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Sample records for cortical gamma rhythms

  1. Temporal interactions between cortical rhythms

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    Anita K Roopun

    2008-12-01

    Full Text Available Multiple local neuronal circuits support different, discrete frequencies of network rhythm in neocortex. Relationships between different frequencies correspond to mechanisms designed to minimise interference, couple activity via stable phase interactions, and control the amplitude of one frequency relative to the phase of another. These mechanisms are proposed to form a framework for spectral information processing. Individual local circuits can also transform their frequency through changes in intrinsic neuronal properties and interactions with other oscillating microcircuits. Here we discuss a frequency transformation in which activity in two coactive local circuits may combine sequentially to generate a third frequency whose period is the concatenation sum of the original two. With such an interaction, the intrinsic periodicity in each component local circuit is preserved – alternate, single periods of each original rhythm form one period of a new frequency - suggesting a robust mechanism for combining information processed on multiple concurrent spatiotemporal scales.

  2. Alpha, beta and gamma electrocorticographic rhythms in somatosensory, motor, premotor and prefrontal cortical areas differ in movement execution and observation in humans.

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    Babiloni, Claudio; Del Percio, Claudio; Vecchio, Fabrizio; Sebastiano, Fabio; Di Gennaro, Giancarlo; Quarato, Pier P; Morace, Roberta; Pavone, Luigi; Soricelli, Andrea; Noce, Giuseppe; Esposito, Vincenzo; Rossini, Paolo Maria; Gallese, Vittorio; Mirabella, Giovanni

    2016-01-01

    In the present study, we tested the hypothesis that both movement execution and observation induce parallel modulations of alpha, beta, and gamma electrocorticographic (ECoG) rhythms in primary somatosensory (Brodmann area 1-2, BA1-2), primary motor (BA4), ventral premotor (BA6), and prefrontal (BA44 and BA45, part of putative human mirror neuron system underlying the understanding of actions of other people) areas. ECoG activity was recorded in drug-resistant epileptic patients during the execution of actions to reach and grasp common objects according to their affordances, as well as during the observation of the same actions performed by an experimenter. Both action execution and observation induced a desynchronization of alpha and beta rhythms in BA1-2, BA4, BA6, BA44 and BA45, which was generally higher in amplitude during the former than the latter condition. Action execution also induced a major synchronization of gamma rhythms in BA4 and BA6, again more during the execution of an action than during its observation. Human primary sensorimotor, premotor, and prefrontal areas do generate alpha, beta, and gamma rhythms and differently modulate them during action execution and observation. Gamma rhythms of motor areas are especially involved in action execution. Oscillatory activity of neural populations in sensorimotor, premotor and prefrontal (part of human mirror neuron system) areas represents and distinguishes own actions from those of other people. This methodological approach might be used for a neurophysiological diagnostic imaging of social cognition in epileptic patients. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Gamma Rhythms and Beta Rhythms Have Different Synchronization Properties

    National Research Council Canada - National Science Library

    N. Kopell; G. B. Ermentrout; M. A. Whittington; R. D. Traub

    2000-01-01

    ...) have a different dynamical structure than that of gamma (30-70 Hz). We use a simplified model to show that the different rhythms employ different dynamical mechanisms to synchronize, based on different ionic currents...

  4. About the cortical origin of the low-delta and high-gamma rhythms observed in EEG signals during treadmill walking.

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    Castermans, Thierry; Duvinage, Matthieu; Cheron, Guy; Dutoit, Thierry

    2014-02-21

    This paper presents a spectral and time-frequency analysis of EEG signals recorded on seven healthy subjects walking on a treadmill at three different speeds. An accelerometer was placed on the head of the subjects in order to record the shocks undergone by the EEG electrodes during walking. Our results indicate that up to 15 harmonics of the fundamental stepping frequency may pollute EEG signals, depending on the walking speed and also on the electrode location. This finding may call into question some conclusions drawn in previous EEG studies where low-delta band (especially around 1 Hz, the fundamental stepping frequency) had been announced as being the seat of angular and linear kinematics control of the lower limbs during walk. Additionally, our analysis reveals that EEG and accelerometer signals exhibit similar time-frequency properties, especially in frequency bands extending up to 150 Hz, suggesting that previous conclusions claiming the activation of high-gamma rhythms during walking may have been drawn on the basis of insufficiently cleaned EEG signals. Our results are put in perspective with recent EEG studies related to locomotion and extensively discussed in particular by focusing on the low-delta and high-gamma bands.

  5. Endogenous cortical rhythms determine cerebral specialization for speech perception and production

    DEFF Research Database (Denmark)

    Giraud, Anne-Lise; Kleinschmidt, Andreas; Poeppel, David

    2007-01-01

    Across multiple timescales, acoustic regularities of speech match rhythmic properties of both the auditory and motor systems. Syllabic rate corresponds to natural jaw-associated oscillatory rhythms, and phonemic length could reflect endogenous oscillatory auditory cortical properties. Hemispheric...... that spontaneous EEG power variations within the gamma range (phonemic rate) correlate best with left auditory cortical synaptic activity, while fluctuations within the theta range correlate best with that in the right. Power fluctuations in both ranges correlate with activity in the mouth premotor region...

  6. A critical role for NMDA receptors in parvalbumin interneurons for gamma rhythm induction and behavior.

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    Carlén, M; Meletis, K; Siegle, J H; Cardin, J A; Futai, K; Vierling-Claassen, D; Rühlmann, C; Jones, S R; Deisseroth, K; Sheng, M; Moore, C I; Tsai, L-H

    2012-05-01

    Synchronous recruitment of fast-spiking (FS) parvalbumin (PV) interneurons generates gamma oscillations, rhythms that emerge during performance of cognitive tasks. Administration of N-methyl-D-aspartate (NMDA) receptor antagonists alters gamma rhythms, and can induce cognitive as well as psychosis-like symptoms in humans. The disruption of NMDA receptor (NMDAR) signaling specifically in FS PV interneurons is therefore hypothesized to give rise to neural network dysfunction that could underlie these symptoms. To address the connection between NMDAR activity, FS PV interneurons, gamma oscillations and behavior, we generated mice lacking NMDAR neurotransmission only in PV cells (PV-Cre/NR1f/f mice). Here, we show that mutant mice exhibit enhanced baseline cortical gamma rhythms, impaired gamma rhythm induction after optogenetic drive of PV interneurons and reduced sensitivity to the effects of NMDAR antagonists on gamma oscillations and stereotypies. Mutant mice show largely normal behaviors except for selective cognitive impairments, including deficits in habituation, working memory and associative learning. Our results provide evidence for the critical role of NMDAR in PV interneurons for expression of normal gamma rhythms and specific cognitive behaviors.

  7. Slow gamma rhythms in CA3 are entrained by slow gamma activity in the dentate gyrus.

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    Hsiao, Yi-Tse; Zheng, Chenguang; Colgin, Laura Lee

    2016-12-01

    In hippocampal area CA1, slow (∼25-55 Hz) and fast (∼60-100 Hz) gamma rhythms are coupled with different CA1 afferents. CA1 slow gamma is coupled to inputs from CA3, and CA1 fast gamma is coupled to inputs from the medial entorhinal cortex (Colgin LL, Denninger T, Fyhn M, Hafting T, Bonnevie T, Jensen O, Moser MB, Moser EI. Nature 462: 353-357, 2009). CA3 gives rise to highly divergent associational projections, and it is possible that reverberating activity in these connections generates slow gamma rhythms in the hippocampus. However, hippocampal gamma is maximal upstream of CA3, in the dentate gyrus (DG) region (Bragin A, Jando G, Nadasdy Z, Hetke J, Wise K, Buzsaki G. J Neurosci 15: 47-60, 1995). Thus it is possible that slow gamma in CA3 is driven by inputs from DG, yet few studies have examined slow and fast gamma rhythms in DG recordings. Here we investigated slow and fast gamma rhythms in paired recordings from DG and CA3 in freely moving rats to determine whether slow and fast gamma rhythms in CA3 are entrained by DG. We found that slow gamma rhythms, as opposed to fast gamma rhythms, were particularly prominent in DG. We investigated directional causal influences between DG and CA3 by Granger causality analysis and found that DG slow gamma influences CA3 slow gamma. Moreover, DG place cell spikes were strongly phase-locked to CA3 slow gamma rhythms, suggesting that DG excitatory projections to CA3 may underlie this directional influence. These results indicate that slow gamma rhythms do not originate in CA3 but rather slow gamma activity upstream in DG entrains slow gamma rhythms in CA3. Copyright © 2016 the American Physiological Society.

  8. Speed controls the amplitude and timing of the hippocampal gamma rhythm.

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    Zhiping Chen

    Full Text Available Cortical and hippocampal gamma oscillations have been implicated in many behavioral tasks. The hippocampus is required for spatial navigation where animals run at varying speeds. Hence we tested the hypothesis that the gamma rhythm could encode the running speed of mice. We found that the amplitude of slow (20-45 Hz and fast (45-120 Hz gamma rhythms in the hippocampal local field potential (LFP increased with running speed. The speed-dependence of gamma amplitude was restricted to a narrow range of theta phases where gamma amplitude was maximal, called the preferred theta phase of gamma. The preferred phase of slow gamma precessed to lower values with increasing running speed. While maximal fast and slow gamma occurred at coincident phases of theta at low speeds, they became progressively more theta-phase separated with increasing speed. These results demonstrate a novel influence of speed on the amplitude and timing of the hippocampal gamma rhythm which could contribute to learning of temporal sequences and navigation.

  9. Resting state cortical electroencephalographic rhythms in subjects with normal and abnormal body weight.

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    Babiloni, Claudio; Marzano, Nicola; Lizio, Roberta; Valenzano, Anna; Triggiani, Antonio Ivano; Petito, Annamaria; Bellomo, Antonello; Lecce, Brunello; Mundi, Ciro; Soricelli, Andrea; Limatola, Cristina; Cibelli, Giuseppe; Del Percio, Claudio

    2011-09-15

    It is well known that resting state regional cerebral blood flow is abnormal in obese when compared to normal-weight subjects but the underlying neurophysiological mechanisms are poorly known. To address this issue, we tested the hypothesis that amplitude of resting state cortical electroencephalographic (EEG) rhythms differ among underweight, normal-weight, and overweight/obese subjects as a reflection of the relationship between cortical neural synchronization and regulation of body weight. Eyes-closed resting state EEG data were recorded in 16 underweight subjects, 25 normal-weight subjects, and 18 overweight/obese subjects. All subjects were psychophysically healthy (no eating disorders or major psychopathologies). EEG rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), beta 2 (20-30Hz), and gamma (30-40Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Statistical results showed that parietal and temporal alpha 1 sources fitted the pattern underweight>normal-weight>overweight/obese (punderweight>overweight/obese (prhythms and fluctuation of global brain arousal. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Slow cortical rhythms: from single-neuron electrophysiology to whole-brain imaging in vivo

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    Olcese, U.; Faraguna, U.

    2015-01-01

    The slow cortical oscillation is the major brain rhythm occurring during sleep, and has been the object of thorough investigation for over thirty years. Despite all these efforts, the function and the neuronal mechanisms behind slow cortical rhythms remain only partially understood. In this review

  11. Slow cortical rhythms: from single-neuron electrophysiology to whole-brain imaging in vivo

    NARCIS (Netherlands)

    U. Olcese; U. Faraguna

    2015-01-01

    The slow cortical oscillation is the major brain rhythm occurring during sleep, and has been the object of thorough investigation for over thirty years. Despite all these efforts, the function and the neuronal mechanisms behind slow cortical rhythms remain only partially understood. In this review w

  12. Neurophysiological and computational principles of cortical rhythms in cognition.

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    Wang, Xiao-Jing

    2010-07-01

    Synchronous rhythms represent a core mechanism for sculpting temporal coordination of neural activity in the brain-wide network. This review focuses on oscillations in the cerebral cortex that occur during cognition, in alert behaving conditions. Over the last two decades, experimental and modeling work has made great strides in elucidating the detailed cellular and circuit basis of these rhythms, particularly gamma and theta rhythms. The underlying physiological mechanisms are diverse (ranging from resonance and pacemaker properties of single cells to multiple scenarios for population synchronization and wave propagation), but also exhibit unifying principles. A major conceptual advance was the realization that synaptic inhibition plays a fundamental role in rhythmogenesis, either in an interneuronal network or in a reciprocal excitatory-inhibitory loop. Computational functions of synchronous oscillations in cognition are still a matter of debate among systems neuroscientists, in part because the notion of regular oscillation seems to contradict the common observation that spiking discharges of individual neurons in the cortex are highly stochastic and far from being clocklike. However, recent findings have led to a framework that goes beyond the conventional theory of coupled oscillators and reconciles the apparent dichotomy between irregular single neuron activity and field potential oscillations. From this perspective, a plethora of studies will be reviewed on the involvement of long-distance neuronal coherence in cognitive functions such as multisensory integration, working memory, and selective attention. Finally, implications of abnormal neural synchronization are discussed as they relate to mental disorders like schizophrenia and autism.

