Intrinsic neuronal dynamics predict distinct functional roles during working memory

Working memory (WM) is characterized by the ability to maintain stable representations over time; however, neural activity associated with WM maintenance can be highly dynamic. We explore whether complex population coding dynamics during WM relate to the intrinsic temporal properties of single neurons in lateral prefrontal cortex (lPFC), the frontal eye fields (FEF), and lateral intraparietal cortex (LIP) of two monkeys (Macaca mulatta). We find that cells with short timescales carry memory information relatively early during memory encoding in lPFC; whereas long-timescale cells play a greater role later during processing, dominating coding in the delay period. We also observe a link between functional connectivity at rest and the intrinsic timescale in FEF and LIP. Our results indicate that individual differences in the temporal processing capacity predict complex neuronal dynamics during WM, ranging from rapid dynamic encoding of stimuli to slower, but stable, maintenance of mnemonic information.Biotechnology and Biological Sciences Research Council (Great Britain) (BB/M010732/1)United States. Office of Naval Research (N00014-14-1-0681)National Institute of Mental Health (U.S.) (R00MH092715)National Institute of Mental Health (U.S.) (R37MH087027)Massachusetts Institute of Technology. Picower Innovation FundUnited States. Office of Naval Research. Multidisciplinary University Research Initiative (grant N00014-16-1-2832)National Institute for Health Research (Great Britain). Wellcome Trust (203139/Z/16/Z

Understanding the interplay between social and spatial behaviour

According to personality psychology, personality traits determine many aspects of human behaviour. However, validating this insight in large groups has been challenging so far, due to the scarcity of multi-channel data. Here, we focus on the relationship between mobility and social behaviour by analysing trajectories and mobile phone interactions of ∼1000 individuals from two high-resolution longitudinal datasets. We identify a connection between the way in which individuals explore new resources and exploit known assets in the social and spatial spheres. We show that different individuals balance the exploration-exploitation trade-off in different ways and we explain part of the variability in the data by the big five personality traits. We point out that, in both realms, extraversion correlates with the attitude towards exploration and routine diversity, while neuroticism and openness account for the tendency to evolve routine over long time-scales. We find no evidence for the existence of classes of individuals across the spatio-social domains. Our results bridge the fields of human geography, sociology and personality psychology and can help improve current models of mobility and tie formation

Attitudes toward reading, reading self-confidence, family involvement and reading comprehension in the second grade

RESUMEN: Introducción. En la lectura, instrumento cultural clave que hay que aprender a dominar en las sociedades letradas, confluyen aspectos cognitivos, afectivo-motivacionales y contextuales. Pero en el ámbito internacional hay escasez de investigaciones sobre la relación entre comprensión lectora, actitudes hacia la lectura, sentimiento de competencia e implicación familiar en los dos primeros cursos de Educación Primaria. Además, no hay estudios en España que aborden esas variables al mismo tiempo. Método. Nuestro estudio investiga la relación entre estas cuatro variables en alumnado español de segundo curso de Educación Primaria mediante un estudio de corte cuantitativo (descriptivo y correlacional) en el que han participado 181 niños y 167 niñas. Resultados. Se hallaron actitudes muy positivas hacia la lectoescritura así como un elevado sentimiento de competencia. Las niñas obtuvieron puntuaciones más altas que los niños. Esta última variable y la implicación familiar exhibieron correlaciones significativas con la comprensión lectora. Discusión y conclusiones. Se resalta la importancia de trabajar en la implicación de las familias, de mantener un positivo sentimiento de competencia y de conocer las tempranas diferencias en actitudes y preferencias de niños y niñas por parte del profesorado.ABSTRACT: Introduction. In literate societies, reading is a key cultural instrument that must be mastered. This process involves cognitive, affective-motivational and contextual aspects. However, we find little research internationally on the relationship between reading comprehension, attitudes toward reading, reading self-confidence and family involvement in the first two grades of primary education. Furthermore, there are no studies in Spain that address these variables concurrently. Method. Our study investigates the relationship between these four variables in Spanish second-graders using a quantitative (descriptive and correlational) study with the participation of 181 boys and 167 girls. Results. Attitudes towards reading and writing were very positive, and confidence was high. The girls obtained higher scores than the boys. Reading self-confidence and family involvement showed significant correlations with reading comprehension. Discussion and conclusions. It is important to foster the involvement of families in their childrens' acquisition of reading and writing, to maintain the learners? self-confidence, and for teachers to understand early differences between boys and girls in their attitudes and preferences

Sensor feature selection and combination for stress identification using combinatorial fusion

