Locomotion controls spatial integration in mouse visual cortex.

Growing evidence indicates that responses in sensory cortex are modulated by factors beyond direct sensory stimulation. In primary visual cortex (V1), for instance, responses increase with locomotion. Here we show that this increase is accompanied by a profound change in spatial integration. We recorded from V1 neurons in head-fixed mice placed on a spherical treadmill. We characterized spatial integration and found that the responses of most neurons were suppressed by large stimuli. As in primates, this surround suppression increased with stimulus contrast. These effects were captured by a divisive normalization model, where the numerator originates from a central region driving the neuron and the denominator originates from a larger suppressive field. We then studied the effects of locomotion and found that it markedly reduced surround suppression, allowing V1 neurons to integrate over larger regions of visual space. Locomotion had two main effects: it increased spontaneous activity, and it weakened the suppressive signals mediating normalization, relative to the driving signals. We conclude that a fundamental aspect of visual processing, spatial integration, is controlled by an apparently unrelated factor, locomotion. This control might operate through the mechanisms that are in place to deliver surround suppression

Subcortical Source and Modulation of the Narrowband Gamma Oscillation in Mouse Visual Cortex

Primary visual cortex exhibits two types of gamma rhythm: broadband activity in the 30-90 Hz range and a narrowband oscillation seen in mice at frequencies close to 60 Hz. We investigated the sources of the narrowband gamma oscillation, the factors modulating its strength, and its relationship to broadband gamma activity. Narrowband and broadband gamma power were uncorrelated. Increasing visual contrast had opposite effects on the two rhythms: it increased broadband activity, but suppressed the narrowband oscillation. The narrowband oscillation was strongest in layer 4 and was mediated primarily by excitatory currents entrained by the synchronous, rhythmic firing of neurons in the lateral geniculate nucleus (LGN). The power and peak frequency of the narrowband gamma oscillation increased with light intensity. Silencing the cortex optogenetically did not abolish the narrowband oscillation in either LGN firing or cortical excitatory currents, suggesting that this oscillation reflects unidirectional flow of signals from thalamus to cortex

Biochar production from waste rubber-wood-sawdust and its potential use in C sequestration: chemical and physical characterization

Biochars have received increasing attention because of their potential environmental applications such as soil amending and atmospheric C sequestration. In this study, biochar was produced from waste rubber-wood-sawdust. The produced biochars were characterized by Brunauer–Emmett–Teller (BET) gas porosimetry, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Pyrolysis temperature was shown to have a strong influence on both thermal and chemical characteristic of biochar samples. The experimental data shows that the biochar samples can absorb around 5% water by mass (hydrophilic) at lower temperatures (650 °C), biochar samples were thermally stable and became hydrophobic due to the presence of aromatic compounds. Carbon content (over 85%) increased with increasing temperature, and showed an inverse effect to the elemental ratios of H/C and O/C. The very low H/C and O/C ratios obtained for the biochar indicated that carbon in this material is predominantly unsaturated. BET results showed that the sawdust derived biochars have surface areas between 10 and 200 m2 g−1 and FTIR indicated an aromatic functional group about 866 cm−1 in most of the samples. The rate of CO2 adsorption on sawdust derived biochar generally increased with increasing temperature from 450 to 650 °C but then decreased with increase in the production temperature. Derived biochar represents a potential alternative adsorbent for C sequestration

Layer-specific integration of locomotion and sensory information in mouse barrel cortex

During navigation, rodents continually sample the environment with their whiskers. How locomotion modulates neuronal activity in somatosensory cortex, and how it is integrated with whisker-touch remains unclear. Here, we compared neuronal activity in layer 2/3 (L2/3) and L5 of barrel cortex using calcium imaging in mice running in a tactile virtual reality. Both layers increase their activity during running and concomitant whisking, in the absence of touch. Fewer neurons are modulated by whisking alone. Whereas L5 neurons respond transiently to wall-touch during running, L2/3 neurons show sustained activity. Consistently, neurons encoding running-with-touch are more abundant in L2/3 and they encode the run-speed better during touch. Few neurons across layers were also sensitive to abrupt perturbations of tactile flow during running. In summary, locomotion significantly enhances barrel cortex activity across layers with L5 neurons mainly reporting changes in touch conditions and L2/3 neurons continually integrating tactile stimuli with running

A review: carbon dioxide capture: biomass-derived-biochar and its applications

The changes in global temperatures as a result of carbon dioxide (CO2) emissions has suggested that cumulative CO2 emissions will continue to increase over time. Many countries are looking for ways to reduce or alter the amount of CO2 harming our environment; therefore, this review is a compilation of CO2 adsorption on biomass-derived-biochar (BDB). This suggests that effective measures to mitigate the risk of dangerous climate change will need to limit cumulative emissions of CO2. Further, if cumulative CO2 emissions overshoot acceptable limits, it will become necessary to remove CO2 from the air, that is, the so-called “negative emissions.” In this review, we discuss the definitions and classes of technologies for capturing CO2 from the air and the application of biochar in the improvement of soil fertility. We also discuss the economic tradeoff between biochar and bio-oil, agricultural nutrient leaching, the novel magnetic property of biochar and its durability

Locomotion modulates specific functional cell types in the mouse visual thalamus

The visual system is composed of diverse cell types that encode distinct aspects of the visual scene and may form separate processing channels. Here we present further evidence for that hypothesis whereby functional cell groups in the dorsal lateral geniculate nucleus (dLGN) are differentially modulated during behavior. Using simultaneous multi-electrode recordings in dLGN and primary visual cortex (V1) of behaving mice, we characterized the impact of locomotor activity on response amplitude, variability, correlation and spatiotemporal tuning. Locomotion strongly impacts the amplitudes of dLGN and V1 responses but the effects on variability and correlations are relatively minor. With regards to tunings, locomotion enhances dLGN responses to high temporal frequencies, preferentially affecting ON transient cells and neurons with nonlinear responses to high spatial frequencies. Channel specific modulations may serve to highlight particular visual inputs during active behaviors

Fine motor skills in children with rolandic epilepsy

PMID = 2401251

Medication persistence in Turkish children and adolescents with attention-deficit/hyperactivity disorder

PMID = 2501059

Factors related with unintentional injuries in children with newly diagnosed attention-deficit/hyperactivity disorder

PMID = 2535884