Recording Sessions Research Articles

Non-parametric Physiological Classification of Retinal Ganglion Cells in the Mouse Retina.

Retinal ganglion cells, the sole output neurons of the retina, exhibit surprising diversity. A recent study reported over 30 distinct types in the mouse retina, indicating that the processing of visual information is highly parallelised in the brain. The advent of high density multi-electrode arrays now enables recording from many hundreds to thousands of neurons from a single retina. Here we describe a method for the automatic classification of large-scale retinal recordings using a simple stimulus paradigm and a spike train distance measure as a clustering metric. We evaluate our approach using synthetic spike trains, and demonstrate that major known cell types are identified in high-density recording sessions from the mouse retina with around 1,000 retinal ganglion cells. A comparison across different retinas reveals substantial variability between preparations, suggesting pooling data across retinas should be approached with caution. As a parameter-free method, our approach is broadly applicable for cellular physiological classification in all sensory modalities.

Between-speaker rhythmic variability is not dependent on language rhythm, as evidence from Persia reveals

Acoustic measures of speech rhythm based on the durational characteristics of consonantal and vocalic intervals (henceforth C- or V-intervals) as well as syllabic intensity reveal between-speaker variability. The evidence obtained so far is based on speakers of stressed-timed languages, which are assumed to have complex consonant clusters and a higher degree of vowel reduction. Speakers of stressed-timed languages might operate their articulatory organs in different ways due to the syllable complexity and vowel reduction. Complex consonant clusters are released differently, and vowel reduction tends to be produced more or less strongly depending on speakers. When a language lacks such features, it is possible that rhythmic variation between its speakers decreases. In the present study, we aimed at exploring between- and within-speaker rhythmic variability in Persian, an Indo-European language categorised as syllable-timed. Acoustic correlates of speech rhythm (%V, ?V[ln], ?C[ln], n-PVI-V) and articulation rate were obtained from two Persian corpora with different sources of within-speaker variability. In the first corpus, the source of within-speaker variability mainly comes from non-contemporaneous recording sessions, and in the second corpus, from different speech rates. Results revealed that there were significant differences between speakers in all investigated speech rhythm measures in Persian and %V best discriminated between speakers. This reveals that the lack of typical stress-time features does not affect between-speaker variability in speech rhythm.

A Mechanically-Adaptive Polymer Nanocomposite-Based Intracortical Probe and Package for Chronic Neural Recording.

Mechanical, materials, and biological causes of intracortical probe failure have hampered their utility in basic science and clinical applications. By anticipating causes of failure, we can design a system that will prevent the known causes of failure. The neural probe design was centered around a bio-inspired, mechanically-softening polymer nanocomposite. The polymer nanocomposite was functionalized with recording microelectrodes using a microfabrication process designed for chemical and thermal process compatibility. A custom package based upon a ribbon cable, printed circuit board, and a 3D-printed housing was designed to enable connection to external electronics. Probes were implanted into the primary motor cortex of Sprague-Dawley rats for 16 weeks, during which regular recording and electrochemical impedance spectroscopy measurement sessions took place. The implanted mechanically-softening probes had stable electrochemical impedance spectra across the 16 weeks and single units were recorded out to 16 weeks. The demonstration of chronic neural recording with the mechanically-softening probe suggests that probe architecture, custom package, and general design strategy are appropriate for long-term studies in rodents.

Non-pharmacological induction of rat 50 kHz ultrasonic vocalization: Social and non-social contexts differentially induce 50 kHz call subtypes