  13. Period concatenation underlies interactions between gamma and beta rhythms in neocortex

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    Anita K Roopun

    2008-04-01

    Full Text Available The neocortex generates rhythmic electrical activity over a frequency range covering many decades. Specific cognitive and motor states are associated with oscillations in discrete frequency bands within this range, but it is not known whether interactions and transitions between distinct frequencies are of functional importance. When coexpressed rhythms have frequencies that differ by a factor of two or more interactions can be seen in terms of phase synchronization. Larger frequency differences can result in interactions in the form of nesting of faster frequencies within slower ones by a process of amplitude modulation. It is not known how coexpressed rhythms, whose frequencies differ by less than a factor of two may interact. Here we show that two frequencies (gamma – 40 Hz and beta2 – 25 Hz, coexpressed in superficial and deep cortical laminae with low temporal interaction, can combine to generate a third frequency (beta1 – 15 Hz showing strong temporal interaction. The process occurs via period concatenation, with basic rhythm-generating microcircuits underlying gamma and beta2 rhythms forming the building blocks of the beta1 rhythm by a process of addition. The mean ratio of adjacent frequency components was a constant – approximately the golden mean – which served to both minimize temporal interactions, and permit multiple transitions, between frequencies. The resulting temporal landscape may provide a framework for multiplexing – parallel information processing on multiple temporal scales.

  14. Classification of Hand Grasp Kinetics and Types Using Movement-Related Cortical Potentials and EEG Rhythms

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    Mads Jochumsen

    2017-01-01

    Full Text Available Detection of single-trial movement intentions from EEG is paramount for brain-computer interfacing in neurorehabilitation. These movement intentions contain task-related information and if this is decoded, the neurorehabilitation could potentially be optimized. The aim of this study was to classify single-trial movement intentions associated with two levels of force and speed and three different grasp types using EEG rhythms and components of the movement-related cortical potential (MRCP as features. The feature importance was used to estimate encoding of discriminative information. Two data sets were used. 29 healthy subjects executed and imagined different hand movements, while EEG was recorded over the contralateral sensorimotor cortex. The following features were extracted: delta, theta, mu/alpha, beta, and gamma rhythms, readiness potential, negative slope, and motor potential of the MRCP. Sequential forward selection was performed, and classification was performed using linear discriminant analysis and support vector machines. Limited classification accuracies were obtained from the EEG rhythms and MRCP-components: 0.48±0.05 (grasp types, 0.41±0.07 (kinetic profiles, motor execution, and 0.39±0.08 (kinetic profiles, motor imagination. Delta activity contributed the most but all features provided discriminative information. These findings suggest that information from the entire EEG spectrum is needed to discriminate between task-related parameters from single-trial movement intentions.

  15. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms

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    Babiloni, Claudio; Triggiani, Antonio I.; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C.; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B.; del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), beta 2 (20–30 Hz), and gamma (30–40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  16. Sparse gamma rhythms arising through clustering in adapting neuronal networks.

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    Zachary P Kilpatrick

    2011-11-01

    Full Text Available Gamma rhythms (30-100 Hz are an extensively studied synchronous brain state responsible for a number of sensory, memory, and motor processes. Experimental evidence suggests that fast-spiking interneurons are responsible for carrying the high frequency components of the rhythm, while regular-spiking pyramidal neurons fire sparsely. We propose that a combination of spike frequency adaptation and global inhibition may be responsible for this behavior. Excitatory neurons form several clusters that fire every few cycles of the fast oscillation. This is first shown in a detailed biophysical network model and then analyzed thoroughly in an idealized model. We exploit the fact that the timescale of adaptation is much slower than that of the other variables. Singular perturbation theory is used to derive an approximate periodic solution for a single spiking unit. This is then used to predict the relationship between the number of clusters arising spontaneously in the network as it relates to the adaptation time constant. We compare this to a complementary analysis that employs a weak coupling assumption to predict the first Fourier mode to destabilize from the incoherent state of an associated phase model as the external noise is reduced. Both approaches predict the same scaling of cluster number with respect to the adaptation time constant, which is corroborated in numerical simulations of the full system. Thus, we develop several testable predictions regarding the formation and characteristics of gamma rhythms with sparsely firing excitatory neurons.

  17. The maturation of cortical sleep rhythms and networks over early development.

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    Chu, C J; Leahy, J; Pathmanathan, J; Kramer, M A; Cash, S S

    2014-07-01

    Although neuronal activity drives all aspects of cortical development, how human brain rhythms spontaneously mature remains an active area of research. We sought to systematically evaluate the emergence of human brain rhythms and functional cortical networks over early development. We examined cortical rhythms and coupling patterns from birth through adolescence in a large cohort of healthy children (n=384) using scalp electroencephalogram (EEG) in the sleep state. We found that the emergence of brain rhythms follows a stereotyped sequence over early development. In general, higher frequencies increase in prominence with striking regional specificity throughout development. The coordination of these rhythmic activities across brain regions follows a general pattern of maturation in which broadly distributed networks of low-frequency oscillations increase in density while networks of high frequency oscillations become sparser and more highly clustered. Our results indicate that a predictable program directs the development of key rhythmic components and physiological brain networks over early development. This work expands our knowledge of normal cortical development. The stereotyped neurophysiological processes observed at the level of rhythms and networks may provide a scaffolding to support critical periods of cognitive growth. Furthermore, these conserved patterns could provide a sensitive biomarker for cortical health across development. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  18. Generation of theta and gamma rhythms in the hippocampus.

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    Leung, L S

    1998-03-01

    In the behaving rat, theta rhythm was dominant during walking and rapid-eye-movement sleep, while irregular slow activity predominated during immobility and slow-wave sleep. Oscillatory evoked potentials of 20-50 Hz and spontaneous fast (gamma) waves were more prominent during theta compared with non-theta behaviors. The oscillations were simulated by a systems model with recurrent inhibition. The model also predicts a behaviorally dependent inhibition, which was confirmed experimentally using paired-pulse responses. Paired-pulse facilitation (PPF) of the population spikes in CA1 was larger during walking than immobility, mostly mediated by a cholinergic input. Spike responses in vitro were characterized by a relative lack of inhibition or disinhibition compared with the behaving rat. The two-input, two-dipole model of the theta rhythm in CA1 is reviewed. Afferents to the CA1 pyramidal cells are assumed to be rhythmic and consist of atropine-sensitive and atropine-resistant inputs driving the somata and distal dendrites, respectively. The atropine-sensitive theta rhythm was mainly caused by a series of Cl- mediated inhibitory postsynaptic potentials (IPSPs) on pyramidal cells. It is suggested that previous claims of the participation of excitatory postsynaptic potentials (EPSPs) and not IPSPs in the intracellular recordings in vivo were flawed. Single cell recordings in vitro suggested that intrinsic voltage-dependent membrane potential oscillations modulate the response to a theta-frequency driving. Membrane potentials of pyramidal cells in vitro showed resonance in the theta frequency range.

  19. Beta and gamma oscillatory activities associated with olfactory memory tasks: Different rhythms for different functional networks?

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    Claire eMartin

    2014-06-01

    Full Text Available Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform and entorhinal cortices and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to ‘bind’ distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz and gamma (60-100 Hz. While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.

  20. Auditory cortical activity during cochlear implant-mediated perception of spoken language, melody, and rhythm.

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    Limb, Charles J; Molloy, Anne T; Jiradejvong, Patpong; Braun, Allen R

    2010-03-01

    Despite the significant advances in language perception for cochlear implant (CI) recipients, music perception continues to be a major challenge for implant-mediated listening. Our understanding of the neural mechanisms that underlie successful implant listening remains limited. To our knowledge, this study represents the first neuroimaging investigation of music perception in CI users, with the hypothesis that CI subjects would demonstrate greater auditory cortical activation than normal hearing controls. H(2) (15)O positron emission tomography (PET) was used here to assess auditory cortical activation patterns in ten postlingually deafened CI patients and ten normal hearing control subjects. Subjects were presented with language, melody, and rhythm tasks during scanning. Our results show significant auditory cortical activation in implant subjects in comparison to control subjects for language, melody, and rhythm. The greatest activity in CI users compared to controls was seen for language tasks, which is thought to reflect both implant and neural specializations for language processing. For musical stimuli, PET scanning revealed significantly greater activation during rhythm perception in CI subjects (compared to control subjects), and the least activation during melody perception, which was the most difficult task for CI users. These results may suggest a possible relationship between auditory performance and degree of auditory cortical activation in implant recipients that deserves further study.

  1. A thalamo-cortical neural mass model for the simulation of brain rhythms during sleep.

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    Cona, F; Lacanna, M; Ursino, M

    2014-08-01

    Cortico-thalamic interactions are known to play a pivotal role in many brain phenomena, including sleep, attention, memory consolidation and rhythm generation. Hence, simple mathematical models that can simulate the dialogue between the cortex and the thalamus, at a mesoscopic level, have a great cognitive value. In the present work we describe a neural mass model of a cortico-thalamic module, based on neurophysiological mechanisms. The model includes two thalamic populations (a thalamo-cortical relay cell population, TCR, and its related thalamic reticular nucleus, TRN), and a cortical column consisting of four connected populations (pyramidal neurons, excitatory interneurons, inhibitory interneurons with slow and fast kinetics). Moreover, thalamic neurons exhibit two firing modes: bursting and tonic. Finally, cortical synapses among pyramidal neurons incorporate a disfacilitation mechanism following prolonged activity. Simulations show that the model is able to mimic the different patterns of rhythmic activity in cortical and thalamic neurons (beta and alpha waves, spindles, delta waves, K-complexes, slow sleep waves) and their progressive changes from wakefulness to deep sleep, by just acting on modulatory inputs. Moreover, simulations performed by providing short sensory inputs to the TCR show that brain rhythms during sleep preserve the cortex from external perturbations, still allowing a high cortical activity necessary to drive synaptic plasticity and memory consolidation. In perspective, the present model may be used within larger cortico-thalamic networks, to gain a deeper understanding of mechanisms beneath synaptic changes during sleep, to investigate the specific role of brain rhythms, and to explore cortical synchronization achieved via thalamic influences.

  2. Functions of gamma-band synchronization in cognition: from single circuits to functional diversity across cortical and subcortical systems.

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    Bosman, Conrado A; Lansink, Carien S; Pennartz, Cyriel M A

    2014-06-01

    Gamma-band activity (30-90 Hz) and the synchronization of neural activity in the gamma-frequency range have been observed in different cortical and subcortical structures and have been associated with different cognitive functions. However, it is still unknown whether gamma-band synchronization subserves a single universal function or a diversity of functions across the full spectrum of cognitive processes. Here, we address this question reviewing the mechanisms of gamma-band oscillation generation and the functions associated with gamma-band activity across several cortical and subcortical structures. Additionally, we raise a plausible explanation of why gamma rhythms are found so ubiquitously across brain structures. Gamma band activity originates from the interplay between inhibition and excitation. We stress that gamma oscillations, associated with this interplay, originate from basic functional motifs that conferred advantages for low-level system processing and multiple cognitive functions throughout evolution. We illustrate the multifunctionality of gamma-band activity by considering its role in neural systems for perception, selective attention, memory, motivation and behavioral control. We conclude that gamma-band oscillations support multiple cognitive processes, rather than a single one, which, however, can be traced back to a limited set of circuit motifs which are found universally across species and brain structures.

  3. Antiretroviral therapy effects on sources of cortical rhythms in HIV subjects: responders vs. mild responders.

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    Babiloni, Claudio; Pennica, Alfredo; Vecchio, Fabrizio; Onorati, Paolo; Muratori, Chiara; Ferracuti, Stefano; Roma, Paolo; Donato, Nicole; Noce, Giuseppe; Del Percio, Claudio; Bonacci, Cristiano; Di Campli, Francesco; Gianserra, Laura; Teti, Elisabetta; Aceti, Antonio; Soricelli, Andrea; Viscione, Magdalena; Rossini, Paolo M; Andreoni, Massimo

    2015-01-01

    We tested the hypothesis that 5months of combined anti-retroviral therapy (cART) affect cortical sources of resting state cortical electroencephalographic (EEG) rhythms in naïve HIV subjects. Eyes-closed resting state EEG data were recorded at baseline (i.e. pre-treatment; T0), T1 (after 4weeks of cART), T2 (after 8weeks of cART), and T5 (after 5months of cART) in 38 naïve HIV subjects. EEG data were also recorded in 40 age-matched cognitively normal subjects for control purposes. EEG rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), and beta 2 (20-30Hz). Cortical EEG sources were estimated by LORETA software. Compared to the control group, the HIV group at T0 showed greater delta sources and lower widespread alpha sources. cART induced a global improvement of biological (viral load, CD4 count) and EEG (delta, alpha) markers, remarkable even after 4weeks. Compared to HIV Responders (>100cells/μl at 5-month follow up), the HIV Mild Responders (rhythms. The present EEG markers may be useful secondary neurophysiological end points for pharmacological clinical trials in naïve HIV subjects. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Classification of single normal and Alzheimer’s disease individuals from cortical sources of resting state EEG rhythms

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    Claudio eBabiloni

    2016-02-01

    Full Text Available Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG rhythms in groups of Alzheimer’s disease (AD compared to healthy elderly (Nold subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2-4 Hz, theta (4-8 Hz, alpha 1 (8-10.5 Hz, alpha 2 (10.5-13 Hz, beta 1 (13-20 Hz, beta 2 (20-30 Hz, and gamma (30-40 Hz were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC higher than 0.7 as a threshold for a moderate classification rate (i.e. 70%. Results showed that the following EEG markers overcame this threshold: (i central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii frontal theta/alpha 1 current density; (iv occipital delta/alpha 1 inter-hemispherical connectivity; (v occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%. These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%.

