By freeze-fracture replica immunolabeling, > 100 astrocyte gap junctions
but no neuronal gap junctions were found based on immunogold labeling for Cx43, whereas 16 neuronal gap junctions at postnatal day (P)4, P7 and P18 were detected based on Cx36 labeling. Punctate labeling for Cx36 was localized to the somatic and dendritic surfaces of peripherin-positive motoneurons in the Mo5, motoneurons throughout the spinal cord, and sexually dimorphic motoneurons at lower lumbar levels. In studies of electrical synapses and electrical transmission between developing and between adult motoneurons, our results serve to focus attention learn more on mediation of this transmission by gap junctions composed of Cx36. “
“Many forms of brain stimulation utilize the notion of state dependency, whereby greater influences are observed when a given area is more engaged at the time of stimulation. Here, by delivering intracortical microstimulation (ICMS) to the supplementary eye fields (SEF) of monkeys performing interleaved pro- and anti-saccades, we show a surprising diversity of state-dependent effects of
ICMS-SEF. Short-duration ICMS-SEF passed around cue presentation selectively disrupted anti-saccades by SP600125 mouse increasing reaction times and error rates bilaterally, and also recruited neck muscles, favoring contralateral head turning to a greater degree on anti-saccade trials. These results are consistent with the functional relevance
of the SEF for anti-saccades. The multiplicity of stimulation-evoked effects, with ICMS-SEF simultaneously disrupting anti-saccade performance and facilitating contralateral head orienting, probably reflects both the diversity of cortical and subcortical targets of SEF projections, and the response of this oculomotor network to stimulation. We speculate that the bilateral disruption of anti-saccades arises via feedback loops that may include the thalamus, whereas neck muscle recruitment arises via feedforward polysynaptic pathways to the motor periphery. Consideration of both sets of results reveals a more complete picture of the highly complex Tolmetin and multiphasic response to ICMS-SEF that can play out differently in different effector systems. Stimulation remains a central tool for cognitive neuroscience. The effects of many forms of brain stimulation are dependent on the behavioral state at the time of stimulation (Pascual-Leone et al., 2000; Cohen & Newsome, 2004), enabling inference of an area’s activity or critical time of contribution to a task based on the effects of stimulation on behavior. Such state-dependent effects can be quite variable, with stimulation facilitating behavior in some instances and disrupting or delaying behaviors in others.
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