Neuroscience
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Accumulating evidence relates finger gnosis (also called finger sense or finger gnosia), the ability to identify and individuate fingers, to cognitive processing, particularly numerical cognition. Multiple studies have shown that finger gnosis scores correlate with or predict numerical skills in children. Neuropsychological cases as well as magnetic stimulation studies have also shown that finger agnosia (defects in finger gnosis) often co-occurs with cognitive impairments, including agraphia and acalculia. ⋯ We also found sex differences in how GMV is associated with finger gnosis. While females showed a more distributed and extensive set of frontal and parietal clusters, males showed two striatal clusters. This study provides the first findings on structural brain features that correlate with finger gnosis.
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GIN (GFP-expressing inhibitory interneuron) transgenic mice are believed to express the enhanced GFP (eGFP) in a subset of somatostatin (SST)-expressing interneurons in the neocortex and have been widely used in the study on SST interneurons. Previous studies showed that eGFP+ neurons in the neocortex are distributed in the layer II-IV and upper layer V (cortical eGFP neurons) and contain SST. In this study, we reported a new group of eGFP+ neurons in GIN mice at early postnatal ages, which was located in the deep layer of the lateral neocortex as clusters (cluster eGFP neurons). ⋯ Firing rate, afterhyperpolarization, and excitatory synaptic activity significantly enhanced in cortical eGFP neurons during postnatal development, but these properties remained mostly unchanged in cluster eGFP neurons. Short-term plasticity of the excitatory synapse showed robust facilitation in cortical eGFP neurons but depression in cluster eGFP neurons. These results implied that eGFP might also be expressed in other types of cortical neurons in addition to SST-containing interneurons in GIN mice at early postnatal ages.
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The aims of the study were to compare effects of baclofen, a GABAB receptor agonist commonly used as an antispastic drug, on direct current (DC) evoked long-lasting changes in the excitability of afferent fibers traversing the dorsal columns and their terminal branches in the spinal cord, and to examine whether baclofen interferes with the development and expression of these changes. The experiments were performed on deeply anesthetized rats by analyzing the effects of DC before, during and following baclofen administration. Muscle and skin afferent fibers within the dorsal columns were stimulated epidurally and changes in their excitability were investigated following epidural polarization by 1.0-1.1 μA subsequent to i.v. administration of baclofen. ⋯ In contrast, baclofen-reduced effects of intraspinal stimulation combined with intraspinal polarization (0.3 μA) of terminal axonal branches of the afferents within the dorsal horn or in motor nuclei, whether administered ionophoretically or intravenously. Effects of DC on monosynaptically evoked synaptic actions of these fibers (extracellular field potentials) were likewise reduced by baclofen. The study thus provides further evidence for differential effects of DC on afferent fibers in the dorsal columns and the preterminal branches of these fibers and their involvement in spinal plasticity.
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Resting-state functional magnetic resonance imaging (rs-fMRI) has been used to investigate networks within the cortex and has also provided some insight into the networks present in the brainstem (BS) and spinal cord (SC). The purpose of this study was to investigate resting-state blood oxygenation-level dependent (BOLD) fluctuations in the BS/SC and to identify resting-state networks (RSNs) across these regions. Resting-state BOLD fMRI data were obtained from the entire BS and cervical SC in 16 healthy participants, at 3 T, with T2-weighted single-shot fast spin-echo imaging. ⋯ The results indicate the presence of a complex resting-state network which is highly interconnected in the spinal cord. Known anatomical connections between cortical and BS regions support the conclusion that the observed resting-state BOLD fluctuations in the BS/SC may be related to autonomic regulation. Future studies are required to further investigate these resting-state BOLD networks.