Dysfunctional Patterns of Gamma-Band Activity in Response to Human Faces Compared to Non-Facial Stimuli in Patients with Schizophrenia

OBJECTIVE: Healthy individuals show stronger gamma-band activities (GBAs) for socially relevant stimuli (human faces) than for non-relevant ones. This study aimed to examine whether this gamma-band preference occurs in patients with schizophrenia. METHODS: EEG was recorded for 24 patients with schizophrenia and 23 healthy controls while they viewed pictures of human faces, chairs, and nature scenes. The spectral powers of high-beta (20-30 Hz) and gamma (30-80 Hz) frequencies were analyzed along 3 midline cortical regions, and phase synchronization was calculated. RESULTS: Compared to the response to non-facial stimuli, higher event related deactivation to facial stimuli was observed for the high-beta frequency across groups. For the gamma frequency, early-stage GBA was increased and late-stage GBA was decreased for all 3 stimuli in patients with schizophrenia compared to healthy controls. Preferential GBA patterns (100-200 and 200-300 ms) were found in healthy controls, but not in patients with schizophrenia. Significant correlation existed between negative symptoms and GBA in the frontal region for chair and scene stimuli. There was no significant intergroup difference in phase synchronization pattern. CONCLUSION: Our results suggest that patients with schizophrenia have deficits in the preferential pattern of GBA for human faces and the deficits in the preferential pattern were mainly influenced by over-response to socially non-relevant stimuli.

Study of G1 phase synchronization in endometrial carcinoma HEC-1-A cells / 肿瘤研究与临床

Objective To investigate the effects of lovastatin on inducing G1 phase synchromzation in HEC-1-A cells and examine the cell cycle progression after desynchronization.Methods The doubling time of HEC-1-A cells was detected by cell counting Kit-8 assay.To determine the best lovastatin concentration of G1 synchronization,HEC-1-A cells were treated with lovastatin at concentration of 10,20,30 and 40 μmol/L respectively for 1 × doubling time,and the cell cycle was detected by flow cytometry (FCM).To determine the best period of lovastatin treatment to achieve G1 synchronization,HEC-1-A cells were treated with lovastatin at the best concentration for 0.5 × to 2 × doubling time,and the cell cycle was detected every 4 h using FCM.Furthermore,the cell cycle progress of HEC-1-A cells after desynchronization was also observed.Results The doubling time of HEC-1-A cells was 24 h.Treated with lovastatin at concentration of 40 μmol/L for 28 h achieved maximum G1 arrest (87.87±0.70) ％ in HEC-1-A cells.Minimum G1 phase (58.42±0.54) ％ and maximum S phase (33.58±0.62) ％ were observed after desynchronizing for 20 h.Conclusion Maximum G1 synchronization of HEC-1-A cells is induced by lovastatin at concentration of 40 μmol/L for 28 h.The HEC-1-A cells show minimum G1 phase and maximum S phase after desynchronizing for 20 h.

Sincronía neuronal y esquizofrenia: luces y sombras / Neural synchrony and schizophrenia: lights and shadows

Introducción: La sincronía neuronal se muestra como un elemento central en la unificación de la actividad cerebral y en la emergencia de nuestra conciencia, y parece ser fundamental en el desarrollo del pensamiento, atención, memoria, acciones motoras y en la capacidad de percibir estímulos externos e internos de forma balanceada y unificada. La disfunción de estos mecanismos podría dar cuenta de las alteraciones que subyacen a la esquizofrenia. Objetivo: Proporcionar una visión general sobre los mecanismos mediante los cuales nuestro cerebro realiza la integración de la realidad y dar una visión crítica acerca de considerar la alteración de la sincronía neuronal como un proceso subyacente a la amplia gama de problemas observados en la esquizofrenia. Método: Se resumen los resultados de varios estudios en el contexto de una revisión de la literatura. Resultados: Distintos estudios indican que alteraciones en el desarrollo de redes neuronales podrían tener un rol etiológico fundamental en la esquizofrenia, generando disfunciones en la sincronía neuronal. Estas alteraciones en la sincronización se traducirían en regiones hipoconectadas, pero también en otras hiperconectadas, dando lugar a síntomas negativos y positivos, respectivamente. Conclusiones: La sincronía neuronal parece tener un papel crucial en el procesamiento de la información, la integración cerebral y la percepción unitaria de la realidad. La alteración de la sincronía neuronal podría ser un determinante central en el desarrollo de esta enfermedad. La comprensión de estos mecanismos podría otorgar conocimientos valiosos, capaces de mejorar nuestra capacidad predictiva, diagnóstica y terapéutica en relación a la esquizofrenia.

Background: Neuronal synchrony seems to be a central element in the unification ofbrain activity and the emergence ofconsciousness. It appears to be fundamental in the development of thought, attention, memory, motor actions and in the ability to perceive external and internal stimuli in a balanced and unified way. The dysfunction ofthese mechanisms could accountfor the disturbances that underlie schizophrenia. Objective: To provide an overview of the mechanisms underlying schizophrenia and give a critical vision about considering the alteration of neuronal synchrony as a core process in this disease. Methods: The results of several studies are summarized in the context ofa literature review. Results: Several studies indicate that alterations in the development of neural networks may have a fundamental role in schizophrenia, resulting in neuronal synchrony dysfunctions. These dysfunctions seem to determine the presence of hypoconnected, but also of hyperconnected regions, resulting in negative and positive symptoms, respectively. Conclusion: Neuronal synchrony seems to play a crucial role in information processing, brain integration and unified perception ofreality. The alteration of neuronal synchrony could be a central determinant in the development of this disease. Understanding these mechanisms could provide valuable knowledge for improving our predictive, diagnostic and therapeutic capacities in relation to schizophrenia.

Gamma-Band Auditory Steady-State Responses and Psychopathology / 대한정신약물학회지

Gamma band neural oscillations in the human electroencephalogram (EEG) play an important role in perceptual and cognitive processes. Auditory steady state responses (ASSR) can probe neural oscillations with respect to phase synchronization and response magnitude. EEG recordings in bipolar disorder and schizophrenia patients showed reduced evoked power and phase locking for 40 Hz ASSR. Also, several studies have reported increased evoked power and decreased synchronization of the gamma band in patients with Alzheimer's disease. ASSR deficits in various psychiatric disorders may index disturbances of gamma-aminobutyric acid neurotransmission within auditory pathways and cortex. Although, several studies have reported ASSR deficits in various psychopathologies of psychiatric illness, further studies are necessary that investigate biological mechanism based on the ASSRs. In this review, the current concept and biological mechanism of ASSRs are discussed.