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Advances in soft materials, miniaturized electronics, sensors, stimulators, radios, and battery-free power supplies are resulting in a new generation of fully implantable organ interfaces that leverage volumetric reduction and soft mechanics by eliminating electrochemical power storage. This device class offers the ability to provide high-fidelity readouts of physiological processes, enables stimulation, and allows control over organs to realize new therapeutic and diagnostic paradigms. Driven by seamless integration with connected infrastructure, these devices enable personalized digital medicine. Key to advances are carefully designed material, electrophysical, electrochemical, and electromagnetic systems that form implantables with mechanical properties closely matched to the target organ to deliver functionality that supports high-fidelity sensors and stimulators. The elimination of electrochemical power supplies enables control over device operation, anywhere from acute, to lifetimes matching the target subject with physical dimensions that supports imperceptible operation. This review provides a comprehensive overview of the basic building blocks of battery-free organ interfaces and related topics such as implantation, delivery, sterilization, and user acceptance. State of the art examples categorized by organ system and an outlook of interconnection and advanced strategies for computation leveraging the consistent power influx to elevate functionality of this device class over current battery-powered strategies is highlighted.
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Suministros de Energía Eléctrica , Tecnología Inalámbrica , Prótesis e Implantes , ElectrónicaRESUMEN
Remote patient monitoring is a critical component of digital medicine, and the COVID-19 pandemic has further highlighted its importance. Wearable sensors aimed at noninvasive extraction and transmission of high-fidelity physiological data provide an avenue toward at-home diagnostics and therapeutics; however, the infrastructure requirements for such devices limit their use to areas with well-established connectivity. This accentuates the socioeconomic and geopolitical gap in digital health technology and points toward a need to provide access in areas that have limited resources. Low-power wide area network (LPWAN) protocols, such as LoRa, may provide an avenue toward connectivity in these settings; however, there has been limited work on realizing wearable devices with this functionality because of power and electromagnetic constraints. In this work, we introduce wearables with electromagnetic, electronic, and mechanical features provided by a biosymbiotic platform to realize high-fidelity biosignals transmission of 15 miles without the need for satellite infrastructure. The platform implements wireless power transfer for interaction-free recharging, enabling long-term and uninterrupted use over weeks without the need for the user to interact with the devices. This work presents demonstration of a continuously wearable device with this long-range capability that has the potential to serve resource-constrained and remote areas, providing equitable access to digital health.
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Pandemias , Dispositivos Electrónicos Vestibles , Humanos , Monitoreo Fisiológico , ElectrónicaRESUMEN
The Autobiographical Interview, a method for evaluating detailed memory of real-world events, reliably detects differences in episodic specificity at retrieval between young and older adults in the laboratory. Whether this age-associated reduction in episodic specificity for autobiographical event retrieval is present outside of the laboratory remains poorly understood. We used a videoconference format to administer the Autobiographical Interview to cognitively unimpaired older adults (N = 49, M = 69.5, SD = 5.94) and young adults (N = 54, M = 22.5, SD = 4.19) who were in their homes at the time of retrieval. Relative to young adults, older adults showed reduced episodic specificity in their home environment, as reflected by fewer episodic or "internal" details (t (101) = 3.23, p = 0.009) and more "external" details (i.e., semantic, language-based details) (t (101) = 3.60, p = 0.003). These findings, along with detail subtype profiles in the narratives, bolster the ecological validity of the Autobiographical Interview and add promise to the use of virtual cognitive testing to improve the accessibility, participant diversity, scalability, and ecological validity of memory research.
