Search results for "HALO"
showing 10 items of 2623 documents
High frequency repetitive transcranial magnetic stimulation (rTMS) reduces EEG-hypofrontality in patients with schizophrenia.
2015
The reduced metabolic activity in the prefrontal brain lobes, so-called hypofrontality, is associated with increased electrophysiological delta-band activity. Schizophrenia inpatients (N=35) received sham-controlled 10Hz rTMS over the left dorsolateral prefrontal cortex in a randomised design. After treatment, the resting electroencephalography revealed a significant decrease in the delta-band activity, which originated in the right prefrontal cortex and correlated with improvements in facial affect recognition.
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…
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…
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 …
Polybrominated diphenyl ethers in foods from the Region of Valencia: Dietary exposure and risk assessment
2019
Abstract Dietary exposure to polybrominated diphenyl ethers (PBDEs) of the population in the Region of Valencia, Spain, was assessed. A group of 320 composite samples of different fatty foods was collected and analyzed, including the following: vegetable oils, and foods of animal origin such as (a) fish and seafood, (b) eggs, (c) milk and dairy products, and (d) meat and meat products. Two scenarios were assumed for left-censored results: lower-bound (LB) and upper-bound (UB). Vegetable oils, and fish and seafood presented the highest content of PBDEs [mean values of 503 and 464 pg g−1 wet weight (ww) for total PBDEs, respectively, in the UB]. The dominating congeners were BDE47 in the food…
Endoscopic Treatment of Mesencephalic Ependymal Cysts: Technical Case Report
1998
OBJECTIVE: To evaluate the results of different neuroendoscopic surgical procedures for the treatment of mesencephalic ependymal cysts. METHODS: The clinical records of five patients treated for symptomatic mesencephalic ependymal cysts were retrospectively studied. Two patients had been operated on using an endoscope-assisted microsurgical technique and three patients using a pure endoscopic procedure. RESULTS: Adequate fenestration of the cysts was achieved in all of the patients. Two of the patients were symptom-free, and the other three had improved significantly after a mean follow-up duration of 14 months. There was no surgical morbidity. CONCLUSION: Mesencephalic ependymal cysts can …
Ictal functional TCD for the lateralization of the seizure onset zone—a report of two cases
2004
Ictal functional transcranial Doppler sonography (I-fTCD) was used to lateralize the ictal onset zone in the presurgical evaluation of two patients with temporal lobe epilepsy. In one patient, I-fTCD and ictal SPECT were performed simultaneously during EEG-monitoring. In both patients, results were concordant with the ictal SPECT findings, PET and semiology. I-fTCD seems to be an interesting new method to non-invasively lateralize the seizure onset zone with high temporal resolution. I-fTCD and SPECT may give complementary information to lateralize the seizure onset zone.
Temporally stable beta sensorimotor oscillations and cortico–muscular coupling underlie force steadiness
2022
Funding Information: Data and code are available on the Open Science Framework (OSF) at the following link: https://osf.io/4rmex/?view_only=7d17c2334ace4a0d83087bddf2a64a68. Scott Mongold, Thomas Legrand, and Mathieu Bourguignon were supported by the Fonds de la Recherche Scientifique (F.R.S.-FNRS, Brussels, Belgium; grant MIS F.4504.21). Harri Piitulainen was supported by the Academy of Finland (grants 266133, 296240, 326988, 327288 and 311877) including “Brain changes across the life-span” profiling funding to University of Jyväskylä. We thank Helge Kainulainen and Ronny Schreiber at Aalto NeuroImaging for providing technical help and the force sensor system for the study. We thank Riitta…
Surrogate data approaches to assess the significance of directed coherence: Application to EEG activity propagation
2009
This paper addresses the topic of evaluating the significance of frequency domain measures of causal coupling in multivariate time series through generation of surrogate data. The considered approaches are the traditional Fourier Transform (FT) algorithm and a new causal FT (CFT) algorithm for surrogate data generation. Both algorithms preserve the FT modulus of the original series; differences are in the phase relationships, that are completely destroyed for FT surrogates and imposed after switching off the link over the considered causal direction for CFT surrogates. The ability of the algorithms to assess causality in the frequency domain was tested using the directed coherence as discri…
Testing Frequency-Domain Causality in Multivariate Time Series
2010
We introduce a new hypothesis-testing framework, based on surrogate data generation, to assess in the frequency domain, the concept of causality among multivariate (MV) time series. The approach extends the traditional Fourier transform (FT) method for generating surrogate data in a MV process and adapts it to the specific issue of causality. It generates causal FT (CFT) surrogates with FT modulus taken from the original series, and FT phase taken from a set of series with causal interactions set to zero over the direction of interest and preserved over all other directions. Two different zero-setting procedures, acting on the parameters of a MV autoregressive (MVAR) model fitted on the ori…