The emission of 50 kHz ultrasonic vocalizations (USVs) by rats is thought to represent a measurable expression of the individuals underlying emotional state. These calls are also posited as fulfilling important communicative functions among conspecifics. In addition to social situations, 50 kHz USVs are recorded in a variety of reward-related contexts including sugary foods and drink, consumable ethanol, and drugs of abuse. The current study sought to directly compare several of these behavioural contexts in their capability to induce and modulate 50 kHz USV emission in adult male rats. Using two social conditions (exposure of naïve rat to a naturally cycling female and reuniting with a same-sex cage partner) and two non-social conditions (access to consumables as Fruit Loops or 2% ethanol v/v), we analyzed USVs recorded in 6 stimulus-presentation sessions. Only the female-exposure condition was found to increase 50 kHz call rate significantly over baseline, and this induction sensitized across 4 standard recording sessions. The use of a same-sex cage-mate and the two consumable food rewards did not elicit higher than baseline 50 kHz calling. None of the behavioural contexts altered the acoustic parameters (peak frequency, duration, and bandwidth) of emitted 50 kHz calls. In counter-balanced recording sessions, calling across all groups was significantly reduced by pre-treatment with the dopamine antagonist haloperidol compared with vehicle. Non-social conditions appeared to induce a greater proportion of flat calls at the expense of non-trill FM calls, while the reverse was seen for social conditions. However, the type of food reward and the type of social context mattered for proportion of flat and trill calls respectively. When compared with a control, access to sugary food but not ethanol induced a greater proportion of flat calls, and the female but not the cage-mate stimulus induced a greater proportion of trill calls.

Clinician vs. Machine: Estimating Vocalizations Rates in Young Children With Developmental Disorders.

The purpose of this study was to investigate the reliability of an automated language analysis system, the Language Environment Analysis (LENA), compared with a human transcriber to determine the rate of child vocalizations during recording sessions that were significantly shorter than recommended for the automated device. Participants were 6 nonverbal male children between the ages of 28 and 46 months. Two children had autism diagnoses, 2 had Down syndrome, 1 had a chromosomal deletion, and 1 had developmental delay. Participants were recorded by the LENA digital language processor during 14 play-based interactions with a responsive adult. Rate of child vocalizations during each of the 84 recordings was determined by both a human transcriber and the LENA software. A statistically significant difference between the 2 methods was observed for 4 of the 6 participants. Effect sizes were moderate to large. Variation in syllable structure did not explain the difference between the 2 methods. Vocalization rates from the 2 methods were highly correlated for 5 of the 6 participants. Estimates of vocalization rates from nonverbal children produced by the LENA system differed from human transcription during sessions that were substantially shorter than the recommended recording length. These results confirm the recommendation of the LENA Foundation to record sessions of at least 1 hr.

Syringe-injectable Mesh Electronics for Stable Chronic Rodent Electrophysiology

Implantable brain electrophysiology probes are valuable tools in neuroscience due to their ability to record neural activity with high spatiotemporal resolution from shallow and deep brain regions. Their use has been hindered, however, by mechanical and structural mismatches between the probes and brain tissue that commonly lead to micromotion and gliosis with resulting signal instability in chronic recording experiments. In contrast, following the implantation of ultraflexible mesh electronics via syringe injection, the mesh probes form a seamless, gliosis-free interface with the surrounding brain tissue that enables stable tracking of individual neurons on at least a year timescale. This protocol details the key steps in a typical mouse neural recording experiment using syringe-injectable mesh electronics, including the fabrication of mesh electronics in a standard photolithography-based process possible at many universities, loading mesh electronics into standard capillary needles, stereotaxic injection in vivo, connection of the mesh input/output to standard instrumentation interfaces, restrained or freely moving recording sessions, and histological sectioning of brain tissue containing mesh electronics. Representative neural recordings and histology data are presented. Investigators familiar with this protocol will have the knowledge necessary to incorporate mesh electronics into their own experiments and take advantage of the unique opportunities afforded by long-term stable neural interfacing, such as studies of aging processes, brain development, and the pathogenesis of brain disease.

Syringe-injectable Mesh Electronics for Stable Chronic Rodent Electrophysiology.

Implantable brain electrophysiology probes are valuable tools in neuroscience due to their ability to record neural activity with high spatiotemporal resolution from shallow and deep brain regions. Their use has been hindered, however, by mechanical and structural mismatches between the probes and brain tissue that commonly lead to micromotion and gliosis with resulting signal instability in chronic recording experiments. In contrast, following the implantation of ultraflexible mesh electronics via syringe injection, the mesh probes form a seamless, gliosis-free interface with the surrounding brain tissue that enables stable tracking of individual neurons on at least a year timescale. This protocol details the key steps in a typical mouse neural recording experiment using syringe-injectable mesh electronics, including the fabrication of mesh electronics in a standard photolithography-based process possible at many universities, loading mesh electronics into standard capillary needles, stereotaxic injection in vivo, connection of the mesh input/output to standard instrumentation interfaces, restrained or freely moving recording sessions, and histological sectioning of brain tissue containing mesh electronics. Representative neural recordings and histology data are presented. Investigators familiar with this protocol will have the knowledge necessary to incorporate mesh electronics into their own experiments and take advantage of the unique opportunities afforded by long-term stable neural interfacing, such as studies of aging processes, brain development, and the pathogenesis of brain disease.

