Modulating Consciousness through Awareness Training Program and Its Impacts on Psychological Stress and Age-Related Gamma Waves.

Aging often leads to awareness decline and psychological stress. Meditation, a method of modulating consciousness, may help individuals improve overall awareness and increase emotional resilience toward stress. This study explored the potential influence of the Awareness Training Program (ATP), a form of consciousness modulation, on age-related brain wave changes and psychological stress in middle-aged adults. Eighty-five participants with mild stress were recruited and randomly assigned to ATP (45.00 ± 8.00 yr) or control (46.67 ± 7.80 yr) groups, matched by age and gender. Ten-minute resting-state EEG data, obtained while the participants' eyes were closed, were collected using a 128-channel EEG system (EGI). A strong positive Pearson correlation was found between fast-wave (beta wave, 12-25 Hz; gamma wave, 25-40 Hz) EEG and age. However, after the 7-week ATP intervention, this correlation became insignificant in the ATP group. Furthermore, there was a significant reduction in stress levels, as measured by the Chinese version of the 10 item Perceived Stress Scale (PSS-10), in the ATP group. These results suggest that ATP may help modulate age-related effects on fast brain waves, as evidenced by the reduced correlation magnitude between age and gamma waves, and lower psychological stress. This suggests that ATP, as a form of consciousness modulation, may improve stress resilience and modulate age-related gamma wave changes.

Intensity-dependent gamma electrical stimulation regulates microglial activation, reduces beta-amyloid load, and facilitates memory in a mouse model of Alzheimer's disease.

BACKGROUND: Gamma sensory stimulation may reduce AD-specific pathology. Yet, the efficacy of alternating electrical current stimulation in animal models of AD is unknown, and prior research has not addressed intensity-dependent effects. METHODS: The intensity-dependent effect of gamma electrical stimulation (GES) with a sinusoidal alternating current at 40 Hz on Aß clearance and microglia modulation were assessed in 5xFAD mouse hippocampus and cortex, as well as the behavioral performance of the animals with the Morris Water Maze. RESULTS: One hour of epidural GES delivered over a month significantly (1) reduced Aß load in the AD brain, (2) increased microglia cell counts, decreased cell body size, increased length of cellular processes of the Iba1 + cells, and (3) improved behavioral performance (learning & memory). All these effects were most pronounced when a higher stimulation current was applied. CONCLUSION: The efficacy of GES on the reduction of AD pathology and the intensity-dependent feature provide guidance for the development of this promising therapeutic approach.

Shape and Rule Information Is Reflected in Different Local Field Potential Frequencies and Different Areas of the Primate Lateral Prefrontal Cortex.

The lateral prefrontal cortex (LFPC) plays a crucial role in executive function by adaptively storing behavior-relevant information as working memory. Neural mechanisms associated with local field potentials (LFPs) may underlie the adaptive properties of the LFPC. Here, we analyzed how LFPs recorded from the monkey LFPC are modulated by the crucial factors of a shape manipulation task. In this task, the test shape is transformed by manipulating a lever to match the size and orientation of the sample shape. The subject is required to temporarily memorize the rules such as the arm-movement-manipulation relationship and the sample shape to generate the sequential behavior of operations. In the present study, we focused on task variables about shape and rules, and examined among which aspects distinguish the ventral and dorsal sides of the LFPC. We found that the transformed shape in the sample period strongly affected the theta and delta waves in the delay period on the ventral side, while the arm-manipulation assignment influenced the gamma components on the dorsal side. These findings suggest that area- and frequency-selective LFP modulations are involved in dynamically recruiting different behavior-relevant information in the LFPC.

Magnetoencephalography for Mild Traumatic Brain Injury and Posttraumatic Stress Disorder.

Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) are leading causes of sustained physical, cognitive, emotional, and behavioral deficits in the general population, active-duty military personnel, and veterans. However, the underlying pathophysiology of mTBI/PTSD and the mechanisms that support functional recovery for some, but not all individuals is not fully understood. Conventional MR imaging and computed tomography are generally negative in mTBI and PTSD, so there is interest in the development of alternative evaluative strategies. Of particular note are magnetoencephalography (MEG) -based methods, with mounting evidence that MEG can provide sensitive biomarkers for abnormalities in mTBI and PTSD.

