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1.
J Gen Intern Med ; 39(4): 636-642, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37985610

ABSTRACT

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.


Subject(s)
Internship and Residency , Sexual Harassment , Humans , Male , Female , Sexism , Stereotyping , Leadership
2.
Biol Psychiatry Glob Open Sci ; 3(3): 398-408, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37519457

ABSTRACT

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.

3.
Brain ; 144(6): 1898-1910, 2021 07 28.
Article in English | MEDLINE | ID: mdl-33710282

ABSTRACT

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.


Subject(s)
Parietal Lobe/physiopathology , Schizophrenia/physiopathology , Social Cognition , Temporal Lobe/physiopathology , Adult , Female , Humans , Magnetic Resonance Imaging , Male
4.
Psychol Med ; 51(16): 2923-2932, 2021 12.
Article in English | MEDLINE | ID: mdl-32498743

ABSTRACT

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.


Subject(s)
Schizophrenia , Humans , Facial Expression , Visual Perception , Emotions , Social Perception
5.
J Gen Intern Med ; 34(1): 146-149, 2019 01.
Article in English | MEDLINE | ID: mdl-30276658

ABSTRACT

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.


Subject(s)
Attitude of Health Personnel , Clinical Competence , Education, Medical, Graduate/organization & administration , Faculty, Medical/organization & administration , Internship and Residency/organization & administration , Job Satisfaction , Total Quality Management/methods , Career Choice , Humans , Negotiating/methods , United States
8.
J Am Acad Child Adolesc Psychiatry ; 57(3): 166-174, 2018 03.
Article in English | MEDLINE | ID: mdl-29496125

ABSTRACT

OBJECTIVE: Working memory (WM) deficits are consistently reported in schizophrenia and are related to poor functional outcomes. Functional magnetic resonance imaging studies of adult-onset schizophrenia have reported decreased functional activations and connectivity in the WM network, but no prior functional magnetic resonance imaging study has examined WM in childhood-onset schizophrenia (COS). The aim of this study was to examine the neural correlates of WM in COS. METHOD: Adult patients with COS (n = 32, 21.3 ± 1.1 years), nonpsychotic siblings of patients with COS (n = 30, 19.4 ± 0.8 years), and healthy controls (n = 39, 20.0 ± 0.7 years) completed 1- and 2-back WM tasks during 3-T functional magnetic resonance imaging. Functional activation and connectivity analyses were conducted. A separate group of 23 younger patients with COS (17.9 ± 7.4 years) could not perform the tasks after twice completing a standard training and are not included in this report. RESULTS: Patients with COS who were included scored significantly lower than controls on all tasks (p < .001). Patients with COS showed significantly lower activations in the dorsolateral prefrontal cortices, posterior parietal cortices, cerebellum, and caudate and decreased frontoparietal and corticostriatal functional connectivity compared with controls (p < .05, corrected). Siblings had functional activations and connectivity intermediate between those of patients and controls in a similar set of regions (p < .05, corrected). In patients, functional connectivity strength in the left frontoparietal network correlated positively with accuracy scores during the 1-back task (p = .0023, corrected). CONCLUSION: Decreased functional activation and connectivity in the WM network in COS supports pathophysiologic continuity with adult-onset schizophrenia. The low participation rate and accuracy of the patients highlights the disease severity of COS. Hypo-activations and hypo-connectivity were shared by siblings of patients with COS, suggesting COS as a potential endophenotype. CLINICAL TRIAL REGISTRATION INFORMATION: Evaluating Genetic Risk Factors for Childhood-Onset Schizophrenia; http://ClinicalTrials.gov;NCT00001198.