  5. Cortical plasticity induced by short-term multimodal musical rhythm training.

    Directory of Open Access Journals (Sweden)

    Claudia Lappe

    Full Text Available Performing music is a multimodal experience involving the visual, auditory, and somatosensory modalities as well as the motor system. Therefore, musical training is an excellent model to study multimodal brain plasticity. Indeed, we have previously shown that short-term piano practice increase the magnetoencephalographic (MEG response to melodic material in novice players. Here we investigate the impact of piano training using a rhythmic-focused exercise on responses to rhythmic musical material. Musical training with non musicians was conducted over a period of two weeks. One group (sensorimotor-auditory, SA learned to play a piano sequence with a distinct musical rhythm, another group (auditory, A listened to, and evaluated the rhythmic accuracy of the performances of the SA-group. Training-induced cortical plasticity was evaluated using MEG, comparing the mismatch negativity (MMN in response to occasional rhythmic deviants in a repeating rhythm pattern before and after training. The SA-group showed a significantly greater enlargement of MMN and P2 to deviants after training compared to the A- group. The training-induced increase of the rhythm MMN was bilaterally expressed in contrast to our previous finding where the MMN for deviants in the pitch domain showed a larger right than left increase. The results indicate that when auditory experience is strictly controlled during training, involvement of the sensorimotor system and perhaps increased attentional recources that are needed in producing rhythms lead to more robust plastic changes in the auditory cortex compared to when rhythms are simply attended to in the auditory domain in the absence of motor production.

  6. Cortical plasticity induced by short-term multimodal musical rhythm training.

    Science.gov (United States)

    Lappe, Claudia; Trainor, Laurel J; Herholz, Sibylle C; Pantev, Christo

    2011-01-01

    Performing music is a multimodal experience involving the visual, auditory, and somatosensory modalities as well as the motor system. Therefore, musical training is an excellent model to study multimodal brain plasticity. Indeed, we have previously shown that short-term piano practice increase the magnetoencephalographic (MEG) response to melodic material in novice players. Here we investigate the impact of piano training using a rhythmic-focused exercise on responses to rhythmic musical material. Musical training with non musicians was conducted over a period of two weeks. One group (sensorimotor-auditory, SA) learned to play a piano sequence with a distinct musical rhythm, another group (auditory, A) listened to, and evaluated the rhythmic accuracy of the performances of the SA-group. Training-induced cortical plasticity was evaluated using MEG, comparing the mismatch negativity (MMN) in response to occasional rhythmic deviants in a repeating rhythm pattern before and after training. The SA-group showed a significantly greater enlargement of MMN and P2 to deviants after training compared to the A- group. The training-induced increase of the rhythm MMN was bilaterally expressed in contrast to our previous finding where the MMN for deviants in the pitch domain showed a larger right than left increase. The results indicate that when auditory experience is strictly controlled during training, involvement of the sensorimotor system and perhaps increased attentional recources that are needed in producing rhythms lead to more robust plastic changes in the auditory cortex compared to when rhythms are simply attended to in the auditory domain in the absence of motor production.

  7. Fast Gamma Rhythms in the Hippocampus Promote Encoding of Novel Object-Place Pairings.

    Science.gov (United States)

    Zheng, Chenguang; Wood Bieri, Kevin; Hwaun, Ernie; Lee Colgin, Laura

    2016-01-01

    Hippocampal gamma rhythms increase during mnemonic operations (Johnson and Redish, 2007; Montgomery and Buzsáki, 2007; Sederberg et al., 2007; Jutras et al., 2009; Trimper et al., 2014) and may affect memory encoding by coordinating activity of neurons that code related information (Jensen and Lisman, 2005). Here, a hippocampal-dependent, object-place association task (Clark et al., 2000; Broadbent et al., 2004; Eacott and Norman, 2004; Lee et al., 2005; Winters et al., 2008; Barker and Warburton, 2011) was used in rats to investigate how slow and fast gamma rhythms in the hippocampus relate to encoding of memories for novel object-place associations. In novel object tasks, the degree of hippocampal dependence has been reported to vary depending on the type of novelty (Eichenbaum et al., 2007; Winters et al., 2008). Therefore, gamma activity was examined during three novelty conditions: a novel object presented in a location where a familiar object had been (NO), a familiar object presented in a location where no object had been (NL), and a novel object presented in a location where no object had been (NO+NL). The strongest and most consistent effects were observed for fast gamma rhythms during the NO+NL condition. Fast gamma power, CA3-CA1 phase synchrony, and phase-locking of place cell spikes increased during exploration of novel, compared to familiar, object-place associations. Additionally, place cell spiking during exploration of novel object-place pairings was increased when fast gamma rhythms were present. These results suggest that fast gamma rhythms promote encoding of memories for novel object-place associations.

  8. Transitions between beta and gamma rhythms in neural systems

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Setsinsky, D; Fausbøll, Anders;

    2002-01-01

    We study the coexistence of different rhythms in a local network of one inhibitory and two excitatory nerve cells for a wide range of the excitatory synapse strength and of the slow K+-channel conductance. The dynamic features of spike trains in the presence of noise are discussed. It is found th...

  9. Frontal midline theta rhythm and gamma power changes during focused attention on mental calculation: an MEG beamformer analysis

    Directory of Open Access Journals (Sweden)

    Ryouhei eIshii

    2014-06-01

    Full Text Available Frontal midline theta rhythm (Fmθ appears widely distributed over medial prefrontal areas in EEG recordings, indicating focused attention. Although mental calculation is often used as an attention-demanding task, little has been reported on calculation-related activation in Fmθ experiments. In this study we used spatially filtered MEG and permutation analysis to precisely localize cortical generators of the magnetic counterpart of Fmθ, as well as other sources of oscillatory activity associated with mental calculation processing (i.e., arithmetic subtraction. Our results confirmed and extended earlier EEG/MEG studies indicating that Fmθ during mental calculation is generated in the dorsal anterior cingulate and adjacent medial prefrontal cortex. Mental subtraction was also associated with gamma event-related synchronization, as an index of activation, in right parietal regions subserving basic numerical processing and number-based spatial attention. Gamma event-related desynchronization appeared in the right lateral prefrontal cortex, likely representing a mechanism to interrupt neural activity that can interfere with the ongoing cognitive task.

  10. Sensorimotor rhythm-based brain-computer interface training: the impact on motor cortical responsiveness

    Science.gov (United States)

    Pichiorri, F.; De Vico Fallani, F.; Cincotti, F.; Babiloni, F.; Molinari, M.; Kleih, S. C.; Neuper, C.; Kübler, A.; Mattia, D.

    2011-04-01

    The main purpose of electroencephalography (EEG)-based brain-computer interface (BCI) technology is to provide an alternative channel to support communication and control when motor pathways are interrupted. Despite the considerable amount of research focused on the improvement of EEG signal detection and translation into output commands, little is known about how learning to operate a BCI device may affect brain plasticity. This study investigated if and how sensorimotor rhythm-based BCI training would induce persistent functional changes in motor cortex, as assessed with transcranial magnetic stimulation (TMS) and high-density EEG. Motor imagery (MI)-based BCI training in naïve participants led to a significant increase in motor cortical excitability, as revealed by post-training TMS mapping of the hand muscle's cortical representation; peak amplitude and volume of the motor evoked potentials recorded from the opponens pollicis muscle were significantly higher only in those subjects who develop a MI strategy based on imagination of hand grasping to successfully control a computer cursor. Furthermore, analysis of the functional brain networks constructed using a connectivity matrix between scalp electrodes revealed a significant decrease in the global efficiency index for the higher-beta frequency range (22-29 Hz), indicating that the brain network changes its topology with practice of hand grasping MI. Our findings build the neurophysiological basis for the use of non-invasive BCI technology for monitoring and guidance of motor imagery-dependent brain plasticity and thus may render BCI a viable tool for post-stroke rehabilitation.

  11. [Changes in Spatial Organization of Cortical Rhythm Vibrations in Children uner the Influence of Music].

    Science.gov (United States)

    Shepovalnikov, A N; Egorov, M V

    2015-01-01

    Changes is systemic brain activity under influence of classical music (minor and major music) were studied at two groups of healthy children aged 5-6 years (n = 53). In 25 of studied children the Luscher test showed increased level of anxiety which significantly decreased after music therapy sessions. Bioelectrical cortical activity registered from 20 unipolar leads was subjected to correlation, coherence and factor analysis. Also the dynamics of the power spectrum for each of the EEG was studied. According to EEG all children after listening to both minor and major tones showed reorganization of brain rhythm structure accompanied by a decrease in the level of coherence and correlation of EEG; also was found significant and almost universal decrease in the EEG power spectrum. Registered EEG changes under the influence of classical music seems to reflect a decrease in excess of "internal tension" and weakening degree of "stiffness" to ensure the activity of cerebral structures responsible for mechanisms of "basic integration" which maintain constant readiness of brain to rapid and complete inclusion in action.

  12. GABAB receptor blockade enhances theta and gamma rhythms in the hippocampus of behaving rats.

    Science.gov (United States)

    Leung, L Stan; Shen, Bixia

    2007-01-01

    The participation of GABA(B) receptors in hippocampal EEG generation was studied by intracerebroventricular (icv) and intracerebral infusions of GABA(B) receptor antagonist p-(3-aminopropyl)-p-diethoxymethyl-phosphinic acid (CGP35348) in freely behaving rats. During awake-immobility, icv CGP35348 induced a theta rhythm and increased gamma waves (30-100 Hz) in the hippocampus. The immobility theta peaked at 6-7 Hz and had a theta phase in CA1 stratum radiatum of approximately 160 degrees with reference to the theta at the alveus, when compared with approximately 130 degrees during walking. Immobility theta power peaks at 6-7 Hz was also found in normal rats, and it was detected in 27% of the EEG segments during immobility. Incidence of immobility theta increased to 87.5% after 480 nmol of CGP35348 icv. Muscarinic antagonist scopolamine (5 mg/kg, ip) suppressed the induction of immobility theta and the gamma power increase after icv CGP35348. CGP35348 icv did not significantly change the hippocampal theta power at 7-8 Hz during walking (theta fundamental), but it increased power at 12-15 Hz, at the second harmonic of theta. CGP35348 icv also increased 30-50 Hz gamma power during walking. Medial septal infusion of CGP35348 (12 nmol in 0.4 microl) increased the power and the frequency of the hippocampal theta second harmonic during walking, but did not increase gamma activity. Infusion of CGP35348 (8 nmol in 0.4 microl) in the hippocampus increased the local gamma activity at 30-100 Hz, but did not induce immobility theta or affect the walking theta rhythm. In conclusion, icv GABA(B) receptor blockade increased an atropine-sensitive input that generated an immobility theta rhythm, while GABA(B) receptor blockade of the medial septum increased atropine-resistant theta harmonics possibly generated by apical dendritic spikes. GABA(B) receptor blockade may enhance cognitive task performance by activating hippocampal theta and gamma rhythms in behaving rats.

  13. Comodulation of dopamine and serotonin on prefrontal cortical rhythms: A theoretical study

    Directory of Open Access Journals (Sweden)

    Da-Hui eWang

    2013-08-01

    Full Text Available The prefrontal cortex (PFC is implicated to play an important role in cognitive control. Abnormal PFC activities and rhythms have been observed in some neurological and neuropsychiatric disorders, and evidences suggest influences from the neuromodulators dopamine (DA and serotonin (5-HT. Despite the high level of interest in these brain systems, the combined effects of DA and 5-HT modulation on PFC dynamics remain unknown. In this work, we build a mathematical model that incorporates available experimental findings to systematically study the comodulation of DA and 5-HT on the network behavior, focusing on beta and gamma band oscillations. Single neuronal model shows pyramidal cells with 5-HT1A and 2A receptors can be non-monotonically modulated by 5-HT. Two-population excitatory-inhibitory type network consisting of pyramidal cells with D1 receptors can provide rich repertoires of oscillatory behavior. In particular, 5-HT and DA can modulate the amplitude and frequency of the oscillations, which can emerge or cease, depending on receptor types. Certain receptor combinations are conducive for the robustness of the oscillatory regime, or the existence of multiple discrete oscillatory regimes. In a multi-population heterogeneous model that takes into account possible combination of receptors, we demonstrate that robust network oscillations require high DA concentration. We also show that selective D1 receptor antagonists (agonists tend to suppress (enhance network oscillations, increase the frequency from beta toward gamma band, while selective 5-HT1A antagonists (agonists act in opposite ways. Selective D2 or 5-HT2A receptor antagonists (agonists can lead to decrease (increase in oscillation amplitude, but only 5-HT2A antagonists (agonists can increase (decrease the frequency. These results are comparable to some pharmacological effects. Our work illustrates the complex mechanisms of DA and 5-HT when operating simultaneously through multiple

  14. Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in Tissue Slices

    Science.gov (United States)

    1986-04-01

    Neurol. 234: 242-263. Peters, A. and Proskauer, c. C. (1980) Synaptic relationships between a multipolar stellate cell and a pyramidal neuron in rat...APR 1986 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in...AIR FORCE MEDICAL CENTER Title of Thesis: Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in Tissue Slices Name of Candidate

  15. On-going electroencephalographic rhythms related to cortical arousal in wild-type mice: the effect of aging.

    Science.gov (United States)

