Precisely timed theta oscillations are selectively required during the encoding phase of memory.

Brain oscillations have been hypothesized to support cognitive function by coordinating spike timing within and across brain regions, yet it is often not known when timing is either critical for neural computations or an epiphenomenon. The entorhinal cortex and hippocampus are necessary for learning and memory and exhibit prominent theta oscillations (6-9 Hz), which are controlled by pacemaker cells in the medial septal area. Here we show that entorhinal and hippocampal neuronal activity patterns were strongly entrained by rhythmic optical stimulation of parvalbumin-positive medial septal area neurons in mice. Despite strong entrainment, memory impairments in a spatial working memory task were not observed with pacing frequencies at or below the endogenous theta frequency and only emerged at frequencies ≥10 Hz, and specifically when pacing was targeted to maze segments where encoding occurs. Neural computations during the encoding phase were therefore selectively disrupted by perturbations of the timing of neuronal firing patterns.

Pre-operative patient optimization to prevent postoperative pulmonary complications-Insights and roles for the respiratory therapist: A narrative review.

BACKGROUND: The preoperative period has gained recognition as a crucial time to identify and manage preoperative medical conditions for preventing perioperative complications. Consequently, preoperative clinics have now become an essential component of perioperative care at many large hospitals. As the prevalence of preoperative clinics continues to grow, and the field of perioperative medicine progresses, respiratory therapists (RTs) will inevitably find a growing role to participate in preoperative patient optimization to mitigate pulmonary complications. METHODS: Keyword searches on perioperative pulmonary complications were conducted on the Medline database via PubMed and identified over 2000 candidate articles for review. Articles were included if they were English only and resulted with one or more of the following search terms; pulmonary complications, postoperative complications, postoperative pulmonary complications (PPCs), prehabilitation, incentive spirometry, smoking cessation, noninvasive ventilation. Preference was given for meta-analyses, randomized controlled trials, and systematic reviews. Publications within the past two decades were given additional preference toward final inclusion. The authors discussed eligible articles in group meetings over the span of multiple years to assess relevance and quality of data for narrowing eligible articles to the final selection of publications for the review. FINDINGS: The following narrative review examines preoperative optimization strategies to prevent PPCs and highlight areas where RTs may play a key role. After examining challenges in defining PPCs, the review examines key risk models available to predict PPCs and their implications for subsequent discussion on preventive measures that RTs may assist with in a multidisciplinary team. CONCLUSION: RTs can reduce the health care burden of PPCs by assisting fellow perioperative clinicians in providing respiratory care for patients with premorbid conditions. While much of our review focused on pre-existing pulmonary pathologies and both the pharmacological and nonpharmacological optimization of these pathologies, there are other factors contributing to PPCs deserving future exploration.