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Scott R Sponheim

Publications and source records attributed to Scott R Sponheim.

9 recordsLinked to original sources
PubMed2025

A whole-brain voxel-based analysis of structural abnormalities in PTSD: An ENIGMA-PGC study.

BACKGROUND: Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group. METHODS: T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9). RESULTS: PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges' g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges' g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (p corrected  = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (p corrected  = .001). CONCLUSIONS: PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.

Humans↗
PubMed2006

Neural anomalies during sustained attention in first-degree biological relatives of schizophrenia patients.

BACKGROUND: A deficit in sustained attention might serve as an endophenotype for schizophrenia and therefore be a useful tool in understanding the genetic underpinnings of the disorder. We sought to detail functional brain abnormalities associated with sustained attention (i.e., vigilance) in individuals with genetic liability for schizophrenia. METHODS: We gathered electrophysiological data from 23 schizophrenia patients, 28 first-degree biological relatives of schizophrenia patients, and 23 nonpsychiatric control subjects while they performed a degraded-stimulus continuous performance task. Inclusion of sensory control trials allowed separation of target detection and vigilance effects on brain potentials. RESULTS: Schizophrenia patients, but not relatives, showed a behavioral deficit in sustained attention. During target detection, relatives exhibited diminished late positive amplitudes (P3b, i.e., P300) over parietal brain regions and augmented early posterior (P1) and right frontal (anterior N1) potentials. Electrophysiological anomalies were still evident after the exclusion of three relatives with histories of psychosis. CONCLUSIONS: Genetic liability for schizophrenia is associated with augmented early and diminished late brain potentials during sustained attention. Electrophysiological anomalies suggestive of right frontal-posterior parietal dysfunction might represent neural expression of genetic liability for schizophrenia. Electrophysiological indices also seem to be more sensitive than behavioral measures in assessing genetic liability for schizophrenia.

Analysis of Variance↗
PubMed2006

Does cognition predict community function only in schizophrenia?: a study of schizophrenia patients, bipolar affective disorder patients, and community control subjects.

Cognitive deficits predict functioning in schizophrenia; however, little is known as to whether the association is present in other mental disorders. If specific cognitive deficits uniquely predict functional impairment in schizophrenia the association of select aspects of brain dysfunction with daily living would suggest an intervention target and perhaps a means by which to improve the functioning of schizophrenia patients. The relationship of cognition and functioning was investigated in schizophrenia (n=39), bipolar affective disorder (n=27), and nonpsychiatric control (n=38) participants to determine whether the associations varied across groups. We examined verbal memory, verbal learning, verbal fluency, vigilance, executive functioning, symptomatology, and generalized cognitive functioning for associations with social function. Correlational analyses revealed particular cognitive domains (e.g., verbal memory) to be associated with social functioning in schizophrenia, bipolar, and control subjects; however generalized cognitive function and symptomatology were also associated with social functioning in patients. Multiple regression analyses revealed that in schizophrenia poor verbal memory predicted worse social functioning even after the effects of generalized cognitive dysfunction were considered. Verbal memory indices failed to account for variance in social function in bipolar patients and control subjects after consideration of generalized cognitive function. Bipolar patients with worse planning and problem solving tended to have worse social functioning. Therefore, unlike schizophrenia patients who may fail to process verbally mediated material, bipolar patients' difficulty with logical approaches to problems in daily living may have the greatest impact on their community function.

Adult↗
PubMed2005

Neural anomalies during visual search in schizophrenia patients and unaffected siblings of schizophrenia patients.

Schizophrenia patients and their unaffected first-degree relatives exhibit performance deficits on attention tasks, perhaps indicating genetic influence over attentional abnormalities in schizophrenia. To identify anomalous brain function associated with attention in individuals who likely have unexpressed genetic liability for schizophrenia, we studied electrophysiological characteristics of unaffected siblings of schizophrenia patients during a visual serial search task. We gathered behavioral and electrophysiological data from 19 schizophrenia patients, 18 unaffected biological siblings of schizophrenia patients, and 19 nonpsychiatric control participants during performance of the Span of Apprehension (Span) task and a control task. Schizophrenia patients had lower Span task accuracy than the other two groups. Schizophrenia and sibling groups exhibited diminished late positive potentials (P300) over parietal brain regions during Span trials. Compared to control task stimuli, attentional demands of Span stimuli elicited augmented early negative potentials (N1, P2) over posterior brain regions. The degree of augmentation was reduced in schizophrenia patients but not in siblings compared to control subjects. Unaffected siblings of schizophrenia patients appear to modulate early attentional functions of posterior brain regions more effectively than schizophrenia patients but show later electrophysiological anomalies suggestive of abnormal updating of task-relevant information. While the latter may reflect neural mechanisms predisposing performance deficits on attentional tasks, the former may reflect compensatory processes present in unaffected relatives of schizophrenia patients.