The limbic-reticular coupling theory of memory processing in the brain and its greater compatibility over other theories.

The limbic-reticular coupling theory suggests that the hippocampus and amygdala regulate such descending limbic structures as the mammillary bodies, septum, hypothalamus and epithalamus to regulate the ascending noradrenergic, serotonergic, dopaminergic and cholinergic systems, performing declarative memory consolidation and recall. Recent studies have revealed that, less sensitive to familiarity, the hippocampus functions via the fornix, mammillary bodies and hypothalamus for memory recall. Lesions to the thalamic nuclei were complicated with damage to adjacent fornix, stria medullaris and habenula, simultaneously destroying two kinds of structures respectively for familiarity and recall. Furthermore, the orbitofrontal cortex was shown to be clinically irrelevant for memory recall. Electrophysiologically, the hippocampus regulates the raphe nuclei in complex ways, and the hippocampal theta wave activates the dopaminergic cells in ventral tegmental area and cholinergic neurons in basal forebrain, while cholinergic-modulated theta-gamma coupling mediates cortical recall. These concurrent advances support the limbic-reticular coupling theory for elucidation of memory recall.

A teoria do acoplamento límbico-reticular sugere que o hipocampo e a amígdala regulam estruturas límbicas descendentes como os corpos mamilares, septum, hipotálamo e epitálamo para regular os sistemas ascendentes noradrenérgico, serotoninérgico, dopaminérgico e colinérgico, realizando a consolidação da memória declarativa e a recordação. Estudos recentes revelaram que, menos sensível à familiaridade, o hipocampo funcionava via fórnice, corpos mamilares e hipotálamo para a recordação da memória. Lesões aos núcleos talâmicos são complicadas com danos ao fórnice, estria medullaris e habenula adjacentes, destruindo simultaneamente dois tipos de estruturas, respectivamente, para familiaridade e recordação. Além disso, o córtex orbitofrontal mostrou-se clinicamente irrelevante para a recordação da memória. Eletrofisiologicamente, o hipocampo regula os núcleos da rafe de maneiras complexas, e a onda teta hipocampal ativa as células dopaminérgicas na área tegmentar ventral e os neurônios colinérgicos no prosencéfalo basal, enquanto que o acoplamento teta-gama colinergicamente modulado medeia a evocação cortical. Esses avanços concorrentes sugerem que a teoria do acoplamento límbico-reticular apropriada para a elucidação da recordação da memória.

The limbic-reticular coupling theory of memory processing in the brain and its greater compatibility over other theories / A teoria do acoplamento límbico-reticular do processamento de memória no cérebro e sua maior compatibilidade com outras teorias

Abstract The limbic-reticular coupling theory suggests that the hippocampus and amygdala regulate such descending limbic structures as the mammillary bodies, septum, hypothalamus and epithalamus to regulate the ascending noradrenergic, serotonergic, dopaminergic and cholinergic systems, performing declarative memory consolidation and recall. Recent studies have revealed that, less sensitive to familiarity, the hippocampus functions via the fornix, mammillary bodies and hypothalamus for memory recall. Lesions to the thalamic nuclei were complicated with damage to adjacent fornix, stria medullaris and habenula, simultaneously destroying two kinds of structures respectively for familiarity and recall. Furthermore, the orbitofrontal cortex was shown to be clinically irrelevant for memory recall. Electrophysiologically, the hippocampus regulates the raphe nuclei in complex ways, and the hippocampal theta wave activates the dopaminergic cells in ventral tegmental area and cholinergic neurons in basal forebrain, while cholinergic-modulated theta-gamma coupling mediates cortical recall. These concurrent advances support the limbic-reticular coupling theory for elucidation of memory recall.

Resumo A teoria do acoplamento límbico-reticular sugere que o hipocampo e a amígdala regulam estruturas límbicas descendentes como os corpos mamilares, septum, hipotálamo e epitálamo para regular os sistemas ascendentes noradrenérgico, serotoninérgico, dopaminérgico e colinérgico, realizando a consolidação da memória declarativa e a recordação. Estudos recentes revelaram que, menos sensível à familiaridade, o hipocampo funcionava via fórnice, corpos mamilares e hipotálamo para a recordação da memória. Lesões aos núcleos talâmicos são complicadas com danos ao fórnice, estria medullaris e habenula adjacentes, destruindo simultaneamente dois tipos de estruturas, respectivamente, para familiaridade e recordação. Além disso, o córtex orbitofrontal mostrou-se clinicamente irrelevante para a recordação da memória. Eletrofisiologicamente, o hipocampo regula os núcleos da rafe de maneiras complexas, e a onda teta hipocampal ativa as células dopaminérgicas na área tegmentar ventral e os neurônios colinérgicos no prosencéfalo basal, enquanto que o acoplamento teta-gama colinergicamente modulado medeia a evocação cortical. Esses avanços concorrentes sugerem que a teoria do acoplamento límbico-reticular apropriada para a elucidação da recordação da memória.