    Del Percio, Claudio; Drinkenburg, Wilhelmus; Lopez, Susanna; Infarinato, Francesco; Bastlund, Jesper Frank; Laursen, Bettina; Pedersen, Jan T; Christensen, Ditte Zerlang; Forloni, Gianluigi; Frasca, Angelisa; Noè, Francesco M; Bentivoglio, Marina; Fabene, Paolo Francesco; Bertini, Giuseppe; Colavito, Valeria; Kelley, Jonathan; Dix, Sophie; Richardson, Jill C; Babiloni, Claudio

    2017-01-01

    Resting state electroencephalographic (EEG) rhythms reflect the fluctuation of cortical arousal and vigilance in a typical clinical setting, namely the EEG recording for few minutes with eyes closed (i.e., passive condition) and eyes open (i.e., active condition). Can this procedure be back-translated to C57 (wild type) mice for aging studies? On-going EEG rhythms were recorded from a frontoparietal bipolar channel in 85 (19 females) C57 mice. Male mice were subdivided into 3 groups: 25 young (4.5-6 months), 18 middle-aged (12-15 months), and 23 old (20-24 months) mice to test the effect of aging. EEG power density was compared between short periods (about 5 minutes) of awake quiet behavior (passive) and dynamic exploration of the cage (active). Compared with the passive condition, the active condition induced decreased EEG power at 1-2 Hz and increased EEG power at 6-10 Hz in the group of 85 mice. Concerning the aging effects, the passive condition showed higher EEG power at 1-2 Hz in the old group than that in the others. Furthermore, the active condition exhibited a maximum EEG power at 6-8 Hz in the former group and 8-10 Hz in the latter. In the present conditions, delta and theta EEG rhythms reflected changes in cortical arousal and vigilance in freely behaving C57 mice across aging. These changes resemble the so-called slowing of resting state EEG rhythms observed in humans across physiological and pathological aging. The present EEG procedures may be used to enhance preclinical phases of drug discovery in mice for understanding the neurophysiological effects of new compounds against brain aging. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Reduction in Cortical Gamma Synchrony during Depolarized State of Slow Wave Activity in Mice

    Directory of Open Access Journals (Sweden)

    EUNJIN eHWANG

    2013-12-01

    Full Text Available EEG gamma band oscillations have been proposed to account for the neural synchronization crucial for perceptual integration. While increased gamma power and synchronization is generally observed during cognitive tasks performed during wake, several studies have additionally reported increased gamma power during sleep or anesthesia, raising questions about the characteristics of gamma oscillation during impaired consciousness and its role in conscious processing. Phase-amplitude modulation has been observed between slow wave activity (SWA, 0.5–4 Hz and gamma oscillations during ketamine/xylazine anesthesia or sleep, showing increased gamma activity corresponding to the depolarized (ON state of SWA. Here we divided gamma activity into its ON and OFF (hyperpolarized state components based on the phase of SWA induced by ketamine/xylazine anesthesia and compared their power and synchrony with wake state levels in mice. We further investigated the state-dependent changes in both gamma power and synchrony across primary motor and primary somatosensory cortical regions and their interconnected thalamic regions throughout anesthesia and recovery. As observed previously, gamma power was as high as during wake specifically during the ON state of SWA. However, the synchrony of this gamma activity between somatosensory-motor cortical regions was significantly reduced compared to the baseline wake state. In addition, the somatosensory-motor cortical synchrony of gamma oscillations was reduced and restored in an anesthetic state-dependent manner, reflecting the changing depth of anesthesia. Our results provide evidence that during anesthesia changes in long-range information integration between cortical regions might be more critical for changes in consciousness than changes in local gamma oscillatory power.

  17. [Correspondence between spectral power and synchronization of the brain rhythms in the norm and cognitive pathology].

    Science.gov (United States)

    Strelets, V B; Garakh, Zh B; Novototskiĭ-Vlasov, V Iu; Magomedov, R A

    2005-01-01

    The work is aimed at the study of correlations between the measures of spectral power and cortical interactions of EEG rhythms in healthy subjects and schizophrenic patients ("acute" and chronic cases). All brain rhythms in healthy subjects appeared to be symmetrical and synchronous both in phase and frequency. In "acute" schizophrenics, opposite to healthy subjects, the distribution of cortical activity is asymmetrical, and in the chronic cases, the spectral power of most cortical rhythms is decreased as compared to healthy subjects. In the "acute" patients, interhemispheric connections are absent in all rhythms but alpha. In the chronic patients, the number of cortical connections is slightly higher than in the acute patients; and they are located in the posterior areas in the gamma rhythm. These neurophysiological aberrations evidently underlie the multiple mental activity disorders in schizophrenic patients. Thus, the correspondence between the brain rhythms and their synchronization is a necessary condition for normal perception, emotions and cognition evidently influencing behavior and consciousness.

  18. Comparison of Sensory-motor Rhythm and Movement Related Cortical Potential during Ballistic and Repetitive Motor Imagery

    Institute of Scientific and Technical Information of China (English)

    XU Ren; JIANG Ning; MRACHACZ-KERSTING Natalie; DREMSTRUP Kim; FARINA Dario

    2014-01-01

    In this study, we compared two types of EEG modalities, sensory-motor rhythms (SMR) and movement related cortical potentials (MRCP), on four healthy subjects performing ballistic or repetitive movement imagination. The EEG waveform morphology across subjects was similar for MRCPs, whereas there was not a clear pattern for SMRs. The rank-sum test showed a significant difference between the amplitude of baseline and that of the MRCP as early as 2 s prior to imagery onset, for both types of motor imageries, indicating strong discriminative power of MRCPs for predicting movement onset. For SMR, this type of discriminative power was relatively weak and highly subject-specific. On the other hand, the SMR landscape under the two movement imagery types was distinctive, holding a potential for discriminating the two movement imagery types. These preliminary results presented different characteristics of SMR and MRCP under different motor imageries, providing valuable information regarding the design and implementation of motor imagery based on BCI system.

  19. Asymmetric function of theta and gamma activity in syllable processing: an intra-cortical study

    Directory of Open Access Journals (Sweden)

    Benjamin eMorillon

    2012-07-01

    Full Text Available Low-gamma (25-45 Hz and theta (4-8 Hz oscillations are proposed to underpin the integration of phonemic and syllabic information, respectively. How these two scales of analysis split functions across hemispheres is unclear. We analyzed cortical responses from an epileptic patient with a rare bilateral electrode implantation (stereotactic EEG in primary (A1/BA41 and A2/BA42 and association auditory cortices (BA22. Using time-frequency analyses, we confirmed the dominance of a 5-6 Hz theta activity in right and of a low-gamma (25-45 Hz activity in left primary auditory cortices (A1/A2, during both resting state and syllable processing. We further detected high-theta (7-8 Hz resting activity in left primary, but also associative auditory regions. In left BA22, its phase correlated with high-gamma induced power. Such a hierarchical relationship across theta and gamma frequency bands (theta/gamma phase-amplitude coupling could index the process by which the neural code shifts from stimulus feature- to phonological- encoding, and is associated with the transition from evoked to induced power responses. These data suggest that theta and gamma activity in right and left auditory cortices bear different functions. They support a scheme where slow parsing of the acoustic information dominates in right-hemisphere at a syllabic (5-6 Hz rate, and left auditory cortex exhibits a more complex cascade of oscillations, reflecting the possible extraction of transient acoustic cues at a fast (~25-45 Hz rate, subsequently integrated at a slower, e.g. syllabic one. Slow oscillations could functionally participate to speech processing by structuring gamma activity in left BA22, where abstract percepts emerge.

  20. Computational model of thalamo-cortical networks: dynamical control of alpha rhythms in relation to focal attention.

    Science.gov (United States)

    Suffczynski, P; Kalitzin, S; Pfurtscheller, G; Lopes da Silva, F H

    2001-12-01

    EEG/MEG rhythmic activities such as alpha rhythms, of the visual or of the somato-sensory cortex, are commonly modulated as subjects perform certain tasks or react to specific stimuli. In general, these activities change depending on extrinsic or intrinsic events. A decrease of the amplitude of alpha rhythmic activity occurring after a given event, which manifests as a decrease of a spectral peak, is called event-related desynchronization (ERD), whereas the inverse is called event-related synchronization (ERS), since it is assumed that the power of a spectral peak is related to the degree of synchrony of the underlying oscillating neuronal populations. An intriguing observation in this respect [Pfurtscheller and Neuper, Neurosci. Lett. 174 (1994) 93-96] was that ERD of alpha rhythms recorded over the central areas was accompanied by ERS, within the same frequency band, recorded over neighboring areas. In case the event was a hand movement, ERD was recorded over the scalp overlying the hand cortical area, whereas ERS was concomitantly recorded over the midline, whereas if the movement was of the foot the opposite was found. We called this phenomenon 'focal ERD/surround ERS'. The question of how this phenomenon may be generated was approached by means of a computational model of thalamo-cortical networks, that incorporates basic properties of neurons and synaptic interactions. These simulation studies revealed that this antagonistic ERD/ERS phenomenon depends on the functional interaction between the populations of thalamo-cortical cells (TCR) and reticular nucleus cells (RE) and on how this interaction is modulated by cholinergic inputs. An essential feature of this interaction is the existence of cross-talk between different sectors of RE that correspond to distinct sensory modules (e.g. hand, foot). These observations led us to formulate the hypothesis that this basic neurophysiological mechanism can account for the general observation that enhanced attention

  1. Mechanical strength of cortical allografts with gamma radiation versus ethylene oxide sterilization.

    Science.gov (United States)

    Zhou, Zongke; Qin, Tingwu; Yang, Jing; Shen, Bin; Kang, Pengde; Peil, Fuxing

    2011-10-01

    We investigated the effects of gamma irradiation versus ethylene oxide (ETO) sterilization on the mechanical strength of cortical bone grafts. Tibias were collected from cadavers of mature goats. Sixty test specimens were randomized into four groups: fresh (no processing), frozen (freezing at -70 degrees C), gamma-irradiated, and ETO-sterilized specimens. Torsion, three-point bending, and compression testing were separately performed with a material testing machine. Parameters studied included maximum stress, strain, deflection, extension, load, shear modulus, and E-modulus. Compared with findings for the fresh specimens, findings were as follows for gamma-irradiated specimens: maximal shear modulus, reduced by 48%; shear stress, by 55%; deflection, by 71%; bending stress, by 51%; bending strain, by 74%; extension, by 60%; and compression strain, by 50%. However, there were no reductions in those parameters for the frozen specimens or the ETO-sterilized specimens. These findings confirm that shear, bending, and compression strength of cortical allografts are weakened by gamma irradiation at room temperature. To maintain optimum mechanical properties, ETO sterilization of allografts is better than gamma sterilization, especially for cortical bone, because it is usually used in load-bearing settings.

  2. Hippocampal theta rhythm and its coupling with gamma oscillations require fast inhibition onto parvalbumin-positive interneurons.

    Science.gov (United States)

    Wulff, Peer; Ponomarenko, Alexey A; Bartos, Marlene; Korotkova, Tatiana M; Fuchs, Elke C; Bähner, Florian; Both, Martin; Tort, Adriano B L; Kopell, Nancy J; Wisden, William; Monyer, Hannah

    2009-03-03

    Hippocampal theta (5-10 Hz) and gamma (35-85 Hz) oscillations depend on an inhibitory network of GABAergic interneurons. However, the lack of methods for direct and cell-type-specific interference with inhibition has prevented better insights that help link synaptic and cellular properties with network function. Here, we generated genetically modified mice (PV-Deltagamma(2)) in which synaptic inhibition was ablated in parvalbumin-positive (PV+) interneurons. Hippocampal local field potential and unit recordings in the CA1 area of freely behaving mice revealed that theta rhythm was strongly reduced in these mice. The characteristic coupling of theta and gamma oscillations was strongly altered in PV-Deltagamma(2) mice more than could be accounted for by the reduction in theta rhythm only. Surprisingly, gamma oscillations were not altered. These data indicate that synaptic inhibition onto PV+ interneurons is indispensable for theta- and its coupling to gamma oscillations but not for rhythmic gamma-activity in the hippocampus. Similar alterations in rhythmic activity were obtained in a computational hippocampal network model mimicking the genetic modification, suggesting that intrahippocampal networks might contribute to these effects.

  3. Dynamic modulation of shared sensory and motor cortical rhythms mediates speech and non-speech discrimination performance

    Directory of Open Access Journals (Sweden)

    Andrew Lee Bowers

    2014-05-01

    Full Text Available Oscillatory models of speech processing have proposed that rhythmic cortical oscillations in sensory and motor regions modulate speech sound processing from the bottom-up via phase reset at low frequencies (3-10Hz and from the top-down via the disinhibition of alpha/beta rhythms (8-30Hz. To investigate how the proposed rhythms mediate perceptual performance, EEG was recorded while participants passively listened to or actively identified speech and tone-sweeps in a two-force choice in noise discrimination task presented high and low signal-to-noise ratios. EEG data were decomposed using independent component analysis (ICA and clustered across participants using principle component methods in EEGLAB. Clustering analysis showed left and right hemisphere sensorimotor and posterior temporal lobe components. In posterior temporal clusters, increases in phase reset at low-frequencies were driven by the quality of bottom-up acoustic information for speech and non-speech stimuli, whereas phase reset in sensorimotor clusters was associated with top-down active task demands. A comparison of correct discrimination trials to those identified at chance showed an earlier performance related effect for the left sensorimotor cluster relative to the left-temporal lobe cluster during the syllable discrimination task only. The right sensorimotor cluster was associated with performance related differences for tone-sweep stimuli only. Alpha/beta suppression was associated with active tasks only in sensorimotor and temporal clusters. Findings are consistent with internal model accounts suggesting that early efferent sensorimotor models transmitted along alpha and beta channels reflect a release from inhibition related to active attention to auditory stimuli. Results are discussed in the broader context of dynamic, oscillatory models of cognition proposing that top-down internally generated states interact with bottom-up sensory processing to enhance task performance.

