e…
Working memory performance is tied to stimulus complexity
2021
1. Summary Working memory is the cognitive capability to maintain and process information over short periods. Recent behavioral and computational studies have shown that increased visual information of the presented stimulus material is associated with enhanced working memory performance. However, the underlying neural correlates of this association are unknown. To identify how stimuli of different visual information levels affect working memory performance, we conducted behavioral experiments and single unit recordings in the avian analog of the prefrontal cortex, the nidopallium caudolaterale (NCL). On the behavioral level, we confirmed that feature-rich complex stimuli demonstrated highe…
Don’t Stress, It’s Under Control: Neural Correlates of Stressor Controllability in Humans
2021
AbstractAnimal research has repeatedly shown that experience of control over an aversive event can protect against the negative consequences of later uncontrollable stress. Neurobiologically, this effect is assumed to correspond to persistent changes in the pathway linking the ventromedial prefrontal cortex (vmPFC) and the dorsal raphe nucleus. However, it remains unclear to what extent these findings translate to humans. During functional magnetic resonance imaging, we subjected participants to controllable and uncontrollable aversive but non-painful electric stimuli, as well as to a control condition without aversive stimulation. In each trial, a symbol signalled whether participants coul…
Making a mountain out of a molehill: on the role of the rostral dorsal anterior cingulate and dorsomedial prefrontal cortex in conscious threat appra…
2013
According to appraisal theories fear and anxiety are elicited by the subjective evaluation of a situation or internal state as threatening. From this perspective anxiety disorders result from maladaptive, exaggerated threat appraisals that over-estimate the threatening consequences of often innocuous stimuli and situations. When these threat over-estimations occur at the level of conscious processing, they are referred to as catastrophizing and worrying. Both are major pathogenic processes in many clinical theories of anxiety. Until recently, little has been known about the neurobiological basis of normal and pathological conscious threat appraisal. Here, we review functional neuroimaging s…