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Biomedical subjects

G Northoff

Publications and source records attributed to G Northoff.

At least 19 recordsLinked to original sources
PubMed2006

[Neuroethics--a future discipline?].

Progress in neuroscience leads not only to novel therapeutic opportunities but also raises several ethical problems. These problems are often subsumed under the term "neuroethics," of which the definition and purpose often remain unclear. We discuss the problems of informed consent, free will, sense of self, and personality in light of recent neuroscientific progress. Due to distinct categories and frames of reference, these philosophical-ethical terms cannot be limited only to the brain; the development of systematic relations is suggested. This accounts for the "special ethical position of the brain." It is concluded that only this sense can neuroethics account for the ethical complexity in neuropsychiatric disorders.

Ethics, Medical↗
PubMed2006

[Subjective experience and neuronal integration in the brain: do we need a first-person neuroscience?].

Unlike other medical disciplines psychiatry can be characterized by the special importance of subjective experience. Since subjective experience is tied to First-Person-Perspective and investigation of the brain is possible only in Third-Person-Perspective, the question how subjective experience can be linked to neuronal processes is raised in psychiatry. We suggest a novel methodological approach, First-Person-Neuroscience where subjective experience can be linked directly and systematically to neuronal processes. Due to complexity of the structures and contents of subjective experience, localization in specific brain regions seems inappropriate. Instead, the interplay and coordination of neuronal activity across several brain regions, so-called neuronal integration, should be considered in First-Person-Neuroscience. This is illustrated by two principles of neuronal integration, top-down modulation and reciprocal modulation, whose abnormal function can be related to subjective experience of patients with catatonia and depression. It is concluded that First-Person-Neuroscience can contribute to reveal abnormal brain function in psychiatric disorders and ultimately to development of diagnostic and therapeutic markers.

Brain↗
PubMed2006

[Neurobiological basis of depressive disorders].

Depressive disorders belong to the most frequent diseases worldwide showing a lifetime prevalence of up to 20%. Moreover they are one of the leading causes for the amount of years lived with disability. Increasing knowledge about the pathological mechanisms underlying depressive syndromes is obtained by using modern neurobiological research-techniques. Thereby some older theories that have been the basis of emotion-research for decades--like the monoamine hypothesis--have been strengthened. In addition new aspects of the pathological processes underlying depressive disturbances have been unraveled. In this review established models and recent findings will be discussed, to bridge various research-fields, ranging from genetics, epigenetics and morphological changes to the functional consequences of depression. Finally therapeutic implications that could be derived from these results will be presented, showing up putative possibilities for diagnosis and treatment of depressive syndromes.

Brain↗
PubMed2003

Differential effects of low-frequency rTMS at the occipital pole on visual-induced alpha desynchronization and visual-evoked potentials.

Visual-induced alpha desynchronization (VID) and visual-evoked potentials (VEPs) characterize occipital activation in response to visual stimulation but their exact relationship is unclear. Here, we tested the hypothesis that VID and VEPs reflect different aspects of cortical activation. For this purpose, we determined whether VID and VEPs are differentially modulated by low-frequency repetitive transcranial magnetic stimulation (rTMS) over the occipital pole. Scalp EEG responses to visual stimuli (flashed either to the left or to the right visual field) were recorded for 8 min in six healthy subjects (1) before, (2) immediately following, and (3) 20 min after left occipital rTMS (1 Hz, 10 min). The parameters aimed to reduce cortical excitability beyond the end of the TMS train. In addition, simple reaction times to visual stimulation were recorded (left or right hand in separate blocks). In all subjects, VID was significantly and prominently reduced by rTMS (P = 0.0001). In contrast, rTMS failed to modulate early VEP components (P1/N1). A moderate effect was found on a late VEP component close to manual response onset (P = 0.014) but this effect was in the opposite direction to the VID change. All changes were restricted to the targeted left occipital cortex. The effects were present only after right visual field stimulation when a right hand response was required, were associated with a behavioral effect, and had washed out 20 min after rTMS. We conclude that VID and early VEPs represent different aspects of cortical activation. The findings that rTMS did not change early VEPs and selectively affected VID and late VEPs in conditions where the visual input must be transferred intrahemispherically for visuomotor integration (right visual field/right hand) are suggestive of rTMS interference with higher-order visual functions beyond visual input. This is consistent with the idea that alpha desynchronization serves an integrative role through a corticocortical "gating function."