  4. Resting state cortical rhythms in mild cognitive impairment and Alzheimer's disease: electroencephalographic evidence.

    Science.gov (United States)

    Babiloni, Claudio; Vecchio, Fabrizio; Lizio, Roberta; Ferri, Raffaele; Rodriguez, Guido; Marzano, Nicola; Frisoni, Giovanni B; Rossini, Paolo M

    2011-01-01

    Physiological brain aging is characterized by a combination of synaptic pruning, loss of cortico-cortical connections and neuronal apoptosis that provoke age-dependent decline of cognitive functions. Neural/synaptic redundancy and plastic remodeling of brain networking, also secondary to mental and physical training, promotes maintenance of brain activity in healthy elderly for everyday life and fully productive affective and intellectual capabilities. Unfortunately, in pathological situations, aging triggers neurodegenerative processes that impact on cognition, like Alzheimer's disease (AD). Oscillatory electromagnetic brain activity is a hallmark of neuronal network function in various brain regions. Modern neurophysiological techniques including digital electroencephalography (EEG) allow non-invasive analysis of cortico-cortical connectivity and neuronal synchronization of firing, and coherence of brain rhythmic oscillations at various frequencies. The present review of field EEG literature suggests that discrimination between physiological and pathological brain aging clearly emerges at the group level, with some promising result on the informative value of EEG markers at the individual level. Integrated approaches utilizing neurophysiological techniques together with biological markers and structural and functional imaging are promising for large-scale, low-cost, widely available on the territory and non-invasive screening of at-risk populations.

  5. Human cortical rhythms during visual delayed choice reaction time tasks. A high-resolution EEG study on normal aging.

    Science.gov (United States)

    Babiloni, Claudio; Babiloni, Fabio; Carducci, Filippo; Cappa, Stefano F; Cincotti, Febo; Del Percio, Claudio; Miniussi, Carlo; Vito Moretti, Davide; Rossi, Simone; Sosta, Katiuscia; Rossini, Paolo Maria

    2004-08-12

    Neuroimaging cognitive study of aging requires simple tasks ensuring a high rate of correct performances even in stressful neurophysiological settings. Here two simple delayed choice reaction time tasks were used to unveil event-related desynchronization (ERD) of theta (4-6 Hz) and alpha (6-12 Hz) electroencephalographic rhythms across normal aging. In the first condition, a cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). The explicit demand was visuo-spatial, but the retention could be also based on phonological and somatomotor coding. In the second condition, the cue stimulus remained available along the delay period. Correct performances were higher than 95% in both groups and tasks, although they were significantly better in young than elderly subjects (P < 0.03). During the delay period, theta and alpha ERD accompanying correct responses were recognized in the two groups, the alpha ERD being stronger and prolonged during the memory than non-memory task. On the other hand, the fronto-parietal theta and parietal alpha ERD were stronger in young than elderly subjects during both tasks. Notably, the frontal alpha ERD was negligible in elderly subjects. In conclusion, the present simple tasks unveiled in elderly compared to young subjects (i) a weaker involvement of (para)hippocampal-cortical circuits as revealed by theta ERD and (ii) a weaker involvement of "executive" thalamo-cortical circuits as revealed by frontal alpha ERD. These effects might worsen behavioral performances to the simple cognitive tasks with age. The present protocol is promising for the neuroimaging study of pathological aging.

  6. Distinct Thalamic Reticular Cell Types Differentially Modulate Normal and Pathological Cortical Rhythms

    Directory of Open Access Journals (Sweden)

    Alexandra Clemente-Perez

    2017-06-01

    Full Text Available Integrative brain functions depend on widely distributed, rhythmically coordinated computations. Through its long-ranging connections with cortex and most senses, the thalamus orchestrates the flow of cognitive and sensory information. Essential in this process, the nucleus reticularis thalami (nRT gates different information streams through its extensive inhibition onto other thalamic nuclei, however, we lack an understanding of how different inhibitory neuron subpopulations in nRT function as gatekeepers. We dissociated the connectivity, physiology, and circuit functions of neurons within rodent nRT, based on parvalbumin (PV and somatostatin (SOM expression, and validated the existence of such populations in human nRT. We found that PV, but not SOM, cells are rhythmogenic, and that PV and SOM neurons are connected to and modulate distinct thalamocortical circuits. Notably, PV, but not SOM, neurons modulate somatosensory behavior and disrupt seizures. These results provide a conceptual framework for how nRT may gate incoming information to modulate brain-wide rhythms.

  7. Cognitive-Neural Effects of Brush Writing of Chinese Characters: Cortical Excitation of Theta Rhythm

    Directory of Open Access Journals (Sweden)

    Min Xu

    2013-01-01

    Full Text Available Chinese calligraphy has been scientifically investigated within the contexts and principles of psychology, cognitive science, and the cognitive neuroscience. On the basis of vast amount of research in the last 30 years, we have developed a cybernetic theory of handwriting and calligraphy to account for the intricate interactions of several psychological dimensions involved in the dynamic act of graphic production. Central to this system of writing are the role of sensory, bio-, cognitive, and neurofeedback mechanisms for the initiation, guidance, and regulation of the writing motions vis-a-vis visual-geometric variations of Chinese characters. This experiment provided the first evidence of cortical excitation in EEG theta wave as a neural hub that integrates information coming from changes in the practitioner’s body, emotions, and cognition. In addition, it has also confirmed neurofeedback as an essential component of the cybernetic theory of handwriting and calligraphy.

  8. Cognitive-neural effects of brush writing of chinese characters: cortical excitation of theta rhythm.

    Science.gov (United States)

    Xu, Min; Kao, Henry S R; Zhang, Manlin; Lam, Stewart P W; Wang, Wei

    2013-01-01

    Chinese calligraphy has been scientifically investigated within the contexts and principles of psychology, cognitive science, and the cognitive neuroscience. On the basis of vast amount of research in the last 30 years, we have developed a cybernetic theory of handwriting and calligraphy to account for the intricate interactions of several psychological dimensions involved in the dynamic act of graphic production. Central to this system of writing are the role of sensory, bio-, cognitive, and neurofeedback mechanisms for the initiation, guidance, and regulation of the writing motions vis-a-vis visual-geometric variations of Chinese characters. This experiment provided the first evidence of cortical excitation in EEG theta wave as a neural hub that integrates information coming from changes in the practitioner's body, emotions, and cognition. In addition, it has also confirmed neurofeedback as an essential component of the cybernetic theory of handwriting and calligraphy.

  9. High frequency deep brain stimulation attenuates subthalamic and cortical rhythms in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Diane eWhitmer

    2012-06-01

    Full Text Available Parkinson’s disease (PD is marked by excessive synchronous activity in the beta (8-35 Hz band throughout the cortico-basal ganglia network. The optimal location of high frequency deep brain stimulation (HF DBS within the subthalamic nucleus (STN region and the location of maximal beta hypersynchrony are currently matters of debate. Additionally, the effect of STN HF DBS on neural synchrony in functionally connected regions of motor cortex is unknown and of great interest. Scalp EEG studies demonstrated that stimulation of the STN can activate motor cortex antidromically, but the spatial specificity of this effect has not been examined. The present study examined the effect of STN HF DBS on neural synchrony within the cortico-basal ganglia network in patients with PD. We measured local field potentials dorsal to and within the STN of PD patients, and additionally in the motor cortex in a subset of these patients. We used diffusion tensor imaging (DTI to guide the placement of subdural cortical surface electrodes over the DTI-identified origin of the hyperdirect pathway between motor cortex and the STN. The results demonstrated that local beta power was attenuated during HF DBS both dorsal to and within the STN. The degree of attenuation was monotonic with increased DBS voltages in both locations, but this voltage-dependent effect was greater in the central STN than dorsal to the STN (p < 0.05. Cortical signals over the estimated origin of the hyperdirect pathway also demonstrated attenuation of beta hypersynchrony during DBS dorsal to or within STN, whereas signals from non-specific regions of motor cortex were not attenuated. The spatially specific suppression of beta synchrony in the motor cortex support the hypothesis that DBS may treat Parkinsonism by reducing excessive synchrony in the functionally connected sensorimotor network.

  10. [Characteristics of cortical activity in persons with high and low verbal creativity: analysis of alpha1,2 rhythms].

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    Razumnikova, O M; Tarasova, I V; Vol'f, N V

    2009-01-01

    Creativity-related changes in alpha power in low-frequency (8-10 Hz) and high-frequency (10-13 Hz) bands were studied in university students having regard to generation of original ideas during performance of two verbal tasks. A high-creative group enrolled 16 subjects asked to generate original words--associates to the triads of verbal stimuli and 14 subjects who were asked to compose a sentence using triads of nouns from remote semantic categories. Low-creative groups included 22 and 13 individuals, respectively. In low-frequency band, highly creative subjects showed a higher level of alpha power than low creative individuals. In the high-frequency band, task-related alpha2 power desynchronization was different in these groups: high-creative individuals had higher power score than low-creative mostly in the anterior and parietal cortical areas. These data and a factor structure of alpha rhythm indices may be evidence of different strategies of information selection in highly and low creative persons.

  11. Gamma Oscillations and Neural Field DCMs Can Reveal Cortical Excitability and Microstructure

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    Dimitris Pinotsis

    2014-05-01

    Full Text Available This paper shows how gamma oscillations can be combined with neural population models and dynamic causal modeling (DCM to distinguish among alternative hypotheses regarding cortical excitability and microstructure. This approach exploits inter-subject variability and trial-specific effects associated with modulations in the peak frequency of gamma oscillations. Neural field models are used to evaluate model evidence and obtain parameter estimates using invasive and non-invasive gamma recordings. Our overview comprises two parts: in the first part, we use neural fields to simulate neural activity and distinguish the effects of post synaptic filtering on predicted responses in terms of synaptic rate constants that correspond to different timescales and distinct neurotransmitters. We focus on model predictions of conductance and convolution based field models and show that these can yield spectral responses that are sensitive to biophysical properties of local cortical circuits like synaptic kinetics and filtering; we also consider two different mechanisms for this filtering: a nonlinear mechanism involving specific conductances and a linear convolution of afferent firing rates producing post synaptic potentials. In the second part of this paper, we use neural fields quantitatively—to fit empirical data recorded during visual stimulation. We present two studies of spectral responses obtained from the visual cortex during visual perception experiments: in the first study, MEG data were acquired during a task designed to show how activity in the gamma band is related to visual perception, while in the second study, we exploited high density electrocorticographic (ECoG data to study the effect of varying stimulus contrast on cortical excitability and gamma peak frequency.

  12. Detection of the onset of upper-limb movements based on the combined analysis of changes in the sensorimotor rhythms and slow cortical potentials

    Science.gov (United States)

    Ibáñez, J.; Serrano, J. I.; del Castillo, M. D.; Monge-Pereira, E.; Molina-Rueda, F.; Alguacil-Diego, I.; Pons, J. L.

    2014-10-01

    Objective. Characterizing the intention to move by means of electroencephalographic activity can be used in rehabilitation protocols with patients’ cortical activity taking an active role during the intervention. In such applications, the reliability of the intention estimation is critical both in terms of specificity ‘number of misclassifications’ and temporal accuracy. Here, a detector of the onset of voluntary upper-limb reaching movements based on the cortical rhythms and the slow cortical potentials is proposed. The improvement in detections due to the combination of these two cortical patterns is also studied. Approach. Upper-limb movements and cortical activity were recorded in healthy subjects and stroke patients performing self-paced reaching movements. A logistic regression combined the output of two classifiers: (i) a naïve Bayes classifier trained to detect the event-related desynchronization preceding the movement onset and (ii) a matched filter detecting the bereitschaftspotential. The proposed detector was compared with the detectors by using each one of these cortical patterns separately. In addition, differences between the patients and healthy subjects were analysed. Main results. On average, 74.5 ± 13.8% and 82.2 ± 10.4% of the movements were detected with 1.32 ± 0.87 and 1.50 ± 1.09 false detections generated per minute in the healthy subjects and the patients, respectively. A significantly better performance was achieved by the combined detector (as compared to the detectors of the two cortical patterns separately) in terms of true detections (p = 0.099) and false positives (p = 0.0083). Significance. A rationale is provided for combining information from cortical rhythms and slow cortical potentials to detect the onsets of voluntary upper-limb movements. It is demonstrated that the two cortical processes supply complementary information that can be summed up to boost the performance of the detector. Successful results have been also

  13. Cortical gamma generators suggest abnormal auditory circuitry in early-onset psychosis.

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    Wilson, Tony W; Hernandez, Olivia O; Asherin, Ryan M; Teale, Peter D; Reite, Martin L; Rojas, Donald C

    2008-02-01

    Neurobiological theories of schizophrenia and related psychoses have increasingly emphasized impaired neuronal coordination (i.e., dysfunctional connectivity) as central to the pathophysiology. Although neuroimaging evidence has mostly corroborated these accounts, the basic mechanism(s) of reduced functional connectivity remains elusive. In this study, we examine the developmental trajectory and underlying mechanism(s) of dysfunctional connectivity by using gamma oscillatory power as an index of local and long-range circuit integrity. An early-onset psychosis group and a matched cohort of typically developing adolescents listened to monaurally presented click-trains, as whole-head magnetoencephalography data were acquired. Consistent with previous work, gamma-band power was significantly higher in right auditory cortices across groups and conditions. However, patients exhibited significantly reduced overall gamma power relative to controls, and showed a reduced ear-of-stimulation effect indicating that ipsi- versus contralateral presentation had less impact on hemispheric power. Gamma-frequency oscillations are thought to be dependent on gamma-aminobutyric acidergic interneuronal networks, thus these patients' impairment in generating and/or maintaining such activity may indicate that local circuit integrity is at least partially compromised early in the disease process. In addition, patients also showed abnormality in long-range networks (i.e., ear-of-stimulation effects) potentially suggesting that multiple stages along auditory pathways contribute to connectivity aberrations found in patients with psychosis.

