No abstract

This study examines the links between human perceptions, cognitive biases and neural processing of symmetrical stimuli. While preferences for symmetry have largely been examined in the context of disorders such as obsessive-compulsive disorder and autism spectrum disorders, we examine various these phenomena in non-clinical subjects and suggest that such preferences are distributed throughout the typical population as part of our cognitive and neural architecture. In Experiment 1, 82 young adults reported on the frequency of their obsessive-compulsive spectrum behaviors. Subjects also performed an emotional Stroop or variant of an Implicit Association Task (the OC-CIT) developed to assess cognitive biases for symmetry. Data not only reveal that subjects evidence a cognitive conflict when asked to match images of positive affect with asymmetrical stimuli, and disgust with symmetry, but also that their slowed reaction times when asked to do so were predicted by reports of OC behavior, particularly checking behavior. In Experiment 2, 26 participants were administered an oddball Event-Related Potential task specifically designed to assess sensitivity to symmetry as well as the OC-CIT. These data revealed that reaction times on the OC-CIT were strongly predicted by frontal electrode sites indicating faster processing of an asymmetrical stimulus (unparallel lines) relative to a symmetrical stimulus (parallel lines). The results point to an overall cognitive bias linking disgust with asymmetry and suggest that such cognitive biases are reflected in neural responses to symmetrical/asymmetrical stimuli.

Abstractsiii114 NEURO-ONCOLOGY • MAY 2017 ment of Neurosurgery, University Hospital of Münster. Since 2013, we performed solely "awake-awake-awake" surgeries using the a 2 -receptor agonist, dexmedetomidine, as sole anaesthetic drug. The aim of this study was to compare both techniques and evaluate the clinical use of dexmedetomidine in the setting of awake craniotomies for glioma surgery. MATERIAL AND METHODS: We retrospectively analysed patients that were operated in the Department of Neurosurgery, University Hospital of Muenster either under "asleep-awake-asleep" using propofol-remifentanil sedation, or under "awake-awake-awake" conditions, using dexmedetomidine infusions. In the,,asleep-awake-asleep"-group patients were intubated with laryngeal mask and extubated for the assessment period. Patients in the fully awake group were sedated with dexmedetomidine beyond the test phase. A scalp block was used in both conditions. We evaluated the electronical medical record and the digitalized anesthetic protocols from each patient. Adverse events, as well as applied drugs with doses and frequency of usage were recorded. Compliance was evaluated according to the surgeons' perception. RESULTS: Two-hundred twenty-four (n=224) awake surgeries were performed in the period from October 2009 till September 2015. One-hundred eighty (n=180) of these were performed for the resection of gliomas and included into the study. In the "awake-awake-awake"-group (n=75) significantly less opiates (p<0.000), less vasoactive (p<0.000) and antihypertensive (p<0.000) drugs were used in comparison to the "asleep-awake-asleep"-group (n=105). In addition, compliance was much higher rated in the "awakeawake-awake"-group. Furthermore, the overall length of stay (p<0.000) and the surgical time (p<0.000) was significantly lower in the "awakeawake-awake" group. CONCLUSIONS: Dexmedetomidine provides excellent setting for fully awake surgeries. Our experience shows that using dexmedetomidine as sole anaesthetic drug during awake craniotomies sedates moderately and acts anxiolytic. Thus, after ceasing infusion it enables quick and reliable clinical neurological assessment of patients. Furthermore, according to our experience, it reduces the length of hospital stay and duration of the whole surgical procedure.