RESUMO
BACKGROUND: Despite similar numbers of women and men in internal medicine (IM) residency, women face unique challenges. Stereotype threat is hypothesized to contribute to underrepresentation of women in academic leadership, and exploring how it manifests in residency may provide insight into forces that perpetuate gender disparities. OBJECTIVE: To quantify the prevalence of stereotype threat in IM residency and explore experiences contributing to that stereotype threat. DESIGN: We used a mixed methods study design. First, we surveyed IM residents using the Stereotype Vulnerability Scale (SVS) to screen for stereotype threat. Second, we conducted focus groups with women who scored high on the SVS to understand experiences that led to stereotype threat. PARTICIPANTS: The survey was sent to all IM residents at University of California, San Francisco (UCSF), in September-November 2019. Focus groups were conducted at UCSF in Spring 2020. APPROACH: The survey included an adapted version of the SVS. For focus groups, we developed a focus group guide informed by literature on stereotype threat. We used a thematic approach to data analysis. The mixed methods design enabled us to draw metainferences by integrating the two data sources. KEY RESULTS: Survey response rate was 61% (110/181). Women were significantly more likely than men to have a score indicating stereotype threat vulnerability (77% vs 0%, p < 0.001). Four themes from focus groups characterized women's experiences of gender bias and stereotype threat: gender norm tension, microaggressions and sexual harassment, authority questioned, and support and allyship. CONCLUSIONS: Gender-based stereotype threat is highly prevalent among women IM residents. This phenomenon poses a threat to confidence and ability to execute patient care responsibilities, detracting from well-being and professional development. These findings indicate that, despite robust representation of women in IM training, further attention is needed to address gendered experiences and contributors to women's vulnerability to stereotype threat.
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Internato e Residência , Assédio Sexual , Humanos , Masculino , Feminino , Sexismo , Estereotipagem , LiderançaRESUMO
Schizophrenia is associated with marked impairments in social cognition. However, the neural correlates of these deficits remain unclear. Here we use naturalistic stimuli to examine the role of the right temporoparietal junction/posterior superior temporal sulcus (TPJ-pSTS)-an integrative hub for the cortical networks pertinent to the understanding complex social situations-in social inference, a key component of social cognition, in schizophrenia. Twenty-seven schizophrenia participants and 21 healthy control subjects watched a clip of the film The Good, the Bad and the Ugly while high resolution multiband functional MRI images were collected. We used inter-subject correlation to measure the evoked activity, which we then compared to social cognition as measured by The Awareness of Social Inference Test (TASIT). We also compared between groups the TPJ-pSTS blood oxygen level-dependent activity (i) relationship with the motion content in the film; (ii) synchronization with other cortical areas involved in the viewing of the movie; and (iii) relationship with the frequency of saccades made during the movie. Activation deficits were greatest in middle TPJ (TPJm) and correlated significantly with impaired TASIT performance across groups. Follow-up analyses of the TPJ-pSTS revealed decreased synchronization with other cortical areas, decreased correlation with the motion content of the movie, and decreased correlation with the saccades made during the movie. The functional impairment of the TPJm, a hub area in the middle of the TPJ-pSTS, predicts deficits in social inference in schizophrenia participants by disrupting the integration of visual motion processing into the TPJ. This disrupted integration then affects the use of the TPJ to guide saccades during the visual scanning of the movie clip. These findings suggest that the TPJ may be a treatment target for improving deficits in a key component of social cognition in schizophrenia participants.
