Read by QxMD icon Read

Brain Topography

Sarah M Theodoroff, Alexander A Stevens, Garnett McMillan, David R Pettersson, William Woodward, Robert L Folmer
Langguth et al. (2006) described a method for targeting primary auditory cortex (PAC) during transcranial magnetic stimulation (TMS) using the 10-20 electroencephalography system. Study aims were to measure the degree of accuracy in placing the TMS coil on the scalp overlying PAC using the 10-20 method and determine the extent to which accuracy depends on the hemisphere of the coil placement. Twelve participants underwent anatomical magnetic resonance imaging (MRI) of their head in a 3T scanner. Before imaging, a fiducial marker was placed on their scalp corresponding to the TMS coil position...
February 21, 2018: Brain Topography
Maria A Bobes, Agustin Lage-Castellanos, Ela I Olivares, Jhoanna Perez Hidalgo-Gato, Jaime Iglesias, Ana Maria Castro-Laguardia, Pedro Valdes-Sosa
Event related potentials (ERPs) provide precise temporal information about cognitive processing, but with poor spatial resolution, while functional magnetic resonance imaging (fMRI) reliably identifies brain areas involved, but with poor temporal resolution. Here we use fMRI to guide source localization of the ERPs at different times for studying the temporal dynamics of the neural system for recognizing familiar faces. fMRI activation areas were defined in a previous experiment applying the same paradigm used for ERPs...
February 20, 2018: Brain Topography
Sara Parmigiani, Benedetta Zattera, Guido Barchiesi, Luigi Cattaneo
The capacity to produce movements only at appropriate times is fundamental in successful behavior and requires a fine interplay between motor inhibition and facilitation. Evidence in humans indicates that the dorsal premotor cortex (PMCd) is involved in such preparatory and inhibitory processes, but how PMCd modulates motor output in humans is still unclear. We investigated this issue in healthy human volunteers, using a variant of the dual-coil transcranial magnetic stimulation (TMS) technique that allows testing the short-latency effects of conditioning TMS to the left PMCd on test TMS applied to the ipsilateral orofacial primary motor cortex (M1)...
February 19, 2018: Brain Topography
Anthony T Herdman, Alexander Moiseev, Urs Ribary
Adaptive and non-adaptive beamformers have become a prominent neuroimaging tool for localizing neural sources of electroencephalographic (EEG) and magnetoencephalographic (MEG) data. In this study, we investigated single-source and multi-source scalar beamformers with respect to their performances in localizing and reconstructing source activity for simulated and real EEG data. We compared a new multi-source search approach (multi-step iterative approach; MIA) to our previous multi-source search approach (single-step iterative approach; SIA) and a single-source search approach (single-step peak approach; SPA)...
February 15, 2018: Brain Topography
Aline Frey, Benoît Lemaire, Laurent Vercueil, Anne Guérin-Dugué
We investigated how two different reading tasks, namely reading to memorize [Read & Memorize (RM)] and reading to decide whether a text was relevant to a given topic [Read & Decide (RD)], modulated both eye movements (EM) and brain activity. To this end, we set up an ecological paradigm using the eye fixation-related potentials (EFRP) technique, in which participants freely moved their eyes to process short paragraphs, while their electroencephalography (EEG) activity was recorded in synchronization with their EM...
February 15, 2018: Brain Topography
B Marty, M Bourguignon, V Jousmäki, V Wens, S Goldman, X De Tiège
This study investigates whether movement kinematics modulates similarly the rolandic α and β rhythm amplitude during executed and observed goal-directed hand movements. It also assesses if this modulation relates to the corticokinematic coherence (CKC), which is the coupling observed between cortical activity and movement kinematics during such motor actions. Magnetoencephalography (MEG) signals were recorded from 11 right-handed healthy subjects while they performed or observed an actor performing the same repetitive hand pinching action...