The identification of stressfulness under certain driving condition is an important issue for safety, security and health. Sensors and systems have been placed or implemented as wearable devices for drivers. Features are extracted from the data collected and combined to predict symptoms. The challenge is to select the feature set most relevant for stress. In this paper, we propose a feature selection method based on the performance and the diversity between two features. The feature sets selected are then combined using a combinatorial fusion. We also compare our results with other combination methods such as naive Bayes, support vector machine, C4.5, linear discriminant function (LDF), and k-nearest neighbour (kNN). Our experimental results demonstrate that combinatorial fusion is an efficient approach for feature selection and feature combination. It can also improve the stress recognition rate.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000322766600001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701RoboticsSCI(E)EI1ARTICLEnull1

Individual mobility and social behaviour: Two sides of the same coin

According to personality psychology, personality traits determine many aspects of human behaviour. However, validating this insight in large groups has been challenging so far, due to the scarcity of multi-channel data. Here, we focus on the relationship between mobility and social behaviour by analysing two high-resolution longitudinal datasets collecting trajectories and mobile phone interactions of $\sim 1000$ individuals. We show that there is a connection between the way in which individuals explore new resources and exploit known assets in the social and spatial spheres. We point out that different individuals balance the exploration-exploitation trade-off in different ways and we explain part of the variability in the data by the big five personality traits. We find that, in both realms, extraversion correlates with an individual's attitude towards exploration and routine diversity, while neuroticism and openness account for the tendency to evolve routine over long time-scales. We find no evidence for the existence of classes of individuals across the spatio-social domains. Our results bridge the fields of human geography, sociology and personality psychology and can help improve current models of mobility and tie formation

THE THALAMIC RETICULAR NUCLEUS: A MULTIFACETED GUARDIAN

Interactions between the cortex and the thalamus are essential for major brain functions such as sensory information processing and integration, sleep and wake regulation and cognitive processes. The thalamic reticular nucleus (TRN) is strategically positioned within the thalamocortical circuit and has a strong inhibitory control over the thalamus. It can act on a global scale, such as suppressing the flow of sensory information from the thalamus to the cortex during sleep. The TRN also acts locally on the activity of single cells or small cell groups. To reconcile both of these global and local aspects of TRN functions, we studied the cellular, synaptic and functional heterogeneity of the TRN, with a focus on the comparison between the classical sensory TRN and the less well-described limbic TRN. In study 1, using anatomical tracing and cellular electrophysiology, we identified the dorsal presubiculum (dPreS), the retrosplenial cortex (RSC) and the anterior thalamic nuclei (ATN) as part of a novel thalamo-cortical circuit involving the limbic TRN in mice. The dPreS, RSC and ATN are three key structures for spatial navigation. dPreS/RSC excitatory glutamatergic synapses formed on TRN and ATN are part of a feedforward circuit through which TRN-mediated inhibition generates large burst-mediated inhibitory synaptic currents. The PreS/RSC afferents to the TRN showed driver-like characteristics, which is unprecedented for corticoreticular synapses and expands the scope of the TRN heterogeneity to the nature of its synaptic afferents. We further investigated the role of the limbic TRN in the control of head-direction neurons that were previously described to be located in the anterodorsal thalamus. The width of the tuning curve of head-direction neurons in the thalamus was broadened upon chemogenetic silencing of the TRN, revealing a novel form of internal sensory gating by the TRN. About half of the head-direction neurons showed action potential discharge patterns consistent with feedforward inhibitory responses upon light activation of dPreS/RSC. These data suggest that the limbic TRN sharpens the tuning of thalamic head-direction neurons under dPreS/RSC control. Finally, we investigated the potential function of the limbic TRN in the hidden version of the Morris watermaze. We discovered that chemogenetic silencing of the limbic TRN biased the search patterns towards allocentric strategies and generated perseverance to previously learned escape positions, suggesting an impairment of the egocentric system in which the head-direction system plays a critical role. In study 2, we combined opto-tagging of TRN sectors with in vitro electrophysiological recordings and discovered that the limbic TRN neurons produced less repetitive burst firing than their sensory counterpart. The burst discharge of sensory TRN neurons is known to generate sleep spindles that propagate to the cortex, that are a marker of sleep quality and that correlate with memory consolidation. Consistently, local field potential recordings in the prefrontal cortex that is related to the less bursty limbic TRN revealed smaller amplitude and slower sleep spindles compared to sensory ones, making the heterogeneity of the TRN a critical player in local sleep rhythms. This thesis summarizes elements supporting the heterogeneity of the TRN, in particular between the sensory and the limbic TRN. It also provides a novel function for the limbic TRN in the spatial navigation system