Adult↗
PubMed2003

Effects of single-pulse transcranial magnetic stimulation (TMS) on functional brain activity: a combined event-related TMS and evoked potential study.

OBJECTIVE: To further evaluate the potential of slew-rate limiting amplifiers to record electrophysiological signals in spite of concurrent transcranial magnetic stimulation (TMS), and to explore the effects of single-pulse TMS on electroencephalographic (EEG) correlates of functional brain activity. METHODS: Visual-evoked potentials (VEPs) to checkerboards were recorded in 7 right-handed subjects, while single-pulse TMS was applied to the occipital pole either at visual stimulus onset, during the build-up or at the expected peak of the early VEP component P1 (VIS&TMS). Timing of TMS was individually adjusted based on each subject's VEP-latency. A condition of TMS without concurrent visual stimulation (TMS(alone)) served for subtraction purposes (VIS&TMS minus TMS(alone)) to partial out TMS-related contaminations of the EEG signal. RESULTS: When TMS was applied at visual stimulus onset, VEPs (as calculated by subtraction) perfectly matched control VEPs to visual stimulation alone. TMS at around P1, in contrast, modified the targeted (P1) and the subsequent VEP component (N1), independently of whether TMS was given at build-up or peak. CONCLUSIONS: The retrieval of regular VEPs with concomitant TMS at visual stimulus onset suggests that the employed EEG system and subtraction procedure are suited for combined EEG-TMS studies. The VEP changes following TMS at around P1 provide direct clues on the temporal dynamics of TMS pulse effects on functional activity in the human brain. Our data suggest effects of relatively long duration (approximately 100 ms) when TMS is applied while functional neuronal activity evolves.

Adult↗
PubMed2002

Catatonia and neuroleptic malignant syndrome: psychopathology and pathophysiology.

Catatonia was originally described as a psychomotor syndrome in the 19th century by Kahlbaum including motor, affective and behavioral symptoms. Later, at the beginning of the 20th century, catatonia was rather considered as the motoric manifestation of schizophrenia. Accordingly, neuropathological research focused predominantly on those neuroanatomical substrates, i.e. the basal ganglia being primarily involved in the generation of movements. Even though some authors observed minor alterations in the basal ganglia, consistent findings in these subcortical structures could not be obtained. Since neuroleptics can induce catatonic-like symptoms i.e. neuroleptic malignant syndrome (NMS), there has been a recent re-emergence in clinical and scientific interest in catatonia. However, exact psychopathological and pathophysiological characterization of both NMS and catatonia remains unclear.Clinically, catatonia and NMS show more or less similar motor symptoms i.e. akinesia. These may be accounted for by dysregulation in cortical-subcortical circuits between motor/premotor cortex and basal ganglia i.e. the so-called "motor loop". While in NMS the "motor loop" may be dysregulated by neuroleptic blockade of subcortical striatal D-2 receptors one may rather assume cortical gaba-ergic alteration in catatonia. The premotor/motor cortex and consecutively the "motor loop" may be dysregulated by gaba-ergic abnormalities in orbitofrontal cortex. Gaba-ergic cortical dysfunction may account for affective and behavioural abnormalities in catatonia which cannot be observed as such in NMS. Consequently, one may characterize catatonia as a cortical "psychomotor syndrome" while NMS may rather be regarded as subcortical "motor syndrome".

Catatonia↗
PubMed2001

Serum levels of amitriptyline and therapeutic effect in non-delusional moderately to severely depressed in-patients: a therapeutic window relationship.

