The effects of acute gonadal suppression on sexual function and behavior were studied in eight normal men. Administration of a newly developed, potent gonadotropin-releasing hormone antagonist ...induced azoospermia and reduced levels of serum testosterone, luteinizing hormone, and follicle-stimulating hormone. These effects coincided with a reduction in outward-directed aggression in all men. Self-reported measures of anxiety and sexual desire revealed less consistent change over time. Measures of anger control, inward-directed anger, and affective state were unaffected.
Objectives
Cognition is a new treatment target to aid functional recovery and enhance quality of life for patients with bipolar disorder. The International Society for Bipolar Disorders (ISBD) ...Targeting Cognition Task Force aimed to develop consensus‐based clinical recommendations on whether, when and how to assess and address cognitive impairment.
Methods
The task force, consisting of 19 international experts from nine countries, discussed the challenges and recommendations in a face‐to‐face meeting, telephone conference call and email exchanges. Consensus‐based recommendations were achieved through these exchanges with no need for formal consensus methods.
Results
The identified questions were: (I) Should cognitive screening assessments be routinely conducted in clinical settings? (II) What are the most feasible screening tools? (III) What are the implications if cognitive impairment is detected? (IV) What are the treatment perspectives? Key recommendations are that clinicians: (I) formally screen cognition in partially or fully remitted patients whenever possible, (II) use brief, easy‐to‐administer tools such as the Screen for Cognitive Impairment in Psychiatry and Cognitive Complaints in Bipolar Disorder Rating Assessment, and (III) evaluate the impact of medication and comorbidity, refer patients for comprehensive neuropsychological evaluation when clinically indicated, and encourage patients to build cognitive reserve. Regarding question (IV), there is limited evidence for current evidence‐based treatments but intense research efforts are underway to identify new pharmacological and/or psychological cognition treatments.
Conclusions
This task force paper provides the first consensus‐based recommendations for clinicians on whether, when, and how to assess and address cognition, which may aid patients’ functional recovery and improve their quality of life.
BACKGROUND The purpose of this investigation was to test the efficacy of novel antipsychotic medications in the treatment of cognitive impairment in early phase schizophrenia. METHODS Sixty-five ...patients in this multicenter double-blind study were randomly assigned to olanzapine (5-20 mg), risperidone (4-10 mg), or haloperidol (5-20 mg). Standard measures of clinical and motor syndromes were administered, as well as a comprehensive battery of tests to assess (1) motor skills, (2) attention span, (3) verbal fluency and reasoning, (4) nonverbal fluency and construction, (5) executive skills, and (6) immediate recall at baseline and after 6, 30, and 54 weeks of treatment. RESULTS The general cognitive index derived from the 6 domain scores revealed a significantly greater benefit from treatment with olanzapine relative to haloperidol and olanzapine relative to risperidone, but no significant difference was shown between risperidone and haloperidol. The improvement related to olanzapine was apparent after 6 weeks and enhanced after 30 and 54 weeks of treatment. Exploratory within-group analyses of the 6 cognitive domains after a conservative Bonferroni adjustment revealed a significant improvement with olanzapine only on the immediate recall domain, and similar analyses of the 17 individual tests revealed a significant improvement with olanzapine only on the Hooper Visual Organization Test. CONCLUSIONS These data suggest that olanzapine has some superior cognitive benefits relative to haloperidol and risperidone. A larger sample replication study is necessary to confirm and generalize the observations of this study and begin evaluation of the implications of this change to cerebral function and quality of life for people with schizophrenia.Arch Gen Psychiatry. 2000;57:249-258-->
Little is known about ageing-related changes in the brain that affect emergence from general anaesthesia. We used young adult and aged Fischer 344 rats to test the hypothesis that ageing delays ...emergence from general anaesthesia by increasing anaesthetic sensitivity in the brain.
