In the present study, we investigated the electrophysiological and morphological properties of GABAergic neurons in SGI by whole-cell patch-clamp recordings and intracellular Selleckchem BMS354825 staining using biocytin in GAD67-GFP knock-in mice (PND17-22), in which GABAergic neurons specifically express GFP fluorescence. The most common firing properties among these GABAergic neurons (n = 231) were fast spiking (58%), followed by burst spiking (29%), late spiking (8%) and, the least common, regular spiking (2%) and rapid
spike inactivation (3%). Morphological analysis of axonal trajectories of intracellularly-labeled GABAergic neurons revealed three major subclasses: (i) intralaminar interneurons, which were further divided Carfilzomib chemical structure into two subclasses, local and horizontal interneurons; (ii) interlaminar interneurons; and (iii) commissural and tectofugal neurons. These results reveal distinct subsets of GABAergic neurons including neurons that mediate local and long-range inhibition in the SC, neurons that potentially modulate visual and other sensory inputs to the SC, and neurons that project to nuclei outside the SC. “
“Repetitive transcranial magnetic stimulation paradigms such as continuous theta burst stimulation (cTBS) induce long-term potentiation- and long-term depression-like plasticity
in the human motor
cortex. However, responses to cTBS are highly variable and may depend on the activity of the cortex at the time of stimulation. We investigated whether power in different Tolmetin electroencephalogram (EEG) frequency bands predicted the response to subsequent cTBS, and conversely whether cTBS had after-effects on the EEG. cTBS may utilize similar mechanisms of plasticity to motor learning; thus, we conducted a parallel set of experiments to test whether ongoing electroencephalography could predict performance of a visuomotor training task, and whether training itself had effects on the EEG. Motor evoked potentials (MEPs) provided an index of cortical excitability pre- and post-intervention. The EEG was recorded over the motor cortex pre- and post-intervention, and power spectra were computed. cTBS reduced MEP amplitudes; however, baseline power in the delta, theta, alpha or beta frequencies did not predict responses to cTBS or learning of the visuomotor training task. cTBS had no effect on delta, theta, alpha or beta power. In contrast, there was an increase in alpha power following visuomotor training that was positively correlated with changes in MEP amplitude post-training. The results suggest that the EEG is not a useful state-marker for predicting responses to plasticity-inducing paradigms.