Clinical evaluation of different treatment strategies for motor recovery in poststroke rehabilitation during the first 90 days

Background: Motor recovery after stroke is based on neuronal plasticity and the structural reorganization of the brain. Questions are debated about the proper moment to start rehabilitation in the acute period of stroke, the significance of rehabilitation interventions during the so-called “plastic window”, and the advantages of modern and traditional programs. The aims of this study were to evaluate the role of different rehabilitation strategies and their combinations for motor recovery and the impact on functional disability by way of neurological and functional outcomes 3 months after ischemic stroke. Methods: We used three rehabilitation approaches: early rehabilitation from the first day of stroke (Phase I), traditional exercise programs (Phase II), and an author’s new method of biofeedback rehabilitation using motion sensors and augmented reality (AR) rehabilitation (Phase III). Clinical and functional outcomes were measured on the 90th day after stroke. We developed algorithms for quantifying the quality of movements during the execution of tasks in the motor domains of the AR rehabilitation program. Results: Phase I of rehabilitation led to an improvement in functional independence, and the recovery of motor functions of the extremities with an absence of mortality and clinical deterioration. AR rehabilitation led to significant improvement both with respect to clinical and functional scores on scales and to variables reflecting the quality of movements. Patients who were actively treated during Phases II and III achieved the same final level of motor recovery and functional outcomes as that of participants who had only received AR rehabilitation during Phase III. Patients who underwent outpatient observation after Phase I showed a deficit of spontaneous motor recovery on the 90th day after stroke. Conclusions: Early rehabilitation was successful but was not enough; rehabilitation programs should be carried out throughout the entire “sensitive period” of poststroke plasticity. The newly developed AR biofeedback motion training is effective and safe as a separate rehabilitation method in the early recovery period of moderately severe, hemiparalytic, and ischemic stroke. These two rehabilitation approaches must be applied together or after each other, not instead of each other, as shown in clinical practice

Novel digital biomarkers for frontotemporal dementia

Frontotemporal dementia (FTD) is a heterogenous neurodegenerative disease and is caused by an autosomal dominant mutation in around one third of cases. This pattern of inheritance enables FTD to be studied in the presymptomatic phase, where individuals carry the genetic mutation but have yet to develop symptoms. There are currently no approved treatments for FTD, although clinical trials aiming to target interventions at the earliest disease stage, are underway. There is an urgent need for biomarkers that can reliably detect and monitor the progression of disease in the presymptomatic period, though there are a distinct lack of sensitive cognitive measures. This thesis aims to establish the validity and sensitivity of a set of digital biomarkers that can be used to measure cognitive function in FTD. I begin this thesis by describing the Ignite computerised cognitive assessment, developing normative properties for the tests through a remote data collection study in over 2,000 healthy controls. I build upon this validation by establishing the concurrent validity of Ignite with gold-standard pen and paper tasks, the test-retest reliability upon repeated administration, and demonstrate the tests are sensitive to presymptomatic impairment across several cognitive domains. I also describe a novel portable eye tracking experiment that can be completed outside of the lab, first highlighting the validity of the tests as measures of cognitive function and demonstrating their sensitivity in detecting early changes in social cognition in the presymptomatic period. Finally, I investigate a smartphone app that passively monitors human-device interactions to generate digital biomarkers of cognitive function. I establish the acceptability of the app in the general population before demonstrating the measures produced can detect differences in keyboard interactions in presymptomatic FTD mutation carriers. This work provides evidence that biomarkers generated from different digital devices are valid and sensitive measures of cognitive impairment in FTD. Therefore, digital biomarkers could replace outdated pen and paper tasks and be used as outcome measures in clinical trials

Assessment of executive functions in adults: a systematic review and empirical investigation

Abstract available at each chapter

THE IMPACT OF STUDENT DIVERSITY ON COMMUNITY COLLEGE GRADUATION RATES IN OKLAHOMA: WHAT CAN BE LEARNED USING STATE REGENTS DATA?

The United States federal government requires postsecondary schools, including community colleges, to calculate student completion rates and make them public information, which they do through the Integrated Postsecondary Education Data System (IPEDS). Stakeholders are keenly interested in completion rates as a measure of community college quality. Community colleges’ mission compels them to admit nearly every student desiring an opportunity to earn a higher education credential. This policy results in great diversity among students in their academic preparedness and their propensity to complete a college program. Using discrete student records from Oklahoma’s public two-year colleges, this research project seeks to determine how much of the difference in completion rates is attributable to diversity in the background of admitted students