Subject(s)
Brain/physiopathology , Memory, Short-Term/physiology , Neural Pathways/physiopathology , Schizophrenia, Childhood/complications , Adult , Brain Mapping/methods , Endophenotypes , Female , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Schizophrenia, Childhood/genetics , Schizophrenic Psychology , Siblings , Young Adult
9.
Schizophr Res ; 197: 219-225, 2018 07.
Article in English | MEDLINE | ID: mdl-29310911

ABSTRACT

BACKGROUND: Childhood-onset schizophrenia (COS) is a rare, severe form of the adult-onset disorder (AOS). Our previous resting-state fMRI study identified attenuated functional connectivity in COS compared with controls. Here, we ask whether COS and AOS patients and their siblings exhibit similar abnormalities of functional connectivity. METHODS: A whole-brain, data-driven approach was used to assess resting-state functional connectivity differences in COS (patients/siblings/controls, n: 26/28/33) and AOS (n: 19/28/30). There were no significant differences in age, sex, or head motion across groups in each dataset and as designed, the COS dataset has a significantly lower age than the AOS. RESULTS: Both COS and AOS patients showed decreased functional connectivity relative to controls among a wide set of brain regions (P<0.05, corrected), but their siblings did not. Decreased connectivity in COS and AOS patients showed no amplitude differences and was not modulated by age-at-onset or medication doses. Cluster analysis revealed that these regions fell into two large-scale networks: one sensorimotor network and one centered on default-mode network regions, but including higher-order cognitive areas only in COS. Decreased connectivity between these two networks was notable (P<0.05, corrected) for both patient groups. CONCLUSIONS: A shared pattern of attenuated functional connectivity was found in COS and AOS, supporting the continuity of childhood-onset and adult-onset schizophrenia. Connections were altered between sensorimotor areas and default-mode areas in both COS and AOS, suggesting potential abnormalities in processes of self-monitoring and sensory prediction. The absence of substantial dysconnectivity in siblings indicates that attenuation is state-related.


Subject(s)
Cerebral Cortex/physiopathology , Connectome , Nerve Net/physiopathology , Schizophrenia/physiopathology , Adolescent , Adult , Age of Onset , Cerebral Cortex/diagnostic imaging , Female , Humans , Magnetic Resonance Imaging , Male , Nerve Net/diagnostic imaging , Schizophrenia/diagnostic imaging , Siblings , Young Adult
10.
Neuron ; 95(4): 971-981.e5, 2017 Aug 16.
Article in English | MEDLINE | ID: mdl-28757306

ABSTRACT

Neurons within fMRI-defined face patches of the macaque brain exhibit shared categorical responses to flashed images but diverge in their responses under more natural viewing conditions. Here we investigate functional diversity among neurons in the anterior fundus (AF) face patch, combining whole-brain fMRI with longitudinal single-unit recordings in a local population (<1 mm3). For each cell, we computed a whole-brain correlation map based on its shared time course with voxels throughout the brain during naturalistic movie viewing. Based on this mapping, neighboring neurons showed markedly different affiliation with distant visually responsive areas and fell coarsely into subpopulations. Of these, only one subpopulation (∼16% of neurons) yielded similar correlation maps to the local fMRI signal. The results employ the readout of large-scale fMRI networks and, by indicating multiple functional domains within a single voxel, present a new view of functional diversity within a local neural population.


Subject(s)
Action Potentials/physiology , Brain Mapping , Brain/cytology , Face , Magnetic Resonance Imaging , Neurons/physiology , Pattern Recognition, Visual/physiology , Animals , Brain/diagnostic imaging , Electric Stimulation , Female , Image Processing, Computer-Assisted , Macaca mulatta , Male , Oxygen/blood , Photic Stimulation , Statistics as Topic
11.
J Neurophysiol ; 117(4): 1720-1735, 2017 04 01.
Article in English | MEDLINE | ID: mdl-28003409

ABSTRACT

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.


Subject(s)
Brain/cytology , Brain/physiology , Neural Inhibition/physiology , Neurons/physiology , Saccades/physiology , Visual Pathways/physiology , Action Potentials/physiology , Animals , Fixation, Ocular , Functional Laterality , Macaca mulatta , Male , Movement/physiology , Photic Stimulation , Reaction Time/physiology , Visual Fields/physiology
13.
J Neurosci ; 36(37): 9580-9, 2016 09 14.
Article in English | MEDLINE | ID: mdl-27629710

ABSTRACT

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.