In a prospective, open clinical study, the relationship between serum levels of amitriptyline (At) and nortriptyline (Nt) and the therapeutic effect after 6 weeks of treatment was investigated. Serum levels were measured by gas-liquid chromatography and the therapeutic effect was assessed by the Hamilton Depression Rating Scale (HAMD) and the Clinical Global Impression Scale (CGI). A number of 25 non-delusional, moderate to severely depressed inpatients were included. A therapeutic window relationship was detected by means of regression analysis (quadratic model). Low and high serum levels were associated with low therapeutic effect. In an intermediate range, the probability of good therapeutic effect was increased. This relationship reached significance for the serum levels of At (p < 0.05) and a trend for the sum of serum levels of At and Nt (p < 0.1). As expressed by the regression coefficient r2, about 25% to 35% of the variability of therapeutic effect was explained by serum levels. Dichotomized data sets according to limits of final values of HAMD and CGI as well as limits of a therapeutic window of 70 ng/ml and 200 ng/ml (sum of At and Nt) revealed significant differences by means of Fisher's exact test (p < 0.05). Furthermore, increased ratios of serum level of Nt per serum level of At were found to be associated with decreased therapeutic effect. Thus, the present data support the existence of a therapeutic window of serum levels of At in depression. Also taking into account other reports, this therapeutic window can be defined as being between about 70 and 220 ng/ml. The assay of serum levels of At can be used to lower the risk of unsatisfactory therapeutic outcome.

Adult↗
PubMed2000

Delayed onset of late movement-related cortical potentials and abnormal response to lorazepam in catatonia.

Catatonia is a psychomotor syndrome with an inability to execute and terminate movements completely, leading consecutively to akinesia and posturing, which both respond almost immediately to benzodiazepines, i.e. gaba-potentiators like lorazepam. However, pathophysiological mechanisms of cortical motor and gaba-ergic dysfunction remain unclear. We therefore investigated movement-related cortical potentials (MRPs) and movement kinematics during a motor task before and after lorazepam. Ten akinetic catatonic patients were compared with 10 psychiatric (similar age, sex, medication, and underlying psychiatric disease but without catatonic syndrome) and 20 healthy controls. MRPs from frontal (F), central (C), and parietal (P) sites were recorded to obtain measures of early and late readiness potential and movement potential. Kinematic measures included parameters for amplitude of movements, peak velocity, average duration of movements, elevation angle, and angle velocity. The motor task consisted in self-initiated extension of the right index finger. All catatonic and psychiatric control patients received intravenous lorazepam (1mg), whereas healthy controls were subjected to a placebo-controlled (10 received lorazepam, 10 received placebo) double-blind study design.Catatonics showed a significantly delayed onset of late readiness and movement potential in central electrodes (Cz, C3) compared with psychiatric and healthy controls. This delayed onset correlated significantly with catatonic motor symptoms and movement duration. Lorazepam led to significantly stronger delays in onset of late readiness potential in left fronto-parietal (F3, C3, P3) electrodes in catatonic patients than in psychiatric and healthy controls. It is concluded that delayed latencies in late MRP components in catatonic patients may reflect their inability to execute and terminate movements completely. Differential and stronger response to lorazepam in catatonia suggests dysfunction in inhibitory control of cortical motor function with increased gaba-ergic sensitivity.

Adult↗
PubMed2000

[Effect of activation tasks on acute neuroleptic-induced akathisia].

In this study, we investigated experimentally the effects of different activation procedures on both motor and psychic symptoms in of 11 in-patients with acute neuroleptic-induced akathisia using the Hillside and Barnes akathisia rating scales and videotape rating technique. Motor activation was achieved by finger tapping. Cognitive activation tasks consisted of sequences of mental calculations which were designed either to be easy to perform or to produce stress due to a given time limit or to more difficult calculation operations, respectively. Motor as well as psychic symptoms of akathisia decreased during both motor and simple cognitive activation without stress. By contrast, stress-producing calculation tasks led to an increase in motor and psychic symptoms immediately following the task performance. These possibly specific effects of activation procedures on symptoms might be useful in differentiating acute neuroleptic-induced akathisia from other neuroleptic-induced and extrapyramidal movement disorders.