Subthalamic theta activity: a novel human subcortical biomarker for obsessive compulsive disorder

Obsessive-compulsive disorder (OCD) is a common and serious psychiatric disorder. Although subthalamic nucleus deep brain stimulation (DBS) has been studied as a treatment for OCD patients the underlying mechanism of this treatment and the optimal method of stimulation are unknown. To study the neural basis of subthalamic nucleus DBS in OCD patients we used a novel, implantable DBS system with long-term local field potential sensing capability. We focus our analysis on two patients with OCD who experienced severe treatment-resistant symptoms and were implanted with subthalamic nucleus DBS systems. We studied them for a year at rest and during provocation of OCD symptoms (46 recording sessions) and compared them to four Parkinson’s disease (PD) patients implanted with subthalamic nucleus DBS systems (69 recording sessions). We show that the dorsal (motor) area of the subthalamic nucleus in OCD patients displays a beta (25–35 Hz) oscillatory activity similar to PD patients whereas the ventral (limbic-cognitive) area of the subthalamic nucleus displays distinct theta (6.5–8 Hz) oscillatory activity only in OCD patients. The subthalamic nucleus theta oscillatory activity decreases with provocation of OCD symptoms and is inversely correlated with symptoms severity over time. We conclude that beta oscillations at the dorsal subthalamic nucleus in OCD patients challenge their pathophysiologic association with movement disorders. Furthermore, theta oscillations at the ventral subthalamic nucleus in OCD patients suggest a new physiological target for OCD therapy as well as a promising input signal for future emotional-cognitive closed-loop DBS.

Compact standalone platform for neural recording with real-time spike sorting and data logging

Objective. Longitudinal observation of single unit neural activity from large numbers of cortical neurons in awake and mobile animals is often a vital step in studying neural network behaviour and towards the prospect of building effective brain–machine interfaces (BMIs). These recordings generate enormous amounts of data for transmission and storage, and typically require offline processing to tease out the behaviour of individual neurons. Our aim was to create a compact system capable of: (1) reducing the data bandwidth by circa 2 to 3 orders of magnitude (greatly improving battery lifetime and enabling low power wireless transmission in future versions); (2) producing real-time, low-latency, spike sorted data; and (3) long term untethered operation. Approach. We have developed a headstage that operates in two phases. In the short training phase a computer is attached and classic spike sorting is performed to generate templates. In the second phase the system is untethered and performs template matching to create an event driven spike output that is logged to a micro-SD card. To enable validation the system is capable of logging the high bandwidth raw neural signal data as well as the spike sorted data. Main results. The system can successfully record 32 channels of raw neural signal data and/or spike sorted events for well over 24 h at a time and is robust to power dropouts during battery changes as well as SD card replacement. A 24 h initial recording in a non-human primate M1 showed consistent spike shapes with the expected changes in neural activity during awake behaviour and sleep cycles. Significance. The presented platform allows neural activity to be unobtrusively monitored and processed in real-time in freely behaving untethered animals—revealing insights that are not attainable through scheduled recording sessions. This system achieves the lowest power per channel to date and provides a robust, low-latency, low-bandwidth and verifiable output suitable for BMIs, closed loop neuromodulation, wireless transmission and long term data logging.

