Search results for "Psychophysic"
showing 10 items of 97 documents
Neurons in the pigeon nidopallium caudolaterale signal the selection and execution of perceptual decisions
2014
Sensory systems provide organisms with information on the current status of the environment, thus enabling adaptive behavior. The neural mechanisms by which sensory information is exploited for action selection are typically studied with mammalian subjects performing perceptual decision-making tasks, and most of what is known about these mechanisms at the single-neuron level is derived from cortical recordings in behaving monkeys. To explore the generality of neural mechanisms underlying perceptual decision making across species, we recorded single-neuron activity in the pigeon nidopallium caudolaterale (NCL), a non-laminated associative forebrain structure thought to be functionally equiva…
Pilotpētījums par nazālo elpceļu obstrukcijas kvantitatīvo noteikšanu
2020
Pilotpētījums par nazālo elpceļu obstrukcijas kvantificēšanu Ievads Nazālā obstrukcija ir izplatīta problēma visā pasaulē, kas ievērojami ietekmē cilvēka dzīves kvalitāti. Neskatoties uz šīs problēmas prevalenci, pieejamās obstrukcijas pakāpes mērīšanas metodes ir neprecīzas. Ir novērota vāja korelācija starp kvantificēto obstrukcijas pakāpi, kas tiek iegūta lietojot mūsdienu metodes un kvalitatīvo obstrukcijas pakāpi, ko apraksta pacienti. Mērķis Šī ekperimentālā pētījuma mērķis ir, pirmkārt, radīt innovatīvu instrumentu, kas simulē specifiskas deguna obstrukcijas pakāpes. Tas būtu instruments, kas spētu potenciāli kvantificēt pacientu subjektīvās sajūtas par deguna obstrukciju. Otrkārt, m…
Multicenter investigation of 1,036 subjects using a standardized method for the assessment of olfactory function combining tests of odor identificati…
2000
“Sniffin’ Sticks” is a test of nasal chemosensory performance that is based on penlike odor-dispensing devices. It is comprised of three tests of olfactory function: tests for odor threshold, discrimination and identification. Previous work has already established its test-retest reliability and validity in comparison to established measures of olfactory sensitivity. The results of this test are presented as a composite TDI score – i.e., the sum of results obtained for threshold, discrimination and identification measures. The present multicenter investigation aimed at providing normative values in relation to different age groups. To this end, 966 patients were investigated in 11 centers. …
Olfactory function in children assessed with psychophysical and electrophysiological techniques
2007
International audience; The olfactory information processing abilities of children undergo changes during early life. The aims of the present study were to describe these changes and to probe for their electrophysiological correlates. These aims were investigated in two experiments. In Experiment 1, responses of 146 subjects (3-12 years) were tested with psychophysical tools. Approximately 2/3 of the subjects completed the olfactory tests ("Sniffin' Sticks"). In Experiment 2, 12 additional subjects (3-10 years) were tested with electrophysiological tools. Event-related potentials (ERPs) were recorded in response to olfactory stimulation with H(2)S. Results from Experiment 1 indicated that d…
A putative social chemosignal elicits faster cortical responses than perceptually similar odorants.
2006
Social chemosignals, so-called pheromones, have recently attracted much attention in that effects on women's psychophysiology and cortical processing have been reported. We here tested the hypothesis that the human brain would process a putative social chemosignal, the endogenous steroid endrostadienone, faster than other odorants with perceptually matched intensity and hedonic characteristics. Chemosensory event-related potentials (ERP) were recorded in healthy women. ERP analyses indicate that androstadienone was processed significantly faster than the control odorants. Androstadienone elicited shorter latencies for all recorded ERP components but most so for the late positivity. This fin…
Habituation and adaptation to odors in humans
2017
indexation en cours; Habituation, or decreased behavioral response, to odors is created by repeated exposure and several detailed characteristics, whereas adaptation relates to the neural processes that constitute this decrease in a behavioral response. As with all senses, the olfactory system continually encounters an enormous variety of odorants which is why mechanisms must exist to segment them and respond to changes. Although most olfactory habitation studies have focused on animal models, this non-systematic review provides an overview of olfactory habituation and adaptation in humans, and techniques that have been used to measure them. Thus far, psychophysics in combination with moder…
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…
2013
The motion energy sensor has been shown to account for a wide range of physiological and psychophysical results in motion detection and discrimination studies. It has become established as the standard computational model for retinal movement sensing in the human visual system. Adaptation effects have been extensively studied in the psychophysical literature on motion perception, and play a crucial role in theoretical debates, but the current implementation of the energy sensor does not provide directly for modelling adaptation-induced changes in output. We describe an extension of the model to incorporate changes in output due to adaptation. The extended model first computes a space-time r…
European vestibular experiments on the Spacelab-1 mission: 4. Thresholds of perception of whole-body linear oscillation.
1986
Thresholds for the detection of linear oscillatory motion at 0.3 Hz in the X, Y and Z body axes were determined during the flight of Spacelab-1 and on the ground pre- and post-flight, using the method of limits with a single staircase procedure. Pre-flight, Z axis thresholds (mean 0.077 ms-2) were significantly higher than X and Y thresholds (mean 0.029 ms-2). Measures obtained on three crew members in-flight exhibited thresholds greater, by a factor of 1.5-4.3, than those obtained pre-flight. Post-flight, two crew members had significantly elevated X and Y axis thresholds whereas the other two crew members had lowered thresholds in X, Y and Z axes. In general, thresholds had returned to pr…