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Memoria Episódica , Recuerdo Mental , Humanos , Masculino , Femenino , Anciano , Recuerdo Mental/fisiología , Adulto Joven , Adulto , Persona de Mediana Edad , Envejecimiento/fisiología , Envejecimiento/psicología , Narración , Factores de Edad , Adolescente , Comunicación por VideoconferenciaRESUMEN
This study used ratings and event-related potentials (ERPs) to compare the mechanisms through which verbal irony and cognitive reappraisal mitigate negative emotion. Verbal irony is when the literal meaning of words contrasts with their intended meaning. Cognitive reappraisal is when we reconsider emotional stimuli to make them less intense. Our hypothesis was that cognitive reappraisal is a potential mechanism through which irony reduces negative emotion. Participants viewed mildly negative pictures first, then read an ironic or literal statement about it in one block, and used cognitive reappraisal of or attending to the picture in the other block. Participants then viewed the picture for a second time, before rating how negative they felt. Behaviourally, irony reduced negative feelings more than literal statements, and reappraisal reduced negative feelings more than attending, with a larger reduction from reappraisal than from irony. In ERPs, irony elicited a prolonged N400 compared to literal, indexing an initial contrast between picture and word affect and sustained processing of their combination. Cognitive reappraisal elicited a larger late positivity compared to attending at the instruction screen. No differences were found during second picture presentation. These findings suggest that irony and cognitive reappraisal can reduce negative affect in different ways.
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Clinical theories of adaptation in bereavement highlight a need for flexible shifting between mental states. However, prolonged motivational salience of the deceased partner may be a complicating factor, particularly when coupled with perseverative thinking about the loss. We investigated how prolonged grief symptoms might relate to resting state functional brain network connectivity in a sample of older adults (n = 38) who experienced the death of a partner 6-36 months prior, and whether intranasal oxytocin (as a neuropeptide involved in pair-bonding) had differential effects in participants with higher prolonged grief symptoms. Higher scores on the Inventory of Complicated Grief (ICG) were associated with lower anticorrelation (i.e., higher functional connectivity) between the defaultretrosplenial - cingulo-operculardACC network pair. Intranasal oxytocin increased functional connectivity in the same defaultretrosplenial - cingulo-operculardACC circuit but ICG scores did not moderate effects of oxytocin, contrary to our prediction. Higher ICG scores were associated with longer dwell time in a dynamic functional connectivity state featuring positive correlations among default, frontoparietal, and cingulo-opercular networks, across both placebo and oxytocin sessions. Dwell time was not significantly affected by oxytocin, and higher prolonged grief symptoms were not associated with more variability in dynamic functional connectivity states over the scan. Results offer preliminary evidence that prolonged grief symptoms in older adults are associated with patterns of static and time-varying functional network connectivity and may specifically involve a default network-salience-related circuit that is sensitive to oxytocin.
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Aflicción , Oxitocina , Anciano , Humanos , Encéfalo/diagnóstico por imagen , Cognición , Pesar , Imagen por Resonancia Magnética , Oxitocina/farmacologíaRESUMEN
Many individuals spend a significant amount of their time "mind-wandering". Mind-wandering often includes spontaneous, nonintentional thought, and a neural correlate of this kind of thought is the default mode network (DMN). Thoughts during mind-wandering can have positive or negative valence, but only little is known about the neural correlates of positive or negative thoughts. We used resting-state functional magnetic resonance imaging (fMRI) and music to evoke mind-wandering in n = 33 participants, with positive-sounding music eliciting thoughts with more positive valence and negative-sounding music eliciting thoughts with more negative valence. Applying purely data-driven analysis methods, we show that medial orbitofrontal cortex (mOFC, part of the ventromedial prefrontal cortex) and the posterior cingulate sulcus (likely area 23c of the posterior cingulate cortex), two sub-regions of the DMN, modulate the valence of thought-contents during mind-wandering. In addition, across two independent experiments, we observed that the posterior cingulate sulcus, a region involved in pain, shows valence-specific functional connectivity with core regions of the brain's putative pain network. Our results suggest that two DMN regions (mOFC and posterior cingulate sulcus) support the formation of negative spontaneous, nonintentional thoughts, and that the interplay between these structures with regions of the putative pain network forms a neural mechanism by which thoughts can become painful.