Adult↗
PubMed2000

Personality and object relations in patients with affective disorders: idiographic research by means of the repertory grid technique.

BACKGROUND: This paper presents an idiographic approach to evaluate the self concept and the self-object-relationship of patients suffering from affective disorders. METHODS: Significant dimensions of the personality and the object relations of 127 depressive patients and 34 orthopaedic patients were investigated with the repertory grid-technique. The self concept and the object relations were compared by means of nomothetically used idiographic results after recovery from manifest depression. RESULTS: 'Low self esteem' was frequently found in patients with a long lasting course of illness and the ICD-10-diagnoses of 'bipolar affective disorder' and 'dysthymia'. The object relations of the depressive sample were characterised by the dimension 'symbiotic near'; 'ambivalent' and 'indifferent' partnership relationships were found much more frequently in the controls. CONCLUSIONS: The idiographic results help to differentiate the spectrum of affective disorders. They underline the importance of the interpersonal dimension of depression and may be used as a basis of a therapeutic appraisal. LIMITATIONS: The repertory grid-technique may not be used as a diagnostic instrument. However, the combination of idiographic results with further clinical informations enables the multidimensional assessment of the self concept and psychosocial coping mechanisms.

Adaptation, Psychological↗
PubMed2000

Right lower prefronto-parietal cortical dysfunction in akinetic catatonia: a combined study of neuropsychology and regional cerebral blood flow.

BACKGROUND: Catatonia is a psychomotor syndrome that can be characterized by behavioural, affective and motor abnormalities. In order to reveal further underlying pathophysiological mechanisms of psychomotor disturbances in catatonia we investigated neuropsychological function and regional cerebral perfusion (r-CBF) in a combined study. METHODS: Ten catatonic patients were investigated with Tc-99mECD brain SPECT and compared with 10 psychiatric (similar age, sex, medication and underlying psychiatric diagnosis but without catatonic syndrome) and 20 healthy controls. Neuropsychological measures included tests for general intelligence, attention, executive functions and right parietal visual-spatial abilities. Correlational analyses were performed between neuropsychological measures, catatonic symptoms and r-CBF. RESULTS: Catatonic patients showed a significant decrease of r-CBF in right lower and middle prefrontal and parietal cortex compared with psychiatric and healthy controls as well as significantly poorer performance in visual-spatial abilities associated with right parietal function. Correlational analysis revealed significant correlations between visual-spatial abilities and right parietal r-CBF only in psychiatric and healthy controls but not in catatonic patients. In contrast, attentional measures correlated significantly with motor symptoms, visual-spatial abilities and right parietal r-CBF in catatonia only but not in psychiatric or in healthy controls. CONCLUSION: Findings are preliminary but suggest right lower prefronto-parietal cortical dysfunction in catatonia, which may be closely related to psychomotor disturbances.

Adult↗
PubMed2000

[Self concept and object relations of patients with affective disorders--individual centered diagnosis with the repertory-grid technique].

Significant dimensions of the self concept and the object relations of 127 depressive patients and 34 orthopaedic patients were investigated with the repertory-grid-technique. Self concept and object relations were compared by means of nomothethically used idiographic results after recovery from manifest depression. The object relations of the depressive sample were characterised by the dimension "symbiotic near"; "ambivalent" and "indifferent" partnership relationships were found much more frequently in the controls. The idiographic results contribute to a differentiation of the spectrum of affective disorders. They underline the importance of the interpersonal dimension of depression and may be used as a basis of a therapeutic orientation.

Adult↗
PubMed2000

Functional dissociation between medial and lateral prefrontal cortical spatiotemporal activation in negative and positive emotions: a combined fMRI/MEG study.