Time to emergence was determined for isoflurane (1.5 vol% for 45 min) and propofol (8 mg kg−1 i.v.). The dose of isoflurane required to maintain loss of righting (LOR) was established in young adult and aged rats. The efficacy of methylphenidate to reverse LOR from general anaesthesia was tested. Separate young adult and aged rats with implanted electroencephalogram (EEG) electrodes were used to test whether ageing increases sensitivity to anaesthetic-induced burst suppression.
Mean time to emergence from isoflurane anaesthesia was 47 s 95% CI 33, 60; young adult) compared with 243 s (95% CI 185, 308; aged). For propofol, mean time to emergence was 13.1 min (95% CI 11.9, 14.0; young adult) compared with 23.1 min (95% CI 18.8, 27.9; aged). These differences were statistically significant. When methylphenidate was administered after propofol, the mean time to emergence decreased to 6.6 min (95% CI 5.9, 7.1; young adult) and 10.2 min (95% CI 7.9, 12.3; aged). These reductions were statistically significant. Methylphenidate restored righting in all rats during continuous isoflurane anaesthesia. Aged rats had lower EEG power and were more sensitive to anaesthetic-induced burst suppression.
Ageing delays emergence from general anaesthesia. This is due, at least in part, to increased anaesthetic sensitivity in the brain. Further studies are warranted to establish the underlying causes.
•Slow-delta oscillations that alternate with gamma oscillations (gamma burst) occur with ketamine at general anesthesia levels.•Gamma, theta and decreased alpha/beta oscillations are not unique to ...ketamine at general anesthesia levels.•The gamma burst pattern may result from circuit disruptions in cortical and subcortical sites.
Ketamine is an N-methyl-d-aspartate (NMDA) receptor antagonist commonly administered as a general anesthetic. However, neural circuit mechanisms to explain ketamine anesthesia-induced unconsciousness in humans are yet to be clearly defined. Disruption of frontal–parietal network connectivity has been proposed as a mechanism to explain this brain state. However, this mechanism was recently demonstrated at subanesthetic doses of ketamine in awake-patients. Therefore, we investigated whether there is an electroencephalogram (EEG) signature specific for ketamine anesthesia-induced unconsciousness.
We retrospectively studied the EEG in 12 patients who received ketamine for the induction of general anesthesia. We analyzed the EEG dynamics using power spectral and coherence methods.
Following the administration of a bolus dose of ketamine to induce unconsciousness, we observed a “gamma burst” EEG pattern that consisted of alternating slow-delta (0.1–4Hz) and gamma (∼27–40Hz) oscillations. This pattern was also associated with increased theta oscillations (∼4–8Hz) and decreased alpha/beta oscillations (∼10–24Hz).
Ketamine anesthesia-induced unconsciousness is associated with a gamma burst EEG pattern.
The EEG signature of ketamine anesthesia-induced unconsciousness may offer new insights into NMDA circuit mechanisms for unconsciousness.
The sleep onset process (SOP) is a dynamic process correlated with a multitude of behavioral and physiological markers. A principled analysis of the SOP can serve as a foundation for answering ...questions of fundamental importance in basic neuroscience and sleep medicine. Unfortunately, current methods for analyzing the SOP fail to account for the overwhelming evidence that the wake/sleep transition is governed by continuous, dynamic physiological processes. Instead, current practices coarsely discretize sleep both in terms of state, where it is viewed as a binary (wake or sleep) process, and in time, where it is viewed as a single time point derived from subjectively scored stages in 30-second epochs, effectively eliminating SOP dynamics from the analysis. These methods also fail to integrate information from both behavioral and physiological data. It is thus imperative to resolve the mismatch between the physiological evidence and analysis methodologies. In this paper, we develop a statistically and physiologically principled dynamic framework and empirical SOP model, combining simultaneously-recorded physiological measurements with behavioral data from a novel breathing task requiring no arousing external sensory stimuli. We fit the model using data from healthy subjects, and estimate the instantaneous probability that a subject is awake during the SOP. The model successfully tracked physiological and behavioral dynamics for individual nights, and significantly outperformed the instantaneous transition models implicit in clinical definitions of sleep onset. Our framework also provides a principled means for cross-subject data alignment as a function of wake probability, allowing us to characterize and compare SOP dynamics across different populations. This analysis enabled us to quantitatively compare the EEG of subjects showing reduced alpha power with the remaining subjects at identical response probabilities. Thus, by incorporating both physiological and behavioral dynamics into our model framework, the dynamics of our analyses can finally match those observed during the SOP.