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Lobo Parietal/fisiopatologia , Esquizofrenia/fisiopatologia , Cognição Social , Lobo Temporal/fisiopatologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , MasculinoRESUMO
BACKGROUND: Impairments in social cognition contribute significantly to disability in schizophrenia patients (SzP). Perception of facial expressions is critical for social cognition. Intact perception requires an individual to visually scan a complex dynamic social scene for transiently moving facial expressions that may be relevant for understanding the scene. The relationship of visual scanning for these facial expressions and social cognition remains unknown. METHODS: In 39 SzP and 27 healthy controls (HC), we used eye-tracking to examine the relationship between performance on The Awareness of Social Inference Test (TASIT), which tests social cognition using naturalistic video clips of social situations, and visual scanning, measuring each individual's relative to the mean of HC. We then examined the relationship of visual scanning to the specific visual features (motion, contrast, luminance, faces) within the video clips. RESULTS: TASIT performance was significantly impaired in SzP for trials involving sarcasm (p < 10-5). Visual scanning was significantly more variable in SzP than HC (p < 10-6), and predicted TASIT performance in HC (p = 0.02) but not SzP (p = 0.91), differing significantly between groups (p = 0.04). During the visual scanning, SzP were less likely to be viewing faces (p = 0.0001) and less likely to saccade to facial motion in peripheral vision (p = 0.008). CONCLUSIONS: SzP show highly significant deficits in the use of visual scanning of naturalistic social scenes to inform social cognition. Alterations in visual scanning patterns may originate from impaired processing of facial motion within peripheral vision. Overall, these results highlight the utility of naturalistic stimuli in the study of social cognition deficits in schizophrenia.
Assuntos
Esquizofrenia , Humanos , Expressão Facial , Percepção Visual , Emoções , Percepção SocialRESUMO
OBJECTIVE: To describe characteristics and outcomes of Group Well-Child Care programs and provide recommendations for future research. METHODS: Informed by Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, an electronic references database, manual search of bibliographies and peer-reviewed journals, and general Internet search were conducted including research published up to July 2019. English language, peer-reviewed research, with provision of medical care were included. Studies without published outcomes, not specific to well-child care, or included only one visit were excluded. Nineteen articles met review criteria. Study quality was assessed using the Downs and Black tool for rigor. RESULTS: Programs typically included an individual medical examination, check-in, and group discussion. Demographics varied by race, ethnicity, age, income level, education and parity, though many were used specifically with underserved populations. Group size ranged from 3 to 10 and lasted an average of 1.5 h over a period of 6-24 months. Evidence suggests group well-child care is as effective as individual care with improvement noted for health-care utilization, weight outcomes, and more content covered. Design elements such as patient-led discussion, self-check-in, inclusion of other family members, and use of a variety of health care professionals and para-professionals may influence these outcomes. CONCLUSIONS: Group well-child care is useful in providing efficient and patient-centered care and shows promise for use in underserved populations. Future research should utilize more rigorous study design and include evaluations of program components and group processes to address implementation challenges and determine effectiveness.
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Pessoal de Saúde , Assistência Centrada no Paciente , Família , Feminino , Humanos , GravidezRESUMO
Group prenatal care (GPNC) is an alternative model to traditional individual care and may improve public health outcomes. Prior studies suggest that interest in GPNC varies widely and few studies have examined characteristics predictive of interest in this model. The purpose of this study was to inform GPNC recruitment efforts by examining likelihood of participation delineated by characteristics and GPNC perceptions. Pregnant participants received information about GPNC then completed a survey measuring demographic, psychosocial, and reproductive characteristics, likelihood to participate in GPNC, and factors influencing selections. Respondents expressed varied levels of likelihood to participate in GPNC; 16.2% low likelihood, 44.9% moderate likelihood, and 38.9% high likelihood. Characteristics were similar between groups, and thus their use is not recommended when targeting recruitment efforts. Benefits outweighed barriers and threats for the high likelihood category, barriers and threats outweighed benefits for the low likelihood category, and benefits, barriers, and threats were balanced for the moderate likelihood category. Accurately assessing likelihood of participating in GPNC efficiently identifies individuals who are clearly either going to decline or participate, as well as promotes targeted recruitment efforts directed at those who are ambivalent. Understanding and addressing perceived benefits, barriers, and threats supports effective GPNC recruitment.