February 14, 2018: Brain Topography
Anderson Souza Oliveira, Federico Gabriel Arguissain, Ole Kæseler Andersen
The aim of this study was to investigate whether cognitive processing for defining step precision during walking could induce changes in electrocortical activity. Ten healthy adults (21-36 years) were asked to walk overground in three different conditions: (1) normal walking in a straight path (NW); (2) walking in a pre-defined pathway forcing variation in step width and length by stepping on green marks on the floor (only one color: W1C), and (3) walking in the same pre-defined W1C pathway while evaluating different combinations among the colors green, yellow and red, in which only one color was the footfall target (evaluating two colors: W2C)...
February 10, 2018: Brain Topography
Marco Marino, Quanying Liu, Mariangela Del Castello, Cristiana Corsi, Nicole Wenderoth, Dante Mantini
The ballistocardiographic (BCG) artifact is linked to cardiac activity and occurs in electroencephalographic (EEG) recordings acquired inside the magnetic resonance (MR) environment. Its variability in terms of amplitude, waveform shape and spatial distribution over subject's scalp makes its attenuation a challenging task. In this study, we aimed to provide a detailed characterization of the BCG properties, including its temporal dependency on cardiac events and its spatio-temporal dynamics. To this end, we used high-density EEG data acquired during simultaneous functional MR imaging in six healthy volunteers...
February 9, 2018: Brain Topography
David J Arpin, James E Gehringer, Tony W Wilson, Max J Kurz
During active movement the somatosensory cortical responses are often attenuated. This attenuation is referred to as movement-related sensory gating. It is well known that patients with multiple sclerosis (MS) have sensory processing deficits, and recent work has also suggested that these patients display impaired motor control of the ankle musculature. The primary goal of the current study was to: (1) examine the movement-related somatosensory gating in patients with MS and demographically-matched controls, and (2) identify the relationship between the sensory gating and motor control of the ankle musculature...
February 9, 2018: Brain Topography
Giorgia Michelini, Viryanaga Kitsune, Isabella Vainieri, Georgina M Hosang, Daniel Brandeis, Philip Asherson, Jonna Kuntsi
Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) often present with overlapping symptoms and cognitive impairments, such as increased fluctuations in attentional performance measured by increased reaction-time variability (RTV). We previously provided initial evidence of shared and distinct event-related potential (ERP) impairments in ADHD and BD in a direct electrophysiological comparison, but no study to date has compared neural mechanisms underlying attentional impairments with finer-grained brain oscillatory markers...
February 7, 2018: Brain Topography
Antonino Naro, Rocco Salvatore Calabrò, Antonino Leo, Margherita Russo, Demetrio Milardi, Antonino Cannavò, Alfredo Manuli, Antonio Buda, Carmela Casella, Placido Bramanti, Alberto Cacciola, Alessia Bramanti
Advanced functional neuroimaging approaches dealing with motor imagery have disclosed covert cognitive processes in patients with disorders of consciousness (DoC). However, motor impairment and cognitive-motor dissociation can bias such approaches. Fourteen patients with post-traumatic DoC and ten healthy controls (HC) were provided with three motor tasks related to mirror neuron system (MNS) activation (movement observation, movement execution, and passive motor imagery of a movement) while recording electroencephalographic (EEG) metrics [EEG power and Granger Casualty Index (GCI)] to detect residual signs of conscious awareness...
February 7, 2018: Brain Topography
Hanni Kiiski, Lee Jollans, Seán Ó Donnchadha, Hugh Nolan, Róisín Lonergan, Siobhán Kelly, Marie Claire O'Brien, Katie Kinsella, Jessica Bramham, Teresa Burke, Michael Hutchinson, Niall Tubridy, Richard B Reilly, Robert Whelan
Event-related potentials (ERPs) show promise to be objective indicators of cognitive functioning. The aim of the study was to examine if ERPs recorded during an oddball task would predict cognitive functioning and information processing speed in Multiple Sclerosis (MS) patients and controls at the individual level. Seventy-eight participants (35 MS patients, 43 healthy age-matched controls) completed visual and auditory 2- and 3-stimulus oddball tasks with 128-channel EEG, and a neuropsychological battery, at baseline (month 0) and at Months 13 and 26...
