The relationship between skin conductance hyporesponsivity and perseverations in schizophrenia patients

Complexity and Cognitive Engagement in the Rorschach Task: An fMRI Study

Recently, an eye-tracking study found that Complexity and other R-PAS variables located in the Engagement and Cognitive Processing domain correlated with a proxy marker for cognitive effort and engagement. The goal of the current study was to test the robustness and validity of those eye-tracking findings by inspecting fMRI data. We hypothesized that the greater the level of engagement and cognitive effort put in place by a Rorschach test-taker, the greater the engagement of his/her cortical areas reflecting ongoing top-down attentional processes should be. We re-analyzed archival fMRI data from 26 healthy participants exposed to the Rorschach inkblots with the instruction to think of what they might be. The association of various Engagement and Cognitive Processing R-PAS scores to increased BOLD signals in the Dorsal Attention Network of the brain was examined. As expected, Complexity showed the strongest effect size across all R-PAS variables under investigation (d = 0.43), followed by Synthesis (d = 0.32) and Human Movement (d = 0.21). Noteworthy, the correlation between the effect sizes found in the current fMRI study and those found in the previously published eye-tracking study consists of an impressive r = .80.

Complexity and Cognitive Engagement in the Rorschach Task: An Eye-Tracking Study

This study investigated whether complexity and the other related Rorschach Performance Assessment System (R-PAS) variables in the engagement and cognitive processing domain would associate with eye-tracking measures reflecting increased cognitive engagement and effort while visually scanning the Rorschach inkblots. A nonclinical sample of 71 adult volunteers were administered the Rorschach task while their eye movements were recorded using an eye tracker. Then, the average duration of fixations, the average number of fixations, the average amplitude of saccades, and the average maximum pupil size recorded during the response phase (RP) of the Rorschach administration were correlated with protocol-level, R-PAS variables located in the engagement and cognitive processing. As expected, complexity correlated, with a large effect size (r = .526, p < .01), with the number of fixations occurring during the RP of Rorschach administration. Some other variables related to complexity (e.g., Synthesis, Sy) also produced similar associations. The other eye-tracking variables under examination, however, produced weak or nonsignificant correlations.

Neural activity during production of rorschach responses: An fMRI study

Recently, a lot of effort has been made to ground Rorschach interpretations to their evidence base. To date, however, no studies have yet described, via fMRI, what brain areas get involved when one takes the Rorschach. To fill this gap in the literature, we administered the ten-inkblot stimuli to 26 healthy volunteers during fMRI. Analysis of BOLD signals revealed that, compared to fixating a cross, looking at the Rorschach inkblots while thinking of what they might be associated with higher temporo-occipital and fronto-parietal activations, and with greater activity in some small, sub-cortical regions included in the limbic system. These findings are in line with the traditional conceptualization of the test, as they suggest that taking the Rorschach involves (a) high-level visual processing, (b) top-down as well as bottom-up attentional processes, and (c) perception and processing of emotions and emotional memories.

Beat-to-beat heart rate and QT interval variability in first episode neuroleptic-naive psychosis

INTRODUCTION

Though increased risk of sudden death in patients with schizophrenia is well-documented, the mechanisms remain unclear. Recent studies report two known risk factors for sudden cardiac death and other arrhythmias in schizophrenia, i.e., decreased RR interval variability (RRV) and increased QT interval variability (QTV). However, these studies did not control for the effects of medication. Herein, we report the results of our study comparing RRV and QTV in first episode neuroleptic-naive psychosis patients with healthy matched controls.

METHODS

24 patients with first episode neuroleptic naïve psychosis were matched with 26 healthy controls on age and gender. After an overnight fast, all participants underwent an electrocardiogram recording in the morning.

RESULTS

In comparison with matched controls, patients with first episode neuroleptic-naïve psychosis had significantly increased QTV corrected for RRV, and decreased RRV.

CONCLUSIONS

The observed alterations in RRV and QTV may reflect impaired cardiac autonomic function that could underlie risk for abnormal ventricular repolarization and thereby increase the risk of sudden death and other arrhythmias. Our data suggest that RRV and QTV alterations may be independent of medication effects in first episode psychosis patients.

