Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Nurs Res ; 71(4): 303-312, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35302958

RESUMEN

BACKGROUND: Uncontrolled blood pressure (BP) rates are persistently high among African Americans with hypertension. Although self-management is critical to controlling BP, little is known about the brain-behavior connections underlying the processing of health information and the performance of self-management activities. OBJECTIVES: In this pilot study, we explored the associations among neural processing of two types of health information and a set of self-management cognitive processes (self-efficacy, activation, decision-making, and hypertension knowledge) and behaviors (physical activity, dietary intake, and medication taking) and health status indicators (BP, health-related quality of life, anxiety, and depression). METHODS: Using a descriptive cross-sectional design, 16 African Americans with uncontrolled hypertension (mean age = 57.5 years, 68.8% women) underwent functional magnetic resonance imaging to assess activation of two neural networks, the task-positive network and the default mode network, and a region in the ventromedial prefrontal cortex associated with emotion-focused and analytic-focused health information. Participants completed self-reports and clinical assessments of self-management processes, behaviors, and health status indicators. RESULTS: Our hypothesis that neural processing associated with different types of health information would correlate with self-management cognitive processes and behaviors and health status indicators was only partially supported. Home diastolic BP was positively associated with ventromedial prefrontal cortex activation ( r = .536, p = .09); no other associations were found among the neural markers and self-management or health status variables. Expected relationships were found among the self-management processes and behaviors and health status indicators. DISCUSSION: To advance our understanding of the neural processes underlying health information processing and chronic illness self-management, future studies are needed that use larger samples with more heterogeneous populations and additional neuroimaging techniques.


Asunto(s)
Hipertensión , Automanejo , Negro o Afroamericano/psicología , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Calidad de Vida , Automanejo/psicología
2.
Nurs Res ; 69(5): 331-338, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32496401

RESUMEN

BACKGROUND: Racial discrimination is one of many barriers experienced by African Americans that interfere with health self-care management. Discrimination stress may decrease the tendency for individuals to resonate with the social-emotional appeals embedded in persuasive health information, which are known to play a key role in producing behavior change. Understanding the neurobehavioral underpinnings of discrimination stress experienced by African Americans may help reduce or resolve this important health disparity. OBJECTIVES: The purpose of this secondary analysis was to examine the association between neural processing of health information and perceived discrimination. In particular, we focused on three previously identified measures of health information processing associated with distinct brain areas: analytic network, empathy network, and the ventral medial prefrontal cortex. METHODS: Data were obtained from 24 African Americans enrolled in a blood pressure self-care management study. Participants completed surveys assessing racial discrimination and global stress, as well as a 40-minute functional magnetic resonance imaging protocol used to measure neural activation associated with processing different types of health information. RESULTS: Discrimination stress was significantly related to reduced activation of the empathy network and ventral medial prefrontal cortex, whereas there was a nonsignificant positive relationship with activity in the analytic network. DISCUSSION: Uncovering associations between patient experiences, such as racial discrimination, and their neural processing of health information can lead to the development of tailored health messages and self-care management interventions. This may inform strategies to close the gap on health outcomes.


Asunto(s)
Negro o Afroamericano/psicología , Racismo/psicología , Adulto , Negro o Afroamericano/etnología , Anciano , Enfermedad Crítica/epidemiología , Enfermedad Crítica/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicometría/instrumentación , Psicometría/métodos , Racismo/etnología , Encuestas y Cuestionarios
3.
Nurs Res ; 68(2): 127-134, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30540702

RESUMEN

BACKGROUND: Although many of the proposed mediating processes of self-management interventions are operationally defined as cognitive processes (e.g., acquiring and using information, self-efficacy, motivation, and decision-making), little is known about their underlying brain mechanisms. Brain biomarkers of how people process health information may be an important characteristic on which to individualize health information to optimize self-management of chronic conditions. OBJECTIVES: We describe a program of research addressing the identification of brain biomarkers that differentially predict responses to two types of health information (analytic focused and emotion focused) designed to support optimal self-management of chronic conditions. METHODS: We pooled data from two pilot studies (N = 52) that included functional magnetic resonance imaging during a specially designed, ecologically valid protocol to examine brain activation (task differentiation) associated with two large-scale neural networks-the Analytic Network and the Empathy Network-and the ventral medial prefrontal cortex while individuals responded to different types of health information (analytic and emotional). RESULTS: Findings indicate that analytic information and emotional information are processed differently in the brain, and the magnitude of this differentiation in response to type of information varies from person to person. Activation in the a priori regions identified in response to both analytic and emotion information was confirmed. The feasibility of obtaining brain imaging data from persons with chronic conditions also is demonstrated. DISCUSSION: An understanding of brain signatures related to information processing has potential to assist in the design of more individualized, effective self-management interventions.


