Reconstructing habitat types available to hominins and inferring how the paleo-landscape changed through time are critical steps in testing hypotheses about the selective pressures that drove the emergence of bipedalism, tool use, a change in diet, and progressive encephalization. Change in the amount and distribution of woody vegetation has been suggested as one of the important factors that shaped early hominin evolution. Previous models for reconstructing woody cover at eastern African hominin fossil sites used global-scale modern soil comparative datasets.
View Article and Find Full Text PDFImpaired visual target detection is a common finding in schizophrenia that is linked to poor functional outcomes. However, the neural mechanisms that contribute to this deficit remain unclear. Recent research in healthy samples has identified relationships between the phase of pre-stimulus electroencephalographic (EEG) activity in the alpha band (8-12 Hz) or theta band (4-7 Hz) and the likelihood of visual target detection with and without attentional cueing, but these effects have not yet been explored in schizophrenia.
View Article and Find Full Text PDFBiol Psychiatry Cogn Neurosci Neuroimaging
November 2024
Background: Schizophrenia (SCZ) and bipolar disorder (BD) are associated with information processing abnormalities, including visual perceptual and cognitive impairments, that impact daily functioning. Recent work with healthy samples suggests that peak alpha frequency (PAF) is an electrophysiological index of visual information processing speed that is correlated with cognitive ability. There is evidence that PAF is slowed in SCZ, but it remains unclear whether PAF is reduced in BD or whether slower PAF is associated with impaired visual perception and cognition in these clinical disorders.
View Article and Find Full Text PDFBrain Behav Immun
August 2024
Background: Social isolation and loneliness (known as social disconnection, collectively) lead to serious downstream health effects, including shortening of lifespan and higher risk for cardiac disease. We must better understand how isolation and loneliness lead to these negative health outcomes. Previous literature has demonstrated that social motivation and social ability are contributors to the likelihood of social isolation and loneliness.
View Article and Find Full Text PDFDespite different etiologies, people with schizophrenia (SCZ) or with traumatic brain injury (TBI) both show aberrant neuroplasticity. One neuroplastic mechanism that may be affected is prediction error coding. We used a roving mismatch negativity (rMMN) paradigm which uses different lengths of standard tone trains and is optimized to assess predictive coding.
View Article and Find Full Text PDFThe COVID-19 pandemic disproportionately impacted marginalized populations including Black Americans, people with serious mental illness, and individuals experiencing homelessness. Although the double disadvantage hypothesis would suggest that individuals with multiple minoritized statuses would experience worse psychosocial impacts from the pandemic, this may not be the case for vulnerable Black Veterans. The present study investigated the sustained mental health and functional responses to the pandemic in Black and White Veterans with psychosis or recent homelessness and in a control group of Veterans enrolled in the Department of Veterans Affairs healthcare services.
View Article and Find Full Text PDFBackground: People with schizophrenia on average are more socially isolated, lonelier, have more social cognitive impairment, and are less socially motivated than healthy individuals. People with bipolar disorder also have social isolation, though typically less than that seen in schizophrenia. We aimed to disentangle whether the social cognitive and social motivation impairments observed in schizophrenia are a specific feature of the clinical condition social isolation generally.
View Article and Find Full Text PDFPeople with schizophrenia (SCZ) and bipolar disorder (BD) have impairments in processing social information, including faces. The neural correlates of face processing are widely studied with the N170 ERP component. However, it is unclear whether N170 deficits reflect neural abnormalities associated with these clinical conditions or differences in social environments.
View Article and Find Full Text PDFBiol Psychiatry Cogn Neurosci Neuroimaging
December 2023
Schizophrenia is associated with a heavy economic burden in the United States that is partly due to the high rates of chronic unemployment. Individual Placement and Support (IPS) is an evidenced-based type of supported employment that can improve job obtainment and work outcomes in psychotic disorders. Outcomes vary widely and a persistent challenge for IPS is low levels of engagement in the initial job search phase.
View Article and Find Full Text PDFWhile our understanding of human origins has been enriched by extensive efforts to reconstruct the ancient environmental context of early hominins using information from hominin-bearing localities, comparatively little effort has been focused on contemporaneous fossil localities with abundant vertebrate fossils, but lacking hominins. We report here on new paleoenvironmental reconstructions of the Mursi Formation, Ethiopia, from which strata dated to >4 Ma preserve an abundant vertebrate fossil record lacking any known hominins, despite being part of a contiguous sedimentary basin known for its rich hominin fossil record. We combine new stratigraphic and sedimentological observations with data from paleosols preserved in the sedimentary sequence, along with isotopic data from pedogenic carbonate, paleosol organic matter, and sulfur minerals preserved in the sediments (gypsum, native sulfur).
