http://precedings.nature.com/tags/EEG Recently posted documents tagged with 'EEG' Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://precedings.nature.com/documents/3720/version/1 The most conspicuous signal in the human EEG is the so-called alpha wave, oscillations in the frequency range of 8 to 12 Hz. Visual stimulation of the retina suppresses the amplitude of alpha waves (Berger effect), and increased attention can reduce them. Here I show that one more parameter significantly affects the amplitudes of alpha waves: the intention to act by a motor response. Together with data from the literature, these results show that alpha waves are not part of the visual processing network but rather part of a long-range neuromodulatory network. The modulation modifies latencies in perception or motor response. The relevant mechanisms are located in early cortical visual areas; their activity may contribute to hemodynamic changes in these areas and thus explain dissociations between Bold signals and spike activities mentioned in the literature. http://precedings.nature.com/documents/3720/version/1 Fri, 04 Sep 2009 11:17:14 UTC The modulation of alpha-wave amplitude in human EEG by the intention to act with a motor response hdl:10101/npre.2009.3720.1 2009-09-04 Kuno Kirschfeld Nature Precedings 2009-09-04T11:17:14Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/3454/version/1 The bond that exists between a horse and human was examined using EEG from the horse and human simultaneously. Three volunteers ranging from novice to elite horse experience participated with an unfamiliar horse. The elite participant was also recorded with her own horse. A dose-response effect was tested using 6 conditions requiring increasing interaction between the horse and human (baseline – apart, standing together, petting, grooming, sitting, and riding). EEG was recorded from 10 locations on the horse and the human. EEG brain maps illustrated that increasing interaction between the horse and human showed more synchronous EEG. The elite horse person showed greater synchronization with her own familiar horse. Perhaps these findings illustrate the bond that exists between horses and humans. http://precedings.nature.com/documents/3454/version/1 Fri, 24 Jul 2009 12:26:52 UTC The Bond Between a Horse and a Human hdl:10101/npre.2009.3454.1 2009-07-24 Debbie Crews Nature Precedings 2009-07-24T12:26:52Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2784/version/1 The objective of the present study was to elucidate evidence of and to revisit chaotic itinerancy in human brains by means of noninvasive scalp electroencephalogram (EEG) in normal subjects; with the assumed tenet that chaotic itinerancy occurs in sequences of cortical states marked by state transitions that appear as temporal discontinuities in neural activity patterns. The present study was based on unprecedented advances in spatial and temporal resolution of the phase of oscillations in scalp EEG. The EEG data was processed and modeled by the technique of curve fitting and temporal resolution was advanced by the use of Hilbert Transform (in Matlab version 7.0), which re-affirmed the variations in phase and amplitude in all scalp EEG electrical signals from 0 through 99 Hz frequencies. The numerical derivative of the analytic phase revealed plateaus in phase. The plateaus were bracketed by sudden jumps in phase. The widespread synchrony of the jumps in analytic phase manifests a metastable cortical state in accord with the theory of self-organized criticality. The jumps appear to be subcritical bifurcations. They reflect the aperiodic evolution of brain states through sequences of attractors that on access support the experience of remembering. State changes resembling phase transitions occur continually everywhere in cortex. Only the largest and longest-lasting state appears in scalp EEG, giving the appearance of chaotic itinerancy. The 1/fα spatial and temporal spectra of scalp EEG denote that brain maintains a state of self-organized criticality (SOC) as the basis of for its capacity for rapid adjustment to environmental changes. http://precedings.nature.com/documents/2784/version/1 Wed, 14 Jan 2009 11:56:38 UTC Chaotic Neural Dynamics as Evinced from Scalp Electroencephalography (EEG) hdl:10101/npre.2009.2784.1 2009-01-14 Amitabh Dube Nature Precedings 2009-01-14T11:56:38Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2477/version/1 Electro-cortical changes associated with learning and performing were investigated in eighteen pianists over three closely-spaced performances of sight-reading a novel music score. Six musical criteria were assessed: right hand errors, left hand errors, rhythmic errors, speed accuracy, fluency, and musical expression. These skills correlated specifically to electrical rhythms of 8.5-10.5 cycles per second near the sensory-motor cortex and the supplementary area. The correlations progressively reduced with each performance as it improved and learning occurred. Further, these electro-cortical potentials can predict the quality of performer and performance at the same or later occasion based on the