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Processos Grupais , Gestantes/psicologia , Cuidado Pré-Natal/organização & administração , Adolescente , Adulto , Feminino , Humanos , Intenção , Gravidez , Fatores Socioeconômicos , Adulto JovemRESUMO
Negotiation skills are critical to career success, yet many physicians feel ill-equipped to negotiate for professional opportunities. Enhancing competencies in this arena may be especially critical for women and underrepresented minorities to reduce disparities in compensation and resources that begin upon entry into the workforce as junior faculty. This perspective offers a comprehensive overview of negotiation strategies and the job search process for individuals finishing medical training and seeking first-time employment. First, we extrapolate lessons from clinical medicine to provide a negotiation roadmap for residents and fellows. We use both a clinical and an employment scenario to illustrate the concept of principled negotiation in which negotiating partners elicit each other's values and interests and identify options for mutual gain. We then describe approaches to seeking and negotiating job opportunities and discuss typical timelines for these activities. We supply a list of professional needs to consider before a negotiation begins and introduce the concept of a best alternative to negotiated agreement to help ensure essential requirements are met in a final employment offer. Finally, we explore the utility of third-party assistance and published benchmarks and offer best practices for negotiating.
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Atitude do Pessoal de Saúde , Competência Clínica , Educação de Pós-Graduação em Medicina/organização & administração , Docentes de Medicina/organização & administração , Internato e Residência/organização & administração , Satisfação no Emprego , Gestão da Qualidade Total/métodos , Escolha da Profissão , Humanos , Negociação/métodos , Estados UnidosRESUMO
Saccadic eye movements direct the high-resolution foveae of our retinas toward objects of interest. With each saccade, the image jumps on the retina, causing a discontinuity in visual input. Our visual perception, however, remains stable. Philosophers and scientists over centuries have proposed that visual stability depends upon an internal neuronal signal that is a copy of the neuronal signal driving the eye movement, now referred to as a corollary discharge (CD) or efference copy. In the old world monkey, such a CD circuit for saccades has been identified extending from superior colliculus through MD thalamus to frontal cortex, but there is little evidence that this circuit actually contributes to visual perception. We tested the influence of this CD circuit on visual perception by first training macaque monkeys to report their perceived eye direction, and then reversibly inactivating the CD as it passes through the thalamus. We found that the monkey's perception changed; during CD inactivation, there was a difference between where the monkey perceived its eyes to be directed and where they were actually directed. Perception and saccade were decoupled. We established that the perceived eye direction at the end of the saccade was not derived from proprioceptive input from eye muscles, and was not altered by contextual visual information. We conclude that the CD provides internal information contributing to the brain's creation of perceived visual stability. More specifically, the CD might provide the internal saccade vector used to unite separate retinal images into a stable visual scene. SIGNIFICANCE STATEMENT: Visual stability is one of the most remarkable aspects of human vision. The eyes move rapidly several times per second, displacing the retinal image each time. The brain compensates for this disruption, keeping our visual perception stable. A major hypothesis explaining this stability invokes a signal within the brain, a corollary discharge, that informs visual regions of the brain when and where the eyes are about to move. Such a corollary discharge circuit for eye movements has been identified in macaque monkey. We now show that selectively inactivating this brain circuit alters the monkey's visual perception. We conclude that this corollary discharge provides a critical signal that can be used to unite jumping retinal images into a consistent visual scene.
Assuntos
Atenção/fisiologia , Retroalimentação Sensorial/fisiologia , Rede Nervosa/fisiologia , Movimentos Sacádicos/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Animais , Macaca mulatta , Masculino , Vias Visuais/fisiologiaRESUMO
UNLABELLED: Visual motion responses in the brain are shaped by two distinct sources: the physical movement of objects in the environment and motion resulting from one's own actions. The latter source, termed visual reafference, stems from movements of the head and body, and in primates from the frequent saccadic eye movements that mark natural vision. To study the relative contribution of reafferent and stimulus motion during natural vision, we measured fMRI activity in the brains of two macaques as they freely viewed >50 hours of naturalistic video footage depicting dynamic social interactions. We used eye movements obtained during scanning to estimate the level of reafferent retinal motion at each moment in time. We also estimated the net stimulus motion by analyzing the video content during the same time periods. Mapping the responses to these distinct sources of retinal motion, we found a striking dissociation in the distribution of visual responses throughout the brain. Reafferent motion drove fMRI activity in the early retinotopic areas V1, V2, V3, and V4, particularly in their central visual field representations, as well as lateral aspects of the caudal inferotemporal cortex (area TEO). However, stimulus motion dominated fMRI responses in the superior temporal sulcus, including areas MT, MST, and FST as well as more rostral areas. We discuss this pronounced separation of motion processing in the context of natural vision, saccadic suppression, and the brain's utilization of corollary discharge signals. SIGNIFICANCE STATEMENT: Visual motion arises not only from events in the external world, but also from the movements of the observer. For example, even if objects are stationary in the world, the act of walking through a room or shifting one's eyes causes motion on the retina. This "reafferent" motion propagates into the brain as signals that must be interpreted in the context of real object motion. The delineation of whole-brain responses to stimulus versus self-generated retinal motion signals is critical for understanding visual perception and is of pragmatic importance given the increasing use of naturalistic viewing paradigms. The present study uses fMRI to demonstrate that the brain exhibits a fundamentally different pattern of responses to these two sources of retinal motion.
