Neuroscience
-
Scans without evidence of dopaminergic deficit (SWEDD) patients are often misdiagnosed with Parkinson's disease (PD) but have normal dopamine transporter scans. We hypothesised that white matter tracts associated with motor and cognition functions may be affected differently by SWEDD and PD. Automatically annotated fibre clustering (AAFC) is a novel clustering method based on diffusion magnetic resonance imaging (dMRI) tractography that enables highly robust reconstruction of white matter tracts that are composed of corresponding clusters. ⋯ The support vector machine classifier achieved high accuracies in PD-NC, PD-SWEDD and NC-SWEDD classifications. This outcome validated these local white matter differences were useful to separate the three groups. These results suggest that PD exerts more significant effects on thalamo tracts than SWEDD, and unique microstructural changes occur in CB tract in SWEDD.
-
Acquired information is stabilized into long-term memory through a process known as consolidation. Though, after consolidation, when stored information is retrieved they can be again susceptible, allowing modification, updating and strengthening and to be re-stabilized they need a new process referred to as memory reconsolidation. However, the molecular mechanisms of recognition memory consolidation and reconsolidation are not fully understood. ⋯ We verified that the blockade of AMPA receptors (AMPAr) and L-VDCCs calcium channels impaired ORM consolidation and reconsolidation when administered into CA1 immediately after sample phase or reactivation phase and that these impairments were blocked by the administration of AMPAr agonist and of neurotrophin BDNF. Also, the blockade of CaMKII impaired ORM consolidation when administered 3 h after sample phase but had no effect on ORM reconsolidation and its effect was blocked by the administration of BDNF, but not of AMPAr agonist. So, this study provides new evidence of the molecular mechanisms involved on the consolidation and reconsolidation of ORM, demonstrating that AMPAr and L-VDCCs are necessary for the consolidation and reconsolidation of ORM while CaMKII is necessary only for the consolidation and also that there is a link between BDNF and AMPAr, L-VDCCs and CaMKII as well as a link between AMPAr and L-VDCCs on ORM consolidation and reconsolidation.
-
Interleaved rather than repetitive practice (RP) is associated with superior retention of motor skills. It has been argued that this results from improved post-practice consolidation reflected in greater offline gains following interleaved practice (IP). The magnitude of this offline benefit has been associated with greater recruitment of supplementary motor area (SMA) during encoding. ⋯ Enhanced offline gain following interleaved training resulted from rapid stabilization of performance within the first 6-h following encoding and overnight improvement that continued over multiple sleep episodes. Administration of anodal stimulation at SMA during RP improved performance during training compared to sham but this benefit was short lived as forgetting during the first 6-h after practice was consistent with that observed for the sham counterpart. However, supplementing RP with anodal stimulation at SMA did foster overnight offline performance gains not displayed by individuals that experienced RP in the absence of stimulation.
-
Traditional Chinese medicine has been reported to influence the proliferation and differentiation of neural stem cells (NSCs) that may be protective against nervous system diseases. Recent evidence indicates the importance of musk ketone in nerve recovery and preventing secondary damage after cerebral ischemic injury. A middle cerebral artery occlusion (MCAO) rat model was established by a transient filament model, and rats were treated with musk ketone (0.9 or 1.8 μM). ⋯ In addition, NSCs treated with musk ketone showed enhanced proliferation and differentiation along with increased PI3K/Akt signaling pathway activation. The effects of muck ketone were reversed by Akti-1/2. Altogether, musk ketone promoted NSC proliferation and differentiation and protected against cerebral ischemia by activating the PI3K/Akt signaling pathway, highlighting the potential of musk ketone as a physiologically validated approach for the treatment of cerebral ischemia.
-
High impulsivity characterizes a myriad of neuropsychiatric diseases, and identifying targets for neuropharmacological intervention to reduce impulsivity could reveal transdiagnostic treatment strategies. Motor impulsivity (impulsive action) reflects in part the failure of "top-down" executive control by the medial prefrontal cortex (mPFC). The present study profiled the complete set of mRNA molecules expressed from genes (transcriptome) in the mPFC of male, outbred rats stably expressing high (HI) or low (LI) motor impulsivity based upon premature responses in the 1-choice serial reaction time (1-CSRT) task. ⋯ Transcription factor enrichment identified mothers against decapentaplegic homolog 4 (SMAD4) and RE1 silencing transcription factor (REST) as overrepresented in the mPFC of HI rats relative to LI rats, while in silico analysis predicted a conserved SMAD binding site within the voltage-gated calcium channel subunit alpha1 E (CACNA1E) promoter region. qRT-PCR analyses confirmed that mRNA expression of CACNA1E, as well as expression of leucyl and cystinyl aminopeptidase (LNPEP), were higher in the mPFC of HI vs. LI rats. These outcomes establish a transcriptomic landscape in the mPFC that is related to individual differences in motor impulsivity and propose novel gene targets for future impulsivity research.