Visual cortical activity before and after cochlear implantation: A follow up ERP prospective study in deaf children

ERPs were recorded in response to presentation of static colored patterned stimuli in 25 children (19 to 80months of age at cochlear implantation, CI) with very early prelingual profound deafness (PreLD), 21 postlingual profoundly deaf children (PostLD) (34 to 180months of age at CI) and gender- and age-matched control hearing children. Recording sessions were performed before CI, then 6 and 24months after CI.Results showed that prelingual and, at a lesser degree, postlingual auditory deprivation altered cortical visual neural activity associated to colored shapes from both P1 and N1 cortical processing stages. The P1 and N1 amplitude modifications vanished about 24months after CI in both PreLD and PostLD deaf children. In PreLD the visual processing pattern becomes similar to the typical one essentially by an amplitude decrease of P1 on the left hemisphere together with an amplitude increase of the N1 on the right hemisphere. Finally, in PreLD, increased LH advantage over the RH in N1 amplitude on the cerebellar-occipito-parietal region before CI showed a significant inverse relationship with speech perception outcomes 3years after CI.Investigating early visual processing development and its neural substrates in deaf children would help to understand the variability of CI outcome, because their cortical visual organization diverged from the one of typically developing hearing children, and cannot be predicted from what is observed in deaf adults.

InvisibleEye

Analysis of everyday human gaze behaviour has significant potential for ubiquitous computing, as evidenced by a large body of work in gaze-based human-computer interaction, attentive user interfaces, and eye-based user modelling. However, current mobile eye trackers are still obtrusive, which not only makes them uncomfortable to wear and socially unacceptable in daily life, but also prevents them from being widely adopted in the social and behavioural sciences. To address these challenges we present InvisibleEye, a novel approach for mobile eye tracking that uses millimetre-size RGB cameras that can be fully embedded into normal glasses frames. To compensate for the cameras’ low image resolution of only a few pixels, our approach uses multiple cameras to capture different views of the eye, as well as learning-based gaze estimation to directly regress from eye images to gaze directions. We prototypically implement our system and characterise its performance on three large-scale, increasingly realistic, and thus challenging datasets: 1) eye images synthesised using a recent computer graphics eye region model, 2) real eye images recorded of 17 participants under controlled lighting, and 3) eye images recorded of four participants over the course of four recording sessions in a mobile setting. We show that InvisibleEye achieves a top person-specific gaze estimation accuracy of 1.79° using four cameras with a resolution of only 5 × 5 pixels. Our evaluations not only demonstrate the feasibility of this novel approach but, more importantly, underline its significant potential for finally realising the vision of invisible mobile eye tracking and pervasive attentive user interfaces.

Therapist verbal behavior in the multidimensional system for coding behaviors in therapeutic interaction (SiMCCIT)

Therapeutic interaction has been considered one of the main factors of change in psychotherapy, and its investigation is called process research. Audio and video recording sessions are used to code behaviors which, subsequently, permit the analysis of interaction patterns. The objectives of the study were the presentation of part of a coding system called “Multidimensional System for Categorization of Behaviors in Therapeutic Interaction” and the evaluation of agreement between observers in its use. From a systematic assessment of the literature regarding the classification of vocal verbal behavior, it was found that the existing category systems were not satisfactory for the study of behavior analytic therapy, thus requiring the construction of a new system. A System for Coding Verbal Therapist Behavior was developed containing 16 categories, nine of vocal verbal behavior, three for non-vocal verbal behavior and four residual categories. A standardized training for observers was also developed. Its application to one participant produced satisfactory Kappa indexes of agreement ranging from 0.67 to 0.84. The implications of using the system for process research in behavior analytic therapy and in other therapeutic modalities in its different stages are discussed as well as the possibility of using the instrument and its training software for teaching therapeutic skills.

S56 Added value of EEG signal analysis in presurgical evaluation for drug-resistant epilepsy

Objectives To assess the role of signal analysis methods for accurate delineation of the epileptogenic zone during surgery for drug resistant epilepsy. Methods We used surface video EEG as well as invasive studies by means of the stereo-EEG method to identify the epileptogenic networks. Signal analysis tools have been applied systematically during pre surgical evaluation to study ictal as well as interictal activity and responses to different stimulation protocols. Connectivity charts were computed based on analysis of cortico-cortical evoked potentials on single pulse electrical stimulation (SPES). The results were interpreted according with an individual patient hypothesis and integrated with clinical and anatomic data. Results We explored 63 patients at the University Hospital of Bucharest in the National Program for Epilepsy Surgery between 2012 and 2016 of which 57 received either open surgeries or undergone a procedure of radio frequency thermocoagulation (RFTC) applied on intracranial electrodes. In the group of patients ( n = 34) with more than 2 years follow up after surgery, 25 (74%) are seizure free. Signal post processing analysis was critical for surgical planning in 12 cases (48%). Discussion Systematic use of signal analysis approach improved the definition of surgical resection limits, made the recording sessions shorter without sacrificing information, and allowed a better definition of targets for RFTC protocols during SEEG recordings. Conclusion Signal analysis tools added complementary information where the traditional visual analysis was not helpful for surgical planning. Significance Post processing methods of the EEG signal integrated with the anatomo-clinical hypothesis offer unbiased valuable data to improve surgical outcome.

