M. J. Velden

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The effect of experimentally induced anxiety on pain perception was examined using a signal detection discrimination experiment. The experimental condition consisted in unsignalled application of very painful stimuli which substantially raised state anxiety. The discrimination task included the total range of painful stimuli. The results indicated a(More)
Since a valid non-invasive method for continuously measuring blood pressure is available for the psychophysiological laboratory, a procedure must be found for depicting blood pressure characteristics (systolic, diastolic, pulse pressure) on a real time scale, that is not simply from one heartbeat to the next. Values for blood pressure characteristics are(More)
The interpretation of the 'cardiac cycle time effect', also named 'time-dependent primary bradycardia' by the Laceys, who first observed it, has been controversial in psychophysiology. Unconfounded evidence for the dependence of a vagal effect of psychological stimuli on time of stimulation within the cardiac cycle has been missing to date. An experiment in(More)
Since the now classical experiments by Brown and Eccles in 1934, the effect of a stimulation of the vagus nerve on the heart has been derived from changes in the length of cardiac periods. Based on a simple model for the genesis of heartbeats, it is shown that the procedure employed by Brown and Eccles gives a distorted picture of the actual vagal effect. A(More)