Points that need attention in auditory N100 gating research in schizophrenia

Publication date: Available online 22 November 2018

Source: Clinical Neurophysiology

Author(s): Ming H. Hsieh, Hong-Hsiang Liu

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Acknowledgment to reviewers

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Baboon vocal repertoires and the evolution of primate vocal diversity

Publication date: January 2019

Source: Journal of Human Evolution, Volume 126

Author(s): Kurt Hammerschmidt, Julia Fischer

Abstract

A remarkable and derived trait of humans is the faculty for language, and considerable research effort has been devoted to understanding the evolution of speech. In contrast to spoken language, which constitutes a (learned) symbolic communication system, the acoustic structure of nonhuman primate vocalizations is largely genetically fixed. Yet, appreciable differences between different genera and species may exist. Environmental conditions, sexual selection, and characteristics of the social system have been invoked to explain these differences. Here, we studied the acoustic variation of call types and vocal repertoires in the genus Papio. Because the genus comprises both stable groups as well as multi-level societies, and reveals striking variation in the degree of aggressiveness from south to north, it constitutes a promising model to assess the link between social system characteristics and vocal communication. We found that, the vocal repertoires of the different species were composed of the same general call types. A quantitative analysis of the acoustic features of the grunts and loud calls of chacma (Papio ursinus), olive (P. anubis), and Guinea (P. papio) baboons showed subtle acoustic differences within call types, however. Social system characteristics did not map onto acoustic variation. We found no correlation between the structure of grunts and geographic distance; the same was true for female loud calls. Only for male loud calls from three populations, call structure varied with geographic distance. Our findings corroborate the view that the structure of nonhuman primate vocalizations is highly conserved, despite the differences in social systems. Apparently, variation in rate and intensity of occurrence of signals, probably due to different behavioral dispositions in species, are sufficient to allow for plasticity at the level of the social relationships, mating patterns, and social organization.

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Can we feel like being neither alert nor sleepy? The electroencephalographic signature of this subjective sub-state of wake state yields an accurate measure of objective sleepiness level

Publication date: Available online 22 November 2018

Source: International Journal of Psychophysiology

Author(s): Arcady A. Putilov, Olga G. Donskaya, Evgeniy G. Verevkin

Abstract

Accurate measurement of objective level of sleepiness can have important implications for experimental and field studies of sleep deprived individuals. We proposed to accurately quantify changes in sleepiness level with single electroencephalographic (EEG) measures obtained from EEG spectra consisting of 16 spectral powers within the frequency interval from 1 to 16 Hz. The EEG signal was recorded every other hour from 19:00 of Friday to 19:00 of Sunday in 48 study participants. The differential spectra were calculated for the 1st minute with eyes closed as the differences between EEG spectra for pairs of distinct subjective sub-states (alert, neither alert nor sleepy, sleepy, and very sleepy sub-states scored on the Karolinska Sleepiness Scale as 3, 5, 7, and 9, respectively).The differential spectra were calculated for the sub-samples of those participants who succeeded and failed to succeed in completing all 25 EEG recording sessions (n = 25 and 23, respectively) and for the addition sample of 130 participants deprived from sleep for only one night. Single spectral EEG measures were then calculated by summation of 16 spectral powers weighted by a differential spectrum. The strongest correlation coefficients (0.981, 0.987, and 0.985) were attained between the time courses of subjective and objective measures when data on 130, 23 and 25 participants, respectively, were used for calculation of frequency waiting curve differentiating alert sub-sate either from sleepy sub-state or from neither alert nor sleepy sub-state. We recommended implementation of the proposed objective measure into experimental procedures requiring accurate estimation of objective sleepiness level.

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Monitoring multiple cortical regions during walking in young and older adults: Dual-task response and comparison challenges

Publication date: Available online 22 November 2018

Source: International Journal of Psychophysiology

Author(s): Samuel Stuart, Lisa Alcock, Lynn Rochester, Rodrigo Vitorio, Annette Pantall

Abstract

Performance of several tasks simultaneously (dual-tasks) is common in everyday walking. Studies indicate that dual-task walking performance declines with age together with cognitive function, but neural mechanisms underpinning deficits remain unclear. Recent developments in mobile imaging techniques, such as functional near infrared spectroscopy (fNIRS), allow real-time monitoring of cortical activity during walking. This study aimed to: 1) examine activity in motor and cognitive cortical regions when walking with a dual-task in young and older adults; and 2) determine the effect of cognition on dual-task cortical activity changes.