Asunto(s)
Cognición/fisiología , Emociones/fisiología , Automanejo/psicología , Función Ejecutiva , Humanos , Imagen por Resonancia Magnética , Vías Nerviosas/fisiología
4.
J Relig Health ; 57(1): 157-190, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28601927

RESUMEN

Better understanding the psychological factors related to certainty in one's beliefs (i.e., dogmatism) has important consequences for both individuals and social groups. Generally, beliefs can find support from at least two different routes of information processing: social/moral considerations or analytic/empirical reasoning. Here, we investigate how these two psychological constructs relate to dogmatism in two groups of individuals who preferentially draw on the former or latter sort of information when forming beliefs about the world-religious and nonreligious individuals. Across two studies and their pooled analysis, we provide evidence that although dogmatism is negatively related to analytic reasoning in both groups of individuals, it shares a divergent relationship with measures of moral concern depending on whether one identifies as religious or not. Study 1 showed that increasing levels of dogmatism were positively related to prosocial intentions among the religious and negatively related to empathic concern among the nonreligious. Study 2 replicated and extended these results by showing that perspective taking is negatively related to dogmatism in both groups, an effect which is particularly robust among the nonreligious. Study 2 also showed that religious fundamentalism was positively related to measures of moral concern among the religious. Because the current studies used a content-neutral measure to assess dogmatic certainty in one's beliefs, they have the potential to inform practices for most effectively communicating with and persuading religious and nonreligious individuals to change maladaptive behavior, even when the mode of discourse is unrelated to religious belief.


Asunto(s)
Principios Morales , Prejuicio/psicología , Religión y Psicología , Religión , Pensamiento , Adulto , Cristianismo , Cognición/fisiología , Femenino , Humanos , Masculino , Teoría de la Mente/fisiología
5.
Neuroimage ; 79: 313-28, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-23657147

RESUMEN

The process of dehumanization, or thinking of others as less than human, is a phenomenon with significant societal implications. According to Haslam's (2006) model, two concepts of humanness derive from comparing humans with either animals or machines: individuals may be dehumanized by likening them to either animals or machines, or humanized by emphasizing differences from animals or machines. Recent work in cognitive neuroscience emphasizes understanding cognitive processes in terms of interactions between distributed cortical networks. It has been found that reasoning about internal mental states is associated with activation of the default mode network (DMN) and deactivation of the task positive network (TPN); whereas reasoning about mechanical processes produces the opposite pattern. We conducted two neuroimaging studies. The first examined the neural bases of dehumanization and its relation to these two brain networks, using images and voice-over social narratives which either implicitly contrasted or implicitly likened humans to either animals or machines. The second study addressed a discrepancy between findings from the first study and prior work on the neural correlates of dehumanization: using a design similar to prior work we examined neural responses to pictures of humans, animals and machines, presented without any social context. In both studies, human and humanizing conditions were associated with relatively high activity in the DMN and relatively low activity in the TPN. However, the non-human and dehumanizing conditions deviated in different ways: they demonstrated more marked changes either in the DMN or in the TPN. Notably, differences between the animal dehumanizing and humanizing conditions were most evident in regions associated with mechanistic reasoning, not in the mentalizing network. Conjunction analysis of contrasts from both paradigms revealed that only one region was consistently more active when participants saw human, a medial parietal region regarded as the central hub of the DMN. These findings provide a neural basis for Haslam's distinction between two types of dehumanization, and suggest that the DMN and TPN play opposing roles in creating a sense of moral concern.


