Dataset Information

Cerebral responses to local and global auditory novelty under general anesthesia.

ABSTRACT: Primate brains can detect a variety of unexpected deviations in auditory sequences. The local-global paradigm dissociates two hierarchical levels of auditory predictive coding by examining the brain responses to first-order (local) and second-order (global) sequence violations. Using the macaque model, we previously demonstrated that, in the awake state, local violations cause focal auditory responses while global violations activate a brain circuit comprising prefrontal, parietal and cingulate cortices. Here we used the same local-global auditory paradigm to clarify the encoding of the hierarchical auditory regularities in anesthetized monkeys and compared their brain responses to those obtained in the awake state as measured with fMRI. Both, propofol, a GABAA-agonist, and ketamine, an NMDA-antagonist, left intact or even enhanced the cortical response to auditory inputs. The local effect vanished during propofol anesthesia and shifted spatially during ketamine anesthesia compared with wakefulness. Under increasing levels of propofol, we observed a progressive disorganization of the global effect in prefrontal, parietal and cingulate cortices and its complete suppression under ketamine anesthesia. Anesthesia also suppressed thalamic activations to the global effect. These results suggest that anesthesia preserves initial auditory processing, but disturbs both short-term and long-term auditory predictive coding mechanisms. The disorganization of auditory novelty processing under anesthesia relates to a loss of thalamic responses to novelty and to a disruption of higher-order functional cortical networks in parietal, prefrontal and cingular cortices.

SUBMITTER: Uhrig L

PROVIDER: S-EPMC5635967 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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Cerebral responses to local and global auditory novelty under general anesthesia.

Uhrig Lynn L Janssen David D Dehaene Stanislas S Jarraya Béchir B

NeuroImage 20160805

Primate brains can detect a variety of unexpected deviations in auditory sequences. The local-global paradigm dissociates two hierarchical levels of auditory predictive coding by examining the brain responses to first-order (local) and second-order (global) sequence violations. Using the macaque model, we previously demonstrated that, in the awake state, local violations cause focal auditory responses while global violations activate a brain circuit comprising prefrontal, parietal and cingulate ...[more]

PMID: 27502046

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Project description:Elucidating changes in sensory processing across attentional and arousal states is a major focus in neuroscience. The local/global deviant (LGD) stimulus paradigm engages auditory predictive coding over short (local deviance, LD) and long (global deviance, GD) time scales, and has been used to assay disruption of auditory predictive coding upon loss of consciousness. Our previous work (Nourski et al., 2018, J Neurosci 38:8441-52) examined effects of general anesthesia on short- and long-term novelty detection. GD effects were suppressed at subhypnotic doses of propofol, suggesting that they may be more related to task engagement than consciousness per se. The present study addressed this hypothesis by comparing cortical responses to auditory novelty during passive versus active listening conditions in awake listeners. Subjects were seven adult neurosurgical patients undergoing chronic invasive monitoring for medically intractable epilepsy. LGD stimuli were sequences of four identical vowels followed by a fifth identical or different vowel. In the passive condition, the stimuli were presented to subjects as they watched a silent TV program and were instructed to attend to its content. In the active condition, stimuli were presented in the absence of a TV program, and subjects were instructed to press a button in response to GD target stimuli. Intracranial recordings were made from multiple brain regions, including core and non-core auditory, auditory-related, prefrontal and sensorimotor cortex. Metrics of task performance included hit rate, sensitivity index, and reaction times. Cortical activity was measured as averaged auditory evoked potentials (AEPs) and event-related band power in high gamma (70-150 Hz) and alpha (8-14 Hz) frequency bands. The vowel stimuli and LD elicited robust AEPs in all studied brain areas in both passive and active conditions. High gamma responses to stimulus onset and LD were localized predominantly to the auditory cortex in the superior temporal plane and had a comparable prevalence and spatial extent between the two conditions. In contrast, GD effects (AEPs, high gamma and alpha suppression) were greatly enhanced during the active condition in all studied brain areas. The prevalence of high gamma GD effects was positively correlated with individual subjects' task performance. The data demonstrate distinct task engagement-related effects on responses to auditory novelty across the auditory cortical processing hierarchy. The results motivate a closer examination of effective connectivity underlying attentional modulation of cortical sensory responses, and serve as a foundation for examining changes in sensory processing associated with general anesthesia, sleep and disorders of consciousness.

Project description:ObjectivesTo compare data on transperineal template biopsy (TPTB) under general anesthesia (GA) compared with local anesthesia (LA) procedures using the PrecisionPoint™ Transperineal Access System (PPTAS) in relation to tolerability, cancer detection rate, complications, and cost.MethodsA prospective pilot cohort study of patients undergoing transperineal biopsy was performed. Patients were excluded if they had concurrent flexible cystoscopy or language barriers. Patients had a choice of GA or LA. A prospective questionnaire on Days 0, 1, 7, and 30 was applied. The primary outcome was patient tolerability. Secondary outcomes were cancer detection rate, complication rate, and theater utilization.ResultsThis study included 80 patients (40 GA TPTB and 40 LA PPTAS). Baseline characteristics including age, prostate-specific antigen (PSA), digital rectal examination (DRE), findings, and prostate volume were comparable between the groups (p = 0.3790, p = 0.9832, p = 0.444, p = 0.3939, respectively). Higher median prostate imaging-reporting and data system (PI-RADS) score of 4 (interquartile range [IQR] 2) versus 3 (IQR 1) was noted in the LA group (p = 0.0326). Pain was higher leaving recovery in the GA group however not significantly (p = 0.0555). Median pain score at LA infiltration was 5/10 (IQR 3), with no difference in pain at Days 1, 7, or 30 (p = 0.2722, 0.6465, and 0.8184, respectively). For GA versus LA, the overall cancer detection rate was 55% versus 55% (p = 1.000) with clinically significant cancer in 22.5% versus 35% (p = 0.217). Acute urinary retention (AUR) occurred in 5% of GA and 2.5% of LA patients (p = 1.000). The GA cohort spent longer in theater and in recovery with a median of 93.5 min versus 57 min for the LA group (p = <0.0001).ConclusionThis study demonstrates that transperineal biopsy is safely performed under LA with no difference between the cohorts in relation cancer detection or AUR. LA biopsy also consumed less theater and recovery resources. A further larger prospective randomized controlled trial is required to confirm the findings of this study.

Dataset Information

Cerebral responses to local and global auditory novelty under general anesthesia.

Publications

Cerebral responses to local and global auditory novelty under general anesthesia.

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