Search results for "Physical Stimulation"
showing 9 items of 79 documents
Fourier analysis of the stimuli for pattern-induced flicker colors.
1992
Pattern-induced flicker colors (PIFCs) were observed and color matched in rotating discs from which higher-harmonic Fourier components in the square-wave temporal luminance functions of a conventional black-and-white Benham disc had been removed. Since both reddish-brown and blue PIFCs were visible with purely sinusoidal stimuli they cannot result from differences in temporal stimulus shape or pattern and do not provide evidence for a temporal coding theory of color. Green PIFCs differed in that they did require the presence of additional harmonics. In a second experiment the luminance means upon which the sinusoidal PIFC stimuli were imposed were varied. The results show that color is dete…
Flow field, swimming velocity and boundary layer: parameters which affect the stimulus for the lateral line organ in blind fish
1988
The data presented support the hypothesis that the flow field supplies the stimulus to the lateral line organ (LLO) in blind cave fish (Anoptichthys jordani). Two basic predictions from the theoretical analysis of the flow field were confirmed: (i) individual blind cave fish prefer particular swimming velocities, (ii) the velocity preferred depends on the cross-sectional area (CSA) of the fish, i.e. the smaller the CSA the higher the swimming velocity. This relationship was found also in experimentally blinded fish of other species. Furthermore, when placed in unfamiliar surroundings, blind cave fish swim at higher velocities than in familiar surroundings for a certain habituation period. T…
The role of the dorsolateral prefrontal cortex in implicit procedural learning.
1996
We studied the role of the dorsolateral prefrontal cortex in procedural learning. Normal subjects completed several blocks of a serial reaction time task using only one hand without or with concurrent non-invasive repetitive transcranial magnetic stimulation. To disrupt their function transiently, stimulation was applied at low intensity over the supplementary motor area or over the dorsolateral prefrontal cortex contralateral or ipsilateral to the hand used for the test. Stimulation to the contralateral dorsolateral prefrontal cortex markedly impaired procedural implicit learning, as documented by the lack of significant change in response times during the task. Stimulation over the other …
The effects of intensity, frequency, static load, and shore hardness on different parameters in vibration sensitivity measurements.
1987
The effects of shore hardness, static load, frequency, and intensity of vibration on the amplitude and dynamic force effects of vibration were studied in conditions corresponding to those occurring in vibrotactile sensitivity measurements. The measurements were performed on three silicon plates of known shore hardness. The results indicated that the effect of differences in elasticity on the vibration amplitudes was evident at lower frequencies up to about 200 Hz whereas at higher frequencies the amplitudes remained at the same level, regardless of elasticity. On dynamic force the effect of elasticity was observed at all frequencies studied (50-500 Hz). The static load of the contractor had…
Altered processing of sensory stimuli in patients with migraine.
2014
Migraine is a cyclic disorder, in which functional and morphological brain changes fluctuate over time, culminating periodically in an attack. In the migrainous brain, temporal processing of external stimuli and sequential recruitment of neuronal networks are often dysfunctional. These changes reflect complex CNS dysfunction patterns. Assessment of multimodal evoked potentials and nociceptive reflex responses can reveal altered patterns of the brain's electrophysiological activity, thereby aiding our understanding of the pathophysiology of migraine. In this Review, we summarize the most important findings on temporal processing of evoked and reflex responses in migraine. Considering these d…
Effects of different lower-limb sensory stimulation strategies on postural regulation-a Systematic review and metaanalysis
2017
Systematic reviews of balance control have tended to only focus on the effects of single lower-limb stimulation strategies, and a current limitation is the lack of comparison between different relevant stimulation strategies. The aim of this systematic review and meta-analysis was to examine evidence of effects of different lower-limb sensory stimulation strategies on postural regulation and stability. Moderate- to high-pooled effect sizes (Unbiased (Hedges' g) standardized mean differences (SMD) = 0.31-0.66) were observed with the addition of noise in a Stochastic Resonance Stimulation Strategy (SRSS), in three populations (i.e., healthy young adults, older adults, and individuals with low…
Increased pain and neurogenic inflammation in mice deficient of neutral endopeptidase
2009
The complex regional pain syndrome (CRPS) is characterized by enhanced neurogenic inflammation, mediated by neuropeptides. Neutral endopeptidase (NEP) is a key enzyme in neuropeptide catabolism. We used NEP knock out (ko) mice to investigate whether NEP deficiency leads to increased pain behavior and signs of neurogenic inflammation after soft tissue trauma with and without nerve injury. After chronic constriction injury (CCI) of the right sciatic nerve, NEP ko mice were more sensitive to heat, to mechanical stimuli, and to cold than wild type mice. Tissue injury without nerve injury produced no differences between genotypes. After CCI, NEP ko mice showed increased hind paw edema but lower …
Effect of water immersion on post-rotatory and caloric nystagmus.
1991
Caloric nystagmus and post-rotatory nystagmus were recorded with and without head-out water immersion. As water immersion reduces body weight by about 90% owing to buoyancy, it decreases somatosensory inputs. Thus water immersion can be used to simulate a weightless environment. Caloric nystagmus was enhanced significantly by water immersion; however, post-rotatory nystagmus was not. These findings demonstrate that caloric nystagmus is easily affected by water immersion which decreases somatosensory inputs, but that post-rotatory nystagmus is not.
Study and modulation of human cortical excitability with transcranial magnetic stimulation.
1998
Transcranial magnetic stimulation (TMS) can be applied in different paradigms to obtain a measure of various aspects of cortical excitability. These different TMS paradigms provide information about different neurotransmitter systems, enhance our understanding about the pathophysiology of neuropsychiatric conditions, and in the future may be helpful as a guide for pharmacological interventions. In addition, repetitive TMS (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. These effects can be demonstrated neurophysiologically or by combining rTMS…