Asunto(s)
Afecto/fisiología , Concienciación/fisiología , Encéfalo/fisiología , Deshumanización , Principios Morales , Red Nerviosa/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad
6.
Neuroimage ; 66: 385-401, 2013 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-23110882

RESUMEN

Two lines of evidence indicate that there exists a reciprocal inhibitory relationship between opposed brain networks. First, most attention-demanding cognitive tasks activate a stereotypical set of brain areas, known as the task-positive network and simultaneously deactivate a different set of brain regions, commonly referred to as the task negative or default mode network. Second, functional connectivity analyses show that these same opposed networks are anti-correlated in the resting state. We hypothesize that these reciprocally inhibitory effects reflect two incompatible cognitive modes, each of which may be directed towards understanding the external world. Thus, engaging one mode activates one set of regions and suppresses activity in the other. We test this hypothesis by identifying two types of problem-solving task which, on the basis of prior work, have been consistently associated with the task positive and task negative regions: tasks requiring social cognition, i.e., reasoning about the mental states of other persons, and tasks requiring physical cognition, i.e., reasoning about the causal/mechanical properties of inanimate objects. Social and mechanical reasoning tasks were presented to neurologically normal participants during fMRI. Each task type was presented using both text and video clips. Regardless of presentation modality, we observed clear evidence of reciprocal suppression: social tasks deactivated regions associated with mechanical reasoning and mechanical tasks deactivated regions associated with social reasoning. These findings are not explained by self-referential processes, task engagement, mental simulation, mental time travel or external vs. internal attention, all factors previously hypothesized to explain default mode network activity. Analyses of resting state data revealed a close match between the regions our tasks identified as reciprocally inhibitory and regions of maximal anti-correlation in the resting state. These results indicate the reciprocal inhibition is not attributable to constraints inherent in the tasks, but is neural in origin. Hence, there is a physiological constraint on our ability to simultaneously engage two distinct cognitive modes. Further work is needed to more precisely characterize these opposing cognitive domains.


Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Cognición/fisiología , Atención/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Descanso/fisiología , Adulto Joven
7.
Front Hum Neurosci ; 17: 1128209, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37600554

RESUMEN

Many coaching approaches aim to change behavior by increasing self-knowledge. However, self-knowledge can be difficult to achieve. One hypothesis (e.g., Jung, Rogers) is that self-knowledge is challenging because there is inherent conflict between different aspects of the self. This hypothesis is foundational to Boyatzis' intentional change theory (ICT). ICT holds that effective coaching requires deliberate sequencing of the client's exploration of different aspects of their self. Coaches initially encourage clients to focus exclusively on their Ideal self. The ICT approach differs from that advocated by most coaching organizations that suggest collaborative goal setting at the start of the coaching engagement, encouraging clients to focus on fixing performance deficits and problematic behaviors-aspects of the Real self. If there is conflict between thinking about Ideal and Real selves, then this strategy will be suboptimal. The hypothesis of attentional conflict therefore has significant implications for coaching practice. Previous findings establish a link between attention to Ideal vs. Real selves and global vs. local visual processing, respectively. This association alone does not imply conflict because, in naturalistic settings, global and local perceptual processes usually work in concert. However, certain stimuli such as Navon figures (letters made from many smaller letters, e.g., a large E made of small R's) create conflict due to incongruence between the global and local features. Does thinking about the self inherently generate conflict, like a Navon figure, or is it more akin to everyday perception? To answer this question the current study uses functional magnetic resonance imaging to examine the overlap in brain activity in young adults between two pairs of otherwise very dissimilar tasks: coaching interactions focused on Ideal vs. Real self; and attention to global vs. local features of Navon figures. Despite the ostensible absence of overlap in the psychological processes involved in these pairs of tasks, we find a remarkable degree of overlap in brain activity. This overlap was pronounced in higher (parietal and temporal) areas known to be involved in resolving attentional conflict. These findings provide compelling biological evidence for inherent conflict between thinking about Ideal and Real selves.

