| 1 | Neuropsychopharmacology 2008 Feb 33: 473-9 |
|---|---|
| PMID | 17473838 |
| Title | The formation of abnormal associations in schizophrenia: neural and behavioral evidence. |
| Abstract | It is hypothesized that due to an abnormal functioning of the reward system patients with schizophrenia form context-inappropriate associations. It has been shown that the dopamine target regions, especially the ventral striatum, are critical in the formation of reward associations. We wanted to examine how the ventral striatum responds as patients learn reward-related associations and how this neural response is linked to objective and subjective behavioral measures. Functional magnetic resonance imaging (fMRI) Blood oxygen level dependent (BOLD) responses were examined using aversive Pavlovian learning in 13 medicated patients with schizophrenia and 13 matched healthy controls. Colored circles served as conditioned stimulus (CS+) while a loud, individually adjusted, noise served as the unconditioned stimulus. Circles of another color served as neutral comparators (CS-). Subjective indices were assessed by a post-scan self-report, and galvanic skin responses (GSR) were used as objective measures of associative learning. fMRI data were analyzed using a random effects model in SPM2. Patients showed inappropriately strong activations in the ventral striatum in response to the neutral stimulus (CS-) as compared to the healthy controls. Consistent with this neural evidence of aberrant learning, patients also showed evidence of abnormal learning by self-report and as indexed by GSR. The main finding here is that patients with schizophrenia, when exposed to neutral stimuli in a threatening situation, show an abnormal pattern of learning. The aberrant activations and response are consistent with the idea that patients aberrantly assign motivational salience to neutral stimuli, and this process may be one of the aberrations that predisposes them to psychosis. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |
| 2 | Front Hum Neurosci 2011 -1 4: 239 |
| PMID | 21267430 |
| Title | Aberrant Effective Connectivity in Schizophrenia Patients during Appetitive Conditioning. |
| Abstract | It has recently been suggested that schizophrenia involves dysfunction in brain connectivity at a neural level, and a dysfunction in reward processing at a behavioral level. The purpose of the present study was to link these two levels of analyses by examining effective connectivity patterns between brain regions mediating reward learning in patients with schizophrenia and healthy, age-matched controls. To this aim, we used functional magnetic resonance imaging and galvanic skin recordings (GSR) while patients and controls performed an appetitive conditioning experiment with visual cues as the conditioned (CS) stimuli, and monetary reward as the appetitive unconditioned stimulus (US). Based on explicit stimulus contingency ratings, conditioning occurred in both groups; however, based on implicit, physiological GSR measures, patients failed to show differences between CS+ and CS- conditions. Healthy controls exhibited increased blood-oxygen-level dependent (BOLD) activity across striatal, hippocampal, and prefrontal regions and increased effective connectivity from the ventral striatum to the orbitofrontal cortex (OFC BA 11) in the CS+ compared to the CS- condition. Compared to controls, patients showed increased BOLD activity across a similar network of brain regions, and increased effective connectivity from the striatum to hippocampus and prefrontal regions in the CS- compared to the CS+ condition. The findings of increased BOLD activity and effective connectivity in response to the CS- in patients with schizophrenia offer insight into the aberrant assignment of motivational salience to non-reinforced stimuli during conditioning that is thought to accompany schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |
| 3 | Transl Psychiatry 2015 -1 5: e575 |
| PMID | 26035059 |
| Title | Altered functional connectivity of the cingulate subregions in schizophrenia. |
| Abstract | schizophrenia patients have shown altered resting-state functional connectivity (rsFC) of the cingulate cortex; however, it is unknown whether rsFCs of the cingulate subregions are differentially affected in this disorder. We aimed to clarify the issue by comparing rsFCs of each cingulate subregion between healthy controls and schizophrenia patients. A total of 102 healthy controls and 94 schizophrenia patients underwent resting-state functional magnetic resonance imaging with a sensitivity-encoded spiral-in imaging sequence to reduce susceptibility-induced signal loss and distortion. The cingulate cortex was divided into nine subregions, including the subgenual anterior cingulate cortex (ACC), areas 24 and 32 of the pregenual ACC, areas 24 and 32 of the anterior mid-cingulate cortex (aMCC), posterior MCC (pMCC), dorsal (dPCC) and ventral (vPCC) posterior cingulate cortex (PCC) and retrosplenial cortex (RSC). The rsFCs of each cingulate subregion were compared between the two groups and the atrophy effect was considered. Results with and without global signal regression were reported. Most cingulate subregions exhibited decreased rsFCs in schizophrenia after global signal regression (GSR). Without GSR, only increased rsFC was found in schizophrenia, which primarily restricted to the aMCC, PCC and RSC. Some of these increased rsFCs were also significant after GSR. These findings suggest that GSR can greatly affect between-group differences in rsFCs and the consistently increased rsFCs may challenge the functional disconnection hypothesis of schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |
| 4 | Front Psychol 2015 -1 6: 320 |
| PMID | 25859230 |
| Title | Complexities of emotional responses to social and non-social affective stimuli in schizophrenia. |