January 29, 2018: Brain Topography
Eshwar G Ghumare, Maarten Schrooten, Rik Vandenberghe, Patrick Dupont
Time-varying connectivity analysis based on sources reconstructed using inverse modeling of electroencephalographic (EEG) data is important to understand the dynamic behaviour of the brain. We simulated cortical data from a visual spatial attention network with a time-varying connectivity structure, and then simulated the propagation to the scalp to obtain EEG data. Distributed EEG source modeling using sLORETA was applied. We compared different dipole (representing a source) selection strategies based on their time series in a region of interest...
January 27, 2018: Brain Topography
Marcello Giannini, David M Alexander, Andrey R Nikolaev, Cees van Leeuwen
In spontaneous, stimulus-evoked, and eye-movement evoked EEG, the oscillatory signal shows large scale, dynamically organized patterns of phase. We investigated eye-movement evoked patterns in free-viewing conditions. Participants viewed photographs of natural scenes in anticipation of a memory test. From 200 ms intervals following saccades, we estimated the EEG phase gradient over the entire scalp, and the wave activity, i.e. the goodness of fit of a wave model involving a phase gradient assumed to be smooth over the scalp...
January 25, 2018: Brain Topography
Peiyang Li, Xiaoye Huang, Xuyang Zhu, Huan Liu, Weiwei Zhou, Dezhong Yao, Peng Xu
Partial directed coherence (PDC), which is capable of estimating directed brain networks in the frequency domain, has been widely used in various physiological recordings such as electroencephalograms (EEGs) and functional magnetic resonance imaging. However, clinical data from EEGs are inevitably contaminated with unexpected outlier artifacts. This will result in biased networks, which are different from the original physiological mechanism because of the L2 norm structure utilized in PDC to estimate the directed links...
January 25, 2018: Brain Topography
Chiara Todaro, Laura Marzetti, Pedro A Valdés Sosa, Pedro A Valdés-Hernandez, Vittorio Pizzella
Electrocorticography (ECoG) is an electrophysiological technique that records brain activity directly from the cortical surface with high temporal (ms) and spatial (mm) resolution. Its major limitations are in the high invasiveness and in the restricted field-of-view of the electrode grid, which partially covers the cortex. To infer brain activity at locations different from just below the electrodes, it is necessary to solve the electromagnetic inverse problem. Limitations in the performance of source reconstruction algorithms from ECoG have been, to date, only partially addressed in the literature, and a systematic evaluation is still lacking...
January 23, 2018: Brain Topography
Konstantina Kalogianni, Andreas Daffertshofer, Frans C T van der Helm, Alfred C Schouten, Jan C de Munck
In searching for clinical biomarkers of the somatosensory function, we studied reproducibility of somatosensory potentials (SEP) evoked by finger stimulation in healthy subjects. SEPs induced by electrical stimulation and especially after median nerve stimulation is a method widely used in the literature. It is unclear, however, if the EEG recordings after finger stimulation are reproducible within the same subject. We tested in five healthy subjects the consistency and reproducibility of responses through bootstrapping as well as test-retest recordings...
January 20, 2018: Brain Topography
René J Huster, Vince D Calhoun
No abstract text is available yet for this article.
January 3, 2018: Brain Topography
Xiaoyun Liang, David N Vaughan, Alan Connelly, Fernando Calamante
The conventional way to estimate functional networks is primarily based on Pearson correlation along with classic Fisher Z test. In general, networks are usually calculated at the individual-level and subsequently aggregated to obtain group-level networks. However, such estimated networks are inevitably affected by the inherent large inter-subject variability. A joint graphical model with Stability Selection (JGMSS) method was recently shown to effectively reduce inter-subject variability, mainly caused by confounding variations, by simultaneously estimating individual-level networks from a group...
December 29, 2017: Brain Topography
Li Zhang, John Q Gan, Wenming Zheng, Haixian Wang
In action intention understanding, the mirror system is involved in perception-action matching process and the mentalizing system underlies higher-level intention inference. By analyzing the dynamic functional connectivity in α (8-12 Hz) and β (12-30 Hz) frequency bands over a "hand-cup interaction" observation task, this study investigates the topological transition from the action observation network (AON) to the mentalizing network (MZN), and estimates their functional relevance for intention identification from other's different action kinematics...
December 20, 2017: Brain Topography
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"