Assuntos
Encéfalo/diagnóstico por imagem , Movimentos Oculares/fisiologia , Imageamento por Ressonância Magnética , Percepção de Movimento/fisiologia , Movimento (Física) , Vias Visuais/diagnóstico por imagem , Animais , Encéfalo/fisiologia , Mapeamento Encefálico , Feminino , Processamento de Imagem Assistida por Computador , Macaca mulatta , Modelos Biológicos , Dinâmica não Linear , Oxigênio/sangue , Estimulação Luminosa , Vias Visuais/fisiologiaRESUMO
Saccades should cause us to see a blur as the eyes sweep across a visual scene. Specific brain mechanisms prevent this by producing suppression during saccades. Neuronal correlates of such suppression were first established in the visual superficial layers of the superior colliculus (SC) and subsequently have been observed in cortical visual areas, including the middle temporal visual area (MT). In this study, we investigated suppression in a recently identified circuit linking visual SC (SCs) to MT through the inferior pulvinar (PI). We examined responses to visual stimuli presented just before saccades to reveal a neuronal correlate of suppression driven by a copy of the saccade command, referred to as a corollary discharge. We found that visual responses were similarly suppressed in SCs, PI, and MT. Within each region, suppression of visual responses occurred with saccades into both visual hemifields, but only in the contralateral hemifield did this suppression consistently begin before the saccade (~100 ms). The consistency of the signal along the circuit led us to hypothesize that the suppression in MT was influenced by input from the SC. We tested this hypothesis in one monkey by inactivating neurons within the SC and found evidence that suppression in MT depends on corollary discharge signals from motor SC (SCi). Combining these results with recent findings in rodents, we propose a complete circuit originating with corollary discharge signals in SCi that produces suppression in visual SCs, PI, and ultimately, MT cortex.NEW & NOTEWORTHY A fundamental puzzle in visual neuroscience is that we frequently make rapid eye movements (saccades) but seldom perceive the visual blur accompanying each movement. We investigated neuronal correlates of this saccadic suppression by recording from and perturbing a recently identified circuit from brainstem to cortex. We found suppression at each stage, with evidence that it was driven by an internally generated signal. We conclude that this circuit contributes to neuronal suppression of visual signals during eye movements.
Assuntos
Encéfalo/citologia , Encéfalo/fisiologia , Inibição Neural/fisiologia , Neurônios/fisiologia , Movimentos Sacádicos/fisiologia , Vias Visuais/fisiologia , Potenciais de Ação/fisiologia , Animais , Fixação Ocular , Lateralidade Funcional , Macaca mulatta , Masculino , Movimento/fisiologia , Estimulação Luminosa , Tempo de Reação/fisiologia , Campos Visuais/fisiologiaRESUMO
Schizophrenia is increasingly recognized as a neurodevelopmental disorder with altered connectivity among brain networks. In the current study we examined large-scale network interactions in childhood-onset schizophrenia, a severe form of the disease with salient genetic and neurobiological abnormalities. Using a data-driven analysis of resting-state functional magnetic resonance imaging fluctuations, we characterized data from 19 patients with schizophrenia and 26 typically developing controls, group matched for age, sex, handedness, and magnitude of head motion during scanning. This approach identified 26 regions with decreased functional correlations in schizophrenia compared to controls. These regions were found to organize into two function-related networks, the first with regions associated with social and higher-level cognitive processing, and the second with regions involved in somatosensory and motor processing. Analyses of across- and within-network regional interactions revealed pronounced across-network decreases in functional connectivity in the schizophrenia group, as well as a set of across-network relationships with overall negative coupling indicating competitive or opponent network dynamics. Critically, across-network decreases in functional connectivity in schizophrenia predicted the severity of positive symptoms in the disorder, such as hallucinations and delusions. By contrast, decreases in functional connectivity within the social-cognitive network of regions predicted the severity of negative symptoms, such as impoverished speech and flattened affect. These results point toward the role that abnormal integration of sensorimotor and social-cognitive processing may play in the pathophysiology and symptomatology of schizophrenia.
