Optogenetic analyses of neuronal network function and synaptic transmission in Caenorhabditis elegans
Abstract
The transparent nematode Caenorhabditis elegans, with its anatomically well-defined nervous system comprising 302 neurons that regulate quantifiable behaviors, is an ideal model system for the development and application of optogenetic methods. Optogenetically modified neurons can be acutely excited or inhibited by light and the effects on a distinct behavior observed. Special lighting systems allow the manipulation of several nerve cells that act as “nodes” of small neural circuits, with different colors of light, so as to control different optogenetic tools independently and simultaneous...
Source: e-Neuroforum - November 1, 2014 Category: Neuroscience Source Type: research
Pigeons as a model species for cognitive neuroscience
This article illustrates some insights gained from research with pigeons with applicability beyond the class of aves. (Source: e-Neuroforum)
Source: e-Neuroforum - September 17, 2014 Category: Neuroscience Source Type: research
How light traverses the inverted vertebrate retina
Abstract
In our eyes, as in the eyes of all vertebrates, images of the environment are projected onto an inverted retina, where photons must pass through most of the retinal layers before being captured by the light-sensitive cells. Light scattering in these retinal layers must decrease the signal-to-noise ratio of the images and thus interfere with clear vision. Surprisingly however, our eyes display splendid visual abilities. This apparent contradiction could be resolved if intraretinal light scattering were to be minimized by built-in optical elements that facilitate light transmission through the tiss...
Source: e-Neuroforum - September 17, 2014 Category: Neuroscience Source Type: research
Transcranial brain stimulation: potential and limitations
Abstract
The brain adapts to new requirements in response to activity, learning or reactions to environmental stimuli by continuous reorganization. These reorganization processes can be facilitated and augmented, or also inhibited and prevented, by transcranial neurostimulation. The most common methods are electrical or magnetic stimulation. However, few studies have dealt with the newer methods using near infrared or ultrasound stimulation.
Transcranial magnetic stimulation (TMS) allows the pain-free transfer of very short bursts of high intensity electrical energy through the skull...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
Giant synapses in the central auditory system
Abstract
Giant synapses occur in four nuclei of the auditory brainstem. They are characterized by numerous active zones concentrated on the soma of the postsynaptic neuron and by rapid postsynaptic currents. At these sites, in the ventral cochlear nucleus, the medial and lateral nucleus of the trapezoid body and the ventral nucleus of the lateral lemniscus, faithful preservation of the temporal relation of action potentials to the sound—intercellular precision—is of the utmost importance for neuronal function. The precision of action potential transfer is supported by the largely unimodal integratio...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
Hereditary hearing loss in humans: the importance of genetic approaches for clinical medicine and basic science
Abstract
Hereditary hearing loss is one of the most common monogenic diseases in humans and, depending on the severity of symptoms and age of onset, dysfunction of one of the main sensory systems can cause significant problems for the affected individual and his/her social environment. The diagnostic workup of hearing impairment is complicated by a pronounced phenotypic variability and extensive genetic heterogeneity. Nevertheless, many forms of monogenic hearing impairment have been elucidated in recent years by genetic approaches. In addition to improved counselling and medical management of patients ...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
L-type calcium channels in the auditory system
Abstract
The voltage-activated L-type calcium channels Cav1.2 and Cav1.3 mediate Ca2+ influx into neurons at the soma or at dendrites, whereas they are not observed at the presynapse. Surprisingly, in the inner ear, Cav1.3 is indispensable for signal transmission from the presynaptic cochlear inner hair cells to the postsynaptic auditory nerve fibers. Due to Cav1.3 channel clustering at ribbons, i.e., specific presynaptic structures of the hair cells, they promote Ca2+ influx, which triggers calcium-dependent fusion of synaptic vesicles with the plasma membrane. Mutations in Cacna1d, a gene that encodes...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
Mechanisms and genes in Drosophila hearing
Abstract