Adult↗
PubMed2004

Verbal memory processes in schizophrenia patients and biological relatives of schizophrenia patients: intact implicit memory, impaired explicit recollection.

Verbal memory deficits are arguably the most common cognitive abnormalities in biological relatives of schizophrenia patients. Because verbal memory is a complex cognitive function, it is necessary to differentiate its intact and compromised aspects in order to reveal aberrant neural systems that reflect genetic risk in relatives of schizophrenia patients. Using an experimental verbal memory task, we examined encoding, free-recall, repetition priming, and recognition of verbal material in 22 schizophrenia patients, 22 first-degree biological relatives of schizophrenia patients, and 23 nonpsychiatric control participants. Schizophrenia patients exhibited intact repetition priming, but worse size judgment task performance (encoding), recall, and recognition than the control participants. Biological relatives of schizophrenia patients exhibited intact size judgment task performance, repetition priming, and recognition, but a free-recall deficit. Although size judgment task performance at encoding was associated with recall of verbal material in schizophrenia and control groups, in the relative group encoding performance was associated with the degree of repetition priming. Findings are consistent with impaired explicit recollection of verbal material, but intact implicit verbal memory in schizophrenia patients and biological relatives of schizophrenia patients.

Brief Psychiatric Rating Scale↗
PubMed2004

Functional neuroanatomy of the human near/far response to blur cues: eye-lens accommodation/vergence to point targets varying in depth.

The purpose of this study was to identify the networks involved in the regulation of visual accommodation/vergence by contrasting the cortical functions subservient to eye-lens accommodation with those evoked by foveal fixation. Neural activity was assessed in normal volunteers by changes in rCBF measured with PET. Thirteen right-handed subjects participated in three monocular tasks: (i) resting with eyes closed; (ii) sustained foveal fixation upon a LED at 1.2 m (0.83 D); and (iii) accommodating alternately on a near (24 cm, 4.16 D) vs. a far (3.0 m, 0.33 D) LED alternately illuminated in sequential 2 s epochs. The contrast between the conditions of near/far accommodation and of constant foveal fixation revealed activation in cerebellar hemispheres and vermis; middle and inferior temporal cortex (BA 20, 21, 37); striate cortex and associative visual areas (BA 17/18). Comparison of the condition of constant fixation with the condition of resting with closed eyes indicated activation of cerebellar hemispheres and vermis; visual cortices (BA 17/18); a right hemisphere dominant network encompassing prefrontal (BA 6, 9, 47), superior parietal (BA 7), and superior temporal (BA 40) cortices; and bilateral thalamus. The contrast between the conditions of near/far accommodation with closed-eye rest reflected an incremental summation of the activations found in the previous comparisons (i.e. activations associated with constant fixation). Neural circuits activated selectively during the near/far response to blur cues over those during constant visual fixation, occupy posterior structures that include occipital visual regions, cerebellar hemispheres and vermis, and temporal cortex.

Accommodation, Ocular↗
PubMed2003

Proverb interpretation in schizophrenia: the significance of symptomatology and cognitive processes.

Although clinicians have patients interpret proverbs in mental status exams for psychosis, there are few empirical studies investigating the significance of proverb interpretation. In schizophrenia patients, we found abstraction positively correlated with overall intelligence but no symptom measures, concreteness negatively correlated with overall intelligence, executive functioning, attention, and memory, and bizarre-idiosyncratic responses associated with positive formal thought disorder but no cognitive functions.

Adult↗
PubMed2003

Sensitivity and specificity of select biological indices in characterizing psychotic patients and their relatives.

BACKGROUND: Although studies have detailed biological abnormalities in schizophrenia patients and their first-degree biological relatives, few studies have directly compared the utility of biological indices in these individuals. METHODS: Measures of global smooth-pursuit ocular motor (OM) function, low frequency and alpha band electroencephalogram (EEG) power, and nonspecific fluctuations (NSF) in electrodermal activity and visibility of the plexus in the nailfold were collected from 136 schizophrenia patients and 67 of their first-degree biological relatives, 71 affective disorder psychotic patients and 68 of their first-degree biological relatives, and 169 nonpsychiatric comparison subjects. We conducted receiver operator characteristic (ROC) analyses to determine how well each index differentiated the patient groups and the groups of first-degree relatives. RESULTS: Smooth-pursuit ocular motor function, low frequency and alpha band EEG power, and nailfold plexus visibility differentiated schizophrenia patients from nonpsychiatric comparison subjects. Nailfold plexus visibility was the only measure that significantly differentiated schizophrenia patients from both nonpsychiatric controls and affective patients. Smooth-pursuit ocular motor function and the number of electrodermal nonspecific fluctuations differentiated relatives of schizophrenia patients from nonpsychiatric comparison subjects. CONCLUSION: Increased nailfold plexus visibility may mark a process associated with abnormal brain development leading to schizophrenia. Smooth-pursuit dysfunction may mark genetic vulnerability that is relatively specific to schizophrenia.

Adult↗