  14. Synchronous Chaos and Broad Band Gamma Rhythm in a Minimal Multi-Layer Model of Primary Visual Cortex

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    Battaglia, Demian; Hansel, David

    2011-01-01

    Visually induced neuronal activity in V1 displays a marked gamma-band component which is modulated by stimulus properties. It has been argued that synchronized oscillations contribute to these gamma-band activity. However, analysis of Local Field Potentials (LFPs) across different experiments reveals considerable diversity in the degree of oscillatory behavior of this induced activity. Contrast-dependent power enhancements can indeed occur over a broad band in the gamma frequency range and spectral peaks may not arise at all. Furthermore, even when oscillations are observed, they undergo temporal decorrelation over very few cycles. This is not easily accounted for in previous network modeling of gamma oscillations. We argue here that interactions between cortical layers can be responsible for this fast decorrelation. We study a model of a V1 hypercolumn, embedding a simplified description of the multi-layered structure of the cortex. When the stimulus contrast is low, the induced activity is only weakly synchronous and the network resonates transiently without developing collective oscillations. When the contrast is high, on the other hand, the induced activity undergoes synchronous oscillations with an irregular spatiotemporal structure expressing a synchronous chaotic state. As a consequence the population activity undergoes fast temporal decorrelation, with concomitant rapid damping of the oscillations in LFPs autocorrelograms and peak broadening in LFPs power spectra. We show that the strength of the inter-layer coupling crucially affects this spatiotemporal structure. We predict that layer VI inactivation should induce global changes in the spectral properties of induced LFPs, reflecting their slower temporal decorrelation in the absence of inter-layer feedback. Finally, we argue that the mechanism underlying the emergence of synchronous chaos in our model is in fact very general. It stems from the fact that gamma oscillations induced by local delayed

  15. Synchronous chaos and broad band gamma rhythm in a minimal multi-layer model of primary visual cortex.

    Directory of Open Access Journals (Sweden)

    Demian Battaglia

    2011-10-01

    Full Text Available Visually induced neuronal activity in V1 displays a marked gamma-band component which is modulated by stimulus properties. It has been argued that synchronized oscillations contribute to these gamma-band activity. However, analysis of Local Field Potentials (LFPs across different experiments reveals considerable diversity in the degree of oscillatory behavior of this induced activity. Contrast-dependent power enhancements can indeed occur over a broad band in the gamma frequency range and spectral peaks may not arise at all. Furthermore, even when oscillations are observed, they undergo temporal decorrelation over very few cycles. This is not easily accounted for in previous network modeling of gamma oscillations. We argue here that interactions between cortical layers can be responsible for this fast decorrelation. We study a model of a V1 hypercolumn, embedding a simplified description of the multi-layered structure of the cortex. When the stimulus contrast is low, the induced activity is only weakly synchronous and the network resonates transiently without developing collective oscillations. When the contrast is high, on the other hand, the induced activity undergoes synchronous oscillations with an irregular spatiotemporal structure expressing a synchronous chaotic state. As a consequence the population activity undergoes fast temporal decorrelation, with concomitant rapid damping of the oscillations in LFPs autocorrelograms and peak broadening in LFPs power spectra. We show that the strength of the inter-layer coupling crucially affects this spatiotemporal structure. We predict that layer VI inactivation should induce global changes in the spectral properties of induced LFPs, reflecting their slower temporal decorrelation in the absence of inter-layer feedback. Finally, we argue that the mechanism underlying the emergence of synchronous chaos in our model is in fact very general. It stems from the fact that gamma oscillations induced by

  16. Aberrant gamma band cortical sources and functional connectivity in adolescents with psychogenic non-epileptic seizures: A preliminary report.

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    Umesh, Shreekantiah; Tikka, Sai Krishna; Goyal, Nishant; Sinha, Vinod Kumar; Nizamie, Shamshul Haque

    2017-01-01

    Psychogenic non-epileptic seizures (PNES) resemble epileptic seizures, but lack clinically evident abnormal electrical activity in the brain. We aimed to assess resting gamma spectral power, current source distribution and functional connectivity in adolescents with PNES. Interictal, 32 channels electroencephalographic recording of 15 adolescents with PNES was compared with 10 matched healthy controls. Spectral power, current source distribution and lagged linear coherence were assessed. Statistically significant gamma spectral power, cortical sources and connectivity pattern was found in some brain areas. Region specific aberrant gamma activity and its relationship to psychopathology are discussed. Copyright © 2016. Published by Elsevier Ireland Ltd.

  17. Gamma distribution model describes maturational curves for delta wave amplitude, cortical metabolic rate and synaptic density.

    Science.gov (United States)

    Feinberg, I; Thode, H C; Chugani, H T; March, J D

    1990-01-23

    We analyzed the available ontogenetic data (birth to 30 years of age) for: amplitude of delta EEG (DA) waves during sleep; cortical metabolic rate (CMR) measured with positron emission tomography; and synaptic density (SD) in frontal cortex. Each is at the adult level at birth, increases to about twice this level by 3 years of age, and then gradually falls back to the adult level over the next two decades. Statistical analyses revealed that individual gamma distribution models fit each data set as well as did the best ad hoc polynomial. A test of whether a single gamma distribution model could describe all three data sets gave good results for DA and CMR but the fit was unsatisfactory for SD. However, because so few data were available for SD, this test was not conclusive. We proposed the following model to account for these changes. First, cortical neurons are stimulated by birth to enter a proliferative state (PS) that creates many connections. Next, as a result of interactions in the PS, neurons are triggered into a transient organizational state (OS) in which they make enduring connections. The OS has a finite duration (minutes to years), and is characterized by high rates of information-processing and metabolism. Levels of CMR, SD and DA, therefore, are proportional to the number of neurons in the OS at any time. Thus, the cortex after birth duplicates, over a vastly greater time scale, the overproduction and regression of neural elements that occurs repeatedly in embryonic development. Finally, we discussed the implications of post-natal brain changes for normal and abnormal brain function. Mental disorders that have their onset after puberty (notably schizophrenia and manic-depressive psychoses) might be caused by errors in these late maturational processes. In addition to age of onset, this neurodevelopmental hypothesis might explain several other puzzling features of these subtle disorders.

  18. To the Beat of Your Own Drum: Cortical Regularization of Non-Integer Ratio Rhythms toward Metrical Patterns

    Science.gov (United States)

    Motz, Benjamin A.; Erickson, Molly A.; Hetrick, William P.

    2013-01-01

    Humans perceive a wide range of temporal patterns, including those rhythms that occur in music, speech, and movement; however, there are constraints on the rhythmic patterns that we can represent. Past research has shown that sequences in which sounds occur regularly at non-metrical locations in a repeating beat period (non-integer ratio…

  19. To the Beat of Your Own Drum: Cortical Regularization of Non-Integer Ratio Rhythms toward Metrical Patterns

    Science.gov (United States)

    Motz, Benjamin A.; Erickson, Molly A.; Hetrick, William P.

    2013-01-01

    Humans perceive a wide range of temporal patterns, including those rhythms that occur in music, speech, and movement; however, there are constraints on the rhythmic patterns that we can represent. Past research has shown that sequences in which sounds occur regularly at non-metrical locations in a repeating beat period (non-integer ratio…

  20. Rhythm generation through period concatenation in rat somatosensory cortex.

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    Mark A Kramer

    Full Text Available Rhythmic voltage oscillations resulting from the summed activity of neuronal populations occur in many nervous systems. Contemporary observations suggest that coexistent oscillations interact and, in time, may switch in dominance. We recently reported an example of these interactions recorded from in vitro preparations of rat somatosensory cortex. We found that following an initial interval of coexistent gamma ( approximately 25 ms period and beta2 ( approximately 40 ms period rhythms in the superficial and deep cortical layers, respectively, a transition to a synchronous beta1 ( approximately 65 ms period rhythm in all cortical layers occurred. We proposed that the switch to beta1 activity resulted from the novel mechanism of period concatenation of the faster rhythms: gamma period (25 ms+beta2 period (40 ms = beta1 period (65 ms. In this article, we investigate in greater detail the fundamental mechanisms of the beta1 rhythm. To do so we describe additional in vitro experiments that constrain a biologically realistic, yet simplified, computational model of the activity. We use the model to suggest that the dynamic building blocks (or motifs of the gamma and beta2 rhythms combine to produce a beta1 oscillation that exhibits cross-frequency interactions. Through the combined approach of in vitro experiments and mathematical modeling we isolate the specific components that promote or destroy each rhythm. We propose that mechanisms vital to establishing the beta1 oscillation include strengthened connections between a population of deep layer intrinsically bursting cells and a transition from antidromic to orthodromic spike generation in these cells. We conclude that neural activity in the superficial and deep cortical layers may temporally combine to generate a slower oscillation.

  1. Investigating the effects of a sensorimotor rhythm-based BCI training on the cortical activity elicited by mental imagery

    Science.gov (United States)

    Toppi, J.; Risetti, M.; Quitadamo, L. R.; Petti, M.; Bianchi, L.; Salinari, S.; Babiloni, F.; Cincotti, F.; Mattia, D.; Astolfi, L.

    2014-06-01

    Objective. It is well known that to acquire sensorimotor (SMR)-based brain-computer interface (BCI) control requires a training period before users can achieve their best possible performances. Nevertheless, the effect of this training procedure on the cortical activity related to the mental imagery ability still requires investigation to be fully elucidated. The aim of this study was to gain insights into the effects of SMR-based BCI training on the cortical spectral activity associated with the performance of different mental imagery tasks. Approach. Linear cortical estimation and statistical brain mapping techniques were applied on high-density EEG data acquired from 18 healthy participants performing three different mental imagery tasks. Subjects were divided in two groups, one of BCI trained subjects, according to their previous exposure (at least six months before this study) to motor imagery-based BCI training, and one of subjects who were naive to any BCI paradigms. Main results. Cortical activation maps obtained for trained and naive subjects indicated different spectral and spatial activity patterns in response to the mental imagery tasks. Long-term effects of the previous SMR-based BCI training were observed on the motor cortical spectral activity specific to the BCI trained motor imagery task (simple hand movements) and partially generalized to more complex motor imagery task (playing tennis). Differently, mental imagery with spatial attention and memory content could elicit recognizable cortical spectral activity even in subjects completely naive to (BCI) training. Significance. The present findings contribute to our understanding of BCI technology usage and might be of relevance in those clinical conditions when training to master a BCI application is challenging or even not possible.

  2. Circadian rhythms, Wnt/beta-catenin pathway and PPAR alpha/gamma profiles in diseases with primary or secondary cardiac dysfunction

    Science.gov (United States)

    Lecarpentier, Yves; Claes, Victor; Duthoit, Guillaume; Hébert, Jean-Louis

    2014-01-01

    Circadian clock mechanisms are far-from-equilibrium dissipative structures. Peroxisome proliferator-activated receptors (PPAR alpha, beta/delta, and gamma) play a key role in metabolic regulatory processes, particularly in heart muscle. Links between circadian rhythms (CRs) and PPARs have been established. Mammalian CRs involve at least two critical transcription factors, CLOCK and BMAL1 (Gekakis et al., 1998; Hogenesch et al., 1998). PPAR gamma plays a major role in both glucose and lipid metabolisms and presents circadian properties which coordinate the interplay between metabolism and CRs. PPAR gamma is a major component of the vascular clock. Vascular PPAR gamma is a peripheral regulator of cardiovascular rhythms controlling circadian variations in blood pressure and heart rate through BMAL1. We focused our review on diseases with abnormalities of CRs and with primary or secondary cardiac dysfunction. Moreover, these diseases presented changes in the Wnt/beta-catenin pathway and PPARs, according to two opposed profiles. Profile 1 was defined as follows: inactivation of the Wnt/beta-catenin pathway with increased expression of PPAR gamma. Profile 2 was defined as follows: activation of the Wnt/beta-catenin pathway with decreased expression of PPAR gamma. A typical profile 1 disease is arrhythmogenic right ventricular cardiomyopathy, a genetic cardiac disease which presents mutations of the desmosomal proteins and is mainly characterized by fatty acid accumulation in adult cardiomyocytes mainly in the right ventricle. The link between PPAR gamma dysfunction and desmosomal genetic mutations occurs via inactivation of the Wnt/beta-catenin pathway presenting oscillatory properties. A typical profile 2 disease is type 2 diabetes, with activation of the Wnt/beta-catenin pathway and decreased expression of PPAR gamma. CRs abnormalities are present in numerous pathologies such as cardiovascular diseases, sympathetic/parasympathetic dysfunction, hypertension, diabetes

  3. Variation in the topography of the speech production cortex verified by cortical stimulation and high gamma activity.

    Science.gov (United States)

    Babajani-Feremi, Abbas; Rezaie, Roozbeh; Narayana, Shalini; Choudhri, Asim F; Fulton, Stephen P; Boop, Frederick A; Wheless, James W; Papanicolaou, Andrew C

    2014-12-17

    In this study, we have addressed the question of functional brain reorganization for language in the presence and absence of anatomical lesions in two patients with epilepsy using cortical stimulation mapping and high gamma (HG) activity in subdural grid recordings. In both, the expressive language cortex was defined as the cortical patch below the electrode(s) that when stimulated resulted in speech arrest, and during speech expression tasks generated HG activity. This patch fell within the borders of Broca's area, as defined anatomically, in the case of the patient with a lesion, but outside that area in the other, lesion-free patient. Such results highlight the necessity for presurgical language mapping in all cases of surgery involving the language-dominant hemisphere and suggest that HG activity during expressive language tasks can be informative and helpful in conjunction with cortical stimulation mapping for expressive language mapping.