same or different skill. Understanding this physiology will help to improve the rate, and success, of learning or detect loss of performance-related attention long before sleep onset measures indicate the persistence of loss of vehicle control from exhaustion or drug action. This knowledge can be used in electromechanical coupling allowing direct brain control of devices. http://precedings.nature.com/documents/2477/version/1 Thu, 06 Nov 2008 15:40:31 UTC Electrocortical activity can predict pianist’s proficiency hdl:10101/npre.2008.2477.1 2008-11-06 Malcolm M. H. Mills Nature Precedings 2008-11-06T15:40:31Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1563/version/1 A dorsal fronto-parietal network, including regions in intra-parietal sulcus (IPS) and frontal eye field (FEF), has been hypothesized to control the allocation of spatial attention to environmental stimuli. One putative mechanism of control is the de-synchronization of electroencephalography (EEG) alpha rhythms (~8-12 Hz) in parieto-occipital cortex in anticipation of a visual target. We show that brief interference by transcranial magnetic stimulation (rTMS) with preparatory activity in right IPS or right FEF while subjects attend to a spatial location impairs identification of target stimuli ~2 seconds later. Moreover, the visual deficit relates to the disruption of anticipatory (pre-stimulus) alpha desynchronization and its topography in parieto-occipital cortex. After right IPS stimulation, the degree to which alpha desynchronization is suppressed predicts the speed of visual identification. These results demonstrate the causal role of posterior parietal cortex in the control of visuo-spatial attention exerted through the synchronization of visual neurons. http://precedings.nature.com/documents/1563/version/1 Fri, 01 Feb 2008 18:25:26 UTC Posterior parietal cortex controls spatial attention through modulation of anticipatory alpha rhythms hdl:10101/npre.2008.1563.1 2008-02-01 Paolo Capotosto Nature Precedings 2008-02-01T18:25:26Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1244/version/1 As pointed out by William James, “the consciousness is a dynamic process, not a thing” , during which short term integration is succeeded by another differentiated neural state through the continual interplay between the environment, the body, and the brain itself. Thus, the dynamic structure underlying successive states of the brain is important for understanding human consciousness as a process. In order to investigate the dynamic property of human consciousness, we developed a new method to reconstruct a state space from electroencephalogram(EEG), in which a trajectory, reflecting states of consciousness, is constructed based on the global information integration of the brain. EEGs were obtained from 14 subjects received an intravenous bolus of propopol. Here we show that the degree of human consciousness is directly associated with the information integration capacity of gamma wave, which is significantly higher in the conscious state than in the unconscious state. And we found a new time evolutional property of human consciousness. The conscious state showed a lower dimensional dynamic process which changed to a random-like process after loss of consciousness. This characteristic dynamic property, appeared only in the gamma band, might be used as an indicator to distinguish the conscious and unconscious states and also considered as an important fact for the human consciousness model. http://precedings.nature.com/documents/1244/version/1 Wed, 24 Oct 2007 16:33:49 UTC A new dynamic property of human consciousness hdl:10101/npre.2007.1244.1 2008-04-22 UnCheol Lee Nature Precedings 2007-10-24T16:33:49Z Manuscript Neuroscience http://creativecommons.org/licenses/by/2.5/ http://precedings.nature.com/documents/716/version/1 Primate neocortex contains over 30 visual areas. Recent techniques such as functional magnetic resonance imaging (fMRI) have successfully identified many of these areas in the human brain, but have been of limited value for revealing the temporal dynamics between adjacent visual areas, a critical component of understanding visual cognition. The voltages recorded at the scalp, electroencephalography (EEG), is a direct measure of neural activity that reflects the summed activity across all brain areas. Identifying the cortical sources that contribute to the EEG is a difficult problem. We developed an anatomically constrained dipole search method that solves the traditional problems by combining fMRI, EEG and many stimuli that activate small cortical regions. The method provides a means to validate the extracted waveforms. Both V1 and V2 waveforms have similar onset latencies as well as dynamics that can explain previous controversial findings about the responses of these areas. http://precedings.nature.com/documents/716/version/1 Tue, 14 Aug 2007 14:44:55 UTC The folding fingerprint of visual cortex reveals the timing of human V1 and V2 hdl:10101/npre.2007.716.1 2007-08-14 Justin Ales Nature Precedings 2007-08-14T14:44:55Z Manuscript Neuroscience http://creativecommons.org/licenses/by/2.5/