Biomedical subjects

Andres O Ceballos-Baumann

Publications and source records attributed to Andres O Ceballos-Baumann.

9 recordsLinked to original sources

PubMed2005

The functional neuroanatomy of coordinated orofacial movements: sparse sampling fMRI of whistling.

Whistling serves as a model for a skilful coordinated orofacial movement with sensorimotor integration of auditory and proprioceptive input. The neural substrate of whistling was investigated by sparse sampling functional MRI (fMRI) where the motor task occurred during a silent interval between successive image acquisitions to minimize task-related imaging artefacts. Whistling recruited a symmetrically represented neural network including primary motor and ventral premotor cortex (PMv), SMA, cingulate gyrus, basal ganglia, primary and secondary somatosensory cortex, amygdala, thalamus and cerebellum. A temporal analysis revealed higher activity of left sensory cortex, right PMv and cerebellum during late execution compared to initiation of whistling. Task-related signal changes in right PMv and right paravermal cerebellum were found to correlate with the amplitude of the whistle sound in a separate correlation analysis. The findings emphasize the role of ventral premotor cortex, cerebellum and somatosensory areas as integrators of afferent input within a distributed orofacial sensorimotor network.

Adult↗

PubMed2005

A common neural basis for receptive and expressive communication of pleasant facial affect.

There is accumulating evidence suggesting that the visual representation of facial affect is closely linked to its motor representation. To examine whether perception of pleasant facial affect involves neural circuitries associated with its production, we performed an fMRI experiment with 'compressed image acquisition' where subjects smiled and observed movies depicting other people smiling within scan-free time intervals between the acquisition of each image volume. Overlaps between the brain activation during observation and execution of smile expressions were located in the right premotor cortex and pars opercularis of the inferior frontal gyrus, right parietal operculum (SII) and left anterior insula. Observation of smile expressions further yielded signal increases within the posterior superior temporal sulcus (STS), fusiform gyrus and ventral amygdala. The results show that perceiving and expressing pleasant facial affect share a common neural basis in areas concerned with motor as well as somato- and limbic-sensory processing. In concert with temporal regions serving the visual analysis of facial expressive features, a mapping of the observed expressions onto neural circuitries associated with the production of these expressions and its somatosensory consequences could provide a description of what the expression would feel like if produced in the observer. Such a mechanism is suggested to be important for empathic understanding of others' feelings.

Adult↗

PubMed2005

Left inferior parietal dominance in gesture imitation: an fMRI study.

The inability to imitate gestures is an essential feature of apraxia. However, discrepancies exist between clinical studies in apraxic patients and neuroimaging findings on imitation. We therefore aimed to investigate: (1) which areas are recruited during imitation under conditions similar to clinical tests for apraxic deficits; (2) whether there are common lateralized areas subserving imitation irrespective of the acting limb side; and also (3) whether there are differences between hand and finger gestures. We used fMRI in 12 healthy, right handed subjects to investigate the imitation of four types of variable gestures that were presented by video clips (16 different finger and 16 different hand gestures with either the right or the left arm). The respective control conditions consisted of stereotyped gestures (only two gestures presented in pseudorandom order). Subtraction analysis of each type of gesture imitation (variable>stereotyped) revealed a bilateral activation pattern including the inferior parietal cortex Brodmann Area (BA 40), the superior parietal cortex, the inferior frontal cortex (opercular region), the prefrontal motor cortex, the lateral occipito-temporal junction, and the cerebellum. These results were supported by statistical conjunction of all four subtraction analyses and by the common analysis of all four types of gesture imitation. The direct comparison of the right and left hemispheric activation revealed a lateralization to the left only of the inferior parietal cortex. Comparisons between different types of gesture imitation yielded no significant results. In conclusion, gesture imitation recruits bilateral fronto-parietal regions, with significant lateralization of only one area, namely the left inferior parietal cortex. These in vivo data indicate left inferior parietal dominance for gesture imitation in right handers, confirming lesion-based theories of apraxia.

Adult↗

PubMed2003

Subthalamic nucleus stimulation affects a frontotemporal network: a PET study.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an effective strategy in the treatment of motor symptoms in advanced Parkinson's disease. However, clinical studies have shown that DBS can affect verbal fluency. Seven Parkinson's disease patients with bilateral DBS of the STN were studied with positron emission tomography (PET) to investigate the effects of STN stimulation on regional cerebral blood flow during a verbal fluency task. Activation of the right orbitofrontal cortex and verbal fluency-associated activation within a left-sided frontotemporal network were decreased during STN stimulation compared with the OFF state. Our results offer an explanation for the commonest neuropsychological side effect of STN stimulation and show that STN stimulation affects a frontotemporal network during a fluency task.

Aged↗

PubMed2003

Functional imaging in Parkinson's disease: activation studies with PET, fMRI and SPECT.