View Article and Find Full Text PDFThe COVID-19 pandemic disproportionately impacted the physical health of some vulnerable groups, but further study is needed to investigate the pandemic's impact on financial health and mental well-being. We analyzed data from 158 participants, consisting of 59 veterans with a psychotic disorder (PSY), 49 recently housed veterans (RHV), and a control group of 50 veterans (CTL) who were assessed five times from May 2020-July 2021. This study compared the financial health of these three groups and examined the relation between financial health and psychiatric symptoms.
View Article and Find Full Text PDFBackground: Individuals with psychosis spectrum disorders (PSD) have difficulty developing social relationships. This difficulty may reflect reduced response to social feedback involving functional alterations in brain regions that support the social motivation system: ventral striatum, orbital frontal cortex, insula, dorsal anterior cingulate cortex, and amygdala. Whether these alterations span PSD is unknown.
View Article and Find Full Text PDFSoc Psychiatry Psychiatr Epidemiol
January 2024
Purpose: Mental health trajectories during the COVID-19 pandemic have been examined in Veterans with tenuous social connections, i.e., those with recent homelessness (RHV) or a psychotic disorder (PSY), and in control Veterans (CTL).
View Article and Find Full Text PDFObjective: Three rounds of stimulus checks were distributed to middle- and low-income U.S. adults during the COVID-19 pandemic.
View Article and Find Full Text PDFPeople with schizophrenia experience difficulties with social interactions. One contributor to these social deficits is dysfunction in processing facial features and facial emotional expressions. However, it is not known whether face processing deficits are evident in those with other psychotic disorders or in those genetically at-risk for psychosis (i.
View Article and Find Full Text PDFSeveral studies of reward processing in schizophrenia have shown reduced sensitivity to positive, but not negative, outcomes although inconsistencies have been reported. In addition, few studies have investigated whether patients show a relative deficit to social versus nonsocial rewards, whether deficits occur across the spectrum of psychosis, or whether deficits relate to negative symptoms and functioning. This study examined probabilistic implicit learning via two visually distinctive slot machines for social and nonsocial rewards in 101 outpatients with diverse psychotic disorders and 48 community controls.
View Article and Find Full Text PDFSchizophrenia is associated with deficits in both object perception and visual attention. However, few studies in schizophrenia have investigated object-based attention, which is dissociable from other forms of visuospatial attention. Recent research in healthy populations has shown that the 'spotlight' of sustained visual attention flickers in a rhythmic, oscillatory fashion at specific frequencies in the 4-12 Hz range.
View Article and Find Full Text PDFBackground: The COVID-19 pandemic has had unprecedented effects on mental health and community functioning. Negative effects related to disruption of individuals' social connections may have been more severe for those who had tenuous social connections prior to the pandemic. Veterans who have recently experienced homelessness (RHV) or have a psychotic disorder (PSY) are considered particularly vulnerable because many had poor social connections prior to the pandemic.
View Article and Find Full Text PDFEvent-related potential (ERP) studies of motivated attention in schizophrenia typically show intact sensitivity to affective vs. non-affective images depicting diverse types of content. However, it is not known whether this ERP pattern: 1) extends to images that solely depict social content, (2) applies across a broad sample with diverse psychotic disorders, and (3) relates to self-reported trait social anhedonia.
View Article and Find Full Text PDFThe COVID-19 pandemic continues to disproportionately impact people of color and individuals experiencing psychosis and homelessness. However, it is unclear whether there are differences by race in psychosocial responses to the pandemic in vulnerable populations. The double jeopardy hypothesis posits that multiply marginalized individuals would experience worse psychosocial outcomes.
View Article and Find Full Text PDFDiminished social motivation is a core feature of schizophrenia that might reflect disturbances in social reward processing. It is not known whether these disturbances reflect anticipatory ("wanting") and/or consummatory ("liking") pleasure deficits. The primary aim of this study was to examine social versus nonsocial reward processing during these temporally distinct substages using event-related potential (ERP) components.
View Article and Find Full Text PDFBlack Americans are overrepresented in Veteran and non-Veteran homeless populations. Community integration remains a problem for many Veterans after they obtain housing, and Black Veterans may encounter additional difficulties due to systemic racism. However, no prior study has specifically examined whether there are racial differences in community integration; similarly, no study has considered racial differences in psychosocial correlates of community integration in homeless Veterans.
View Article and Find Full Text PDFRepresentation of people who identify as members of sexual and gender minority (SGM) groups is lacking in psychiatric research. Few researchers openly identify as members of an SGM group, and those who do continue to face career obstacles. Separately, in the context of psychiatric research studies, little attention has been paid to how participants' SGM identities might intersect with other factors to influence each individual's experience of mental illness.
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