Electroencephalographic (EEG) monitoring to indicate brain state during anesthesia has become widely available. It remains unclear whether EEG-guided anesthesia influences perioperative outcomes. The ...sixth Perioperative Quality Initiative (POQI-6) brought together an international team of multidisciplinary experts from anesthesiology, biomedical engineering, neurology, and surgery to review the current literature and to develop consensus recommendations on the utility of EEG monitoring during anesthesia. We retrieved a total of 1023 articles addressing the use of EEG monitoring during anesthesia and conducted meta-analyses from 15 trials to determine the effect of EEG-guided anesthesia on the rate of unintentional awareness, postoperative delirium, neurocognitive disorder, and long-term mortality after surgery. After considering current evidence, the working group recommends that EEG monitoring should be considered as part of the vital organ monitors to guide anesthetic management. In addition, we encourage anesthesiologists to be knowledgeable in basic EEG interpretation, such as raw waveform, spectrogram, and processed indices, when using these devices. Current evidence suggests that EEG-guided anesthesia reduces the rate of awareness during total intravenous anesthesia and has similar efficacy in preventing awareness as compared with end-tidal anesthetic gas monitoring. There is, however, insufficient evidence to recommend the use of EEG monitoring for preventing postoperative delirium, neurocognitive disorder, or postoperative mortality.
Propofol-mediated unconsciousness elicits strong alpha/low-beta and slow oscillations in the electroencephalogram (EEG) of patients. As anesthetic dose increases, the EEG signal changes in ways that ...give clues to the level of unconsciousness; the network mechanisms of these changes are only partially understood. Here, we construct a biophysical thalamocortical network involving brain stem influences that reproduces transitions in dynamics seen in the EEG involving the evolution of the power and frequency of alpha/low-beta and slow rhythm, as well as their interactions. Our model suggests that propofol engages thalamic spindle and cortical sleep mechanisms to elicit persistent alpha/low-beta and slow rhythms, respectively. The thalamocortical network fluctuates between two mutually exclusive states on the timescale of seconds. One state is characterized by continuous alpha/low-beta-frequency spiking in thalamus (C-state), whereas in the other, thalamic alpha spiking is interrupted by periods of co-occurring thalamic and cortical silence (I-state). In the I-state, alpha colocalizes to the peak of the slow oscillation; in the C-state, there is a variable relationship between an alpha/beta rhythm and the slow oscillation. The C-state predominates near loss of consciousness; with increasing dose, the proportion of time spent in the I-state increases, recapitulating EEG phenomenology. Cortical synchrony drives the switch to the I-state by changing the nature of the thalamocortical feedback. Brain stem influence on the strength of thalamocortical feedback mediates the amount of cortical synchrony. Our model implicates loss of low-beta, cortical synchrony, and coordinated thalamocortical silent periods as contributing to the unconscious state.
GABAergic anesthetics induce alpha/low-beta and slow oscillations in the EEG, which interact in dose-dependent ways. We constructed a thalamocortical model to investigate how these interdependent oscillations change with propofol dose. We find two dynamic states of thalamocortical coordination, which change on the timescale of seconds and dose-dependently mirror known changes in EEG. Thalamocortical feedback determines the oscillatory coupling and power seen in each state, and this is primarily driven by cortical synchrony and brain stem neuromodulation.
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