Activation studies with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) represent a powerful tool to study the functional anatomy of Parkinson's disease (PD). Activation studies offer the opportunity to study regional cerebral function in man in vivo under different conditions with the analysis of task specific changes in regional cerebral blood flow (rCBF) with PET or in the blood oxygenation level dependent (BOLD) effect with fMRI. The combination of PET and deep brain stimulation is particularly attractive to study the effects of discrete perturbations at different target structures throughout the basal ganglia-thalamocortical circuitries. The use of rCBF PET and fMRI to study the pathophysiology of PD in the motor and sensory system and mechanisms of dopaminergic therapy as well as surgical interventions will be reviewed.

Brain↗

PubMed2003

High psychiatric comorbidity in spasmodic torticollis: a controlled study.

Disturbed body image and negative self-referent cognitions caused by the postural disfigurement of the head are regarded as the main reason for elevated depression scores in spasmodic torticollis (ST), but this factor was never controlled for. We therefore compared 48 patients with ST and 48 patients with alopecia areata (AA) who were matched for age, sex, and body image dissatisfaction. Psychiatric diagnoses were based on a structured psychiatric interview (SCID-I). Results of patients with ST and AA were compared with a matched sample of the representative German population. Odds ratios to develop psychiatric comorbidity for patients with ST compared with patients with AA were significantly increased throughout nearly all assessed DSM-IV categories. Logistic regression analysis showed that (1) depressive coping and (2) belonging to the group of patients with ST correlated with a significantly higher rate of current psychiatric diagnosis. We conclude that high psychiatric comorbidity in ST is unlikely to be a mere consequence of chronic disease and disfigurement.

Alopecia Areata↗

PubMed2002

[Increased level of tonic sympathetic arousal in high-vs. low-alexithymic cervical dystonia patients].

The purpose of this study was to assess whether alexithymia is a risk factor for autonomic dysregulation in cervical dystonia (spasmodic torticollis, ST). Alexithymia was assessed by an authorized German version of the TAS-20. In a first step, we recruited 10 ST-patients with high alexithymia scores (> 62; M = 69.2, SD = 3.0) and compared them with 10 ST-patients with low alexithymia scores (< 35; M = 28.7, SD = 4.3) on physiological and subjective responses to a cognitive and an emotional laboratory stressor. High-alexithymic ST-patients generally showed increased levels of autonomic arousal (higher SCL, more NS.SCF and lower T; 0.016 </= p </= 0.065) under all experimental conditions. In a second step, we used a less extreme alexithymia-definition (high >/= 57 vs. low </= 36) in a sample of 2 x 20 probands and found no significant differences. Our results suggest a chronically increased level of sympathetic activation in high-alexithymic patients with spasmodic torticollis.

Adult↗

PubMed2002

[Psychodynamic and neurobiological influences in the etiology of alexithymia].

This article discusses modern theories about the influence of developmental factors on the genesis of alexithymia and about its influence on maturing neurobiological structures. Against this background it becomes clear that core concepts of psychodynamic psychotherapy, like the concept of a unconscious level of experience, are confirmed by modern neurobiological research. Thus, modern psychosomatic research should strive to validate clinical core concepts by the use of empirical studies which also consider neurobiological parameters.

Affective Symptoms↗

PubMedDate not supplied

Alexithymia correlates with the size of the right anterior cingulate.

OBJECTIVE: The authors investigated a possible relationship between interindividual variability in anterior cingulate gyrus (ACG) morphology and alexithymia. MATERIALS AND METHODS: Magnetic resonance images were obtained in 100 healthy university graduates (51 female, 49 male; mean age 25.6 y). Surface area measurements of the ACG were performed on reformatted sagittal views in both hemispheres. The Toronto Alexithymia Scale (TAS-20) and the Temperament and Character Inventory (TCI) were administered. RESULTS: Right ACG surface area significantly correlated with TAS-20 total score in men (r = 0.37; p = 0.009) and in women (r = 0.30; p = 0.034). After controlling for three TCI subscales (harm avoidance, self-directedness, and self-transcendency), the correlation between TAS-20 total and right ACG became nonsignificant in women, but was only slightly reduced (r = 0.32; p = 0.032) in men. A linear regression model with right ACG as a dependent variable revealed brain volume, TCI-harm avoidance and TAS 20 total score as significant predictors in the total sample (explained proportion of total variation (EPTV) 37%). In men, beside brain volume, only TAS-20 total score showed a highly significant contribution (EPTV 41%), whereas in women only TCI-harm avoidance was a significant predictor (EPTV 36%). CONCLUSIONS: The authors' findings indicate that there is a significant positive relation between the size of the right ACG and alexithymia as measured with the TAS in healthy subjects. This applies especially for men whereas in women ACG size is more associated with the subscale harm avoidance of the TCI. Our findings also suggest a partial lateralization of human emotion processing, especially negative emotion.

Adult↗