Search results for "Postsynaptic potential"

Cannabinoid Control of Learning and Memory through HCN Channels

2016

The mechanisms underlying the effects of cannabinoids on cognitive processes are not understood. Here we show that cannabinoid type-1 receptors (CB1Rs) control hippocampal synaptic plasticity and spatial memory through the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that underlie the h-current (Ih), a key regulator of dendritic excitability. The CB1R-HCN pathway, involving c-Jun-N-terminal kinases (JNKs), nitric oxide synthase, and intracellular cGMP, exerts a tonic enhancement of Ih selectively in pyramidal cells located in the superficial portion of the CA1 pyramidal cell layer, whereas it is absent from deep-layer cells. Activation of the CB1R-HCN pathway impairs d…

Activation of Corticothalamic Layer 6 Cells Decreases Angular Tuning in Mouse Barrel Cortex.

2019

In the mouse whisker system, the contribution of L6 corticothalamic cells (L6 CT) to cortical and thalamic processing of the whisker deflection direction was investigated. A genetically defined population of L6 CT cells project to infragranular GABAergic interneurons that hyperpolarize neurons in somatosensory barrel cortex (BC). Optogenetic activation of these neurons switched BC to an adapted mode in which excitatory cells lost their angular tuning. In contrast, however, this was not the case with a general activation of inhibitory interneurons via optogenetic activation of Gad2-expressing cells. The decrease in angular tuning, when L6 CT cells were activated, was due to changes in cortic…

Reduced interneuronal dendritic arborization in CA1 but not in CA3 region of mice subjected to chronic mild stress

2016

Abstract Introduction Chronic stress induces dendritic atrophy and decreases spine density in excitatory hippocampal neurons, although there is also ample evidence indicating that the GABAergic system is altered in the hippocampus after this aversive experience. Chronic stress causes dendritic remodeling both in excitatory neurons and interneurons in the medial prefrontal cortex and the amygdala. Methods In order to know whether it also has an impact on the structure and neurotransmission of hippocampal interneurons, we have analyzed the dendritic arborization, spine density, and the expression of markers of inhibitory synapses and plasticity in the hippocampus of mice submitted to 21 days …

Immature excitatory neurons develop during adolescence in the human amygdala.

2019

The human amygdala grows during childhood, and its abnormal development is linked to mood disorders. The primate amygdala contains a large population of immature neurons in the paralaminar nuclei (PL), suggesting protracted development and possibly neurogenesis. Here we studied human PL development from embryonic stages to adulthood. The PL develops next to the caudal ganglionic eminence, which generates inhibitory interneurons, yet most PL neurons express excitatory markers. In children, most PL cells are immature (DCX+PSA-NCAM+), and during adolescence many transition into mature (TBR1+VGLUT2+) neurons. Immature PL neurons persist into old age, yet local progenitor proliferation sharply d…

Maternal inflammation has a profound effect on cortical interneuron development in a stage and subtype-specific manner

2018

AbstractSevere infections during pregnancy are one of the major risk factors for cognitive impairment in the offspring. It has been suggested that maternal inflammation leads to dysfunction of cortical GABAergic interneurons that in turn underlies cognitive impairment of the affected offspring. However, the evidence comes largely from studies of adult or mature brains and how the impairment of inhibitory circuits arises upon maternal inflammation is unknown. Here we show that maternal inflammation affects multiple steps of cortical GABAergic interneuron development, i.e., proliferation of precursor cells, migration and positioning of neuroblasts, as well as neuronal maturation. Importantly,…

Proteomic Analysis of Brain Region and Sex-Specific Synaptic Protein Expression in the Adult Mouse Brain

2020

Genetic disruption of synaptic proteins results in a whole variety of human neuropsychiatric disorders including intellectual disability, schizophrenia or autism spectrum disorder (ASD). In a wide range of these so-called synaptopathies a sex bias in prevalence and clinical course has been reported. Using an unbiased proteomic approach, we analyzed the proteome at the interaction site of the pre- and postsynaptic compartment, in the prefrontal cortex, hippocampus, striatum and cerebellum of male and female adult C57BL/6J mice. We were able to reveal a specific repertoire of synaptic proteins in different brain areas as it has been implied before. Additionally, we found a region-specific set…

Dopaminergic-GABAergic interplay and alcohol binge drinking

2019

© 2019 Elsevier Ltd The dopamine D 3 receptor (D 3 R), in the nucleus accumbens (NAc), plays an important role in alcohol reward mechanisms. The major neuronal type within the NAc is the GABAergic medium spiny neuron (MSN), whose activity is regulated by dopaminergic inputs. We previously reported that genetic deletion or pharmacological blockade of D 3 R increases GABA A α6 subunit in the ventral striatum. Here we tested the hypothesis that D 3 R-dependent changes in GABA A α6 subunit in the NAc affect voluntary alcohol intake, by influencing the inhibitory transmission of MSNs. We performed in vivo and ex vivo experiments in D 3 R knockout (D 3 R −/− ) mice and wild type littermates (D 3 …

Neuronal Excitability And Spontaneous Synaptic Transmission In The Entorhinal Cortex Of Bdnf Heterozygous Mice

2018

Abstract Brain Derived Neurotropic Factor (BDNF) is a neutrophic factor that is required for the normal neuronal development and function. BDNF is involved in regulation of synapses as well as neuronal excitability. Entorhinal Cortex (EC) is a key brain area involved in many physiological and pathological processes. In this study we investigated the effects of chronically reduced BDNF levels on layer 3 pyramidal neurons of EC. We aimed to assess the effects of reduced levels of BDNF on firing properties, spontaneous synaptic currents and excitation/inhibition balance from acute brain slices. Patch clamp recordings were obtained from pyramidal neurons of Entorhinal Cortex Layer 3. Findings o…

Interhemispheric inhibition is dynamically regulated during action observation

2016

International audience; It is now well established that the motor system plays a pivotal role in action observation and that the neurophysiological processes underlying perception and action overlaps. However, while various experiments have shown a specific facilitation of the contralateral motor cortex during action observation, no information is available concerning the dynamics of interhemispheric interactions. The aim of the present study was, therefore, to assess interhemispheric inhibition during the observation of others' actions. We designed a transcranial magnetic stimulation (TMS) experiment in which we measured both corticospinal excitability and interhemispheric inhibition, this…

2016

Neuronal activity has been shown to be essential for the proper formation of neuronal circuits, affecting developmental processes like neurogenesis, migration, programmed cell death, cellular differentiation, formation of local and long-range axonal connections, synaptic plasticity or myelination. Accordingly, neocortical areas reveal distinct spontaneous and sensory-driven neuronal activity patterns already at early phases of development. At embryonic stages, when immature neurons start to develop voltage-dependent channels, spontaneous activity is highly synchronized within small neuronal networks and governed by electrical synaptic transmission. Subsequently, spontaneous activity pattern…