  4. Mindfulness starts with the body: somatosensory attention and top-down modulation of cortical alpha rhythms in mindfulness meditation.

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    Kerr, Catherine E; Sacchet, Matthew D; Lazar, Sara W; Moore, Christopher I; Jones, Stephanie R

    2013-01-01

    Using a common set of mindfulness exercises, mindfulness based stress reduction (MBSR) and mindfulness based cognitive therapy (MBCT) have been shown to reduce distress in chronic pain and decrease risk of depression relapse. These standardized mindfulness (ST-Mindfulness) practices predominantly require attending to breath and body sensations. Here, we offer a novel view of ST-Mindfulness's somatic focus as a form of training for optimizing attentional modulation of 7-14 Hz alpha rhythms that play a key role in filtering inputs to primary sensory neocortex and organizing the flow of sensory information in the brain. In support of the framework, we describe our previous finding that ST-Mindfulness enhanced attentional regulation of alpha in primary somatosensory cortex (SI). The framework allows us to make several predictions. In chronic pain, we predict somatic attention in ST-Mindfulness "de-biases" alpha in SI, freeing up pain-focused attentional resources. In depression relapse, we predict ST-Mindfulness's somatic attention competes with internally focused rumination, as internally focused cognitive processes (including working memory) rely on alpha filtering of sensory input. Our computational model predicts ST-Mindfulness enhances top-down modulation of alpha by facilitating precise alterations in timing and efficacy of SI thalamocortical inputs. We conclude by considering how the framework aligns with Buddhist teachings that mindfulness starts with "mindfulness of the body." Translating this theory into neurophysiology, we hypothesize that with its somatic focus, mindfulness' top-down alpha rhythm modulation in SI enhances gain control which, in turn, sensitizes practitioners to better detect and regulate when the mind wanders from its somatic focus. This enhanced regulation of somatic mind-wandering may be an important early stage of mindfulness training that leads to enhanced cognitive regulation and metacognition.

  5. Mindfulness starts with the body: Somatosensory attention and top-down modulation of cortical alpha rhythms in mindfulness meditation

    Directory of Open Access Journals (Sweden)

    Catherine E Kerr

    2013-02-01

    Full Text Available Mindfulness Based Stress Reduction (MBSR and Mindfulness Based Cognitive Therapy (MBCT use a common set of exercises to reduce distress in chronic pain and decrease risk of depression relapse. These standardized mindfulness (ST-Mindfulness practices predominantly require attending to breath and body sensations. Here, we offer a novel view of ST-Mindfulness’s somatic focus as a form of training for optimizing attentional modulation of 7-14 Hz alpha rhythms that play a key role in filtering inputs to primary sensory neocortex and organizing the flow of sensory information. In support of the framework, we describe our previous finding (Kerr et al, 2011 that ST-Mindfulness enhanced attentional regulation of alpha in primary somatosensory cortex (SI. The framework allows us to make several predictions. In chronic pain, we predict somatic attention in ST-Mindfulness de-biases alpha in SI, freeing up pain-focused attentional resources. In depression relapse, we predict ST-Mindfulness’s somatic attention competes with internally focused rumination, as internally focused cognitive processes (e.g., working and short term memory rely on alpha filtering of sensory input. Our computational model (Jones et al, 2009 predicts ST-Mindfulness enhances top-down modulation of alpha by facilitating precise alterations in timing and efficacy of SI thalamocortical inputs. We conclude by considering how the proposed framework aligns with Buddhist teachings that mindfulness starts with mindfulness of the body. Translating this theory into neurophysiology, we hypothesize that with its somatic focus, mindfulness’ top-down alpha rhythm modulation in SI enhances gain control which, in turn, sensitizes practitioners to better detect and regulate when the mind wanders from its somatic focus. This enhanced regulation of somatic mind-wandering may be an early stage of mindfulness training, leading to cognitive regulation and metacognition.

  6. Optimized gamma synchronization enhances functional binding of fronto-parietal cortices in mathematically gifted adolescents during deductive reasoning

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    Li eZhang

    2014-06-01

    Full Text Available As enhanced fronto-parietal network has been suggested to support reasoning ability of math-gifted adolescents, the main goal of this EEG source analysis is to investigate the temporal binding of the gamma-band (30-60Hz synchronization between frontal and parietal cortices in adolescents with exceptional mathematical ability, including the functional connectivity of gamma neurocognitive network, the temporal dynamics of fronto-parietal network (phase-locking durations and network lability in time domain, and the self-organized criticality of synchronizing oscillation. Compared with the average-ability subjects, the math-gifted adolescents show a highly integrated fronto-parietal network due to distant gamma phase-locking oscillations, which is indicated by lower modularity of the global network topology, more connector bridges between the frontal and parietal cortices and less connector hubs in the sensorimotor cortex. The time-domain analysis finds that, while maintaining more stable phase dynamics of the fronto-parietal coupling, the math-gifted adolescents are characterized by more extensive fronto-parietal connection reconfiguration. The results from sample fitting in the power-law model further find that the phase-locking durations in the math-gifted brain abides by a wider interval of the power-law distribution. This phase-lock distribution mechanism could represent a relatively optimized pattern for the functional binding of frontal-parietal network, which underlies stable fronto-parietal connectivity and increases flexibility of timely network reconfiguration.

  7. Reduction in LFP cross-frequency coupling between theta and gamma rhythms associated with impaired STP and LTP in a rat model of brain ischemia.

    Science.gov (United States)

    Xu, Xiaxia; Zheng, Chenguang; Zhang, Tao

    2013-01-01

    The theta-gamma cross-frequency coupling (CFC) in hippocampus was reported to reflect memory process. In this study, we measured the CFC of hippocampal local field potentials (LFPs) in a two-vessel occlusion (2VO) rat model, combined with both amplitude and phase properties and associated with short and long-term plasticity indicating the memory function. Male Wistar rats were used and a 2VO model was established. STP and LTP were recorded in hippocampal CA3-CA1 pathway after LFPs were collected in both CA3 and CA1. Based on the data of relative power spectra and phase synchronization, it suggested that both the amplitude and phase coupling of either theta or gamma rhythm were involved in modulating the neural network in 2VO rats. In order to determine whether the CFC was also implicated in neural impairment in 2VO rats, the coupling of CA3 theta-CA1 gamma was measured by both phase-phase coupling (n:m phase synchronization) and phase-amplitude coupling. The attenuated CFC strength in 2VO rats implied the impaired neural communication in the coordination of theta-gamma entraining process. Moreover, compared with modulation index (MI) a novel algorithm named cross frequency conditional mutual information (CF-CMI), was developed to focus on the coupling between theta phase and the phase of gamma amplitude. The results suggest that the reduced CFC strength probably attributed to the disruption of the phase of CA1 gamma envelop. In conclusion, it implied that the phase coupling and CFC of hippocampal theta and gamma played an important role in supporting functions of neural network. Furthermore, synaptic plasticity on CA3-CA1 pathway was reduced in line with the decreased CFC strength from CA3 to CA1. It partly supported our hypothesis that directional CFC indicator might probably be used as a measure of synaptic plasticity.

  8. Reduction in LFP cross-frequency coupling between theta and gamma rhythms associated with impaired STP and LTP in a rat model of brain ischemia

    Directory of Open Access Journals (Sweden)

    Tao eZhang

    2013-04-01

    Full Text Available The theta-gamma cross-frequency coupling (CFC in hippocampus was reported to reflect memory process. In this study, we measured the CFC of hippocampal local field potentials (LFPs in a two-vessel occlusion (2VO rat model, combined with both amplitude and phase properties and associated with short and long-term plasticity indicating the memory function. Male Wistar rats were used and a 2VO model was established. STP and LTP were recorded in hippocampal CA3-CA1 pathway after LFPs were collected in both CA3 and CA1. Based on the data of relative power spectra and phase synchronization, it suggested that both the amplitude and phase coupling of either theta or gamma rhythm were involved in modulating the neural network in 2VO rats. In order to determine whether the CFC was also implicated in neural impairment in 2VO rats, the coupling of CA3 theta–CA1 gamma was measured by both phase-phase coupling (n:m phase synchronization and phase-amplitude coupling. The attenuated CFC strength in 2VO rats implied the impaired neural communication in the coordination of theta-gamma entraining process. Moreover, compared with modulation index (MI a novel algorithm named cross frequency conditional mutual information (CF-CMI, was developed to focus on the coupling between theta phase and the phase of gamma amplitude. The results suggest that the reduced CFC strength probably attributed to the disruption of the phase of CA1 gamma envelop. In conclusion, it implied that the phase coupling and CFC of hippocampal theta and gamma played an important role in supporting functions of neural network. Furthermore, synaptic plasticity on CA3-CA1 pathway was reduced in line with the decreased CFC strength from CA3 to CA1. It partly supported our hypothesis that directional CFC indicator might probably be used as a measure of synaptic plasticity.

  9. Relationship between EEG power and rhythm synchronization in health and cognitive pathology.

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    Strelets, V B; Garakh, Zh V; Novototskii-Vlasov, V Yu; Magomedov, R A

    2006-07-01

    We report here studies of comparative measures of spectral density and cortical interactions in EEG rhythms in health and schizophrenia. In healthy subjects, all rhythms were symmetrical and synchronous. In "acute" schizophrenia, unlike the situation in health, there was asymmetry (predominantly right-sided) in the distribution of the spectral power of EEG rhythms. In chronic patients, asymmetry was less marked, though the power of most EEG rhythms was significantly lower than in the other two study groups. "Acute" patients showed a lack of interhemisphere interactions for all rhythms apart from the alpha rhythm, while the number of cortical interactions in chronic patients was rather lower than that in the "acute" patients, though there were significantly fewer than in healthy subjects. In addition, the gamma range showed only one interhemisphere association in the posterior areas. These neurophysiological characteristics may underlie a number of the impairments of mental activity in patients with schizophrenia. These data may also indicate that the linkage between power characteristics and synchronization of EEG rhythms is a necessary condition for normal perceptive and cognitive activity and the organization of behavior.

  10. Classification of Healthy Subjects and Alzheimer's Disease Patients with Dementia from Cortical Sources of Resting State EEG Rhythms: A Study Using Artificial Neural Networks.

    Science.gov (United States)

    Triggiani, Antonio I; Bevilacqua, Vitoantonio; Brunetti, Antonio; Lizio, Roberta; Tattoli, Giacomo; Cassano, Fabio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Barulli, Maria R; Tortelli, Rosanna; Cardinali, Valentina; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Stocchi, Fabrizio; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Lacidogna, Giordano; Orzi, Francesco; Buttinelli, Carla; Giubilei, Franco; Del Percio, Claudio; Frisoni, Giovanni B; Babiloni, Claudio

    2016-01-01

    Previous evidence showed a 75.5% best accuracy in the classification of 120 Alzheimer's disease (AD) patients with dementia and 100 matched normal elderly (Nold) subjects based on cortical source current density and linear lagged connectivity estimated by eLORETA freeware from resting state eyes-closed electroencephalographic (rsEEG) rhythms (Babiloni et al., 2016a). Specifically, that accuracy was reached using the ratio between occipital delta and alpha1 current density for a linear univariate classifier (receiver operating characteristic curves). Here we tested an innovative approach based on an artificial neural network (ANN) classifier from the same database of rsEEG markers. Frequency bands of interest were delta (2-4 Hz), theta (4-8 Hz Hz), alpha1 (8-10.5 Hz), and alpha2 (10.5-13 Hz). ANN classification showed an accuracy of 77% using the most 4 discriminative rsEEG markers of source current density (parietal theta/alpha 1, temporal theta/alpha 1, occipital theta/alpha 1, and occipital delta/alpha 1). It also showed an accuracy of 72% using the most 4 discriminative rsEEG markers of source lagged linear connectivity (inter-hemispherical occipital delta/alpha 2, intra-hemispherical right parietal-limbic alpha 1, intra-hemispherical left occipital-temporal theta/alpha 1, intra-hemispherical right occipital-temporal theta/alpha 1). With these 8 markers combined, an accuracy of at least 76% was reached. Interestingly, this accuracy based on 8 (linear) rsEEG markers as inputs to ANN was similar to that obtained with a single rsEEG marker (Babiloni et al., 2016a), thus unveiling their information redundancy for classification purposes. In future AD studies, inputs to ANNs should include other classes of independent linear (i.e., directed transfer function) and non-linear (i.e., entropy) rsEEG markers to improve the classification.