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Percepción Auditiva/fisiología , Conectoma , Red en Modo Predeterminado/fisiología , Emociones/fisiología , Giro del Cíngulo/fisiología , Música , Red Nerviosa/fisiología , Dolor/fisiopatología , Corteza Prefrontal/fisiología , Pensamiento/fisiología , Adulto , Red en Modo Predeterminado/diagnóstico por imagen , Femenino , Giro del Cíngulo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , Dolor/diagnóstico por imagen , Corteza Prefrontal/diagnóstico por imagen , Adulto JovenRESUMEN
Connectivity of the brain at rest can reflect individual differences and impact behavioral outcomes, including memory. The present study investigated how culture influences functional connectivity with regions of the medial temporal lobe. In this study, 46 Americans and 59 East Asians completed a resting state scan after encoding pictures of objects. To investigate cross-cultural differences in resting state functional connectivity, left parahippocampal gyrus (anterior and posterior regions) and left hippocampus were selected as seed regions. These regions were selected, because they were previously implicated in a study of cultural differences during the successful encoding of detailed memories. Results revealed that left posterior parahippocampal gyrus had stronger connectivity with temporo-occipital regions for East Asians compared with Americans and stronger connectivity with parieto-occipital regions for Americans compared with East Asians. Left anterior parahippocampal gyrus had stronger connectivity with temporal regions for East Asians than Americans and stronger connectivity with frontal regions for Americans than East Asians. Although connectivity did not relate to memory performance, patterns did relate to cultural values. The degree of independent self-construal and subjective value of tradition were associated with functional connectivity involving left anterior parahippocampal gyrus. Findings are discussed in terms of potential cultural differences in memory consolidation or more general trait or state-based processes, such as holistic versus analytic processing.
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Imagen por Resonancia Magnética , Lóbulo Temporal , Humanos , Imagen por Resonancia Magnética/métodos , Lóbulo Temporal/diagnóstico por imagen , Mapeo Encefálico/métodos , Encéfalo/diagnóstico por imagen , HipocampoRESUMEN
COVID-19 has led to mental health adversities worldwide. The current study examined whether daily practice of brief mindfulness training has a beneficial impact on affective well-being, and mitigates the negative impact of exposure to COVID-19 news during the pandemic. Participants were randomly assigned into a mindfulness training (MT) group or a waitlist control (WC) group. Participants in the MT group practiced guided mindfulness meditation for a minimum of 10 min each day for 10 days. Both groups completed questionnaires assessing well-being at baseline and after the 10-day period. We also included four ecological momentary assessments (EMA) interspersed throughout the day to measure fine-grained affective states and recent exposure to COVID-19-related news, which has been linked to negative affect. We observed an increase in positive affect in the MT group compared to the WC group in the post-training assessment. However, no group differences emerged in the other three post-training affective measures of negative affect, anxiety and depression. EMA revealed that the MT group also showed more positive affective valence than the WC group across the 10 days. Notably, the WC group reported more negative affective valence following COVID-19 news exposure, whereas the MT group was not impacted. Taken together, our study indicates brief sessions of guided mindfulness meditation during COVID-19 may boost positive affect and serve as a protective buffer against the negative impact of exposure to COVID-19-related news on affective well-being. These findings highlight the utility of mindfulness meditation as an accessible and cost-effective technique to elevate positive affect amidst the COVID-19 pandemic.
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COVID-19 , Meditación , Atención Plena , Ansiedad/terapia , COVID-19/epidemiología , Humanos , Meditación/psicología , Atención Plena/métodos , PandemiasRESUMEN
Mind wandering represents the human capacity for internally focused thought and relies upon the brain's default network and its interactions with attentional networks. Studies have characterized mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This paper used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioral variant frontotemporal dementia [(bvFTD); n = 35] and Alzheimer's disease [(AD); n = 24], compared with older controls (n = 37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks and well-defined impairments in cognitive processes that support mind wandering. Relative to the controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift toward stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with gray matter integrity in the hippocampus/parahippocampus, striatum, insula, and orbitofrontal cortex. Resting-state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders and structural and functional integrity of the default and frontoparietal networks. This paper highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders and validates current models of mind wandering in a clinical population.
