Brain research
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The majority of studies support a role of the anterior cingulate cortex (ACC) in the attentional control necessary for conflict resolution in the Stroop task; however, the time course of activation and the neural substrates underlying the Stroop task remain contentious. We used high-density EEG to record visual-evoked potentials from 16 healthy subjects while performing a manual version of the traditional Stroop colour-word task. Difference waveforms for congruent-control and incongruent-control conditions were similar in amplitude and had a similar spatial distribution in the time window of 260-430 ms post stimulus onset. ⋯ As congruent-control and incongruent-control differences have a similar timeframe and cingulate source, we propose that this indicates early attentional allocation processes. That is, the identification of two sources of information (the word and the colour it is printed in) and the selective attention to one. The later peak in the incongruent-congruent difference wave, originating in anterior cingulate, likely reflects identification (and subsequent resolution) of conflict in the two sources of information.
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We examined the effect of the peripheral application of glutamate and capsaicin to the temporomandibular joint (TMJ) in influencing the activation and central sensitization of TMJ-responsive nociceptive neurons in the trigeminal subnucleus caudalis/upper cervical cord (Vc/UCC). The activity of single neurons activated by noxious mechanical stimulation of the TMJ was recorded in the Vc/UCC of 49 halothane-anesthetized male rats. Cutaneous mechanoreceptive field (RF), cutaneous mechanical activation threshold (MAT), and TMJ MAT of each neuron were assessed before and after injection of 0.5 M glutamate (or vehicle) and 1% capsaicin (or vehicle) into the TMJ. ⋯ W., 2008a. Glutamate and capsaicin effects on trigeminal nociception I: activation and peripheral sensitization of deep craniofacial nociceptive afferents. Brain Res. doi:10.1016/j.brainres.2008.11.029], suggesting that peripheral and central sensitization may be differentially involved in the nociceptive effects of glutamate and capsaicin applied to deep craniofacial tissues.
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In tauopathies such as Alzheimer's disease (AD), the molecular mechanisms of tau protein aggregation into neurofibrillary tangles (NFTs) and their contribution to neurodegeneration remain not understood. It was recently demonstrated that tau, regardless of its aggregation, might represent a key mediator of neurodegeneration. Therefore, reduction of tau levels might represent a mechanism of neuroprotection. ⋯ These data indicate that GSK3beta might be selectively involved in the regulation of tau protein levels. Moreover, inhibition of PP2A by okadaic acid, but not that of PP2B (protein phosphatase-2B)/calcineurin by FK506, dose-dependently reversed lithium-induced tau decrease. These data indicate that GSK3beta regulates both tau phosphorylation and total tau levels through PP2A.