The fruit fly Drosophila melanogaster communicates acoustically and hears with its antennae. Fundamental aspects of hearing can be studied in these antennal ears, the auditory sensory cells of which are evolutionarily related to vertebrate hair cells and are specified developmentally by homologous transcription factors. Like vertebrate hair cells, Drosophila auditory sensory cells are also motile and actively amplify the mechanical vibrations they transduce. The transduction and amplification mechanisms rely on the interplay between mechanically activated ion channels and motor proteins, whose ...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
The human brain project: neuroscience perspectives and German contributions
This article is designed to give a brief overview of the HBP organization, and to illustrate the German neuroscientific contributions to the HBP and indicate the relationship to other projects within the HBP. (Source: e-Neuroforum)
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
Hearing
(Source: e-Neuroforum)
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
ADAM10: α-secretase in Alzheimer’s disease and regulator of neurobiology
Abstract
Proteolytic and amyloidogenic processing of amyloid precursor protein (APP) by β- and γ-secretases are pathological hallmarks of Alzheimer’s disease (AD). These proteolytic activities lead to release of the amyloid-β peptides believed to cause neurological pathology and be linked to pathological progression in AD. Due to its capability to cleave APP within the toxic peptide sequence, the metalloproteinase ADAM10 (“a disintegrin and metalloprotease”) is a known antagonist of the disease-causing pathway. ADAM10 also plays a major role in the ectodomain shedding of a number of important c...
Source: e-Neuroforum - September 1, 2014 Category: Neuroscience Source Type: research
Studying motor cortex function using the rodent vibrissal system
Abstract
The function of the mammalian motor cortex was one of the first problems studied in neuroscience. But until today, the major principles of the workings of the motor cortex have remained conjectural. It is clear that motor cortex holds a topographic map of body parts. But does that mean that the motor cortex itself is undertaking the challenging task of converting motor plans (i.e., intended trajectories and effects of actions) into low level motor commands appropriate to drive the muscles? Work of many decades on motor function has revealed the existence of dedicated networks, the so-called cen...
Source: e-Neuroforum - March 1, 2014 Category: Neuroscience Source Type: research
BDNF: a regulator of learning and memory processes with clinical potential
Abstract
Memories are believed to be represented by facilitated synaptic transmission of electrical signals in neuronal networks. The ability to acquire new memories or to change old memory content results from the plastic properties of the brain. Molecular changes in synaptic plasticity of neuronal networks are considered to be the cellular correlates of learning and memory, and the neurotrophin brain-derived neurotropic factor (BDNF) plays an important role in these processes. This neurotrophic factor coordinates a multitude of biological functions. In addition to its role in neuronal plasticity proce...
Source: e-Neuroforum - March 1, 2014 Category: Neuroscience Source Type: research
New insights into the role of GABAergic inhibition during functional reorganization of the visual cortex post-lesion
Abstract
Cortical injuries are a leading cause of death and disability worldwide. The first weeks post-lesion are usually crucial to predict the final outcome of patients. While most of them experience a spontaneous, at least partial, restoration of function, in some the clinical picture is complicated due to the development of epileptic seizures. A substantial number of studies suggest that these phenomena may be triggered by complex functional alterations in intracortical inhibition, often observed in perilesional cortical areas. Pathophysiological changes in GABAergic transmission are indeed likely t...
Source: e-Neuroforum - March 1, 2014 Category: Neuroscience Source Type: research
Neuropharmacological functional imaging
Abstract
The marriage of psychopharmacology with functional neuroimaging enables the investigation of neurochemical modulation of cognitive functions in the human brain. From the point of basic neurocognitive research, pharmacological functional neuroimaging is hence a valuable completion of animal experiments. From the point of clinical neuroscience, pharmacological neuroimaging contributes to the understanding and development of pharmacological treatment approaches for patients with neurological and psychiatric disorders. The present paper provides an overview of the methodological approach and illust...
Source: e-Neuroforum - December 1, 2013 Category: Neuroscience Source Type: research