| Abstract | Adaptive emotional responses are important in interpersonal relationships. We investigated self-reported emotional experience, physiological reactivity, and micro-facial expressivity in relation to the social nature of stimuli in individuals with schizophrenia (SZ). Galvanic skin response (GSR) and facial electromyography (fEMG) were recorded in medicated outpatients with SZ and demographically matched healthy controls (CO) while they viewed social and non-social images from the International Affective Pictures System. Participants rated the valence and arousal, and selected a label for experienced emotions. Symptom severity in the SZ and psychometric schizotypy in CO were assessed. The two groups did not differ in their labeling of the emotions evoked by the stimuli, but individuals with SZ were more positive in their valence ratings. Although self-reported arousal was similar in both groups, mean GSR was greater in SZ, suggesting differential awareness, or calibration of internal states. Both groups reported social images to be more arousing than non-social images but their physiological responses to non-social vs. social images were different. Self-reported arousal to neutral social images was correlated with positive symptoms in SZ. Negative symptoms in SZ and disorganized schizotypy in CO were associated with reduced mean fEMG. Greater corrugator mean fEMG activity for positive images in SZ indicates valence-incongruent facial expressions. The patterns of emotional responses differed between the two groups. While both groups were in broad agreement in self-reported arousal and emotion labels, their mean GSR, and fEMG correlates of emotion diverged in relation to the social nature of the stimuli and clinical measures. Importantly, these results suggest disrupted self awareness of internal states in SZ and underscore the complexities of emotion processing in health and disease. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |
| 5 | Front Psychol 2015 -1 6: 320 |
| PMID | 25859230 |
| Title | Complexities of emotional responses to social and non-social affective stimuli in schizophrenia. |
| Abstract | Adaptive emotional responses are important in interpersonal relationships. We investigated self-reported emotional experience, physiological reactivity, and micro-facial expressivity in relation to the social nature of stimuli in individuals with schizophrenia (SZ). Galvanic skin response (GSR) and facial electromyography (fEMG) were recorded in medicated outpatients with SZ and demographically matched healthy controls (CO) while they viewed social and non-social images from the International Affective Pictures System. Participants rated the valence and arousal, and selected a label for experienced emotions. Symptom severity in the SZ and psychometric schizotypy in CO were assessed. The two groups did not differ in their labeling of the emotions evoked by the stimuli, but individuals with SZ were more positive in their valence ratings. Although self-reported arousal was similar in both groups, mean GSR was greater in SZ, suggesting differential awareness, or calibration of internal states. Both groups reported social images to be more arousing than non-social images but their physiological responses to non-social vs. social images were different. Self-reported arousal to neutral social images was correlated with positive symptoms in SZ. Negative symptoms in SZ and disorganized schizotypy in CO were associated with reduced mean fEMG. Greater corrugator mean fEMG activity for positive images in SZ indicates valence-incongruent facial expressions. The patterns of emotional responses differed between the two groups. While both groups were in broad agreement in self-reported arousal and emotion labels, their mean GSR, and fEMG correlates of emotion diverged in relation to the social nature of the stimuli and clinical measures. Importantly, these results suggest disrupted self awareness of internal states in SZ and underscore the complexities of emotion processing in health and disease. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |
| 6 | Front Psychol 2015 -1 6: 320 |
| PMID | 25859230 |
| Title | Complexities of emotional responses to social and non-social affective stimuli in schizophrenia. |
| Abstract | Adaptive emotional responses are important in interpersonal relationships. We investigated self-reported emotional experience, physiological reactivity, and micro-facial expressivity in relation to the social nature of stimuli in individuals with schizophrenia (SZ). Galvanic skin response (GSR) and facial electromyography (fEMG) were recorded in medicated outpatients with SZ and demographically matched healthy controls (CO) while they viewed social and non-social images from the International Affective Pictures System. Participants rated the valence and arousal, and selected a label for experienced emotions. Symptom severity in the SZ and psychometric schizotypy in CO were assessed. The two groups did not differ in their labeling of the emotions evoked by the stimuli, but individuals with SZ were more positive in their valence ratings. Although self-reported arousal was similar in both groups, mean GSR was greater in SZ, suggesting differential awareness, or calibration of internal states. Both groups reported social images to be more arousing than non-social images but their physiological responses to non-social vs. social images were different. Self-reported arousal to neutral social images was correlated with positive symptoms in SZ. Negative symptoms in SZ and disorganized schizotypy in CO were associated with reduced mean fEMG. Greater corrugator mean fEMG activity for positive images in SZ indicates valence-incongruent facial expressions. The patterns of emotional responses differed between the two groups. While both groups were in broad agreement in self-reported arousal and emotion labels, their mean GSR, and fEMG correlates of emotion diverged in relation to the social nature of the stimuli and clinical measures. Importantly, these results suggest disrupted self awareness of internal states in SZ and underscore the complexities of emotion processing in health and disease. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics, schizotypy, schizotypal |