Search results for "imulation"
showing 10 items of 7271 documents
Neck Muscle Vibration and Spatial Orientation During Stepping in Place in Humans
2002
Unilateral long-lasting vibration was applied to the sternomastoid muscle to assess the influence of asymmetric neck proprioceptive input on body orientation during stepping-in-place. Blindfolded subjects performed 3 sequences of 3 trials, each lasting 60 s: control, vibration applied during stepping (VDS), and vibration applied before stepping (VBS). VDS caused clear-cut whole body rotation toward the side opposite to vibration. The body rotated around a vertical axis placed at about arm's length from the body. The rotation did not begin immediately on switching on the vibrator. The delay varied from subject to subject from a few seconds to about 10 s. Once initiated, the angular velocity…
Temporal expectation and spectral expectation operate in distinct fashion on neuronal populations
2013
The formation of temporal expectation (i.e., the prediction of ‘when’) is of prime importance to sensory processing. It can modulate sensory processing at early processing stages probably via the entrainment of low-frequency neuronal oscillations in the brain. However, sensory predictions involve not only temporal expectation but also spectral expectation (i.e., the prediction of ‘what’). Here we investigated how temporal expectation may interrelate with spectral expectation by explicitly setting up temporal expectation and spectral expectation in a target detection task. We found that temporal expectation and spectral expectation interacted on reaction time (RT). RT was shorter when target…
Brand Discrimination: An Implicit Measure of the Strength of Mental Brand Representations
2015
While mental associations between a brand and its marketing elements are an important part of brand equity, previous research has yet to provide a sound methodology to measure the strength of these links. The following studies present the development and validation of an implicit measure to assess the strength of mental representations of brand elements in the mind of the consumer. The measure described in this paper, which we call the Brand Discrimination task, requires participants to identify whether images of brand elements (e.g. color, logo, packaging) belong to a target brand or not. Signal detection theory (SDT) is used to calculate a Brand Discrimination index which gives a measure …
Transcranial direct current stimulation of the motor cortex induces distinct changes in thermal and mechanical sensory percepts
2009
Abstract Objective The aim of this single-blinded, complete crossover study was to evaluate the effects of tDCS on thermal and mechanical perception, as assessed by quantitative sensory testing (QST). Methods QST was performed upon the radial part of both hands of eight healthy subjects (3 female, 5 male, 25–41 years of age). These subjects were examined before and after cathodal, anodal or sham tDCS, applied in a random order. TDCS was administered for 15 min at a 1 mA current intensity, with the active electrode placed over the left primary motor cortex and the reference electrode above the right orbit. Results After cathodal tDCS, cold detection thresholds (CDT), mechanical detection thr…
Intraoperative brain mapping of language, cognitive functions, and social cognition in awake surgery of low-grade gliomas located in the right non-do…
2020
Abstract Objective The aim of our study was to evaluate the usefulness of cortical-subcortical intraoperative brain mapping (ioBM) in resective awake surgery of low-grade gliomas (LGG) of the right non-dominant hemisphere (RndH). It was estimated how ioBM may affect both the extent of resection and postoperative outcome of language, spatial cognition, social cognition, and executive functions including attention and working memory. Patients and Methods : Fifteen patients that underwent ioBM in resective awake surgery of LGG located on the RndH, were included. A cohort of 15 patients with the same tumour location operated under general anaesthesia without brain mapping was used as control. S…
Evidence for early activation of primary motor cortex and SMA after electrical lower limb stimulation using EEG source reconstruction
2006
Compared to median nerve somatosensory evoked potentials (SEP), less is known about activity evoked by nerve stimulation of the lower limb. To understand the mechanisms and the physiology of sensor- and motor control it is useful to investigate the sensorimotor functions as revealed by a standardized functional status. Therefore, we investigated SEPs of the lower limb in 6 healthy male volunteers. For each side, tibial and peroneal nerves were stimulated transcutaneously at the fossa poplitea. The tibial nerves were also stimulated further distally at the ankle joint. Source localization was applied to 64-EEG-channel data of the SEPs. In contrast to somatosensory areas, which are activated …
Contour integration with corners.
2016
Contour integration refers to the ability of the visual system to bind disjoint local elements into coherent global shapes. In cluttered images containing randomly oriented elements a contour becomes salient when its elements are coaligned with a smooth global trajectory, as described by the Gestalt law of good continuation. Abrupt changes of curvature strongly diminish contour salience. Here we show that by inserting local corner elements at points of angular discontinuity, a jagged contour becomes as salient as a straight one. We report results from detection experiments for contours with and without corner elements which indicate their psychophysical equivalence. This presents a challeng…
Conceptual proposition selection and the LIFG: neuropsychological evidence from a focal frontal group.
2010
Much debate surrounds the role of the left inferior frontal gyrus (LIFG). Evidence from lesion and neuroimaging studies suggests the LIFG supports a selection mechanism used in single word generation. Single case studies of dynamic aphasic patients with LIFG damage concur with this and extend the finding to selection of sentences at the conceptual preparation stage of language generation. A neuropsychological group with unselected focal frontal and non-frontal lesions is assessed on a sentence generation task that varied the number of possible conceptual propositions available for selection. Frontal patients with LIFG damage when compared to Frontal patients without LIFG damage and Posterio…
Two Distinct Auditory-Motor Circuits for Monitoring Speech Production as Revealed by Content-Specific Suppression of Auditory Cortex
2015
Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehear…
Proactive interference of a sequence of tones in a two-tone pitch comparison task
2000
Subjects compared pitches of a standard tone and a comparison tone separated by 1,300-3,000 msec and responded according to whether the comparison tone sounded higher or lower in pitch than the standard tone. Three interfering tones at 300-msec intervals were presented before each pair of tones. Their pitch range varied, being either below or above the pitch of the standard tone; in some of the trials, their pitches were identical to the pitch of the standard tone (no interference). The highest error rate in performance was found when the interfering tones and the comparison tone deviated in the same direction in pitch from the standard tone. In turn, their deviations in the opposite direct…