8.
Neuron ; 51(1): 135-47, 2006 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-16815338

RESUMEN

Functional magnetic resonance imaging (fMRI) was used while normal human volunteers engaged in simple detection and discrimination tasks, revealing separable modulations of early visual cortex associated with spatial attention and task structure. Both modulations occur even when there is no change in sensory stimulation. The modulation due to spatial attention is present throughout the early visual areas V1, V2, V3, and VP, and varies with the attended location. The task structure activations are strongest in V1 and are greater in regions that represent more peripheral parts of the visual field. Control experiments demonstrate that the task structure activations cannot be attributed to visual, auditory, or somatosensory processing, the motor response for the detection/discrimination judgment, or oculomotor responses such as blinks or saccades. These findings demonstrate that early visual areas are modulated by at least two types of endogenous signals, each with distinct cortical distributions.


Asunto(s)
Vías Aferentes/fisiología , Atención/fisiología , Neuronas/fisiología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Corteza Visual/fisiología , Adulto , Vías Aferentes/anatomía & histología , Percepción Auditiva/fisiología , Parpadeo/fisiología , Mapeo Encefálico , Circulación Cerebrovascular/fisiología , Movimientos Oculares/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Movimiento/fisiología , Pruebas Neuropsicológicas , Estimulación Luminosa , Tiempo de Reacción/fisiología , Factores de Tiempo , Tacto/fisiología , Corteza Visual/anatomía & histología
9.
J Neurosci ; 29(34): 10671-82, 2009 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-19710319

RESUMEN

Covert attention is associated with prestimulus blood oxygenation level-dependent (BOLD) modulations in visual cortex. In some situations, this preparatory activity can predict how well human subjects will perceive upcoming visual objects. Preparatory activity may mediate this behavioral effect by affecting the stimulus-evoked response, but the relationship between preparatory and stimulus-evoked BOLD modulations is unclear. Here, we examine this relationship by comparing the effects of spatial attention on anticipatory and stimulus-evoked signals and by measuring the trial-to-trial correlation between prestimulus and poststimulus modulations. We find that in extrastriate visual cortex (V4), modulations related to spatial attention are relatively large, extend from prestimulus through the peak of the evoked response, and are slightly larger in the evoked response compared with the prestimulus response. In striate cortex (V1), the frontal eye fields (FEF), and the intraparietal sulcus (IPS), modulations related to spatial attention are relatively small, are confined primarily to the prestimulus period, and are slightly larger in preparatory versus stimulus-evoked activity. Importantly, across visual cortex, the attentional biases (activity for attended versus unattended locations) in preparatory and evoked activity are more positively correlated, trial-by-trial, than would be expected on the basis of activity measured in subjects at rest. We argue that this pattern of results suggests that the same mechanisms underlie preparatory and stimulus-evoked BOLD modulations related to spatial attention and that incoming sensory signals add to preexistent biases in preparatory activity to generate the stimulus-evoked response.


Asunto(s)
Atención/fisiología , Mapeo Encefálico , Potenciales Evocados Visuales/fisiología , Percepción Espacial/fisiología , Corteza Visual/irrigación sanguínea , Adulto , Análisis de Varianza , Circulación Cerebrovascular/fisiología , Sensibilidad de Contraste , Señales (Psicología) , Femenino , Lateralidad Funcional , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Modelos Lineales , Imagen por Resonancia Magnética , Masculino , Reconocimiento Visual de Modelos , Estimulación Luminosa/métodos , Psicofísica , Curva ROC , Análisis y Desempeño de Tareas , Factores de Tiempo
10.
J Neurosci ; 28(26): 6549-56, 2008 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-18579728

RESUMEN

Spatial attention is associated with modulations in prestimulus, anticipatory blood oxygen level-dependent (BOLD) activity across the brain. It is unclear, however, if these anticipatory modulations depend on the computational demands of the upcoming task. Here, we show that anticipation of low-contrast stimuli, relative to high-contrast stimuli, is associated with increased prestimulus BOLD activity in the frontal eye field (FEF) and the posterior inferior frontal sulcus (IFS) but not in the intraparietal sulcus (IPS). In visual cortex, anticipation of low-contrast stimuli is associated with increased suppression of activity corresponding to unattended (but not attended) locations, and this suppression predicts whether subjects will accurately perceive low-contrast stimuli. These results suggest that when a stimulus will be difficult to distinguish from the background, top-down signals from FEF and IFS can facilitate perception by marking its location through the suppression of unattended locations in visual cortex.


