p-Tyrosol Enhances the Production of New Neurons in the Hippocampal CA1 Field after Transient Global Cerebral Ischemia in Rats.

This study aimed at assessing the regenerative effect of p-tyrosol in transient global cerebral ischemia modeled in adult male Wistar rats by reversible occlusion of the three major vessels originating from the aortic arch and supplying the blood to the brain. p-Tyrosol was administered intraperitoneally in a dose of 20 mg/kg over 10 days after surgery. The death of NeuN+ mature neurons and the number of newly formed DCX+ neurons were assessed in the CA1 field of the hippocampus that is highly susceptible to damage in this model. We found that ischemia induced death of more than 50% mature neurons in the hippocampal CA1 field (p<0.001). p-Tyrosol stimulated the formation and growth of new neurons in the normally non-proliferative CA1 region of the hippocampus (p<0.05) and produced a neuroprotective effect on mature neurons (p<0.01).

[Gamma-activity of the cerebral cortex: communication with intelligence and accuracy of perception of time].

Connection of indicators of intelligence and accuracy of perception of time is established with level cortical interactions on frequency of a gamma rhythm, and also phase parities between a gamma rhythm and low-frequency components EEG. Character of these communications differs at young men and girls, depends on a frequency range of a gamma rhythm, a kind and a stage of carried out activity.

[Visual analog of mismatch negativity when stimuli differ in the duration].

Event-related potentials (ERPs) were studied in 10 practically healthy volunteers (6 male, 4 female) aged from 18 to 24 years during presentation of rare deviant and frequent standard visual stimuli in a standard odd-ball paradigm under conditions of active attention and inattention to stimulus duration. The deviation of the duration of deviant stimuli (50, 100 and 150 ms) from that of the standard stimuli (200 ms) varied from 50 to 150 ms. In series where deviations were 100 and 150 ms, a negative difference wave with the latency of 200-400 ms was revealed (ERP to the deviant stimulus under conditions of inattention minus ERP to the control stimulus of the same duration) mainly in the right temporal region. Since this difference negative wave appeared under conditions of inattention, we suppose that this wave is the visual analogue of mismatch negativity (MMN) and related to automatic detection of deviation of stimulus duration.

Iron-Insensitive Quantitative Assessment of Subcortical Gray Matter Demyelination in Multiple Sclerosis Using the Macromolecular Proton Fraction.

BACKGROUND AND PURPOSE: Fast macromolecular proton fraction mapping is a recent quantitative MR imaging method for myelin assessment. The objectives of this study were to evaluate the macromolecular proton fraction as a measure of demyelination in subcortical GM structures in multiple sclerosis and assess a potential relationship between demyelination and excess iron deposition using the macromolecular proton fraction and T2* mapping. MATERIALS AND METHODS: Macromolecular proton fraction and T2* maps were obtained from 12 healthy controls, 18 patients with relapsing-remitting MS, and 12 patients with secondary-progressive MS using 3T MR imaging. Parameter values in the caudate nucleus, globus pallidus, putamen, substantia nigra, and thalamus were compared between groups and correlated to clinical data. RESULTS: The macromolecular proton fraction in all subcortical structures and T2* in the globus pallidus, putamen, and caudate nucleus demonstrated a significant monotonic decrease from controls to patients with relapsing-remitting MS and from those with relapsing-remitting MS to patients with secondary-progressive MS. The macromolecular proton fraction in all subcortical structures significantly correlated with the Expanded Disability Status Scale and MS Functional Composite scores with absolute Pearson correlation coefficient (r) values in a range of 0.4-0.6. Significant correlations (r = -0.4 to -0.6) were also identified between the macromolecular proton fraction and the 9-Hole Peg Test, indicating a potential relationship with nigrostriatal pathway damage. Among T2* values, weak significant correlations with clinical variables were found only in the putamen. The macromolecular proton fraction did not correlate with T2* in any of the studied anatomic structures. CONCLUSIONS: The macromolecular proton fraction provides an iron-insensitive measure of demyelination. Myelin loss in subcortical GM structures in MS is unrelated to excess iron deposition. Subcortical GM demyelination is more closely associated with the disease phenotype and disability than iron overload.

A visual analog of mismatch negativity when stimuli differ in duration.

Event-linked brain potentials were studied in ten essentially healthy volunteers (six men, four women) aged 18-24 years. Subjects were presented with rare deviant and frequent standard visual stimuli in the standard odd-ball paradigm in conditions of active attention to stimulation and in conditions of distracted attention. Differences between deviant stimuli (50, 100, and 150 msec) and standard (200 msec) stimuli ranged from 50 to 150 msec. Negative difference waves (deviant stimulus with distracted attention minus control stimulus of the same duration) were seen at differences of 100 and 150 msec and these were most marked in the right temporal cortex 200-400 msec from stimulus onset. As this wave was seen in conditions of distracted attention, it appears to be a visual analog of mismatch negativity and reflects the process of the automatic detection of stimuli with deviant durations.