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Enfermedad de Alzheimer/fisiopatología , Atrofia/fisiopatología , Encefalopatías/fisiopatología , Hipocampo/fisiopatología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico por imagen , Atrofia/diagnóstico por imagen , Atención/fisiología , Encefalopatías/diagnóstico por imagen , Mapeo Encefálico , Femenino , Demencia Frontotemporal/diagnóstico por imagen , Demencia Frontotemporal/fisiopatología , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/fisiopatología , Hipocampo/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Degeneración Nerviosa/diagnóstico por imagen , Degeneración Nerviosa/fisiopatología , Red Nerviosa/fisiología , Vías Nerviosas/fisiología , Descanso/fisiología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiopatologíaRESUMEN
Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering - how mental states change over time - have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.
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Atención/fisiología , Encéfalo/fisiología , Fantasía , Trastornos Mentales/fisiopatología , Red Nerviosa/fisiología , Pensamiento/fisiología , Animales , Encéfalo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Trastornos Mentales/diagnóstico por imagen , Trastornos Mentales/psicología , Red Nerviosa/diagnóstico por imagenRESUMEN
Episodic autobiographical memories (EAMs) can come to mind through two retrieval routes, one direct (i.e., an EAM is retrieved almost instantaneously) and the other generative (i.e., by using autobiographical/general knowledge to cue an EAM). It is well established that normal cognitive aging is associated with a reduction in the retrieval of EAMs, but the contributions of direct or generative reconstruction to the age-related shift toward general memories remain unknown. Prior studies also have not clarified whether similar cognitive mechanisms facilitate the ability to successfully reconstruct EAMs and elaborate them in event-specific detail. To address these gaps in knowledge, young and older participants were asked to reconstruct EAMs using a "think-aloud" paradigm and then describe in detail a subset of retrieved memories. An adapted scoring procedure was implemented to categorize memories accessed during reconstruction, and the Autobiographical Interview (AI) scoring procedure was utilized for elaboration scoring. Results indicated that in comparison with young adults, older adults not only engaged in direct retrieval less often than young adults but they also more often ended generative retrieval at general events instead of EAMs. The ability to elaborate EAMs with internal details was positively associated with the ability to use generative retrieval to reconstruct EAMs in both young and older adults, but there was no relationship between internal detail elaboration and direct retrieval in either age group. Taken together, these results indicate age-related differences in direct and generative retrieval contribute to overgeneral autobiographical memory and they support a connection between generative retrieval and elaboration.
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Memoria Episódica , Anciano , Humanos , Recuerdo MentalRESUMEN
The frontoparietal control network (FPCN) plays a central role in executive control. It has been predominantly viewed as a unitary domain general system. Here, we examined patterns of FPCN functional connectivity (FC) across multiple conditions of varying cognitive demands, to test for FPCN heterogeneity. We identified two distinct subsystems within the FPCN based on hierarchical clustering and machine learning classification analyses of within-FPCN FC patterns. These two FPCN subsystems exhibited distinct patterns of FC with the default network (DN) and the dorsal attention network (DAN). FPCNA exhibited stronger connectivity with the DN than the DAN, whereas FPCNB exhibited the opposite pattern. This twofold FPCN differentiation was observed across four independent datasets, across nine different conditions (rest and eight tasks), at the level of individual-participant data, as well as in meta-analytic coactivation patterns. Notably, the extent of FPCN differentiation varied across conditions, suggesting flexible adaptation to task demands. Finally, we used meta-analytic tools to identify several functional domains associated with the DN and DAN that differentially predict activation in the FPCN subsystems. These findings reveal a flexible and heterogeneous FPCN organization that may in part emerge from separable DN and DAN processing streams. We propose that FPCNA may be preferentially involved in the regulation of introspective processes, whereas FPCNB may be preferentially involved in the regulation of visuospatial perceptual attention.