Assuntos
Encéfalo/fisiopatologia , Cognição , Esquizofrenia Infantil/fisiopatologia , Esquizofrenia Infantil/psicologia , Comportamento Social , Adolescente , Estudos de Casos e Controles , Imagem Ecoplanar , Feminino , Neuroimagem Funcional , Humanos , Masculino , Vias Neurais/fisiopatologia , Esquizofrenia Infantil/diagnóstico , Adulto JovemRESUMO
Growing access to large-scale longitudinal structural neuroimaging data has fundamentally altered our understanding of cortical development en route to human adulthood, with consequences for basic science, medicine, and public policy. In striking contrast, basic anatomical development of subcortical structures such as the striatum, pallidum, and thalamus has remained poorly described--despite these evolutionarily ancient structures being both intimate working partners of the cortical sheet and critical to diverse developmentally emergent skills and disorders. Here, to begin addressing this disparity, we apply methods for the measurement of subcortical volume and shape to 1,171 longitudinally acquired structural magnetic resonance imaging brain scans from 618 typically developing males and females aged 5-25 y. We show that the striatum, pallidum, and thalamus each follow curvilinear trajectories of volume change, which, for the striatum and thalamus, peak after cortical volume has already begun to decline and show a relative delay in males. Four-dimensional mapping of subcortical shape reveals that (i) striatal, pallidal, and thalamic domains linked to specific fronto-parietal association cortices contract with age whereas other subcortical territories expand, and (ii) each structure harbors hotspots of sexually dimorphic change over adolescence--with relevance for sex-biased mental disorders emerging in youth. By establishing the developmental dynamism, spatial heterochonicity, and sexual dimorphism of human subcortical maturation, these data bring our spatiotemporal understanding of subcortical development closer to that of the cortex--allowing evolutionary, basic, and clinical neuroscience to be conducted within a more comprehensive developmental framework.
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Mapeamento Encefálico/métodos , Córtex Cerebral/anatomia & histologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Adulto JovemRESUMO
BACKGROUND: Workforce projections indicate a potential shortage of up to 31,000 adult primary care providers by the year 2025. Approximately 80 % of internal medicine residents and nearly two-thirds of primary care internal medicine residents do not plan to have a career in primary care or general internal medicine. OBJECTIVE: We aimed to explore contextual and programmatic factors within primary care residency training environments that may influence career choices. DESIGN: This was a qualitative study based on semi-structured, in-person interviews. PARTICIPANTS: Three primary care internal medicine residency programs were purposefully selected to represent a diversity of training environments. Second and third year residents were interviewed. APPROACH: We used a survey guide developed from pilot interviews and existing literature. Three members of the research team independently coded the transcripts and developed the code structure based on the constant comparative method. The research team identified emerging themes and refined codes. ATLAS.ti was used for the analysis. KEY RESULTS: We completed 24 interviews (12 second-year residents, and 12 third-year residents). The age range was 27-39 years. Four recurrent themes characterized contextual and programmatic factors contributing to residents' decision-making: resident expectations of a career in primary care, navigation of the boundary between social needs and medical needs, mentorship and perceptions of primary care, and structural features of the training program. CONCLUSIONS: Addressing aspects of training that may discourage residents from careers in primary care such as lack of diversity in outpatient experiences and resident frustration with their inability to address social needs of patients, and strengthening aspects of training that may encourage interests in careers in primary care such as mentorship and protected time away from inpatient responsibilities during primary care rotations, may increase the proportion of residents enrolled in primary care training programs who pursue a career in primary care.