Asunto(s)
Atención/fisiología , Sensibilidad de Contraste/fisiología , Inhibición Neural/fisiología , Orientación/fisiología , Percepción Espacial/fisiología , Corteza Visual/fisiología , Adulto , Mapeo Encefálico , Circulación Cerebrovascular/fisiología , Cognición/fisiología , Movimientos Oculares/fisiología , Femenino , Fijación Ocular/fisiología , Lóbulo Frontal/anatomía & histología , Lóbulo Frontal/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Estimulación Luminosa
11.
J Assoc Inf Sci Technol ; 70(9): 968-980, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31799335

RESUMEN

Information behavior may enhance hypertension self-management in African-Americans. The goal of this substudy was to examine relationships between measures of self-reported health information behavior and neural measures of health information processing in a sample of 19 prehypertensive African-Americans (mean age=52.5, 52.6% women). We measured 1) health information seeking, sharing, and use (surveys) and 2) neural activity using functional magnetic resonance imaging (fMRI) to assess response to health information videos. We hypothesized that differential activation (comparison of analytic vs. empathic brain activity when watching a specific type of video) would indicate better function in three, distinct cognitive domains: 1) Analytic Network, 2) Default Mode Network (DMN), and 3) ventromedial prefrontal cortex (vmPFC). Scores on the information sharing measure (but not seeking or use) were positively associated with differential activation in the vmPFC (rs=.53, p=.02) and the DMN (rs=.43, p=.06). Our findings correspond with previous work indicating that activation of the DMN and vmPFC is associated with sharing information to persuade others, and with behavior change. Although health information is commonly conveyed as detached and analytic in nature, our findings suggest that neural processing of socially and emotionally salient health information is more closely associated with health information sharing.

12.
West J Nurs Res ; 41(7): 990-1008, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30654713

RESUMEN

People living with HIV (PLHIV) are increasingly diagnosed with comorbidities which require increasing self-management. We examined the effect of a self-management intervention on neurocognitive behavioral processing. Twenty-nine PLHIV completed a two-group, 3-month randomized clinical trial testing a self-management intervention to improve physical activity and dietary intake. At baseline and 3 months later, everyone completed validated assessments of physical, diet, and neurocognitive processing (functional magnetic resonance imaging [fMRI]-derived network analyses). We used linear mixed effects modeling with a random intercept to examine the effect of the intervention. The intervention improved healthy eating (p = .08) but did not improve other self-management behaviors. There was a significant effect of the intervention on several aspects of neurocognitive processing including in the task positive network (TPN) differentiation (p = .047) and an increase in the default mode network (DMN) differentiation (p = .10). Self-management interventions may influence neurocognitive processing in PLHIV, but those changes were not associated with positive changes in self-management behavior.


Asunto(s)
Cognición , Infecciones por VIH/terapia , Promoción de la Salud , Automanejo , Actigrafía/estadística & datos numéricos , Adulto , Dieta , Ejercicio Físico , Femenino , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Obesidad
13.
J Neurosci ; 27(52): 14424-33, 2007 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-18160650

RESUMEN

Humans can use advance information to direct spatial attention before stimulus presentation and respond more accurately to stimuli at the attended location compared with unattended locations. Likewise, spatially directed attention is associated with anticipatory activity in the portion of visual cortex representing the attended location. It is unknown, however, whether and how anticipatory signals predict the locus of spatial attention and perception. Here, we show that prestimulus, preparatory activity is highly correlated across regions representing attended and unattended locations. Comparing activity representing attended versus unattended locations, rather than measuring activity for only one location, dramatically improves the accuracy with which preparatory signals predict the locus of attention, largely by removing this positive correlation common across locations. In V3A, moreover, only the difference in activity between attended and unattended locations predicts whether upcoming visual stimuli will be accurately perceived. These results suggest that the locus of attention is coded in visual cortex by an asymmetry of anticipatory activity between attended and unattended locations and that this asymmetry predicts the accuracy of perception. This coding strategy may bias activity in downstream brain regions to represent the stimulus at the attended location.