Effect of Faculty Development Activities on Dental Hygiene Faculty Perceptions of and Teaching About Motivational Interviewing: A Pilot Study.

The aims of this pilot study were to assess dental hygiene faculty members' perceptions of the importance of motivational interviewing (MI) and their confidence in teaching students about MI and to determine the effect of MI training sessions on those perceptions. Participants were a convenience sample of all 16 dental hygiene faculty members who teach in the clinic at the University of Michigan School of Dentistry. Participants' perceptions were assessed prior to a workshop in MI (pretest), immediately after the workshop (posttest 1), and eight months after the workshop, at the end of the academic year (posttest 2). During the same period, some of the workshop participants took part in team grading sessions of audio recordings of student-patient MI interactions. The results showed that the majority of the faculty members perceived it was important to personally embrace the overall spirit of MI during patient care, and they were confident supporting students as well. Their ratings for embracing the spirit of MI increased from pretest to posttest 1, but slightly decreased at posttest 2. This trend was also seen in their assessment of the importance of and their confidence in teaching the eight MI strategies over time. Among the workshop participants, 56% were part of team grading; they reported the most helpful professional development activities overall were team grading (58%) and the workshop (25%). These results suggest the importance of making use of a variety of faculty development activities and of introducing appropriate follow-up to training sessions over time to ensure long-lasting effects. Future research using carefully designed, multi-institution, longitudinal studies is needed to determine the most effective ways to prepare dental hygiene faculty members to educate their students about MI.

Changes in White Matter Integrity following Intensive Voice Treatment (LSVT LOUD®) in Children with Cerebral Palsy and Motor Speech Disorders

Preliminary evidence suggests that intensive voice and speech treatment based on activity-dependent neuroplasticity principles holds promise for affecting positive change in children with cerebral palsy (CP) and motor speech disorders. Diffusion tensor imaging (DTI) allows researchers to make inferences about the integrity of white matter tracks and provides a sensitive measure of neuroplasticity. Previous treatment studies looking at the effects of training on white matter integrity have shown positive results, but these studies have been limited to gross motor function. Eight children with motor speech disorders and CP (3 females; age 8-16 years) and an age- and sex-matched group of typically developing (TD) children participated. Each child with CP completed a full dose of LSVT LOUD® and a 12-week maintenance program. Participants attended 3 recording sessions: before and after treatment, and after the maintenance period. TD children were tested at the same 3 time points. Recording sessions for both groups of children included measures of white matter integrity using DTI and acoustic measures of voice and speech. Fractional anisotropy (FA) was measured for 2 motor tracts and 5 association tracts. In children with CP, we observed an increase in FA in several motor and association tracts immediately following treatment and 12 weeks after treatment. Acoustic data on untrained tasks were correlated with changes in FA detected immediately following treatment and after the 12-week maintenance program. These findings suggest that long-term practice of skills attained during the treatment phase enhances white matter tract integrity in speech production networks.

Bio-inspired benchmark generator for extracellular multi-unit recordings

The analysis of multi-unit extracellular recordings of brain activity has led to the development of numerous tools, ranging from signal processing algorithms to electronic devices and applications. Currently, the evaluation and optimisation of these tools are hampered by the lack of ground-truth databases of neural signals. These databases must be parameterisable, easy to generate and bio-inspired, i.e. containing features encountered in real electrophysiological recording sessions. Towards that end, this article introduces an original computational approach to create fully annotated and parameterised benchmark datasets, generated from the summation of three components: neural signals from compartmental models and recorded extracellular spikes, non-stationary slow oscillations, and a variety of different types of artefacts. We present three application examples. (1) We reproduced in-vivo extracellular hippocampal multi-unit recordings from either tetrode or polytrode designs. (2) We simulated recordings in two different experimental conditions: anaesthetised and awake subjects. (3) Last, we also conducted a series of simulations to study the impact of different level of artefacts on extracellular recordings and their influence in the frequency domain. Beyond the results presented here, such a benchmark dataset generator has many applications such as calibration, evaluation and development of both hardware and software architectures.

