Pilot Study on Dose-Dependent Effects of Transcranial Photobiomodulation on Brain Electrical Oscillations: A Potential Therapeutic Target in Alzheimer's Disease.

BACKGROUND: Transcranial photobiomodulation (tPBM) has recently emerged as a potential cognitive enhancement technique and clinical treatment for various neuropsychiatric and neurodegenerative disorders by delivering invisible near-infrared light to the scalp and increasing energy metabolism in the brain. OBJECTIVE: We assessed whether transcranial photobiomodulation with near-infrared light modulates cerebral electrical activity through electroencephalogram (EEG) and cerebral blood flow (CBF). METHODS: We conducted a single-blind, sham-controlled pilot study to test the effect of continuous (c-tPBM), pulse (p-tPBM), and sham (s-tPBM) transcranial photobiomodulation on EEG oscillations and CBF using diffuse correlation spectroscopy (DCS) in a sample of ten healthy subjects [6F/4 M; mean age 28.6±12.9 years]. c-tPBM near-infrared radiation (NIR) (830 nm; 54.8 mW/cm2; 65.8 J/cm2; 2.3 kJ) and p-tPBM (830 nm; 10 Hz; 54.8 mW/cm2; 33%; 21.7 J/cm2; 0.8 kJ) were delivered concurrently to the frontal areas by four LED clusters. EEG and DCS recordings were performed weekly before, during, and after each tPBM session. RESULTS: c-tPBM significantly boosted gamma (t = 3.02, df = 7, p < 0.02) and beta (t = 2.91, df = 7, p < 0.03) EEG spectral powers in eyes-open recordings and gamma power (t = 3.61, df = 6, p < 0.015) in eyes-closed recordings, with a widespread increase over frontal-central scalp regions. There was no significant effect of tPBM on CBF compared to sham. CONCLUSION: Our data suggest a dose-dependent effect of tPBM with NIR on cerebral gamma and beta neuronal activity. Altogether, our findings support the neuromodulatory effect of transcranial NIR.

Treatment for anxiety: Mindfulness meditation versus escitalopram (TAME): Design of a randomized, controlled non-inferiority trial.

Anxiety disorders (generalized anxiety disorder, social anxiety disorder, panic disorder, and agoraphobia) are common, distressing, and impairing. While pharmacotherapy and psychotherapy are first-line treatment strategies for anxiety disorders, many patients are reluctant to take psychiatric medication, and many prefer to avoid any kind of mental health treatment due to stigma or distrust of traditional medical care. We present the trial protocol for the first study comparing first-line medication treatment with Mindfulness-Based Stress Reduction (MBSR), a popular mindfulness meditation training program, for the treatment of anxiety disorders. We will use a non-inferiority, comparative effectiveness trial design, in which individuals with diagnosed anxiety disorders will be randomized to either pharmacotherapy with escitalopram or MBSR for 8 weeks of treatment. Treatment outcome will be based on gold standard symptom severity measures assessed by trained independent evaluators blind to treatment allocation. Secondary outcomes will include key symptom and function measures, as well as tolerability and satisfaction with treatment. Findings will provide crucial information to inform decision making about the relative benefits of MBSR versus a first line medication for anxiety disorders by patients, medical care providers, healthcare insurers and other stakeholders.

Assessing vulnerability to panic: a systematic review of psychological and physiological responses to biological challenges as prospective predictors of panic attacks and panic disorder.

BACKGROUND: Cognitive-behavioural theories of panic disorder posit that panic attacks arise from a positive feedback loop between arousal-related bodily sensations and perceived threat. In a recently developed computational model formalising these theories of panic attacks, it was observed that the response to a simulated perturbation to arousal provided a strong indicator of vulnerability to panic attacks and panic disorder. In this review, we evaluate whether this observation is borne out in the empirical literature that has examined responses to biological challenge (eg, CO2 inhalation) and their relation to subsequent panic attacks and panic disorder. METHOD: We searched PubMed, Web of Science and PsycINFO using keywords denoting provocation agents (eg, sodium lactate) and procedures (eg, infusion) combined with keywords relevant to panic disorder (eg, panic). Articles were eligible if they used response to a biological challenge paradigm to prospectively predict panic attacks or panic disorder. RESULTS: We identified four eligible studies. Pooled effect sizes suggest that there is biological challenge response has a moderate prospective association with subsequent panic attacks, but no prospective relationship with panic disorder. CONCLUSIONS: These findings provide support for the prediction derived from cognitive-behavioural theories and some preliminary evidence that response to a biological challenge may have clinical utility as a marker of vulnerability to panic attacks pending further research and development. TRIAL REGISTRATION NUMBER: 135908.

Chronic Ethanol During Adolescence Impacts Corticolimbic Dendritic Spines and Behavior.

BACKGROUND: Risk for alcohol use disorders (AUDs) in adulthood is linked to alcohol drinking during adolescence, but understanding of the neural and behavioral consequences of alcohol exposure during adolescence remains incomplete. Here, we examined the neurobehavioral impact of adolescent chronic intermittent EtOH (CIE) vapor exposure in mice. METHODS: C57BL/6J-background Thy1-EGFP mice were CIE-exposed during adolescence or adulthood and examined, as adults, for alterations in the density and morphology of dendritic spines in infralimbic (IL) cortex, prelimbic (PL) cortex, and basolateral amygdala (BLA). In parallel, adolescent- and adult-exposed C57BL/6J mice were tested as adults for 2-bottle EtOH drinking, sensitivity to EtOH intoxication (loss of righting reflex [LORR]), blood EtOH clearance, and measures of operant responding for food reward. RESULTS: CIE during adolescence decreased IL neuronal spine density and increased the head width of relatively wide-head IL and BLA spines, whereas CIE decreased head width of relatively narrow-head BLA spines. Adolescents had higher EtOH consumption prior to CIE than adults, while CIE during adulthood, but not adolescence, increased EtOH consumption relative to pre-CIE baseline. CIE produced a tolerance-like decrease in LORR sensitivity to EtOH challenge, irrespective of the age at which mice received CIE exposure. Mice exposed to CIE during adolescence, but not adulthood, required more sessions than AIR controls to reliably respond for food reward on a fixed-ratio (FR) 1, but not subsequent FR3, reinforcement schedule. On a progressive ratio reinforcement schedule, break point responding was higher in the adolescent- than the adult-exposed mice, regardless of CIE. Finally, footshock punishment markedly suppressed responding for reward in all groups. CONCLUSIONS: Exposure to CIE during adolescence altered dendritic spine density and morphology in IL and BLA neurons, in parallel with a limited set of behavioral alterations. Together, these data add to growing evidence that key corticolimbic circuits are vulnerable to the effects of alcohol during adolescence, with lasting, potentially detrimental, consequences for behavior.