Activity of attention related structures in multiple sclerosis patients.

Aims: It was investigated whether the cortical activity during tasks requiring focused or divided attention is reduced in multiple sclerosis patients with prominent deficits (MS(+D)) and increased in patients without impairment (MS(-D)) in these specific attention functions.

Methods: Six MS(+D) patients with attention deficits, six unimpaired MS(-D) patients, and age-, gender-, and education-matched healthy control subjects were examined with functional magnetic resonance imaging (fMRI). The experimental paradigm consisted of visual tasks requiring focused or divided attention.

Self-initiated movements in chronic prefrontal traumatic brain injury: an event-related functional MRI study.

Electrophysiological studies found traumatic lesions of the prefrontal cortex (PFC) to affect the preparation of self-initiated movements. However, a precise localization of the observed effects has not been reported yet. Moreover, previous reports did not account for effects of lesion location.

On the neural basis of focused and divided attention.

Concepts of higher attention functions distinguish focused and divided attention. The present study investigated whether these mental abilities are mediated by common or distinct neural substrates. In a first experiment, 19 healthy subjects were examined with functional brain imaging (fMRI) while they attended to either one or both of two simultaneously presented visual information streams and responded to repetitive stimuli.

Prefrontal cortex activity in self-initiated movements is condition-specific, but not movement-related.

Activity of the prefrontal cortex (PFC) has been observed in previous block-design brain imaging studies of self-initiated movements. However, the meaning of these activations remained unclear. A functional MRI experiment was carried out, which utilized an epoch and an event-related analysis approach to the data.

Reorganization of motor execution rather than preparation in poststroke hemiparesis.

Background And Purpose: The aim of the present study was to examine movement-related potentials (MRPs) in patients in the "chronic" stage after cortical stroke with recovered hemiparesis compared with healthy control subjects.

Methods: Right index finger MRPs were derived from 12 patients > or =1 year after infarction in the territory of the left middle cerebral artery as well as from 12 control subjects. MRP components were compared between groups.

[Quantification of acute muscle pain after whiplash injury using computer-aided pressure algesimetry].

Objective And Method: The present study utilised the PC-interactive pressure algesimetry to quantify cervical pain after whiplash injury. Pressure painfulness of the splenius and trapezius muscles was investigated in patients with an acute cervical syndrome after whiplash injury and compared to that of healthy subjects.

Results: Pressure painfulness of neck and shoulder muscles was significantly increased in whiplash patients.

[Reduced contralateral preponderance of the movement-related potential during execution of self-initiated movements in acute prefrontal traumatic brain injury].

Objectives: An enhanced ipsilateral motor potential after prefrontal TBI is known. Our aim was to examine, whether this contributes to movement initiation or execution.

Methods: EEGs of 22 patients and 28 healthy controls were recorded.

Recovery of movement-related potentials in the temporal course after prefrontal traumatic brain injury: a follow-up study.

Objective: The movement-related potential (MRP) is an EEG measure related to self-initiated movements, consisting of the Bereitschaftspotential (BP), the negative slope, and the motor potential. Since in a former study the BP was reduced in acute prefrontal traumatic brain injury (TBI) patients, the present study examined the MRPs' course in follow-up examinations.

Methods: Right index finger MRPs of 22 patients with contusions of the prefrontal cortex were recorded 12, 26, and 52 weeks after TBI and compared to controls.

Movement preparation in self-initiated versus externally triggered movements: an event-related fMRI-study.

In the present study, we used fMRI to investigate whether event-related preparatory processes of self-initiated and externally triggered movements differ. Twenty subjects were examined with 1000 T2*-weighted images in two consecutive sessions. During the first session subjects performed self-initiated abductions of the right index finger.

Sparse imaging and continuous event-related fMRI in the visual domain: a systematic comparison.

Continuous image acquisition as used in most functional magnetic resonance imaging (fMRI) designs may conflict with specific experimental settings due to attendant, noisy gradient switching. In sparse fMRI, single images are recorded with a delay that allows the registration of the predicted peak of an evoked hemodynamic response (HDR). The aim of this study was to assess validity and sensitivity of single-trial sparse imaging within the visual domain.

Impaired movement-related potentials in acute frontal traumatic brain injury.

Objective: Focal brain lesions due to traumatic brain injury (TBI) do not only lead to functional deficits in the lesion area, but also disturb the structurally intact neuronal network connected to the lesion site. Therefore we hypothesized dysfunctions of the cortical motor network after frontal TBI. The movement related potential (MRP) is an EEG component related to voluntary movement consisting of the Bereitschaftspotential (BP), the negative slope (NS), and the motor potential (MP).

Sparse imaging of the auditory oddball task with functional MRI.

Cortical reactions to rare task-related stimuli have been studied with electrophysiological methods in the assessment of the P300 component as well as in functional imaging studies with regard to oddball tasks. While functional magnetic resonance imaging studies using auditory stimuli have to deal with interference between auditory stimuli and scanner noise, the aim of our study was to assess auditory target processing with the sparse imaging method. Single volumes of echo-planar imaging were acquired 4 s following the onset of the stimuli of interest.