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Atitude do Pessoal de Saúde , Escolha da Profissão , Medicina Interna/tendências , Internato e Residência/tendências , Médicos/tendências , Atenção Primária à Saúde/tendências , Adulto , Feminino , Humanos , Internato e Residência/métodos , Masculino , Médicos/psicologia , Atenção Primária à Saúde/métodos , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Managing medications is a complex responsibility of family caregivers caring for end-of-life patients. This study characterizes caregivers with and without formal/informal support managing medications for patients who receive end-of-life care at home. AIM: To explore factors related to caregivers' support with managing medications for end-of-life home hospice patients. DESIGN: A convenience-sampled, cross-sectional telephone survey. SETTING/PARTICIPANTS: Computer-assisted telephone interviews were administered to 120 caregivers managing medications, who were referred by five Chicago-based home hospice services. We measured caregivers' additional formal (paid) and informal (unpaid) support with managing medications, and caregiver/patient socio-demographic, relational, and health characteristics. RESULTS: While 47 (39%) had no additional support with managing medications, 27 (22.5%) had formal support, 37 (31%) informal, and 9 (7.5%) both. Seven caregivers (19%) with formal and 13 (31%) with informal support reported disagreements concerning treatment plans. Caregivers lacking formal support tended to be racial/ethnic minorities, live with the patient in their home, or report greater emotional burden. Caregivers with formal support tended to report higher education/income, lower mutuality, or care for a patient with over 6 months' hospice enrollment. Caregivers lacking informal support tended to be spousal caregivers, live with the patient, or have experience caring for another dying person. CONCLUSION: Our study suggests that high proportions of caregivers may not have support managing medications for patients receiving hospice care at home. More research should examine whether the observed variations in obtaining support indicate disparities or unmet needs among caregivers. Disagreement about treatment with formal/informal support also warrants further investigation.
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Assistência Domiciliar/normas , Conduta do Tratamento Medicamentoso/organização & administração , Apoio Social , Assistência Terminal/normas , Adulto , Idoso , Análise de Variância , Cuidadores/psicologia , Chicago , Estudos Transversais , Feminino , Assistência Domiciliar/organização & administração , Cuidados Paliativos na Terminalidade da Vida/organização & administração , Cuidados Paliativos na Terminalidade da Vida/normas , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e QuestionáriosAssuntos
Sucesso Acadêmico , Medicina Interna/educação , Internato e Residência , Médicas , Editoração , Sexismo , Feminino , Humanos , Estados UnidosRESUMO
Caring Together, Living Better (CTLB), a partnership of nonprofit and faith-based organizations, developed a culturally appropriate regional network of supportive caregiver services in the south suburbs of Chicago, IL. This article describes the findings of a mixed-methods evaluation that included network analysis to track network growth and development, tracking of service delivery, assessment of caregiver-related outcomes using standardized pre-post measures, and analysis of change stories elicited from project partners. Results include documentation of network expansion and statistically significant improvements in caregiving self-efficacy and adequacy of help. Story themes highlight participants' positive experiences with CTLB and improved caregiver quality of life.