Subject(s)
Brain/diagnostic imaging , Eye Movements/physiology , Magnetic Resonance Imaging , Motion Perception/physiology , Motion , Visual Pathways/diagnostic imaging , Animals , Brain/physiology , Brain Mapping , Female , Image Processing, Computer-Assisted , Macaca mulatta , Models, Biological , Nonlinear Dynamics , Oxygen/blood , Photic Stimulation , Visual Pathways/physiology
14.
J Am Acad Child Adolesc Psychiatry ; 55(9): 792-9, 2016 09.
Article in English | MEDLINE | ID: mdl-27566120

ABSTRACT

OBJECTIVE: Gender differences, including younger age of onset and greater premorbid deficits in men, have been reported in adult-onset schizophrenia. This study comprehensively evaluated gender differences in childhood-onset schizophrenia (COS), a rare variant of the disorder. METHOD: Demographic, premorbid, clinical, familial, and cognitive characteristics, presence of chromosomal abnormalities, and brain magnetic resonance imaging cortical volumes were evaluated in 133 patients with COS. Cortical analyses included age- and gender-matched healthy volunteers (n = 124). RESULTS: Males with COS (n = 72) had a slightly but significantly younger age of onset than females with COS (mean age 9.51 ± 2.28 versus 10.29 ± 1.63 years, t131 = 2.21, p = .03), higher verbal IQ scores (83.00 ± 15.97 versus 75.58 ± 15.10, t89 = 2.24, p = .03), and higher rates of comorbid pervasive developmental disorder (28.17% versus 6.90%, χ(2)1 = 9.54, p < .01) and attention-deficit/hyperactivity disorder (43.86% versus 21.43%, χ(2)1 = 5.40, p = .02). There were no significant gender differences across other demographic, IQ, or clinical measurements, frequency of chromosomal abnormalities, family clinical measurements, premorbid functioning, or in gender-by-disorder interactions for magnetic resonance imaging brain measurements. CONCLUSION: The present comprehensive examination found few remarkable gender differences in COS. Although less striking than that seen in adult-onset schizophrenia, males with COS had a younger age of onset. Attention-deficit/hyperactivity disorder and pervasive developmental disorder rates were high in COS overall, suggesting greater neurodevelopmental vulnerability in COS. However, the gender ratios of these comorbidities in COS mirror those of the general populations, indicating that these gender differences might be unrelated to COS.


Subject(s)
Neurodevelopmental Disorders/epidemiology , Schizophrenia/epidemiology , Adolescent , Age Factors , Age of Onset , Child , Comorbidity , Female , Humans , Longitudinal Studies , Male , Sex Factors , United States/epidemiology
15.
J Neurosci ; 36(1): 31-42, 2016 Jan 06.
Article in English | MEDLINE | ID: mdl-26740647

ABSTRACT

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.


Subject(s)
Attention/physiology , Feedback, Sensory/physiology , Nerve Net/physiology , Saccades/physiology , Visual Cortex/physiology , Visual Perception/physiology , Animals , Macaca mulatta , Male , Visual Pathways/physiology
16.
J Am Acad Child Adolesc Psychiatry ; 55(2): 130-136, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26802780

ABSTRACT

OBJECTIVE: This study investigated the relationship between regional cortical gray matter thinning and symptoms of schizophrenia spectrum personality disorders (PDs) in siblings of patients with childhood-onset schizophrenia (COS). METHOD: A total of 66 siblings of patients with COS were assessed for symptoms of schizophrenia spectrum PDs (avoidant, paranoid, schizoid, schizotypal). Structural magnetic resonance images were obtained at approximately 2-year intervals from the siblings and from 62 healthy volunteers matched for age, sex, ethnicity, and handedness. Cortical thickness measures were extracted. Mixed effect regression models were used to test the relationship between symptoms and cortical gray matter thickness in siblings. Cortical thinning was also tested longitudinally in healthy volunteers and siblings. RESULTS: Cortical thinning was found to correlate with symptoms of schizotypal and, to a lesser extent, schizoid PDs. Thinning was most pronounced in the left temporal and parietal lobes and right frontal and parietal regions. Gray matter loss was found to be continuous with that measured in COS. Longitudinal thinning trajectories were found not to differ between siblings and healthy volunteers. CONCLUSION: The present investigation of cortical thinning in siblings of patients with COS indicates that symptoms of schizophrenia spectrum PDs correlate with regional gray matter loss. This finding supports the idea of cortical thinning as a schizophrenia endophenotype.