The orbitofrontal cortex has been cytoarchitectonically and connectionally subdivided into a medial and a lateral part which are assumed to subserve distinct functions in emotional processing. However the exact spatiotemporal mechanisms of negative and positive emotional processing in medial and lateral orbitofrontal cortex remain unclear. We therefore investigated spatiotemporal orbitofrontal and prefrontal cortical activation patterns during emotional stimulation in a combined fMRI/MEG study. We investigated 10 healthy subjects, 5 women and 5 men. Positive and negative pictures from the International Affective Picture system (IAPS) were used for emotional stimulation, whereas neutral and gray pictures were taken as control conditions. fMRI/MEG measurements covered the whole frontal lobe and a time window between -2000 and +200 ms around motor responses (right index finger extension) associated with each picture. Positively and negatively correlated activities were determined in various prefrontal/frontal cortical regions in fMRI. Isocontour maps and single dipoles in MEG were analyzed in 50 ms time windows ranging from -2000 to +200 ms. Dipoles and fMR images were mapped on three-dimensional anatomical MRI so that anatomical localization of single dipoles and regional fMRI activity could be compared. Both negative and positive emotional conditions differed from non-emotional control conditions by strong orbitofrontal and lateral prefrontal activation as well as by the presence of early magnetic fields (-1700 to +1100 ms). Negative emotional processing was characterized by strong medial orbitofrontal activation and earlier (-1700 ms), stronger and more medially oriented orbitofrontal dipoles. In contrast positive emotional processing showed a rather strong activation in lateral prefrontal cortex with later (-1500 ms), weaker and more laterally oriented orbito and prefrontal dipoles. Negative emotional processing can be characterized by strong and early medial orbitofrontal cortical activation, whereas positive emotional processing showed rather later and weaker activation in lateral orbitofrontal/prefrontal cortex. Such a functional dissociation between medial and lateral orbito-frontal/prefrontal cortex during negative and positive emotional processing lends further support to the assumption of a functional subdivision in the orbitofrontal cortex.

Adult↗
PubMed2000

[Reconstruction of mutism. Studies of subjective experiences of former patients with the modified Landfield categories].

OBJECTIVE: The subjective experience of catatonic patients was investigated with the repertory grid-technique after recovery from the acute state of disease and compared with non-catatonic schizoaffective and depressive patients. METHODS: The sample consists of 18 catatonic patients, 22 schizoaffective, 16 unipolar depressive, 8 unipolar manic and 23 patients with bipolar affective disorder as well as of 32 psychiatrically healthy orthopaedic controls. Interviews were held well before discharge. The contents of personal constructs was analyzed by means of modified Landfield categories. RESULTS: "Self" of catatonic patients did not differ significantly from the other groups. The "Idealself" of catatonic patients differed significantly in the categories "high self esteem" (from the controls and the non-catatonic group) and "high empathy" (from the controls). The "disease-self" ("In the acute catatonic state") was construed as isolated (lack of social contact). The results underline the importance of an active therapeutical interaction in the acute catatonic state. The modified Landfield Categories proved to be a useful psychodiagnostic instrument for the idiographic assessment of personality in particular, and for psychiatric therapy research in general.

Adult↗
PubMed1999

Cortical sulcal enlargement in catatonic schizophrenia: a planimetric CT study.

To determine whether patients with catatonic schizophrenia have specific alterations in brain morphology, internal (ventricles) and external (frontal, temporal, parieto-occipital) components of the cerebrospinal fluid (CSF) spaces were examined morphometrically. Planimetric measurements of computed tomographic (CT) scans from 37 patients with catatonic schizophrenia, 28 patients with hebephrenic schizophrenia, and 39 patients with paranoid schizophrenia, all diagnosed according to DSM-III-R criteria, were compared with separate age- and sex-matched non-psychiatric control groups, respectively. The areas of the frontal sulci, the parieto-occipital sulci, the inter-hemispheric fissure, and the lateral and third ventricles were measured separately for the right and left hemispheres. Catatonic patients showed significant enlargements in almost all CSF spaces, especially in the left fronto-temporal area which, in addition, correlated significantly with illness duration. Hebephrenic patients showed selective enlargements in left temporal and left/right lower frontal cortical sulci, whereas paranoid schizophrenic patients showed no enlargements but significant correlations between left temporal cortical sulcal volume and illness duration. Alterations in temporal cortical areas were present in all three sub-types of schizophrenia. In addition to temporal alterations, hebephrenic schizophrenia was characterised by lower frontal (i.e. orbitofrontal) enlargement. Catatonic schizophrenia, the most severe sub-type with regard to clinical symptomatology and brain pathology, showed fronto-parietal cortical alterations.

