Biomedical subjects

Martin Ruchsow

Publications and source records attributed to Martin Ruchsow.

8 recordsLinked to original sources

PubMed2006

Measuring attachment representation in an FMRI environment: a pilot study.

This exploratory study is the first to examine the neural correlates of attachment status in adults. The study examined the feasibility of assessing attachment narratives in the functional magnetic resonance imaging (fMRI) environment by challenging subjects to tell attachment stories to specific attachment pictures from the Adult Attachment Projective (AAP) while being scanned. We investigated theoretically derived hypotheses regarding predicted differences in the brain activation patterns of individuals whose attachment status was organized (resolved) versus disorganized (unresolved) with respect to attachment trauma (e.g., as associated with loss through death, abuse, threat of abandonment). Adult attachment was assessed using the AAP, a new representational attachment measure that we thought might be suitable for use in the fMRI environment. This measure was used to obtain a preliminary picture of the neural processes associated with the activation of attachment in 11 healthy female adults. Results are reported from a second-level analysis (p < 0.001 uncorrected) and confirm that the AAP is a feasible measure for use in a neuroimaging environment. Cerebral activation during continuous speech yielded results consistent with the literature. Brain activation was demonstrated in expected visual and semantic brain regions. Furthermore, we found that the rate of articulation was positively correlated with activation in the right superior temporal gyrus. The results of theoretically derived attachment hypotheses showed no differences at the chosen level of significance when comparing the 'all attachment pictures' effect between both groups (resolved vs. unresolved). More interestingly, we found a significant interaction effect between the sequence of pictures and attachment category. Only the unresolved participants showed increasing activation of medial temporal regions, including the amygdala and the hippocampus, in the course of the AAP task. This pattern was demonstrated especially at the end of the AAP task where the pictures are drawn to portray traumatic situations. We interpret these results as confirming our hypothesis, linking unresolved attachment to emotional dysregulation of the attachment system. These results are discussed in relation to assessing attachment in an fMRI environment and future research in this area.

Adult↗

PubMed2006

Error processing in major depressive disorder: evidence from event-related potentials.

In a previous study we showed that errors following errors activate a strategic (prefrontal) mechanism. In an error trial (trial n) following an erroneous previous trial (trial n - 1) healthy control subjects were found to have enlarged (more negative) amplitudes of the error related negativity (ERN)/error negativity (Ne), an electrophysiological correlate of response monitoring, in response to a negative feedback signal. Contrary to that, patients with major depressive disorder showed smaller (less negative) ERN/Ne amplitudes. It has been discussed controversially whether errors of choice (e.g., pressing an incorrect response button in an Eriksen flanker task) and errors of commission (e.g., pressing a button when one is not supposed to in a Go/Nogo task) are related to different ERN/Ne mechanisms. In the present study, we examined whether our previous result only holds for errors of choice in an Eriksen flankers task or extends to errors of commission in a Go/Nogo task, as well. Ten patients with DSM-IV major depressive disorder and 10 matched controls participated in a Go/Nogo task with performance feedback which signaled monetary reward. Patients with major depressive disorder again showed a less negative ERN/Ne amplitude in error trials following error trials. This result might reflect impaired response monitoring processes in major depressive disorder resulting from an impaired activation of a central reward pathway and/or a deficit in strategic reasoning.

Adult↗

PubMed2005

Electrophysiological correlates of error processing in borderline personality disorder.

The electrophysiological correlates of error processing were investigated in patients with borderline personality disorder (BPD) using event-related potentials (ERP). Twelve patients with BPD and 12 healthy controls were additionally rated with the Barratt impulsiveness scale (BIS-10). Participants performed a Go/Nogo task while a 64 channel EEG was recorded. Three ERP components were of special interest: error-related negativity (ERN)/error negativity (Ne), early error positivity (early Pe) reflecting automatic error processing, and the late Pe component which is thought to mirror the awareness of erroneous responses. We found smaller amplitudes of the ERN/Ne in patients with BPD compared to controls. Moreover, significant correlations with the BIS-10 non-planning sub-score could be demonstrated for both the entire group and the patient group. No between-group differences were observed for the early and late Pe components. ERP measures appear to be a suitable tool to study clinical time courses in BPD.

Adult↗

PubMed2005

Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge.

