3 research outputs found
Sensory detection thresholds are modulated across the cardiac cycle: evidence that cutaneous sensibility is greatest for systolic stimulation
The visceral afferent feedback hypothesis proposes that sensorimotor function is impaired by cortical inhibition associated with increased baroreceptor activation. This study is the first to examine the effects of naturally occurring variations in baroreceptor activity across the cardiac cycle on cutaneous sensory detection thresholds. In each trial, an electrocutaneous stimulus was delivered to the index finger at one of three intervals (0, 300, 600 ms) after the R-wave of the electrocardiogram. Separate interleaving up-down staircases were used to determine the 50% detection threshold for each R-wave to stimulation interval. Cutaneous sensory detection thresholds were lower for stimuli presented at R+300 ms than R+0 ms or R+600 ms. The finding that cutaneous sensibility was greater when stimulated during systole than diastole may be accounted for by a modified afferent feedback hypothesis. Copyright © 2009 Society for Psychophysiological Research
Effects of essential hypertension on short latency human somatosensory-evoked potentials
Reduced perception of somatosensory stimulation in patients with essential hypertension may be due to deficits in the
ascending somatosensory pathway. Function in the ascending somatosensory pathway was assessed bymeasuring N9,
N13, and N20 somatosensory-evoked potentials in 14 unmedicated essential hypertensives and 22 normotensives. N9
amplitudes were smaller and N13 amplitudes marginally smaller in hypertensives than normotensives. N9 amplitudes
were inversely associated with blood pressure. N20 amplitudes and N9, N13, and N20 latencies did not differ between
groups. In addition, plexus-to-cord, cord-to-cortex, and plexus-to-cortex conduction times were not different between
groups. These data suggest that hypertension affects the peripheral nervous system by reducing the number of active
sensory nerve fibers without affecting myelination. However, hypertension does not seem to affect the afferent somatosensory
pathway within the brain
Additional file 1: of Measurement of blood pressure for the diagnosis and management of hypertension in different ethnic groups: one size fits all
Diagnostic output of raw data at different BP thresholds. (DOCX 19 kb