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Función Ejecutiva , Lóbulo Frontal/fisiología , Adulto , Atención , Mapeo Encefálico , Femenino , Lóbulo Frontal/química , Humanos , Imagen por Resonancia Magnética , Masculino , Redes Neurales de la Computación , Adulto JovenRESUMEN
Although task-unrelated thinking (often conceptualised as "mind-wandering") has been increasingly investigated in recent years, the content and correlates of everyday off-task thought in clinical disorders, particularly anxiety disorders, remain poorly understood. We aimed to address this gap by using ecological momentary assessment to assess off-task and on-task thoughts in adults with social anxiety disorder (SAD) and demographically matched controls. Findings showed that individuals with SAD more frequently engaged in internally oriented off-task thinking than healthy controls, but not externally oriented off-task thinking. Compared to thoughts focused on the task at hand, adults with SAD rated their internal off-task thoughts as less controllable, more self-focused, and as associated with worse mood than controls. However, when the SAD group was focused on the task at hand, group differences disappeared. Daily findings were paralleled by higher scores in SAD on a trait measure of unintentional, but not intentional, mind-wandering. In sum, the content and mood correlate of internally oriented off-task thoughts depended on the presence of clinical anxiety. In addition, focusing on the task at hand normalised thought content and mood in SAD, highlighting a window for intervention.
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Fobia Social , Adulto , Cognición , Evaluación Ecológica Momentánea , HumanosRESUMEN
BACKGROUND: Sexually transmitted infections (STIs) cause a major public health problem that affect both men and women in developing and developed countries. The aim of the study was to estimate the prevalence of 11 STIs among women who voluntarily participated in the study, while seeking gynecological checkup. The existence of an association between the presence of pathogens and symptoms and various sociodemographic risk factors was assessed. METHODS: A total of 505 vaginal and cervical specimens were collected from women above 18 years of age, with or without symptoms related to gynecological infections. Nucleic acid was extracted and samples were tested by real-time PCR for the following pathogens: Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Ureaplasma urealyticum, Urealplasma parvum, Trichomonas vaginalis, Mycoplasma hominis, Mycoplasma girerdii, Gardnerella vaginalis, Candida albicans and Human Papillomavirus (HPV). Positive HPV samples underwent genotyping using a microarray system. RESULTS: Of the 505 samples, 312 (62%) were screened positive for at least one pathogen. Of these, 36% were positive for Gardnerella vaginalis, 35% for Ureaplasma parvum, 8% for Candida albicans, 6.7% for HPV, 4.6% for Ureaplasma urealyticum, 3.6% for Mycoplasma hominis, 2% for Trichomonas vaginalis, 0.8% for Chlamydia trachomatis, 0.4% for Mycoplasma girerdii, 0.2% for Mycoplasma genitalium and 0.2% for Neisseria gonorrhoeae. Lack of symptoms was reported in 187 women (37%), among whom 61% were infected. Thirty-four samples were HPV positive, with 17 high risk HPV genotypes (HR-HPV); the highest rates being recorded for types 16 (38%), 18 (21%) and 51 (18%). Out of the 34 HPV positives, 29 participants had HR-HPV. Association with various risk factors were reported. CONCLUSIONS: This is the first study that presents data about the presence of STIs among women in Lebanon and the MENA region by simultaneous detection of 11 pathogens. In the absence of systematic STI surveillance in Lebanon, concurrent screening for HPV and PAP smear is warranted.
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Enfermedades de Transmisión Sexual/epidemiología , Adulto , Cuello del Útero/microbiología , Cuello del Útero/parasitología , Cuello del Útero/virología , Chlamydia trachomatis/genética , Chlamydia trachomatis/aislamiento & purificación , Estudios Transversales , Femenino , Gardnerella vaginalis/genética , Gardnerella vaginalis/aislamiento & purificación , Humanos , Líbano/epidemiología , Masculino , Epidemiología Molecular , Infecciones por Mycoplasma/epidemiología , Mycoplasma genitalium/genética , Mycoplasma genitalium/aislamiento & purificación , Mycoplasma hominis/genética , Mycoplasma hominis/aislamiento & purificación , Neisseria gonorrhoeae/genética , Neisseria gonorrhoeae/aislamiento & purificación , Papillomaviridae/genética , Papillomaviridae/aislamiento & purificación , Factores de Riesgo , Enfermedades de Transmisión Sexual/microbiología , Enfermedades de Transmisión Sexual/parasitología , Enfermedades de Transmisión Sexual/virología , Trichomonas vaginalis/genética , Trichomonas vaginalis/aislamiento & purificación , Ureaplasma/genética , Ureaplasma/aislamiento & purificación , Vagina/microbiología , Vagina/parasitología , Vagina/virología , Frotis Vaginal , Adulto JovenRESUMEN
In young adults, valence not only alters the degree to which future events are imagined in rich episodic detail, but also how memorable these events are later on. For older adults, how valence influences episodic detail generation while imagining future events, or recalling these details at another time, remains unclear. We investigated the effect of valence on the specificity and memorability of episodic future thinking (EFT) in young and older adults. Among young and older adults, negative EFT was accompanied by less episodic detail generation relative to positive and neutral EFT. A similar reduction in episodic specificity for negative EFT was found two days later when participants recalled their previously imagined events. Notably, while older adults generated less episodically specific future thoughts relative to young adults, age did not influence the effect of valence on episodic detail generation at imagination or recollection.