OBJECTIVE: To verify findings of an independently regulated anterior limbic alpha band source. METHODS: In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t-statistical parametric mapping [SPM[t]]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. RESULTS: Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18, and in the anterior cingulate cortex [ACC], BA 32. Statistical parametric mapping showed reduced parieto-occipital, but unaltered frontal alpha band power after lorazepam. This result was confirmed by ROI-based comparison of BA 18 and BA 32. CONCLUSIONS: There was an anterior limbic maximum of alpha band activity which, unlike occipital alpha, was not suppressed by lorazepam. SIGNIFICANCE: The well-known anterior alpha band components may originate from a narrowly circumscribed source, located in the ACC. Frontal and occipital alpha band activities appear to be independently regulated.

Adult↗

PubMed2005

Error processing and impulsiveness in normals: evidence from event-related potentials.

Electrophysiological correlates of impulsiveness were investigated in thirty-two healthy subjects using event-related potentials (ERP). Impulsiveness was determined by calculating individual reaction times (as a function of general response speed) in order to split the entire group into two subgroups with a more controlled (n = 16) and less controlled (n = 16) response style. Participants performed a Go/Nogo task while a 64 channel EEG was recorded. Artifact-free EEG segments were used to compute ERPs on correct Go trials and incorrect Nogo trials, separately. Three ERP components were of special interest: the error-related negativity (ERN)/error negativity (Ne) and the "early" error positivity (Pe) reflecting automatic error processing and the "late" error positivity (Pe) which is thought to mirror the awareness of erroneous responses. Subjects with higher impulsiveness showed smaller amplitudes than subjects with lower impulsiveness for the ERN/Ne component and the "early" Pe component. With regard to the "late" Pe groups did not differ. Hence, ERP measures appear suitable for detailed analyses of impulsiveness in healthy participants. Moreover, present results argue for the necessity of careful control of impulsiveness when including normal comparison groups in the context of clinical studies.

Adult↗

PubMed2004

The effect of erroneous responses on response monitoring in patients with major depressive disorder: a study with event-related potentials.

Perceived failure is reported to have detrimental effects on subsequent performance in patients with major depressive disorder. We investigated the error-related negativity (ERN)/error negativity (Ne), an electrophysiological correlate of response monitoring, using a 64-channel EEG. Sixteen patients with DSM-IV major depressive disorder and 16 matched controls participated in an Eriksen flanker task with continuous performance feedback that signaled monetary reward. Compared to controls, patients with major depressive disorder showed a less negative ERN/Ne in error trials following error trials. This result might reflect impaired response monitoring processes in major depressive disorder resulting from an underactivity in a central reward pathway and/or a deficit in strategic reasoning.

Adult↗

PubMed2003

Semantic and syntactic processes during sentence comprehension in patients with schizophrenia: evidence from event-related potentials.

Language and thought disorders are core symptoms in schizophrenia. We therefore studied language comprehension processes in patients with schizophrenia and control subjects during a sentence processing paradigm using event-related potentials (ERPs). In the ERP, assignment of syntactic structure to a string of words is reflected by an early left anterior negativity (ELAN) at about 80 ms after stimulus onset. Integration of syntactic and semantic information into a coherent representation is indexed by a positive potential at 600 ms (P600). Amplitudes of the ELAN and the P600 components are higher for grammatically incorrect sentences. Semantic processes are associated with a negative deflection peaking at 400 ms (N400). N400 amplitude is higher in semantically incongruent sentences. Nineteen patients with DSM IV schizophrenia and 19 healthy controls were presented with correct, semantically incorrect (semantic mismatch) and grammatically incorrect sentences (syntactic mismatch). Syntactic mismatch elicited an ELAN component in both subject groups. However, only controls but not patients with schizophrenia exhibited a P600 syntactic mismatch effect. Semantic mismatch was associated with a larger N400 potential which did not differ between groups. These results suggest that patients with schizophrenia are not impaired in syntactic structure assignment as reflected by the ELAN, but show deficits in semantic-syntactic integration processes underlying the P600.

Adult↗

PubMed2002

Human anterior cingulate cortex is activated by negative feedback: evidence from event-related potentials in a guessing task.

It has been controversially discussed whether the error-related negativity (ERN) or error negativity (N(e)), an electrophysiological index of anterior cingulate activation, reflects response conflict or response evaluation subserving error monitoring processes. We investigated event-related potentials (ERPs) in a guessing task which did not induce response conflict. Subjects had to guess which of the four aces of a French card play would be presented next and received feedback at random. We observed a negative ERP deflection in trials following negative feedback which was identified as ERN/N(e). Dipole analysis of scalp potentials indicated sources in the anterior cingulate and left inferior prefrontal cortex. The observation of the ERN/N(e) following negative feedback during guessing suggests that this ERP component mirrors response evaluation processes comparing expected and actual response outcome rather than response conflict.

Adult↗