Adult↗
PubMed1999

Impairment in visual-spatial function in catatonia: a neuropsychological investigation.

Catatonia is a psychomotor syndrome with motor and behavioral abnormalities which may be due to alterations in fronto-parietal cortical function. We therefore investigated neuropsychological tasks (attention, executive, visual-spatial, working memory) associated with frontal and parietal cortical function. Thirteen catatonic patients, diagnosed as catatonic according to criteria by Rosebush and Bush, were compared with 13 psychiatric non-catatonic controls (matched with regard to underlying psychiatric diagnosis, age, sex, and medication), and 13 age- and sex-matched healthy controls. Catatonics showed significantly poorer performances and different neuropsychological intercorrelation patterns in visual spatial object perception (VOSPobject) than psychiatric and healthy controls. In addition, we found significant correlations between catatonic symptoms, visual-spatial abilities, and attentional measures (i.e., d2, CWI). Catatonia was characterized by specific visual-spatial deficits which are related to attentional abilities and right parietal cortical function. The data suggest attentional-motor and fronto-parietal dysfunction in catatonia, a conclusion which should be considered as preliminary, however, due to the small sample size.

Adult↗
PubMed1999

Catatonia as a psychomotor syndrome: a rating scale and extrapyramidal motor symptoms.

BACKGROUND: Catatonia was first described by Kahlbaum as a psychomotor disease with motor, behavioral, and affective symptoms. In keeping with this concept, we developed a rating scale for catatonia (Northoff Catatonia Scale [NCS]) with three different categories of symptoms (i.e., motor, behavioral, affective). Furthermore, the question of the relationship among catatonic symptoms, extrapyramidal motor symptoms, and neuroleptics was addressed in the present study. METHOD: 34 acute catatonic patients and 68 age-, sex-, diagnosis-, and medication-matched psychiatric control subjects were investigated on days 0, 1, 3, 7, and 21 with the NCS, with other already validated catatonia rating scales by Rosebush, Bush (BFCRS), and Rogers (MRS), as well as with scales for hypokinetic (SEPS) and dyskinetic (AIMS) extrapyramidal motor features. Validity and reliability of the new scale, factor analysis, correlational analysis, and differences between catatonic patients and psychiatric control subjects were statistically calculated. RESULTS: NCS showed high validity (i.e., significant positive correlations [p <0.0001] with the other scales, significant differences between catatonic and control subjects), high intra-and interrater reliabilities (r = 0.80-0.96), and high affective subscores. Factor analysis revealed four factors best characterized as affective, hypoactive, hyperactive, and behavioral. Catatonic scores in NCS correlated significantly with AIMS on day 0 and SEPS on days 7 and 21. There were no significant differences in catatonic (i.e., NCS, MRS, BFCRS) and extrapyramidal (i.e., AIMS, SEPS) scores between neuroleptically treated and untreated catatonic subjects. CONCLUSIONS: The following conclusions were drawn: (1) the NCS has to be considered as a valid and reliable rating instrument for catatonia; (2) catatonia can be characterized by psychomotor symptoms encompassing motor, affective, and behavioral alterations; and (3) extrapyramidal hyperkinesias like dyskinesias are apparently closely related to catatonic symptoms which, in general, seem to be relatively independent of previous neuroleptic medication.

Acute Disease↗