Assuntos
Adaptação Psicológica , Cuidadores/educação , Cuidadores/psicologia , Serviços de Saúde Comunitária/organização & administração , Religião , Apoio Social , Acesso à Informação , Chicago , Aconselhamento , Feminino , Acessibilidade aos Serviços de Saúde , Humanos , Masculino , Avaliação de Programas e Projetos de Saúde , Qualidade de Vida , Medição de RiscoAssuntos
Negro ou Afro-Americano , Neoplasias da Próstata/etnologia , Idoso , Seguimentos , Disparidades nos Níveis de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Grupos Raciais , Programa de SEER , Estados Unidos/epidemiologiaRESUMO
Background: Efficient processing of complex and dynamic social scenes relies on intact connectivity of many underlying cortical areas and networks, but how connectivity anomalies affect the neural substrates of social perception remains unknown. Here we measured these relationships using functionally based localization of social perception areas, resting-state functional connectivity, and movie-watching data. Methods: In 42 participants with schizophrenia (SzPs) and 41 healthy control subjects, we measured the functional connectivity of areas localized by face-emotion processing, theory-of-mind (ToM), and attention tasks. We quantified the weighted shortest path length between visual and medial prefrontal ToM areas in both populations to assess the impact of these changes in functional connectivity on network structure. We then correlated connectivity along the shortest path in each group with movie-evoked activity in a key node of the ToM network (posterior temporoparietal junction [TPJp]). Results: SzPs had pronounced decreases in connectivity in TPJ/posterior superior temporal sulcus (TPJ-pSTS) areas involved in face-emotion processing (t81 = 4.4, p = .00002). In healthy control subjects, the shortest path connecting visual and medial prefrontal ToM areas passed through TPJ-pSTS, whereas in SzPs, the shortest path passed through the prefrontal cortex. While movie-evoked TPJp activity correlated with connectivity along the TPJ-pSTS pathway in both groups (r = 0.43, p = .002), it additionally correlated with connectivity along the prefrontal cortex pathway only in SzPs (rSzP = 0.56, p = .003). Conclusions: These results suggest that connectivity along the human-unique TPJ-pSTS pathway affects both the network architecture and functioning of areas involved in processing complex dynamic social scenes. These results demonstrate how focal connectivity anomalies can have widespread impacts across the cortex.
RESUMO
We previously established a functional pathway extending from the superficial layers of the superior colliculus (SC) through the inferior pulvinar (PI) to cortical area MT in the primate (Macaca mulatta). Here, we characterized the signals that this pathway conveys to cortex by recording from pulvinar neurons that we identified by microstimulation as receiving input from SC and/or projecting to MT. The basic properties of these ascending-path PI neurons resembled those of SC visual neurons. Namely, they had brisk responses to spots of light, inhibitory surrounds, and relatively large receptive fields that increased with eccentricity, as well as minimal presaccadic activity. Beyond these basic properties, there were two salient results regarding the modulatory and motion signals conveyed by this ascending pathway. First, the PI neurons appeared to convey only a subset of the modulations found in the SC: they exhibited saccadic suppression, the inhibition of activity at the time of the saccade, but did not clearly show the attentional enhancement of the visual response seen in SC. Second, directional selectivity was minimal in PI neurons belonging to the ascending path but was significantly more prominent in PI neurons receiving input from MT. This finding casts doubt on earlier assumptions that PI provides directionally selective signals to MT and instead suggests that PI derives its selectivity from MT. The identification of this pathway and its transmitted activity establishes the first functional pathway from brainstem to cortex through pulvinar and makes it possible to examine its contribution to cortical visual processing, perception, and action.
Assuntos
Pulvinar/fisiologia , Colículos Superiores/fisiologia , Córtex Visual/fisiologia , Animais , Fixação Ocular , Macaca mulatta , Masculino , Neurônios/fisiologia , Estimulação Luminosa , Pulvinar/citologia , Movimentos Sacádicos , Vias VisuaisRESUMO
This paper presents the first chip-scale demonstration of an intra-chip free-space optical interconnect (FSOI) we recently proposed. This interconnect system provides point-to-point free-space optical links between any two communication nodes, and hence constructs an all-to-all intra-chip communication fabric, which can be extended for inter-chip communications as well. Unlike electrical and other waveguide-based optical interconnects, FSOI exhibits low latency, high energy efficiency, and large bandwidth density, and hence can significantly improve the performance of future many-core chips. In this paper, we evaluate the performance of the proposed FSOI interconnect, and compare it to a waveguide-based optical interconnect with wavelength division multiplexing (WDM). It shows that the FSOI system can achieve significantly lower loss and higher energy efficiency than the WDM system, even with optimistic assumptions for the latter. A 1×1-cm2 chip prototype is fabricated on a germanium substrate with integrated photodetectors. Commercial 850-nm GaAs vertical-cavity-surface-emitting-lasers (VCSELs) and fabricated fused silica microlenses are 3-D integrated on top of the substrate. At 1.4-cm distance, the measured optical transmission loss is 5 dB, the crosstalk is less than -20 dB, and the electrical-to-electrical bandwidth is 3.3 GHz. The latter is mainly limited by the 5-GHz VCSEL.