Neuroimaging Phenomenology of the Central Self-Regulation Mechanisms

Functional MRI was used to map the brains of subjects on-line during the process of media training for the acquisition and improvement of self-regulation mechanisms. The temporal and spatial dynamics of the new neural network formation were studied in real and simulated (false) biofeedback game, and their qualitative characteristics were discussed. It has been shown that immersion into a virtual competitive game, controlled by physiological responses, causes a wide involvement of the cortices, characterized by a high volume of activation in the mid-temporal, occipital and frontal areas, the cuneus and the precuneus. In both forms of media training, high values of activation volume were identified in the cerebellar structures.

Quantitative tracking of trans-synaptic nose-to-brain transport of nanoparticles and its modulation by odor,aging,and Parkinson’s disease

Nanoparticles(NPs)can be transported via the nose-to-brain(N_(2)B)route.Nonetheless,quantitative data on their spatiotemporal dynamics and regulation of the N_(2)B transport are largely lacking.We surveyed metal oxide/hydroxide NPs as magnetic resonance imaging(MRI)contrasts for quantitative N_(2)B tracking.NPs containing divalent transition metals were the only ones capable of N_(2)B transmission.Using T1-weighted(T1W)MRI,we showed that Mn_(3)O_(4)-NPs were readily engulfed by olfactory receptor neurons(ORNs)without disrupting olfactory sensing,we mapped their N_(2)B trajectory.Within neurons,the Mn_(3)O_(4)-NPs were localized to the cytosol,mitochondria,vesicles,moved at mixed fast and slow axonal transport velocities intraand extra-vesicularly through ORNs.The NPs’axonal transport is dependent on neuronal activity and microtubule integrity.The Mn_(3)O_(4)-NPs were trans-synaptically transmitted through at least four synapses across the olfactory tract.Trans-synaptic transmission of the NPs was dependent on N-type Ca^(2+)channels and NMDA receptors but blocked by GABAB receptor activation.A five-parameter Weibull signal increase/decrease model fitted to the T1W MRI data allowed for estimating kinetic parameters of Mn_(3)O_(4)-NP accumulation/elimination.Absolute and relative accumulation rates,but not elimination,correlated negatively with the number of synapses from ORNs,indicating a coupling of the NPs’N_(2)B transport with spontaneous neuronal activity.Accordingly,olfactory stimuli(2,5-dimethylpyrazine and acetophenone)significantly modulated and rerouted the Mn_(3)O_(4)-NP N_(2)B transport odor specifically.Finally,the NPs’trans-synaptic transmission was impaired by aging and the onset of Parkinson’s disease.These data suggest new approaches to diagnostics,functional neuroimaging,controlling N_(2)B drug delivery.