Search results for "STIMULATION"
showing 10 items of 2192 documents
Excitability regulation in the dorsomedial prefrontal cortex during sustained instructed fear responses: a TMS-EEG study
2018
AbstractThreat detection is essential for protecting individuals from adverse situations, in which a network of amygdala, limbic regions and dorsomedial prefrontal cortex (dmPFC) regions are involved in fear processing. Excitability regulation in the dmPFC might be crucial for fear processing, while abnormal patterns could lead to mental illness. Notwithstanding, non-invasive paradigms to measure excitability regulation during fear processing in humans are missing. To address this challenge we adapted an approach for excitability characterization, combining electroencephalography (EEG) and transcranial magnetic stimulation (TMS) over the dmPFC during an instructed fear paradigm, to dynamica…
Transcranial magnetic stimulation reveals cortical hyperexcitability in episodic cluster headache
2014
Abstract Evidence shows involvement of the cerebral cortex in the pathophysiology of cluster headache (CH). Here we investigated cortical excitability in episodic CH patients by using transcranial magnetic stimulation. In 25 patients with episodic CH and 13 healthy subjects we evaluated the motor cortical response to single-pulse (ie, motor threshold, input-output curves, cortical silent period) and paired-pulse (ie, intracortical facilitation, short intracortical inhibition) transcranial magnetic stimulation in both hemispheres. Thirteen patients were evaluated outside bout and the remaining 12 patients inside bout. Our results showed increased slope of the input-output curves after stimul…
Soluble Interleukin-2 Receptor Secretion Defectin Vitroin HLA-B8, DR3 Positive Subjects
1990
Several studies have shown that HLA-B8,DR3 positive subjects may display T cell dysfunctions. Recently, a soluble form of the receptor for IL-2 (sIL-2R) has been demonstrated in human sera and in vitro-stimulated culture supernatant from human T lymphocytes. In the present paper we report sIL-2R serum levels and sIL-2R production from peripheral blood mononuclear cells in HLA-B8,DR3 positive subjects. We found that HLA-B8,DR3 positive subjects have the highest values of serum sIL-2R, but comparing the values of these subjects with those of negative ones no significant difference was observed. As regards the in vitro production of sIL-2R, no difference exists for unstimulated cultures, where…
Distinctive Representation of Mispredicted and Unpredicted Prediction Errors in Human Electroencephalography
2015
The predictive coding model of perception proposes that neuronal responses are modulated by the amount of sensory input that the internal prediction cannot account for (i.e., prediction error). However, there is little consensus on what constitutes nonpredicted stimuli. Conceptually, whereas mispredicted stimuli may induce both prediction error generated by prediction that is not perceived and prediction error generated by sensory input that is not anticipated, unpredicted stimuli involves no top-down, only bottom-up, propagation of information in the system. Here, we examined the possibility that the processing of mispredicted and unpredicted stimuli are dissociable at the neurophysiologic…
Decoding Musical Training from Dynamic Processing of Musical Features in the Brain
2018
AbstractPattern recognition on neural activations from naturalistic music listening has been successful at predicting neural responses of listeners from musical features, and vice versa. Inter-subject differences in the decoding accuracies have arisen partly from musical training that has widely recognized structural and functional effects on the brain. We propose and evaluate a decoding approach aimed at predicting the musicianship class of an individual listener from dynamic neural processing of musical features. Whole brain functional magnetic resonance imaging (fMRI) data was acquired from musicians and nonmusicians during listening of three musical pieces from different genres. Six mus…
The effect of paired associative stimulation on fatigue resistance
2015
Paired associative stimulation (PAS) is a non-invasive stimulation method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscles. However, very few studies have shown an association between changes in motor evoked potentials (MEP) after PAS and behavioral changes in healthy subjects. In the present study we hypothesized that the functional relevance of PAS can be seen during fatiguing exercise, since there is always a central contribution to the development of fatigue. Transcranial magnetic stimulation was applied over the motor cortex to measure changes in the MEPs of the soleus muscle before and after PAS. Furthermore, fatigue resis…
Repetition suppression versus enhancement — it's quantity that matters
2013
Upon repetition, certain stimuli induce reduced neural responses (i.e., repetition suppression), whereas others evoke stronger signals (i.e., repetition enhancement). It has been hypothesized that stimulus properties (e.g., visibility) determine the direction of the repetition effect. Here, we show that the very same stimuli can induce both repetition suppression and enhancement, whereby the only determining factor is the number of repetitions. Repeating the same, initially novel low-visible pictures of scenes for up to 5 times enhanced the blood oxygen level-dependent (BOLD) response in scene-selective areas, that is, the parahippocampal place area (PPA) and the transverse occipital sulcus…
The role of Posterior Parietal Cortex in spatial representation of time: a TMS study.
2011
1. Introduction. The existence of a spatial representation of time, where temporal intervals are represented on a mental temporal line (MTL), oriented in ascending order from left to right, was demonstrated manipulating spatial attention by means of Prismatic Adaptation (PA). In young healthy subjects, prisms adaptation inducing a rightward shift of spatialattention produced an overestimation of time intervals, whereas prisms adaptation inducing a leftward shift of spatialattention produced an underestimation of time intervals [4]. The aimof the present study was to investigate the neural basis mediating the effects of PA on spatial time representation. PosteriorParietalCortex (PPC) is the …
Paired pulse TMS over the right posterior parietal cortex modulates visuospatial perception
2006
Abstract Objective We previously observed a relative contralateral neglect by right parietal single-pulse TMS given 150 ms after visual stimulus presentation. Here we investigated the effects of parietal paired TMS in normal subjects performing a visuospatial task. Methods Thirteen right-handed healthy subjects underwent a line-length judgement task during single-pulse and paired (1, 3, 5, 10 ms ISIs) TMS, delivered on the right parietal cortex 150 ms after visual stimulus. Results Single pulse TMS over the right parietal cortex induced a significant rightward bias compared to the baseline condition. At 1 and 3 ms ISIs, paired-pulse TMS did not show any effect in comparison with single puls…
Key issues in decomposing fMRI during naturalistic and continuous music experience with independent component analysis
2014
Background: Independent component analysis (ICA) has been often used to decompose fMRI data mostly for the resting-state, block and event-related designs due to its outstanding advantage. For fMRI data during free-listening experiences, only a few exploratory studies applied ICA.New method: For processing the fMRI data elicited by 512-s modern tango, a FFT based band-pass filter was used to further pre-process the fMRI data to remove sources of no interest and noise. Then, a fast model order selection method was applied to estimate the number of sources. Next, both individual ICA and group ICA were performed. Subsequently, ICA components whose temporal courses were significantly correlated …