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Biomedical subjects

E J Damen

Publications and source records attributed to E J Damen.

7 recordsLinked to original sources
PubMed1996

The differential effects of extremity and movement side on the scalp distribution of the readiness potential (RP) and the stimulus-preceding negativity (SPN).

In a time estimation task subjects had to press a button 3 s after the presentation of a warning stimulus. Two seconds after the movement they were informed about their performance by a knowledge of results (KR) stimulus. Preceding the movement a readiness potential (RP) and prior to the presentation of the KR stimulus a stimulus-preceding negativity (SPN) was recorded. Movement side (left/right) and extremity (hand/foot) were varied within subjects to demonstrate that the RP but not the SPN is affected by such manipulations. The scalp distribution of the late part of the RP was affected by movement side and extremity. Yet it exhibited the expected lateral asymmetry only preceding a movement of the left hand or of the right foot. The scalp distribution of the SPN was not affected by extremity. The size of the right hemisphere preponderance of the SPN depended on movement side following a finger flexion, but not following a plantar flexion of the foot. The experimental design was intended to avoid the temporal overlap between movement-related and stimulus-related activity. Yet it is argued that both results of this experiment can best be explained by such an overlap.

Adolescent↗
PubMed1996

Anticipatory EMG responses of pericranial muscles in relation to heart rate during a warned simple reaction time task.

Obrist's cardiac-somatic coupling hypothesis predicts a widespread inhibition of heart rate and task-irrelevant muscle activity during expectancy situations. This hypothesis was tested by measuring heart rate and pericranial electromyographic (EMG) activity during a warned simple reaction time task with visual or auditory reaction signals and hand or foot responses. In each of three groups of 24 participants, EMG activity of three different facial, masticatory, or neck muscles was recorded. During the warning interval preceding the presentation of the reaction signal, masticatory and lower facial muscles predominantly showed a gradual inhibition in activity concomitant with heart rate deceleration. In contrast, two upper facial muscles showed increasing activity. Pericranial EMG responses were little affected by reaction signal modality and were independent of responding limb. Greater heart rate deceleration was associated with greater inhibition and weaker facilitation of EMG responses. The results suggest a functional role of inhibitory EMG responses in increasing the perceptual sensitivity to expected signals.

Adult↗
PubMed1994

Is a stimulus conveying task-relevant information a sufficient condition to elicit a stimulus-preceding negativity?

Movement-preceding and stimulus-preceding negativities were recorded when a movement was followed by one of three informative visual stimuli. The meaning of the visual stimulus alternated between (a) conveying a task-relevant instruction about a subsequent time production task and (b) providing feedback (knowledge of results) about performance on the current time production task. In a control condition, premovement and postmovement scalp potentials were recorded when subjects made the same movements but in a voluntary, self-paced manner. Under all conditions, movements were preceded by a movement-preceding negativity, and neither the amplitude nor the lateral asymmetry of this negativity was affected by the subsequent presentation of either kind of informative stimulus. When the movement was followed by a stimulus conveying knowledge of results, the negativity in the postmovement epoch was enhanced, but this enhancement was not evident in epochs preceding instruction stimuli. We conclude that not all task relevant stimuli elicit a stimulus-preceding negativity, and we provide a functional interpretation of this negativity in terms of emotional anticipation and the contingency of the stimulus on a previous event.

Adult↗
PubMed1988

Distribution of slow brain potentials related to motor preparation and stimulus anticipation in a time estimation task.

Subjects had to press a button at regular intervals of 20 sec. Two seconds after each button press a stimulus was presented indicating the length of the past interval. EEG was analysed from 2500 msec preceding the button press until the presentation of the stimulus. Preceding the button press a readiness potential (RP) was recorded with amplitudes that were larger over the hemisphere contralateral to the movement side. Preceding the stimulus negative waves were recorded which were larger over the right hemisphere, irrespective of the movement side. In a warned reaction time experiment, the CNV late wave represents both motor preparation and stimulus anticipation. In the present study motor preparation and stimulus anticipation are no longer confounded factors. Thus, it is shown that stimulus anticipation is indeed reflected by negative activity, as is motor preparation. The potential distribution of the RP, however, is different from the stimulus-preceding negativity (SPN), a pointing to a different electrophysiological source. The potential distribution of the SPN has been investigated and a right hemisphere preponderance of the SPN has been found.

Adolescent↗