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Memoria Episódica , Anciano , Emociones , Predicción , Humanos , Imaginación , Recuerdo Mental , Adulto JovenRESUMEN
Increasing evidence suggests that executive functions (EFs) - a set of general-purpose control processes that regulate thoughts and behaviors - are relevant for creativity. However, EF is not a unitary process, and it remains unclear which specific EFs are involved. The present study examined the association between the three EFs, both uniquely (EF-Specific) and together (Common EF), and three measures of creativity. Participants (Nâ¯=â¯47) completed a divergent thinking test, and self-reported their real-life creative accomplishments. A subset of participants indicated their involvement in the artistic or information technology (IT) professions. Results indicated that fluency (but not originality) of divergent thinking was uniquely predicted by working memory Updating. Better response Inhibition predicted higher number of real-world artistic creative achievements. Involvement in the artistic (versus IT) professions was associated with better Common EF, and with enhanced mental set Shifting abilities. Results demonstrate that different EFs predict creativity depending on its operational definition.
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Creatividad , Función Ejecutiva/fisiología , Inhibición Psicológica , Inteligencia/fisiología , Memoria a Corto Plazo/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ocupaciones , Adulto JovenRESUMEN
An intriguing aspect of human cognition is the unique capacity to mentally retreat from our immediate surroundings to consider perspectives distinct from the here and now. Despite increasing interest in this phenomenon, relatively little is known regarding age-related changes in off-task, self-generated thought (often referred to as "mind-wandering"), particularly under conditions of low cognitive demand. While a number of studies have investigated the temporal orientation of mind-wandering with increasing age, findings have been largely inconsistent. Here, we explored the frequency, temporal focus, and self-referential/social content of spontaneous task-unrelated, perceptually decoupled thought in 30 young and 33 healthy older adults using the Shape Expectations task, a validated experimental paradigm in which discrete facets of inner mentation are quantified along a conceptual continuum using open-ended report. Participants also completed the daydreaming subscale of the Imaginal Process Inventory (IPI) as a trait measure of mind-wandering propensity. Significant group differences emerged on the Shape Expectations task, with reduced instances of mind-wandering in the context of elevated task-related thoughts relative to younger adults. In terms of temporal focus, a preponderance of present/atemporal off-task thoughts was evident irrespective of group; however, significantly higher levels of future-oriented thoughts were provided by younger adults, contrasting with significantly higher instances of retrospection in the older group. In addition, older adults displayed significantly fewer incidences of self-referential cognition relative to their younger counterparts. Our findings indicate a distinct attenuation of off-task, self-generated thought processes with increasing age, with evidence for a shift in temporal focus and self-referential quality, during periods of low cognitive demand.