Asunto(s)
Atención , Mapeo Encefálico , Lateralidad Funcional/fisiología , Percepción Espacial/fisiología , Corteza Visual/fisiología , Estimulación Acústica/métodos , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Modelos Lineales , Imagen por Resonancia Magnética/métodos , Masculino , Oxígeno/sangre , Estimulación Luminosa/métodos , Valor Predictivo de las Pruebas , Corteza Visual/irrigación sanguínea
15.
PLoS One ; 11(3): e0149989, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27008093

RESUMEN

Prior work has established that analytic thinking is associated with disbelief in God, whereas religious and spiritual beliefs have been positively linked to social and emotional cognition. However, social and emotional cognition can be subdivided into a number of distinct dimensions, and some work suggests that analytic thinking is in tension with some aspects of social-emotional cognition. This leaves open two questions. First, is belief linked to social and emotional cognition in general, or a specific dimension in particular? Second, does the negative relationship between belief and analytic thinking still hold after relationships with social and emotional cognition are taken into account? We report eight hypothesis-driven studies which examine these questions. These studies are guided by a theoretical model which focuses on the distinct social and emotional processing deficits associated with autism spectrum disorders (mentalizing) and psychopathy (moral concern). To our knowledge no other study has investigated both of these dimensions of social and emotion cognition alongside analytic thinking. We find that religious belief is robustly positively associated with moral concern (4 measures), and that at least part of the negative association between belief and analytic thinking (2 measures) can be explained by a negative correlation between moral concern and analytic thinking. Using nine different measures of mentalizing, we found no evidence of a relationship between mentalizing and religious or spiritual belief. These findings challenge the theoretical view that religious and spiritual beliefs are linked to the perception of agency, and suggest that gender differences in religious belief can be explained by differences in moral concern. These findings are consistent with the opposing domains hypothesis, according to which brain areas associated with moral concern and analytic thinking are in tension.


Asunto(s)
Religión , Teoría de la Mente/fisiología , Pensamiento/fisiología , Encéfalo/fisiología , Cognición/fisiología , Emociones/fisiología , Femenino , Humanos , Masculino , Principios Morales
16.
PLoS One ; 11(5): e0155283, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27167061

RESUMEN

[This corrects the article DOI: 10.1371/journal.pone.0149989.].

17.
PLoS One ; 10(3): e0117942, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25785856

RESUMEN

The conventional fMRI image analysis approach to associating stimuli to brain activation is performed by carrying out a massive number of parallel univariate regression analyses. fMRI blood-oxygen-level dependent (BOLD) signal, the basis of these analyses, is known for its low signal-noise-ratio and high spatial and temporal signal correlation. In order to ensure accurate localization of brain activity, stimulus administration in an fMRI session is often lengthy and repetitive. Real-time fMRI BOLD signal analysis is carried out as the signal is observed. This method allows for dynamic, real-time adjustment of stimuli through sequential experimental designs. We have developed a voxel-wise sequential probability ratio test (SPRT) approach for dynamically determining localization, as well as decision rules for stopping stimulus administration. SPRT methods and general linear model (GLM) approaches are combined to identify brain regions that are activated by specific elements of stimuli. Stimulus administration is dynamically stopped when sufficient statistical evidence is collected to determine activation status across regions of interest, following predetermined statistical error thresholds. Simulation experiments and an example based on real fMRI data show that scan volumes can be substantially reduced when compared with pre-determined, fixed designs while achieving similar or better accuracy in detecting activated voxels. Moreover, the proposed approach is also able to accurately detect differentially activated areas, and other comparisons between task-related GLM parameters that can be formulated in a hypothesis-testing framework. Finally, we give a demonstration of SPRT being employed in conjunction with a halving algorithm to dynamically adjust stimuli.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Modelos Teóricos
18.
J Alzheimers Dis ; 46(1): 271-83, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25720413

