The effect of double biofeedback on functional hemispheric asymmetry and activity: a pilot study

In the current pilot study, we attempt to find out how double neurofeedback influences functional hemispheric asymmetry and activity. We examined 30 healthy participants (8 males; 22 females, mean age = 29; SD= 8). To measure functional hemispheric asymmetry and activity, we used computer laterometry in the 'two-source' lead-lag dichotic paradigm. Double biofeedback included 8 minutes of EEG oscillation recording with five minutes of basic mode. During the basic mode, the current amplitude of the EEG oscillator gets transformed into feedback sounds while the current amplitude of alpha EEG oscillator is used to modulate the intensity of light signals. Double neurofeedback did not directly influence the asymmetry itself but accelerated individual sound perception characteristics during dichotic listening in the preceding effect paradigm. Further research is needed to investigate the effect of double neurofeedback training on functional brain activity and asymmetry taking into account participants' age, gender, and motivation

Development Of More Light Sensitive And Red-Shifted Channelrhodopsin Variants For Optogenetic Vision Restoration

Discovery of channelrhodopsin (ChR), a light sensitive protein from green algae, has revolutionized the field of neuroscience research by empowering scientist to control neuron through the light, the technology popularly known as optogenetics. The ChR based optogenetics is one of the promising approaches for treating blindness caused by photoreceptor degenerative diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Fundamentally, the approach is about imparting light sensitivity to surviving inner retinal cells by ectopic expression of genetically encoded light sensitive proteins, such as ChR2. Although the concept of optogenetic approach has been proved by using ChR2, a major obstacle of using the wild type ChR2 or in general ChRs for vision restoration is their low light-sensitivity. With the molecular engineering approach more light sensitive variants of ChR2 have been created recently, however, their light sensitivity remained 2-3 log units below the threshold of cone photoreceptors. Additionally, most of the ChR variants with improved light sensitivity are blue light sensitive. Since the longer wavelength light can have better tissue penetration and less photo-toxicity, the development of ChR with higher light-sensitivity and red-shifted peak spectra (λmax) was desired. In this study, two newly reported ChRs, the CoChR (Chloromoas oogama ChR) and the ReaChR (Red activable ChR, a chimera variant) were chosen to improve their light sensitivity by molecular engineering. The CoChR was chosen because of its larger photocurrent compared to that of ChR2, while ReaChR was selected because of its red-shifted peak spectral sensitivity (λmax). Additionally, attempts were made to shift the λmax of the CoChR towards the red. For CoChR, three different sites with specific mutations, specifically H94E (HE), L112C (LC) and K264T (KT) were identified, which together created the most light-sensitive CoChR-3Mt (CoChR-HE/LC/KT). The CoChR-3Mt markedly enhances photocurrent to low light intensity and, thus, increases operational light sensitivity in compared to the wild type CoChR (CoChR-Wt). The enhanced light sensitivity was found to be correlated with the slower off-kinetics. However, the λmax of CoChR could not shift towards longer wavelengths (red) either by site-direct mutagenesis or by chimera approaches. This suggested that the spectral sensitivity of the ChR, in general, is tightly regulated by a complex mechanism that is yet to be revealed. For ReaChR, a combination of three mutations, specifically I171M-V302L-N305H (IM-VL-NH), was identified which moderately enhanced its light sensitivity. Again, the enhanced light sensitivity was correlated with slower off-kinetics. In conclusion, the CoChR-3Mt was found to be the most light-sensitive ChR variant that can be a better optogenetic tool for vision restoration

Autism spectrum traits in normal individuals : a preliminary VBM analysis

In light of the new DSM-5 autism spectrum disorders diagnosis in which the autism spectrum reflects a group of neurodevelopmental disorders existing on a continuum from mild to severe expression of autistic traits, and recent empirical findings showing a continuous distribution of autistic traits in the general population, our voxel based morphometry study compares normal individuals with high autistic traits to normal individuals with low autistic traits. We hypothesize that normal individuals with high autistic traits in terms of empathizing and systemizing [high systemizing (HS)/low empathizing (LE)] share brain irregularities with individuals that fall within the clinical autism spectrum disorder. We find differences in several social brain network areas between our groups. Specifically, we find increased gray matter (GM) volume in the orbitofrontal cortex, the cuneus, the hippocampus and parahippocampus and reduced GM volume in the inferior temporal cortex, the insula, and the amygdala in our HS/LE individuals relative to our HE/LS (low autistic traits in terms of empathizing and systemizing) individuals

Electrotonic signal processing in AII amacrine cells: compartmental models and passive membrane properties for a gap junction-coupled retinal neuron

Under embargo until: 14.06.2019Amacrine cells are critical for processing of visual signals, but little is known about their electrotonic structure and passive membrane properties. AII amacrine cells are multifunctional interneurons in the mammalian retina and essential for both rod- and cone-mediated vision. Their dendrites are the site of both input and output chemical synapses and gap junctions that form electrically coupled networks. This electrical coupling is a challenge for developing realistic computer models of single neurons. Here, we combined multiphoton microscopy and electrophysiological recording from dye-filled AII amacrine cells in rat retinal slices to develop morphologically accurate compartmental models. Passive cable properties were estimated by directly fitting the current responses of the models evoked by voltage pulses to the physiologically recorded responses, obtained after blocking electrical coupling. The average best-fit parameters (obtained at − 60 mV and ~ 25 °C) were 0.91 µF cm−2 for specific membrane capacitance, 198 Ω cm for cytoplasmic resistivity, and 30 kΩ cm2 for specific membrane resistance. We examined the passive signal transmission between the cell body and the dendrites by the electrotonic transform and quantified the frequency-dependent voltage attenuation in response to sinusoidal current stimuli. There was significant frequency-dependent attenuation, most pronounced for signals generated at the arboreal dendrites and propagating towards the soma and lobular dendrites. In addition, we explored the consequences of the electrotonic structure for interpreting currents in somatic, whole-cell voltage-clamp recordings. The results indicate that AII amacrines cannot be characterized as electrotonically compact and suggest that their morphology and passive properties can contribute significantly to signal integration and processing.acceptedVersio