"Far from the heart far from the eye": evidence from the Capgras delusion

INTRODUCTION

Capgras syndrome is characterised by the belief that a significant other has been replaced by an identical-looking impostor. These patients have no difficulties with visual recognition but fail to show a skin conductance response (SCR) to the objects of the delusion. A case of Capgras delusion (YY), specifically characterised by the absence of brain lesions, constituted a good opportunity to test the relationship between SCR hyporesponsiveness and eye movement patterns to familiar and unfamiliar faces.

METHODS

Visual scan path and SCR were recorded for YY and 8 controls during the presentation of family members' photographs matched with unfamiliar faces of the same sex, age, and physical likeness. Eye movement patterns were explored by selecting three specific areas of interest (AOI) involving the eyes, the mouth, and the face regions.

RESULTS

In contrast with controls, YY showed a reduction in number and sum of fixation durations to the eyes (p<.01) and no differential SCRs (p>.05) to familiar vs. nonfamiliar faces. SCR and fixation duration to family members' eyes were significantly correlated (r=.77) in both YY and controls.

CONCLUSIONS

Eye region exploration seems to be related to the autonomic reactivity elicited by the affective valence of familiar faces.

Electrodermal responsivity distinguishes ERP activity and symptom profile in schizophrenia

BACKGROUND

Traditional averaging of late component Event Related Potentials (ERPs) might obscure important psychophysiological subprocesses underlying schizophrenia disturbances in cognitive functioning. One such subprocess could be the active orientation of attention to significant or novel stimuli. In this study, we used skin conductance responses (SCRs) to index orienting responses (ORs). ERP activity was examined in relation to concomitant ORs in a schizophrenia and nonpsychiatric control group. Schizophrenia responses were considered with respect to the Reality Distortion, Disorganisation and Psychomotor Poverty syndromes.

METHOD

Forty schizophrenia and 40 age and sex matched control subjects were tested. The three schizophrenia syndromes were derived from a principal component analysis of Positive and Negative Syndrome Scale (PANSS) ratings. Auditory ERPs (N100, N200, P200, P300) were elicited using a conventional auditory oddball paradigm, and electrodermal SCR data were acquired simultaneously.

RESULTS

ERP data were sub-averaged according to the presence/absence of an OR. For both 'with-' and 'without-OR' ERPs, schizophrenia subjects as a group showed reduced N100 (associated with vigilance level) and N200 (associated with response selection) amplitude, and for with-OR responses, they showed an additional reduction in P300 (context processing). Concerning schizophrenia syndromes, Reality Distortion was related primarily to frontal disturbances (earlier N100/N200 latency and decreased P200/P300 amplitude), and Psychomotor Poverty to a generally delayed P300 latency. Similarly delayed P300 in Disorganisation was explained by medication effects. There were no associations with syndromes for without-OR ERPs.

CONCLUSION

These results suggest that schizophrenia syndromes are dissociated with regard to both the direction and nature of speed of information processing disturbances, in relation to task-relevant information that produces active orientation.

Skin conductance and schizophrenic symptomatology

Skin conductance is a psychophysiological parameter that reflects fundamental processes such as attention and arousal. The present study explored whether deviations in skin conductance activity are associated with severity of schizophrenic symptoms. For this purpose, Skin Conductance Responses (SCRs) to discrete stimuli (80 dB noises) and Skin Conductance Levels (SCLs) of 37 schizophrenic patients and 31 healthy volunteers were recorded. In accordance with previous studies, schizophrenic patients were found to be hyporesponsive compared to healthy controls. More specifically, almost half of the patients (46%) did not react with any SCR to the first 3 stimuli, whereas only 10% of the control group exhibited such a non-responding. Accordingly, the mean amplitude of the first 3 SCRs - as measured in u Siemens - was found to be significantly lower in patients compared to controls. As well, mean SCL was found to be (marginally) elevated in the patient group. This was especially the case for patients who did exhibit SCRs. In the patient group, a negative correlation was found between amplitude of SCRs and symptom severity. This association was mainly carried by a significant correlation between positive symptoms and reduced SCRs. The clinical relevance of these findings is discussed in detail.