RESUMEN

The term "brain health" integrates general health and well-being with cognitive fitness, in the context of an environment that includes the spectrum of positive and negative factors affecting the individual. Brain health incorporates the effects of neurodegeneration in an ecological sense and the effects of environment and health practices on brain function. It also provides a framework for understanding and maximizing cognitive function across the lifespan. Despite decades of research into the pathogenesis of neurodegenerative disorders, our understanding of how to treat them is relatively rudimentary. Unidimensional approaches, such as medication monotherapies, have generally produced negative results in treatment trials. New integrative paradigms that cut across the molecular and cellular level to the individual and societal level may provide new approaches to understand and treat these disorders. This report on proceedings of a multi-disciplinary conference held in Cleveland, Ohio, in October 2013 summarizes research progress in understanding neurodegenerative disorders in a brain health context. A new "brain health" paradigm is essential to finally understand neurodegenerative disorders such as Alzheimer's disease and overcome the relative stand-still in therapeutics research that has characterized the last decade. The authors summarize progress in these emerging areas with the aim of producing new integrated scientific models for understanding brain health, potentially modifying disease course and advancing care for individuals and families affected by neurodegenerative conditions.


Asunto(s)
Enfermedad de Alzheimer , Encéfalo/patología , Enfermedades Neurodegenerativas/patología , Enfermedades Neurodegenerativas/terapia , Enfermedad de Alzheimer/epidemiología , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/terapia , Animales , Encéfalo/fisiopatología , Modelos Animales de Enfermedad , Humanos , Relaciones Interpersonales , Enfermedades Neurodegenerativas/epidemiología , Enfermedades Neurodegenerativas/genética , Neuroimagen
19.
Foot Ankle Int ; 36(2): 197-202, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25237171

RESUMEN

BACKGROUND: Turf toe is a hyperextension injury of the hallux metatarsophalangeal joint that can be difficult to diagnose on physical examination and imaging. Diastasis of the bi- or multipartite sesamoid of the hallux has been implicated as 1 potential radiographic finding of turf toe injury, and when present may require operative management. However, the normal interval for the bi-/multipartite sesamoid has not yet been established. METHODS: A total of 671 foot radiograph series were reviewed in effort to quantify the dominant interval of the bi-/multipartite sesamoid bone with respect to potential influencing factors including right versus left foot, medial and/or lateral sesamoid involvement, patient age and gender, and weight versus non-weight-bearing radiograph technique. RESULTS: The prevalence of a bi-/multipartite hallux sesamoid was 14.3% in our population. The dominant sesamoid interval ranged from 0-2 mm, with an average of 0.79 mm. CONCLUSION: We conclude that sesamoid diastasis should be considered, in the appropriate clinical setting, when the sesamoid interval is greater than 2 mm on a routine AP radiograph of the foot. LEVEL OF EVIDENCE: Level III, comparative study.


Asunto(s)
Hallux Valgus/diagnóstico por imagen , Articulación Metatarsofalángica/lesiones , Huesos Sesamoideos/anatomía & histología , Huesos Sesamoideos/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Traumatismos en Atletas/diagnóstico por imagen , Traumatismos en Atletas/epidemiología , Femenino , Humanos , Masculino , Articulación Metatarsofalángica/diagnóstico por imagen , Persona de Mediana Edad , Radiografía , Rango del Movimiento Articular , Soporte de Peso , Adulto Joven
20.
Int J Psychophysiol ; 44(2): 93-100, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-11909644

RESUMEN

The aim of this study was to explore the relationship between electroencephalographic (EEG) activity in the gamma frequency range and conscious awareness of a visual stimulus. EEG was recorded from subjects while they were shown backward-masked words only some of which they were able to discriminate correctly. The results showed that activity in the gamma frequency range increased with reported awareness of a word independently of whether it was correctly discriminated or not. It is concluded that gamma power is associated with awareness-dependent visual processing but not with processing that occurs in the absence of awareness.


Asunto(s)
Atención/fisiología , Concienciación/fisiología , Discriminación en Psicología/fisiología , Enmascaramiento Perceptual/fisiología , Adolescente , Adulto , Electroencefalografía , Femenino , Percepción de Forma , Rayos gamma , Humanos , Lenguaje , Masculino , Lóbulo Occipital/fisiología , Reconocimiento de Normas Patrones Automatizadas , Estimulación Luminosa , Lóbulo Temporal/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA