Neuroscience and biobehavioral reviews
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Neurosci Biobehav Rev · Sep 2018
ReviewA new outlook on cholinergic interneurons in Parkinson's disease and L-DOPA-induced dyskinesia.
Traditionally, dopamine (DA) and acetylcholine (ACh) striatal systems were considered antagonistic and imbalances or aberrant signaling between these neurotransmitter systems could be detrimental to basal ganglia activity and pursuant motor function, such as in Parkinson's disease (PD) and L-DOPA-induced dyskinesia (LID). Herein, we discuss the involvement of cholinergic interneurons (ChIs) in striatally-mediated movement in a healthy, parkinsonian, and dyskinetic state. ⋯ When treating PD with L-DOPA, hyperkinetic side effects, or LID, develop due to increased striatal DA; however, the role of ChIs and ACh transmission, until recently has been unclear. Fortunately, new technology and pharmacological agents have facilitated understanding of ChI function and ACh signaling in the context of LID, thus offering new opportunities to modify existing and discover future therapeutic strategies in movement disorders.
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Neurosci Biobehav Rev · Jun 2018
Review Meta AnalysisModerate effects of noninvasive brain stimulation of the frontal cortex for improving negative symptoms in schizophrenia: Meta-analysis of controlled trials.
Negative symptoms in schizophrenia concern a clinically relevant reduction of goal-directed behavior that strongly and negatively impacts daily functioning. Existing treatments are of marginal effect and novel approaches are needed. Noninvasive neurostimulation by means of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are novel approaches that may hold promise. ⋯ The available evidence indicates that noninvasive prefrontal neurostimulation can improve negative symptoms. This finding suggests a causal role for the lateral frontal cortex in self-initiated goal-directed behavior. The evidence is stronger for rTMS than for tDCS, although this may be due to the small number of studies as yet with tDCS. More research is needed to establish moderator variables that may affect response to neurostimulation and to optimize treatment parameters in order to achieve stable and durable (and thus clinically relevant) effects.
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Neurosci Biobehav Rev · May 2018
ReviewThe role of associative fear and avoidance learning in anxiety disorders: Gaps and directions for future research.
Anxiety disorders are the most common mental disorders and are often chronic and disabling. Although exposure-based treatments are effective, a substantial number of individuals fail to fully remit or experience a return of symptoms after treatment. Understanding the critical processes underlying the development and treatment of anxiety disorders will help identify individuals at risk and optimize treatments. ⋯ Overall, the extant literature supports a key role of aversive associative learning in the development and treatment of anxiety disorders. However, research targeting specific mechanisms such as extinction generalization and avoidance, the fragility of extinction, and moderating influences of individual differences pertinent to anxiety disorders (e.g., age, sex, depression) is needed. We discuss the need for more ecological valid and complex paradigms to model ambiguity and conflict as well as for clinical translation studies to optimize treatment.
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Neurosci Biobehav Rev · Apr 2018
Serotonergic psychedelics and personality: A systematic review of contemporary research.
Serotonergic psychedelics act as agonists at cortical 5-HT2A receptors and seem to induce personality changes. We conducted a systematic review of studies assessing the effects of these drugs on personality. Papers published from 1985-2016 were included from PubMed, LILACS, and SciELO databases. ⋯ Increases in global brain entropy induced by acute psychedelic administration predicted changes in Openness, and Self-Transcendence was negatively correlated with cortical thinning of the posterior cingulate cortex in long-term religious ayahuasca users. Acute and long-term use of psychedelics is associated with personality changes that appear to be modulated by 5-HT2A receptors. These changes seem to induce therapeutic effects that should be further explored in randomized controlled studies.
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Neurosci Biobehav Rev · Mar 2018
Meta AnalysisMultisensory temporal binding window in autism spectrum disorders and schizophrenia spectrum disorders: A systematic review and meta-analysis.
Multisensory temporal integration could be compromised in both autism spectrum disorders (ASD) and schizophrenia spectrum disorders (SSD) and may play an important role in perceptual and cognitive impairment in these two disorders. This review aimed to quantitatively compare the sensory temporal acuity between healthy controls and the two clinical groups (ASD and SSD). ⋯ Such multisensory dysfunction is associated with symptoms like hallucinations and impaired social communications. Future studies focusing on improving multisensory temporal functions may have important implications for the amelioration of schizophrenia and autistic symptoms.