It has been previously demonstrated by our group that a visual stimulus made of dynamically changing luminance evokes an echo or reverberation at ∼10 Hz, lasting up to a second. In this study we aimed to reveal whether similar echoes also exist in the auditory modality. A dynamically changing auditory stimulus equivalent to the visual stimulus was designed and employed in two separate series of experiments, and the presence of reverberations was analyzed based on reverse correlations between stimulus sequences and EEG epochs. The first experiment directly compared visual and auditory stimuli: while previous findings of ∼10 Hz visual echoes were verified, no similar echo was found in the auditory modality regardless of frequency. In the second experiment, we tested if auditory sequences would influence the visual echoes when they were congruent or incongruent with the visual sequences. However, the results in that case similarly did not reveal any auditory echoes, nor any change in the characteristics of visual echoes as a function of audio-visual congruence. The negative findings from these experiments suggest that brain oscillations do not equivalently affect early sensory processes in the visual and auditory modalities, and that alpha (8–13 Hz) oscillations play a special role in vision.

Protective vs. Therapeutic Effects of Mitochondria-Targeted Antioxidant MitoTEMPO on Rat Sciatic Nerve Crush Injury: A Comprehensive Electrophysiological Analysis. Peripheral nerve injuries often result in long-lasting functional deficits, prompting the need for effective interventions. MitoTEMPO (2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride) is a mitochondria-targeted antioxidant that has shown protective and therapeutic effects against pathologies associated with reactive oxygen species. This study explores the utilization of MitoTEMPO as a therapeutic and protective agent for sciatic nerve crush injuries. By employing advanced mathematical approaches, the study seeks to comprehensively analyze nerve conduction parameters, nerve excitability, and the distribution of nerve conduction velocities to gauge the potential. Forty Wistar-Albino rats were randomly divided into following groups: (I) SHAM—animals subjected to sham operation and treated intraperitoneally (i.p.) with vehicle (bidistilled water) for 14 days; (II) CI (crush injury)—animals subjected to CI and treated with vehicle 14 days; (III) MiP—animals subjected to 7 days i.p. MitoTEMPO treatment before CI (0.7 mg/kg/day dissolved in vehicle) and, only vehicle for 7 days after CI, protective MitoTEMPO; and (IV) MiT—animals i.p. treated with only vehicle for 7 days before CI and 7 days with MitoTEMPO (0.7 mg/kg/day dissolved in vehicle) after CI, therapeutic MitoTEMPO. Nerve excitability parameters were measured, including rheobase and chronaxie, along with compound action potential (CAP) recordings. Advanced mathematical analyses were applied to CAP recordings to determine nerve conduction velocities and distribution patterns. The study revealed significant differences in nerve excitability parameters between groups. Nerve conduction velocity was notably reduced in the MiP and CI groups, whereas CAP area values were diminished in the MiP and CI groups compared to the MiT group. Furthermore, CAP velocity was lower in the MiP and CI groups, and maximum depolarization values were markedly lower in the MiP and CI groups compared to the SHAM group. The distribution of nerve conduction velocities indicated alterations in the composition of nerve fiber groups following crush injuries. In conclusion, postoperative MitoTEMPO administration demonstrated promising results in mitigating the detrimental effects of nerve crush injuries.

The multidimensional nature of formal thought disorder (FTD) offers potential diagnostic utility in distinguishing between schizophrenia and affective disorders. This study aimed to assess the diagnostic accuracy of the Thought and Language Disorder Scale (TALD) factors in differentiating schizophrenia, mania, depression, and healthy controls, as well as in distinguishing affective and non-affective psychosis. We included 234 participants: Schizophrenia ( n = 70), mania ( n = 38), depression ( n = 71), and healthy controls ( n = 55). All participants were assessed using TALD, the Positive and Negative Syndrome Scale (PANSS), the Hamilton Depression Rating Scale (HAMD), and the Young Mania Rating Scale (YMANI). In group comparisons, the mania group showed the highest scores in the Objective Positive and Subjective Positive factors, while the schizophrenia group exhibited global disturbances across all TALD factors. The depression group had lower scores for both Objective Negative and Subjective Negative factors compared to the schizophrenia group. Support Vector Machine models revealed that TALD factors achieved 72% accuracy in classifying psychiatric disorders versus healthy controls, with 95%, 94%, and 77% accuracy in distinguishing schizophrenia from controls, mania, and depression, respectively. Affective and non-affective psychosis were distinguished with 90% accuracy, with affective psychosis showing higher positive FTD scores and non-affective psychosis showing higher negative FTD scores. TALD factors were significantly correlated with core symptom domains of each disorder in PANSS, YMANI, and HAMD scores. The TALD scale demonstrated robust diagnostic utility in differentiating schizophrenia, mania, depression, and healthy controls and in distinguishing between affective and non-affective psychosis. Integrating FTD into diagnostic frameworks, alongside machine learning approaches, may enhance the precision of psychiatric diagnoses.

The modulatory role of spontaneous brain oscillations on perception of threshold-level stimuli is well established. Here, we provide evidence that alpha-band (7-14 Hz) oscillations not only modulate but also can drive perception. We used the “triple-flash” illusion: Occasional perception of three flashes when only two spatially-coincident veridical ones are presented, separated by ~100 ms. The illusion was proposed to result from superposition of two hypothetical oscillatory impulse response functions (IRF) generated in response to each flash (Bowen, 1989). In Experiment 1, we varied stimulus onset asynchrony (SOA) and validated Bowen's theory: the optimal SOA for illusion to occur was correlated, across subjects, with the subject-specific IRF period. Experiment 2 revealed that pre-stimulus parietal alpha EEG phase and power, as well as post-stimulus alpha phase-locking, together determine the occurrence of the illusion on a trial-by-trial basis. Thus, oscillatory reverberations create something out of nothing – a third flash where there are only two.