Low gamma wave oscillations in the striatum of mice following morphine administration.

Functional role of the striatum in motor control has been widely studied. In addition, its involvement in reward function as a brain area in the dopamine system has also been mentioned. However, neural signaling in the striatum in response to consumption of emotional enhancing substances remained to be explored. This study aimed to investigate local field potential (LFP) of the striatum following morphine administration. Male Swiss albino mice implanted with electrode into the striatum were given an intraperitoneal injection of either saline or morphine (5 or 15 mg/kg). LFP and locomotor activity of individual animals were simultaneously recorded in the recording chamber following the administration. The inspection of LFP tracings revealed the increase in fast wave induced by morphine particularly at a high dose. Statistical analyses were performed using a one way ANOVA followed by Tukey post hoc test. Frequency analysis using Fast Fourier transform also confirmed a significant elevation of low gamma (30-44.9 Hz) activity. When analyzed in time domain, significant increase in low gamma power was observed from the 15th to 65th min following 15 mg/kg morphine treatment. Moreover, morphine treatment also exhibited a stimulating effect on locomotor speed. However, regression analyses revealed no significant correlation between low gamma power and locomotor speed. In summary, this study demonstrated the increase in low gamma oscillation in the striatum and this effect was not associated with locomotor activity of animals. Thus, it is possible that low gamma oscillation induced by morphine treatment is related with the reward function.

The Meaning of P50 Suppression: Interaction of Gamma and Alpha Waves

OBJECTIVES: Sensory gating dysfunctions in patients with schizophrenia and bipolar disorder have been investigated through two similar methods ; P50 suppression and prepulse inhibition paradigms. However, recent studies have demonstrated that the two measures are not correlated but rather constitute as distinct neural processes. Recent studies adopting spectral frequency analysis suggest that P50 suppression reflects the interaction between gamma and other frequency bands. The aim of the present study is to investigate which frequency component shows more significant interaction with gamma band. METHODS: A total of 108 mood disorder patients and 36 normal subjects were included in the study. The P50 responses to conditioning and test stimuli with an intra-pair interval of 500 msec were measured in the study population. According to P50 ratio (amplitude to the test stimulus/amplitude to the conditioning stimulus), the subjects with P50 ratio less than 0.2 were defined as suppressed group (SG) ; non-suppressed group (NSG) consisted of P50 ratio more than 0.8. Thirty-five and 25 subjects were included in SG and NSG, respectively. Point-to-point correlation coefficients (PPCCs) of both groups were calculated between two time-windows : the first window (S1) was defined as the time-window of one hundred millisecond after the conditioning auditory stimulus and the second window (S2) was defined as the time-window of 100 msec after the test auditory stimulus. Spectral frequency analysis was performed to investigate which frequency band results in the difference of PPCC between SG and NSG. RESULTS: Significant reduction of PPCC between S1 and S2 was observed in the SG (Pearson's r = 0.24), compared to PPCC of the NSG (r = 0.58, p < 0.05). In spectral frequency analysis, gamma band showed "phase-reset" and similar responses after the two auditory stimuli in suppressed and non-suppressed group. However in the case of alpha band, comparison showed significantly low PPCC in SG (r = -0.14) compared to NSG (r = 0.36, p < 0.05). This may be reflecting "phase-out" of alpha band against gamma band at approximately 50 msecs after the test stimulus in the SG. CONCLUSIONS: Our study suggests that normal P50 suppression is caused by phase-out of alpha band against gamma band after the second auditory stimulus. Thus it is demonstrated that normal sensory gating process is constituted with attenuated alpha power, superimposed on consistent gamma response. Implications of preserved gamma and decreased alpha band in sensory gating function are discussed.