Subject(s)
Cerebral Cortex/pathology , Schizophrenia, Childhood/pathology , Schizophrenia/pathology , Schizotypal Personality Disorder/pathology , Adolescent , Adult , Brain Mapping , Case-Control Studies , Cerebral Cortex/diagnostic imaging , Developmental Disabilities/diagnostic imaging , Developmental Disabilities/pathology , Endophenotypes , Female , Humans , Male , Parietal Lobe/diagnostic imaging , Parietal Lobe/pathology , Schizophrenia/diagnostic imaging , Schizophrenia, Childhood/diagnostic imaging , Schizotypal Personality Disorder/diagnostic imaging , Siblings/psychology
17.
Brain ; 139(Pt 1): 276-91, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26493637

ABSTRACT

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.


Subject(s)
Brain/physiopathology , Cognition , Schizophrenia, Childhood/physiopathology , Schizophrenia, Childhood/psychology , Social Behavior , Adolescent , Case-Control Studies , Echo-Planar Imaging , Female , Functional Neuroimaging , Humans , Male , Neural Pathways/physiopathology , Schizophrenia, Childhood/diagnosis , Young Adult
18.
Trends Cogn Sci ; 15(4): 177-84, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21414835

ABSTRACT

Active vision requires the integration of information coming from the retina with that generated internally within the brain, especially by saccadic eye movements. Just as visual information reaches cortex via the lateral geniculate nucleus of the thalamus, this internal information reaches the cerebral cortex through other higher-order nuclei of the thalamus. This review summarizes recent work on four of these thalamic nuclei. The first two pathways convey internal information about upcoming saccades (a corollary discharge) and probably contribute to the neuronal mechanisms that underlie stable visual perception. The second two pathways might contribute to the neuronal mechanisms underlying visual spatial attention in cortex and in the thalamus itself.


Subject(s)
Thalamus/anatomy & histology , Thalamus/physiology , Vision, Ocular/physiology , Visual Pathways/physiology , Animals , Attention/physiology , Humans , Models, Biological , Nerve Net/anatomy & histology , Nerve Net/physiology , Visual Cortex/anatomy & histology , Visual Cortex/physiology
19.
J Neurosci ; 31(2): 373-84, 2011 Jan 12.
Article in English | MEDLINE | ID: mdl-21228149

ABSTRACT

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.


Subject(s)
Pulvinar/physiology , Superior Colliculi/physiology , Visual Cortex/physiology , Animals , Fixation, Ocular , Macaca mulatta , Male , Neurons/physiology , Photic Stimulation , Pulvinar/cytology , Saccades , Visual Pathways
20.
Philos Trans R Soc Lond B Biol Sci ; 366(1564): 492-503, 2011 Feb 27.
Article in English | MEDLINE | ID: mdl-21242138

ABSTRACT

How our vision remains stable in spite of the interruptions produced by saccadic eye movements has been a repeatedly revisited perceptual puzzle. The major hypothesis is that a corollary discharge (CD) or efference copy signal provides information that the eye has moved, and this information is used to compensate for the motion. There has been progress in the search for neuronal correlates of such a CD in the monkey brain, the best animal model of the human visual system. In this article, we briefly summarize the evidence for a CD pathway to frontal cortex, and then consider four questions on the relation of neuronal mechanisms in the monkey brain to stable visual perception. First, how can we determine whether the neuronal activity is related to stable visual perception? Second, is the activity a possible neuronal correlate of the proposed transsaccadic memory hypothesis of visual stability? Third, are the neuronal mechanisms modified by visual attention and does our perceived visual stability actually result from neuronal mechanisms related primarily to the central visual field? Fourth, does the pathway from superior colliculus through the pulvinar nucleus to visual cortex contribute to visual stability through suppression of the visual blur produced by saccades?


Subject(s)
Neurons/physiology , Psychomotor Performance/physiology , Saccades/physiology , Vision, Ocular/physiology , Visual Cortex/physiology , Visual Pathways/physiology , Animals , Humans , Macaca mulatta , Models, Animal
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