Civic Jazz

Civic Jazz

Digital Laboratory Experiences: Creating Videos for Undergraduate Engineering Practical Sessions

<p>This paper will go over the method used to record and present practical sessions to students studying undergraduate engineering as ‘digital laboratory experiences’. The aim of the practical sessions was to give students exposure to simple electrical engineering concepts to supplement their project based learning in a two credit point unit.</p><p>Outlined are the goals the practical sessions, the process of capturing footage and editing a video file for the students; and finally a discussion on student attendance to in person practical sessions once the videos were made available. After this, future work to be completed is discussed, mentioning possible improvements that could be made. </p>

Poetic Inspiration and the Contextualization of Misunderstanding

This paper focuses on performance ethnography in which an academically trained ethnographer produces a corpus of culturally configured verbal art in professional association with a competent performer of the culture of study. More specifically, we will consider the role of inspiration in bridging the gap(s) between cultural references and expressions that are grounded in distinctly different semiotic systems. A stylistic study of Victoria Howard’s “I and my sister‑cousin” (Clackamas Chinook) as told to Melville Jacobs during their ethnographical recording sessions in 1929 will highlight dialogical and contextual indices to artistic motivation inspired by the linguist’s misunderstanding of spiritual beliefs and practices.

매트리스의 종류가 건강한 성인의 주관적, 객관적 수면의 질에 미치는 영향에 대한 탐색적 연구

목 적 : 일반스프링 매트리스에 비교하여 지지력 등을 향상시킨 컨투어 코일 매트리스가 주관적 및 객관적인 수면의 질을 향상시킬 수 있는지 알아보고자 하였다. 방 법 : 건강하게 수면하는 일반인 대상자 15명을 모집하였다. 연구대상자들은 두 종류의 매트리스에서 잠을 자면서 야간수면다원검사를 시행하였고 검사 전, 후 주관적인 수면의 질에 대한 자가설문지를 작성하게 하였다. 한 연구대상자가 각각 다른 매트리스에서 2일에 걸쳐 야간수면다원검사를 시행하여 얻어진 객관적인 수면변인들과 주관적인 자가 설문지 변수들로 교차설계분석을 시행하였다. 결 과 : 야간수면다원검사에서 측정된 수면잠복기가 컨투어 코일 매트리스에서 잠을 잔 경우 일반스프링 매트리스에서 잠을 잔 경우보다 평균 1.9분 감소하였다. 이외에도 주관적으로 느낀 수면 중 각성횟수, 깊게 잠든 느낌 그리고 잠자리의 편안함이 컨투어 코일 매트리스가 유의하게 더 나은 결과를 보였다. 결 론 : 매트리스가 종류에 따라서 주관적인 수면의 질뿐만 아니라 객관적인 수면의 질에도 영향을 미친다고 할 수 있다. Objectives: We aimed to evaluate the effects of mattress type on both objective and subjective sleep quality in healthy good sleepers. Methods: Fifteen healthy good sleepers with a mean age of 30.8 years participated in this study. A randomized crossover trial was carried out using two different mattress types: a standard mattress and a contour coil mattress. After a night of adaptation, all participants were randomized to either a standard mattress or a contour coil mattress. Then, nocturnal polysomnography was conducted for two consecutive nights. Subjective evaluations were obtained using a self-report questionnaire before and after the polysomnographic recording sessions. Results: The polysomnographic showed no differences in total sleep time, sleep stage, or wake time after sleep onset between the two mattress conditions. Of the polysomnographic variables, only sleep onset latency was significantly reduced for the contour coil mattress. Additionally, participants reported better subjective sleep quality when sleeping on the contour coil mattress, according to the questionnaires. Conclusion: The type of mattress might affect not only subjective, but also objective sleep quality, including sleep onset latency.