Seventeen young (20.3 ± 1.2 years) and eighteen older adults (72.6 ± 8.0 years) performed dual-task conditions, lasting 5 min, with alternating 30-second experimental blocks. The primary outcome was cortical activity, assessed by measuring changes in oxygenated haemoglobin (HbO₂) concentrations. Cortical regions of interest (ROI) included motor regions (premotor cortex (PMC), supplementary motor area (SMA), primary motor cortex (M1)), and cognitive regions (prefrontal cortex (PFC)). Cognitive domains were assessed using standard tests and accelerometers were used to extract gait features.

Cortical activity increased with a dual-task in PMC, SMA and M1 but not in PFC regions across groups, with response most evident with initial task exposure. Older adults did not increase SMA activity with a dual-task to the same level as young adults. Dual-task cortical response was consistently associated with greater executive function across groups.

In conclusion, both young and older adults responded in a similar manner to dual-task conditions. Dual-task walking activated multiple motor regions in both groups, but no significant change occurred for cognitive region activation. Cortical activation with a dual-task related to executive function.

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Prognostic Value of Tissue Oxygen Monitoring and Regional Cerebral Oxygen Saturation Monitoring and Their Correlation in Neurological Patients With Sepsis: A Preliminary, Prospective, Observational Study

Background: There is paucity of literature on the prognostic value of tissue oxygen saturation (StO2) and regional cerebral oxygen saturation (rSO2) in neurological patients with sepsis. In this preliminary study, we investigated the prognostic value of StO2 and rSO2 in a group of neurological patients and correlated StO2 and rSO2 with hemodynamic and metabolic parameters. Materials and Methods: This preliminary, prospective observational study was conducted in 45 adult neurological patients admitted to intensive care unit. Once a diagnosis of sepsis or septic shock was established, parameters of oxygenation (StO2, rSO2, central venous oxygen saturation [ScvO2]), serum lactate, illness severity scores (Acute Physiology and Chronic Health Evaluation score, Sequential Organ Failure Assessment score, Glasgow Coma Scale) were recorded at 0, 6, 12, 24, 36, and 48 hours, and once daily thereafter. Outcomes were in-hospital mortality attributable to sepsis and the Glasgow outcome score at hospital discharge. Results: There was a moderately positive correlation between StO2 and rSO2 at baseline (r=0.599; P=0.001). StO2, illness severity scores and serum lactate, but not rSO2, were significantly different between survivors (n=29) and nonsurvivors (n=16) at baseline and during the first 48 hours. An rSO2 of 62.5% had a sensitivity of 83% and specificity of 67% to differentiate survivors and nonsurvivors of septic shock at 48 hours. StO2 had a higher correlation with ScvO2 and serum lactate than rSO2. Conclusions: StO2 prognosticates survival and favorable/unfavorable outcomes in neurological patients with sepsis. The role of rSO2 in predicting survival in milder form of sepsis is doubtful. The authors have no funding or conflicts of interest to disclose. Address correspondence to: Sonia Bansal, MD, DNB, PDF, Department of Neuroanaesthesia and Neurocritical Care, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560029, India (e-mail: itz.sonia77@gmail.com). Received February 13, 2018 Accepted October 4, 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved

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Predictive Factors for Hypotension Associated With Supine-to-Prone Positional Change in Patients Undergoing Spine Surgery

Background: Positional change during general anesthesia can cause hypotension. The objective of this retrospective study was to determine predictive factors for hypotension associated with supine-to-prone positional change in spinal surgery patients. Materials and Methods: Data on demographics, current medications, comorbidity, intraoperative mean arterial pressure (MAP), heart rate, pulse pressure variation, tidal volume, peak inspiratory pressure, and propofol and remifentanil effect-site concentrations were collected from 179 patients undergoing elective spine surgery. Hypotension associated with supine-to-prone positional change was defined as >20% reduction in MAP during positional change. Results: Hypotension associated with supine-to-prone positional change was observed in 16 (8.9%) patients. The median (interquartile range) effect-site concentration of remifentanil (5.3 [4.0 to 8.5] vs. 4.0 [3.1 to 4.0] ng/mL, P

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