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Abstract: Alzheimer''s disease (AD) is a neurodegenerative disease, usually diagnosed by neuropsychological tests, and excluded from other cerebral diseases by brain images. An electroencephalogram (EEG) provides a means of disclosing the reduced functional couplings between brain regions that occurs with AD. In the present study, 16 probable AD patients and 15 age-matched, gender-matched normal subjects were enrolled. Spectral coherence and cross mutual information (CMI) were used to analyze EEGs during intermittent photic stimulation (PS). Ocular- and heartbeat-related source components (SCs) obtained from multi-channel EEGs by the independent component analysis were discarded, and the photic-related SCs were reduced using a comb filter. The undisturbed SCs and photic-related SCs before and after photic reduction were used to reconstruct photic-preserved EEGs and photic-reduced EEGs, from which harmonic coherences (direct photic-driving response) and rhythmic coherences and CMI (indirect photic affection) were computed, respectively. Our results indicate that the rhythmic coherences (particularly in the alpha and beta bands) and CMI variables as well as the harmonic coherences (particularly related to 3-Hz PS) were significantly lower in the probable AD than in normal subjects, whereas the variables derived from the resting EEGs were not statistically significant. This finding implied that the variables obtained during PS could be used to disclose impaired intra-brain associations in probable AD. [Copyright &y& Elsevier]

Abstract: The electrophysiological studies of thalamocortical oscillations were mostly done in animal models. Placement of stimulation electrodes at the anterior nucleus of the thalamus (ANT) for seizure reduction enables the study of the thalamocortical interplay in human subjects. Nocturnal sleep electroencephalograms (EEGs) and local field potentials (LFPs) of the left and right thalamus (LT, RT) were recorded in three subjects receiving ANT stimulation. Sleep stages were scored according to American Academy of Sleep Medicine criteria. The whole-night time–frequency coherence maps between EEG (C3, C4) and LFP (LT, RT) showed specific coherence patterns during non-rapid eye movement (NREM) sleep. Pooled coherence in the NREM stage was significant in slow, delta, theta and spindle frequency ranges. The spindle oscillations had the highest coherence (0.17–0.58) in the homolateral hemisphere. Together, these observations indicate that the oscillations were related to thalamocortical circuitry. [ABSTRACT FROM AUTHOR]

Abstract: Phase space reconstruction, which is performed by converting echocardiogram-derived strain data from different ventricular regions into phase space trajectories, is applied in this study to describe nonlinear behaviour of myocardial coordination. A new method was developed to quantify patterns of phase space trajectories. Echocardiograms of 31 healthy individuals and 63 patients with left bundle branch block (LBBB) and different left ventricular ejection fractions (LVEFs) were used to evaluate this method. The LBBB patients were separated into two groups: LBBB with a LVEF≥50% and LBBB with a LVEF<50%. LVEF is used to represent levels of systolic function and disease severity. A classifying map was constructed to separate the reconstructed phase space into three zones and to acquire the parameters Pz1, Pz2 and Pz3 as percentiles of phase points related to the zones. The criteria used to define the zones were cross-tested. Based on these parameters, significant group-related differences in myocardial coordination were observed. Significantly smaller Pz1 and significantly larger Pz2 values were observed in the healthy group, as compared to the patient group, and similar, significant results were obtained for the patients with LVEF≥50%, as compared to the patients with LVEF<50% (p <.05). A significantly larger Pz3 was observed in patients with LVEF<50%, as compared to the other patients (p <.05). In addition, different inter-regional relationships among strain pairs (all, near-side, middle-side and opposite-wall) were examined to create phase space trajectories. Consistent group-related differences were observed when different inter-regional relationships were applied. Expanding the use of the proposed method to assess various pathological factors and therapeutic impacts is promising. [Copyright &y& Elsevier]

Background: Action semantics have been investigated in relation to context violation but remain less examined in relation to the meaning of gestures. In the present study, we examined tool–gesture incongruity by event-related potentials (ERPs) and hypothesized that the component N400, a neural index which has been widely used in both linguistic and action semantic congruence, is significant for conditions of incongruence. Methods: Twenty participants performed a tool–gesture judgment task, in which they were asked to judge whether the tool–gesture pairs were correct or incorrect, for the purpose of conveying functional expression of the tools. Online electroencephalograms and behavioral performances (the accuracy rate and reaction time) were recorded. Results: The ERP analysis showed a left centro-parieto-temporal N300 effect (220–360 ms) for the correct condition. However, the expected N400 (400–550 ms) could not be differentiated between correct/incorrect conditions. After 700 ms, a prominent late negative complex for the correct condition was also found in the left centro-parieto-temporal area. Conclusions: The neurophysiological findings indicated that the left centro-parieto-temporal area is the predominant region contributing to neural processing for tool–gesture incongruity in right-handers. The temporal dynamics of tool–gesture incongruity are: (1) firstly enhanced for recognizable tool–gesture using patterns, (2) and require a secondary reanalysis for further examination of the highly complicated visual structures of gestures and tools. The evidence from the tool–gesture incongruity indicated altered brain activities attributable to the N400 in relation to lexical and action semantics. The online interaction between gesture and tool processing provided minimal context violation or anticipation effect, which may explain the missing N400. [ABSTRACT FROM AUTHOR]