Locating spatial patterns of waveforms during sensory perception in scalp EEG

Brockmeier, Austin J.; Hazrati, Mehrnaz Kh.; Freeman, Walter J.; Li, Lin; Prı́ncipe, José C.

doi:10.1109/embc.2012.6346479

Cited by 10 publications

(4 citation statements)

References 8 publications

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“…The operation of Hebbian assemblies at this level is revealed by the properties of concept cells [12,13] in the medial temporal lobe that manifest crossmodal generalization and abstraction. Third is the creation of an AM pattern over the entire forebrain [14][15][16], which unifies the sensory and motor cortices in the choice of the next act of search in the action-perception cycle, including the strategic plan, the next series of tactical maneuvers, and the changes in sensory input that are predicted by preafference to result from the intended actions.…”

Section: Discussionmentioning

confidence: 99%

Advanced Models of Cortical Dynamics in Perception

Freeman

Kozma

et al. 2014

Advances in Cognitive Neurodynamics (IV)

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Here the phenomenon of interest is the flash of recognition and accompanying emotion one experiences when one receives a familiar stimulus. We explain the speed and richness of the event by postulating phase transitions in cortical neuropil: condensation from a gas-like phase to a liquid-like phase followed by evaporation. We model the process with a Carnot-like thermodynamic cycle at three successive levels of complexity: primary sensory cortices; limbic system; global neocortex. We replace the thermodynamic state variables of pressure, volume and temperature with neurodynamic variables, respectively mean beta-gamma power, pattern stability (negentropy), and neural feedback gain (mean interaction strength). We cite evidence that all sensory cortices use this cycle, necessarily so for two reasons. They all evolved from the primordial forebrain of vertebrates dominated by olfaction; they all transmit the same form of perceptual information, wave packets, so signals in all modalities armodel by linear matrix concatenation.

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Section: Discussionmentioning

confidence: 99%

Advanced Models of Cortical Dynamics in Perception

Freeman

Kozma

et al. 2014

Advances in Cognitive Neurodynamics (IV)

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“…Capturing these with novel dense array EEG devices, akin to what has been recently achieved with adult EEG (Brockmeier et al, 2012;Panagiotides et al, 2010;Ruiz et al, 2010), may open a novel window to capturing the details of emerging large scale brain processes, such as those related to perception and cognition (Bressler and Menon, 2010).…”

Section: Discussionmentioning

confidence: 99%

Spatial patterning of the neonatal EEG suggests a need for a high number of electrodes

et al. 2013

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TitleSpatial patterning of the neonatal EEG suggests a need for a high number of electrodes There is an increasing demand for source analysis of neonatal EEG, but currently there is inadequate knowledge about i) the spatial patterning of neonatal scalp EEG and hence ii) the number of electrodes needed to capture neonatal EEG in full spatial detail. This study addresses these issues by using a very high density (2.5 mm interelectrode spacing) linear electrode array to assess the spatial power spectrum, by using a high density (64 electrodes) EEG cap to assess the spatial extent of the common oscillatory bouts in the neonatal EEG and by using a neonatal size spherical head model to assess the effects of source depth and skull conductivities on the spatial frequency spectrum. The linear array recordings show that the spatial power spectrum decays rapidly until about 0.5-0.8 cycles per centimeter. The dense array EEG recordings show that the amplitude of oscillatory events decays within 4-6 cm to the level of global background activity, and that the higher frequencies (12)(13)(14)(15)(16)(17)(18)(19)(20) show the most rapid spatial decline in amplitude. Simulation with spherical head model showed that realistic variation in skull conductivity and source depths can both introduce orders of magnitude difference in the spatial frequency of the scalp EEG. Calculation of spatial Nyquist frequencies from the spatial power spectra suggests that an interelectrode distance of about 6-10 mm would suffice to capture the full spatial texture of the raw EEG signal at the neonatal scalp without spatial aliasing or under-sampling. The spatial decay of oscillatory events suggests that a full representation of their spatial characteristics requires an interelectrode distance of 10-20 mm. The findings show that the conventional way of recording neonatal EEG with about 10 electrodes ignores most spatial EEG content, that increasing the electrode density is necessary to improve neonatal EEG source localization and information extraction, and that prospective source models will need to carefully consider the neonatally relevant ranges of tissue conductivities and source depths when source localizing cortical activity in neonates.

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“…Finally, the observation of highly varying spatial patterning and power law-like (1/f) linear slope in the spatial spectrum is consistent with the idea that the development of infant cognition may be able to be studied by analysis of the formation of spatiotemporal patterns like cinematic frames [130] that in some respects resemble "neural avalanches" [143,144]. Capturing these with novel dense array EEG devices, akin to what has been recently achieved with adult EEG [145][146][147], may open a novel window to capturing the details of emerging large scale brain processes, such as those related to perception and cognition [148]. NEONATAL HEAD MODELS 3…”

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confidence: 73%

Neonatal EEG source localization

Odabaee¹

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Knowledge of the relationship between functional brain activity and its anatomical source is vital in many clinical situations. A multidisciplinary research approach is necessary to enhance understanding of the basic mechanisms of normal and pathological brain functions. Although functional neuroimaging techniques such as functional Magnetic Resonance Imaging (fMRI) facilitate noninvasive access to the active brain, the low temporal resolution necessitates using alternative techniques to study brain dynamics. Electroencephalography (EEG) is a non-invasive method for acquiring neural information with high temporal resolution which measures electric potential over the scalp corresponding to neural activity. EEG source localization (ESL) is a technique applied to EEG to localize the sources of the measured potentials. This technique has been applied to EEG in adults in the studies of physiological, psychological, pathological, and functional brain abnormalities such as tumours and epilepsies. There are indications of the early brain developmental roots of specific abnormalities such as autism, Williams syndrome and schizophrenia that are observed in certain developmental and neuropsychiatric disorders. However, these observations have been performed only in adults. Indeed, despite the necessity of research in neonatal brain functional analysis for medical care of preterm and ill infants, there is limited research in neonatal ESL due in part to limitations in acquiring the relevant parameters of the neonatal head. The overall objective of this thesis is to improve neonatal health care through enhancing non-invasive neonatal brain monitoring by developments in neonatal ESL. The accuracy of neonatal ESL is critically dependant on the quality of the head model whose main components, conductivity, thickness, and homogeneity of different layers have not been established. The number of electrodes needed to capture neonatal EEG in full spatial detail is another missing parameter of importance in extracting information about functional brain activity from neonatal scalp recordings. The last step to achieve this objective, neonatal ESL development, is proposing and applying an accurate algorithm to estimate neural currents from scalp potentials, i.e., to solve the inverse EEG problem. This thesis proposes methodologies for estimating the required neonatal head model parameters and then solves the inverse EEG problem in newborns. This has been completed in three steps by: (i) estimating the source depth and spatial resolution of neonatal EEG, (ii) estimating appropriate head model conductivity values including the effect of fontanelles on neonatal skull conductivity, and (iii) fitting an inverse solution to the neonatal ESL problem. Solving EEG inverse problem in this thesis refers to computing the inverse solution in a particular case. After completing these steps, the procedure is validated and evaluated through simulated and real EEG datasets. Parameters such as neonatal skull conductivity cannot be directly calculated in n...

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Locating spatial patterns of waveforms during sensory perception in scalp EEG

Cited by 10 publications

References 8 publications

Advanced Models of Cortical Dynamics in Perception

Advanced Models of Cortical Dynamics in Perception

Spatial patterning of the neonatal EEG suggests a need for a high number of electrodes

Neonatal EEG source localization

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