Search results for "Stimulus"
showing 10 items of 555 documents
Influence of Musical Expertise on the processing of Musical Features in a Naturalistic Setting
2019
Musical training causes structural and functional changes in the brain due to its sensory-motor demands, but the modulatory effect of musical training on music feature processing in the brain in a continuous music listening paradigm, has not been investigated thus far. In this work, we investigate the differences between musicians and non-musicians in the encoding of musical features encompassing musical timbre, rhythm and tone. 18 musicians and 18 non-musicians were scanned using fMRI while listening to 3 varied stimuli. Acoustic features corresponding to timbre, rhythm and tone were computationally extracted from the stimuli and correlated with brain responses, followed by t-tests on grou…
Best not to bet on the horserace: A comment on Forrin and MacLeod (2017) and a relevant stimulus-response compatibility view of colour-word contingen…
2018
International audience; One powerfully robust method for the study of human contingency learning is the colour-word contingency learning paradigm. In this task, participants respond to the print colour of neutral words, each of which is presented most often in one colour. The contingencies between words and colours are learned, as indicated by faster and more accurate responses when words are presented in their expected colour relative to an unexpected colour. In a recent report, Forrin and MacLeod (2017b, Memory & Cognition) asked to what extent this performance (i.e., response time) measure of learning might depend on the relative speed of processing of the word and the colour. With keypr…
Tonically Active Neurons in the Monkey Striatum are Sensitive to Sensory Events in a Manner that Reflects their Predictability in Time
2002
It is now well established that tonically active neurons (TANs) in the monkey striatum respond to motivationally relevant sensory events, such as conditioned stimuli to which the animal had to react correctly to obtain reward. Recent findings obtained in our laboratory suggested that stimulus prediction may influence the responsiveness of the TANs. In the present study we specifically investigated the effects of temporal aspects of prediction on the responses of single TANs recorded both in the caudate nucleus and putamen of two macaque monkeys. Three different behavioral situations were employed: (1) an instrumental task, in which a visual stimulus triggering a rewarded movement was preced…
Sex pheromones are not always attractive: changes induced by learning and illness in mice
2014
A male-specific major urinary protein named darcin is attractive to female mice, Mus musculus, stimulates a learned attraction to volatile components of a male's urinary odour and induces spatial learning. In this article we show that darcin also induces learned attraction for a previously neutral olfactory stimulus (the odorant isoamyl acetate), acquired by repeated presentation of both stimuli together. We hypothesize that this is a case of olfactory–vomeronasal associative learning, in which darcin acts as the unconditioned reinforcer. However, the presence of darcin is not always attractive to adult female mice. Urine from males parasitized by the nematode Aspiculuris tetraptera has no …
The Mona Lisa effect: Neural correlates of centered and off-centered gaze
2014
The Mona Lisa effect describes the phenomenon when the eyes of a portrait appear to look at the observer regardless of the observer's position. Recently, the metaphor of a cone of gaze has been proposed to describe the range of gaze directions within which a person feels looked at. The width of the gaze cone is about five degrees of visual angle to either side of a given gaze direction. We used functional magnetic resonance imaging to investigate how the brain regions involved in gaze direction discrimination would differ between centered and decentered presentation positions of a portrait exhibiting eye contact. Subjects observed a given portrait's eyes. By presenting portraits with varyin…
The Adequate Stimulus
2008
The term adequate stimulus describes that class of environmental phenomena that requires the least amount of energy to elicit a percept mediated by a particular sensory system, implying that the receptive organs of that sensory system are specialized to detect those phenomena. It was difficult to transfer this concept to the perception of pain and to the nociceptive system. Many different stimuli may cause pain (pin prick, burn injury, freeze injury, inflammation, etc.), none of which needs particularly low amounts of energy. The common denominator of those stimuli is that they threaten to cause tissue damage (in Greek: νoξη Noxe). Hence the adequate stimulus to elicit pain is traditionally…
Position Coding in Two-Digit Arabic Numbers
2011
Digit position coding in two-digit Arabic numbers was examined in two masked priming experiments. In Experiment 1, participants had to decide whether the presented stimulus was a two-digit Arabic number (e.g., 67) or not (e.g., G7). Target stimuli could be preceded by a prime which (i) shared one digit in the initial position (e.g., 13-18), (ii) shared one digit but in a different position (83-18), and (iii) was a transposed number (81-18). Two unrelated control conditions, equalized in terms of the distance between primes and targets with the experimental conditions, were also included (e.g., 79-18). Results showed a priming effect only when prime and target shared digits in the same posi…
Signalling and Reception
2002
Communication, a widespread natural phenomenon, occurs in both animals and plants. Signals are evolved traits that transfer information from one individual (the signaller) to another (the receiver); they can occur in any sensory modality. Keywords: cost and benefits; honesty; mimicry; predation; sexual selection
Effectiveness of Self-Hypnosis on the Relief of Experimental Dental Pain: A Randomized Trial.
2016
This randomized, controlled clinical trial evaluates the effectiveness of self-hypnosis on pain perception. Pain thresholds were measured, and a targeted, standardized pain stimulus was created by electrical stimulation of the dental pulp of an upper anterior tooth. Pain stimulus was rated by a visual analogue scale (VAS). The pain threshold under self-hypnosis was higher (57.1 ± 17.1) than without hypnotic intervention (39.5 ± 11.8) (p < .001). Pain was rated lower on the VAS with self-hypnosis (4.0 ± 3.8) than in the basal condition without self-hypnosis (7.1 ± 2.7) (p < .001). Self-hypnosis can be used in clinical practice as an adjunct to the gold standard of local anesthesia for pain m…
Topology of synaptic connectivity constrains neuronal stimulus representation, predicting two complementary coding strategies
2020
In motor-related brain regions, movement intention has been successfully decoded from in-vivo spike train by isolating a lower-dimension manifold that the high-dimensional spiking activity is constrained to. The mechanism enforcing this constraint remains unclear, although it has been hypothesized to be implemented by the connectivity of the sampled neurons. We test this idea and explore the interactions between local synaptic connectivity and its ability to encode information in a lower dimensional manifold through simulations of a detailed microcircuit model with realistic sources of noise. We confirm that even in isolation such a model can encode the identity of different stimuli in a lo…