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Envejecimiento/fisiología , Atención/fisiología , Cognición/fisiología , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Australia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Anticorrelation between the default network (DN) and dorsal attention network (DAN) is thought to be an intrinsic aspect of functional brain organization reflecting competing functions. However, the effect size of functional connectivity (FC) between the DN and DAN has yet to be established. Furthermore, the stability of anticorrelations across distinct DN subsystems, different contexts, and time, remains unexplored. In study 1 we summarize effect sizes of DN-DAN FC from 20 studies, and in study 2 we probe the variability of DN-DAN interactions across six different cognitive states in a new data set. We show that: (i) the DN and DAN have an independent rather than anticorrelated relationship when global signal regression is not used (median effect size across studies: r=-.06; 95% CI: -.15 to .08); (ii) the DAN exhibits weak negative FC with the DN Core subsystem but is uncorrelated with the dorsomedial prefrontal and medial temporal lobe subsystems; (iii) DN-DAN interactions vary significantly across different cognitive states; (iv) DN-DAN FC fluctuates across time between periods of anticorrelation and periods of positive correlation; and (v) changes across time in the strength of DN-DAN coupling are coordinated with interactions involving the frontoparietal control network (FPCN). Overall, the observed weak effect sizes related to DN-DAN anticorrelation suggest the need to re-conceptualize the nature of interactions between these networks. Furthermore, our findings demonstrate that DN-DAN interactions are not stable, but rather, exhibit substantial variability across time and context, and are coordinated with broader network dynamics involving the FPCN.
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Atención/fisiología , Corteza Cerebral/fisiología , Conectoma/métodos , Red Nerviosa/fisiología , Pensamiento/fisiología , Percepción Visual/fisiología , Adulto , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Imaginación/fisiología , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/diagnóstico por imagen , DescansoRESUMEN
The neural basis and cognitive functions of various spontaneous thought processes, particularly mind-wandering, are increasingly being investigated. Although strong links have been drawn between the occurrence of spontaneous thought processes and activation in brain regions comprising the default mode network (DMN), spontaneous thought also appears to recruit other, non-DMN regions just as consistently. Here we present the first quantitative meta-analysis of neuroimaging studies of spontaneous thought and mind-wandering in order to address the question of their neural correlates. Examining 24 functional neuroimaging studies of spontaneous thought processes, we conducted a meta-analysis using activation likelihood estimation (ALE). A number of key DMN areas showed consistent recruitment across studies, including medial prefrontal cortex, posterior cingulate cortex, medial temporal lobe, and bilateral inferior parietal lobule. Numerous non-DMN regions, however, were also consistently recruited, including rostrolateral prefrontal cortex, dorsal anterior cingulate cortex, insula, temporopolar cortex, secondary somatosensory cortex, and lingual gyrus. These meta-analytic results indicate that DMN activation alone is insufficient to adequately capture the neural basis of spontaneous thought; frontoparietal control network areas, and other non-DMN regions, appear to be equally central. We conclude that further progress in the cognitive and clinical neuroscience of spontaneous thought will therefore require a re-balancing of our view of the contributions of various regions and networks throughout the brain, and beyond the DMN.
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Encéfalo/fisiología , Función Ejecutiva/fisiología , Neuroimagen Funcional , Red Nerviosa/fisiología , Pensamiento/fisiología , HumanosRESUMEN
The goal of the present study was to examine relationships between individual differences in resting state functional connectivity as ascertained by fMRI (rs-fcMRI) and performance on tasks of executive function (EF), broadly defined as the ability to regulate thoughts and actions. Unlike most previous research that focused on the relationship between rs-fcMRI and a single behavioral measure of EF, in the current study we examined the relationship of rs-fcMRI with individual differences in subcomponents of EF. Ninety-one adults completed a resting state fMRI scan and three separate EF tasks outside the magnet: inhibition of prepotent responses, task set shifting, and working memory updating. From these three measures, we derived estimates of common aspects of EF, as well as abilities specific to working memory updating and task shifting. Using Independent Components Analysis (ICA), we identified across the group of participants several networks of regions (Resting State Networks, RSNs) with temporally correlated time courses. We then used dual regression to explore how these RSNs covaried with individual differences in EF. Dual regression revealed that increased higher common EF was associated with connectivity of a) frontal pole with an attentional RSN, and b) Crus I and II of the cerebellum with the right frontoparietal RSN. Moreover, higher shifting-specific abilities were associated with increased connectivity of angular gyrus with a ventral attention RSN. The results of the current study suggest that the organization of the brain at rest may have important implications for individual differences in EF, and that individuals higher in EF may have expanded resting state networks as compared to individuals with lower EF.