Wim J. E. P. Lammers

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Peristaltic motor activity of the gut is an essential activity to sustain life. In each gut organ, a multitude of overlapping mechanisms has developed to acquire the ability of coordinated contractile activity under a variety of circumstances and in response to a variety of stimuli. The presence of several simultaneously operating control systems is a(More)
Previous studies have reported on propagation of individual spikes in isolated segments of the pregnant uterus, but there is no information on patterns of spike propagation in the intact organ. There is also no information on propagation of myometrial burst. The aim of this study was to record, at high resolution, patterns of propagation of electrical(More)
The propagation of individual action potentials during spontaneous bursts of activity in isolated pregnant rat myometrium in the final stage of pregnancy was analyzed. Simultaneous recordings from 240 extracellular recording sites (inter-electrode distance 1 mm) made it possible to reconstruct, in spatial and temporal details, the conduction of the(More)
Detailed spatial analysis of propagation of individual action potential was performed during spontaneous bursts of activity in the isolated 17-day pregnant rat myometrium. Use was made of high-resolution mapping with simultaneous recordings from 240 extracellular electrodes. Positioning of the electrode assembly by itself did not have any adverse effects,(More)
In the small intestines, the major task of the slow wave is to induce mechanical movements in the intestinal wall by generating local calcium spikes. High resolution electrical mapping reveals fundamental differences in propagation between slow waves and calcium spikes. These differences suggest that slow waves and spikes are propagated by different(More)
In the isolated pregnant myometrium of the rat, the pattern of propagation was investigated by recording simultaneously from 240 different extracellular sites while the contraction of the tissue was recorded isometrically. Analysis of all recorded electrograms allowed the two-dimensional spread of activity in the myometrium to be reconstructed. From these(More)
The frequency and propagation velocity of distension-induced peristaltic contractions in the antrum and duodenum are distinctly different and depend on activation of intrinsic excitatory motoneurons as well as pacemaker cells, the interstitial cells of Cajal associated with Auerbach's plexus (ICC-AP). Because ICC are critical for coordination of motor(More)
We demonstrate that subjects will often claim to have previously seen a new stimulus if they have previously seen stimuli containing its component features. Memory for studied stimuli was measured using a "yes"/"no" recognition test. There were three types of test stimuli: target stimuli, which had been presented during study, conjunction stimuli,(More)
Whether humans react to olfactory stimuli presented in sleep was assessed. Responses of ten participants (mean age = 22.8 years) were recorded to repeated three-minute periods of either air alone or to a peppermint odor (0.26 mg/liter) during stage 2 sleep. These responses included behavioral (awakening, microswitch closure), autonomic (heart rate, EMG,(More)
In Alzheimer's disease (AD), fatal neuronal cell loss occurs long before relevant evidence can lead to a reliable diagnosis. If characteristic pathological alterations take place in the enteric nervous system (ENS), it could be one of the most promising targets for an early diagnosis, using submucosal biopsies from the gut. We therefore investigated time-(More)