  11. Classification of Healthy Subjects and Alzheimer's Disease Patients with Dementia from Cortical Sources of Resting State EEG Rhythms: A Study Using Artificial Neural Networks

    Science.gov (United States)

    Triggiani, Antonio I.; Bevilacqua, Vitoantonio; Brunetti, Antonio; Lizio, Roberta; Tattoli, Giacomo; Cassano, Fabio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Barulli, Maria R.; Tortelli, Rosanna; Cardinali, Valentina; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Stocchi, Fabrizio; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Lacidogna, Giordano; Orzi, Francesco; Buttinelli, Carla; Giubilei, Franco; Del Percio, Claudio; Frisoni, Giovanni B.; Babiloni, Claudio

    2017-01-01

    Previous evidence showed a 75.5% best accuracy in the classification of 120 Alzheimer's disease (AD) patients with dementia and 100 matched normal elderly (Nold) subjects based on cortical source current density and linear lagged connectivity estimated by eLORETA freeware from resting state eyes-closed electroencephalographic (rsEEG) rhythms (Babiloni et al., 2016a). Specifically, that accuracy was reached using the ratio between occipital delta and alpha1 current density for a linear univariate classifier (receiver operating characteristic curves). Here we tested an innovative approach based on an artificial neural network (ANN) classifier from the same database of rsEEG markers. Frequency bands of interest were delta (2–4 Hz), theta (4–8 Hz Hz), alpha1 (8–10.5 Hz), and alpha2 (10.5–13 Hz). ANN classification showed an accuracy of 77% using the most 4 discriminative rsEEG markers of source current density (parietal theta/alpha 1, temporal theta/alpha 1, occipital theta/alpha 1, and occipital delta/alpha 1). It also showed an accuracy of 72% using the most 4 discriminative rsEEG markers of source lagged linear connectivity (inter-hemispherical occipital delta/alpha 2, intra-hemispherical right parietal-limbic alpha 1, intra-hemispherical left occipital-temporal theta/alpha 1, intra-hemispherical right occipital-temporal theta/alpha 1). With these 8 markers combined, an accuracy of at least 76% was reached. Interestingly, this accuracy based on 8 (linear) rsEEG markers as inputs to ANN was similar to that obtained with a single rsEEG marker (Babiloni et al., 2016a), thus unveiling their information redundancy for classification purposes. In future AD studies, inputs to ANNs should include other classes of independent linear (i.e., directed transfer function) and non-linear (i.e., entropy) rsEEG markers to improve the classification. PMID:28184183

  12. Circadian Rhythms

    Science.gov (United States)

    ... microbes. The study of circadian rhythms is called chronobiology. Are circadian rhythms the same thing as biological ... the eyes cross. Do circadian rhythms have a genetic component? Yes. Researchers have already identified genes that ...

  13. Involvement of glutamatergic and GABAergic transmission in MK-801-increased gamma band oscillation power in rat cortical electroencephalograms.

    Science.gov (United States)

    Hiyoshi, T; Kambe, D; Karasawa, J; Chaki, S

    2014-11-07

    Hypofunction of the N-methyl-D-aspartic acid receptor (NMDAr) has been considered to play a crucial role in the pathophysiology of schizophrenia. In rodent electroencephalogram (EEG) studies, non-competitive NMDAr antagonists have been reported to produce aberrant basal gamma band oscillation (GBO), as observed in schizophrenia. Aberrations in GBO power have attracted attention as a translational biomarker for the development of novel antipsychotic drugs. However, the neuronal mechanisms as well as the pharmacological significance of NMDAr antagonist-induced aberrant GBO power have not been fully investigated. In the present study, to address the above questions, we examined the pharmacological properties of MK-801 (0.1 mg/kg)-increased basal GBO power in rat cortical EEG. Riluzole (3-10 mg/kg), a glutamate release inhibitor, reduced the MK-801-increased basal GBO power. In contrast, L-838,417 (1-3 mg/kg), an α2/3/5 subunit-selective GABAA receptor-positive allosteric modulator, enhanced the GBO increase. Antipsychotics such as haloperidol (0.05-0.3 mg/kg) and clozapine (1-10 mg/kg) dose-dependently attenuated the MK-801-increased GBO power. Likewise, LY379268 (0.3-3 mg/kg), an metabotropic glutamate 2/3 receptor (mGlu2/3 receptor) agonist, reduced the GBO increase in a dose-dependent manner, which was antagonized by an mGlu2/3 receptor antagonist LY341495. These results suggest that an increase in cortical GBO power induced by NMDAr hypofunction can be attributed to the aberrant activities of both excitatory pyramidal neurons and inhibitory interneurons in local circuits. The aberrant cortical GBO power reflecting cortical network dysfunction observed in schizophrenia might be a useful biomarker for the discovery of novel antipsychotic drugs.

  14. Layer-specific entrainment of gamma-band neural activity by the alpha rhythm in monkey visual cortex

    NARCIS (Netherlands)

    Spaak, E.; Bonnefond, M.; Maier, A.; Leopold, D.A.; Jensen, O.

    2012-01-01

    Although the mammalian neocortex has a clear laminar organization, layer-specific neuronal computations remain to be uncovered. Several studies suggest that gamma band activity in primary visual cortex (V1) is produced in granular and superficial layers and is associated with the processing of visua

  15. Painted Rhythms.

    Science.gov (United States)

    Bastian, Duane

    1985-01-01

    In this art activity gifted students, ages 10 to 13, learn about internal and external rhythms and make a painting of an internal rhythm. The lesson can be expanded with a discussion of Kandinsky, Pollock, and other painters who have painted sound or have demonstrated rhythms. (RM)

  16. Sex Differences in Gamma Band Functional Connectivity Between the Frontal Lobe and Cortical Areas During an Auditory Oddball Task, as Revealed by Imaginary Coherence Assessment

    Science.gov (United States)

    Fujimoto, Toshiro; Okumura, Eiichi; Kodabashi, Atsushi; Takeuchi, Kouzou; Otsubo, Toshiaki; Nakamura, Katsumi; Yatsushiro, Kazutaka; Sekine, Masaki; Kamiya, Shinichiro; Shimooki, Susumu; Tamura, Toshiyo

    2016-01-01

    We studied sex-related differences in gamma oscillation during an auditory oddball task, using magnetoencephalography and electroencephalography assessment of imaginary coherence (IC). We obtained a statistical source map of event-related desynchronization (ERD) / event-related synchronization (ERS), and compared females and males regarding ERD / ERS. Based on the results, we chose respectively seed regions for IC determinations in low (30-50 Hz), mid (50-100 Hz) and high gamma (100-150 Hz) bands. In males, ERD was increased in the left posterior cingulate cortex (CGp) at 500 ms in the low gamma band, and in the right caudal anterior cingulate cortex (cACC) at 125 ms in the mid-gamma band. ERS was increased in the left rostral anterior cingulate cortex (rACC) at 375 ms in the high gamma band. We chose the CGp, cACC and rACC as seeds, and examined IC between the seed and certain target regions using the IC map. IC changes depended on the height of the gamma frequency and the time window in the gamma band. Although IC in the mid and high gamma bands did not show sex-specific differences, IC at 30-50 Hz in males was increased between the left rACC and the frontal, orbitofrontal, inferior temporal and fusiform target regions. Increased IC in males suggested that males may acomplish the task constructively, analysingly, emotionally, and by perfoming analysis, and that information processing was more complicated in the cortico-cortical circuit. On the other hand, females showed few differences in IC. Females planned the task with general attention and economical well-balanced processing, which was explained by the higher overall functional cortical connectivity. CGp, cACC and rACC were involved in sex differences in information processing and were likely related to differences in neuroanatomy, hormones and neurotransmitter systems. PMID:27708745

  17. Exploring the relationship between cortical GABA concentrations, auditory gamma-band responses and development in ASD: Evidence for an altered maturational trajectory in ASD.

    Science.gov (United States)

    Port, Russell G; Gaetz, William; Bloy, Luke; Wang, Dah-Jyuu; Blaskey, Lisa; Kuschner, Emily S; Levy, Susan E; Brodkin, Edward S; Roberts, Timothy P L

    2017-04-01

    Autism spectrum disorder (ASD) is hypothesized to arise from imbalances between excitatory and inhibitory neurotransmission (E/I imbalance). Studies have demonstrated E/I imbalance in individuals with ASD and also corresponding rodent models. One neural process thought to be reliant on E/I balance is gamma-band activity (Gamma), with support arising from observed correlations between motor, as well as visual, Gamma and underlying GABA concentrations in healthy adults. Additionally, decreased Gamma has been observed in ASD individuals and relevant animal models, though the direct relationship between Gamma and GABA concentrations in ASD remains unexplored. This study combined magnetoencephalography (MEG) and edited magnetic resonance spectroscopy (MRS) in 27 typically developing individuals (TD) and 30 individuals with ASD. Auditory cortex localized phase-locked Gamma was compared to resting Superior Temporal Gyrus relative cortical GABA concentrations for both children/adolescents and adults. Children/adolescents with ASD exhibited significantly decreased GABA+/Creatine (Cr) levels, though typical Gamma. Additionally, these children/adolescents lacked the typical maturation of GABA+/Cr concentrations and gamma-band coherence. Furthermore, children/adolescents with ASD additionally failed to exhibit the typical GABA+/Cr to gamma-band coherence association. This altered coupling during childhood/adolescence may result in Gamma decreases observed in the adults with ASD. Therefore, individuals with ASD exhibit improper local neuronal circuitry maturation during a childhood/adolescence critical period, when GABA is involved in configuring of such circuit functioning. Provocatively a novel line of treatment is suggested (with a critical time window); by increasing neural GABA levels in children/adolescents with ASD, proper local circuitry maturation may be restored resulting in typical Gamma in adulthood. Autism Res 2017, 10: 593-607. © 2016 International Society for

  18. Directed cortical information flow during human object recognition: analyzing induced EEG gamma-band responses in brain's source space.

    Directory of Open Access Journals (Sweden)

    Gernot G Supp

    Full Text Available The increase of induced gamma-band responses (iGBRs; oscillations >30 Hz elicited by familiar (meaningful objects is well established in electroencephalogram (EEG research. This frequency-specific change at distinct locations is thought to indicate the dynamic formation of local neuronal assemblies during the activation of cortical object representations. As analytically power increase is just a property of a single location, phase-synchrony was introduced to investigate the formation of large-scale networks between spatially distant brain sites. However, classical phase-synchrony reveals symmetric, pair-wise correlations and is not suited to uncover the directionality of interactions. Here, we investigated the neural mechanism of visual object processing by means of directional coupling analysis going beyond recording sites, but rather assessing the directionality of oscillatory interactions between brain areas directly. This study is the first to identify the directionality of oscillatory brain interactions in source space during human object recognition and suggests that familiar, but not unfamiliar, objects engage widespread reciprocal information flow. Directionality of cortical information-flow was calculated based upon an established Granger-Causality coupling-measure (partial-directed coherence; PDC using autoregressive modeling. To enable comparison with previous coupling studies lacking directional information, phase-locking analysis was applied, using wavelet-based signal decompositions. Both, autoregressive modeling and wavelet analysis, revealed an augmentation of iGBRs during the presentation of familiar objects relative to unfamiliar controls, which was localized to inferior-temporal, superior-parietal and frontal brain areas by means of distributed source reconstruction. The multivariate analysis of PDC evaluated each possible direction of brain interaction and revealed widespread reciprocal information-transfer during familiar

  19. Transient increase in the transcript levels of gamma-tubulin complex genes during reorientation of cortical microtubules by gravity in azuki bean (Vigna angularis) epicotyls.

    Science.gov (United States)

    Soga, Kouichi; Kotake, Toshihisa; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    2008-09-01

    By hypergravity treatment, the percentage of cells with transverse microtubules was decreased, while that with longitudinal microtubules was increased in azuki bean (Vigna angularis) epicotyls. The expression of genes encoding gamma-tubulin complex (VaTUG and VaGCP3) was increased transiently in response to changes in the gravitational conditions. Lanthanum and gadolinium ions, potential blockers of mechanosensitive calcium ion-permeable channels (mechanoreceptors), nullified reorientation of microtubules as well as up-regulation of expression of VaTUG and VaGCP3 by hypergravity. These results suggest that mechanoreceptors may perceive the gravity signal, which leads to a transient increase in the transcript levels of gamma-tubulin complex genes and reorientation of cortical microtubules.

  20. Rhythms of consciousness: binocular rivalry reveals large-scale oscillatory network dynamics mediating visual perception.

    Directory of Open Access Journals (Sweden)

    Sam M Doesburg

    Full Text Available Consciousness has been proposed to emerge from functionally integrated large-scale ensembles of gamma-synchronous neural populations that form and dissolve at a frequency in the theta band. We propose that discrete moments of perceptual experience are implemented by transient gamma-band synchronization of relevant cortical regions, and that disintegration and reintegration of these assemblies is time-locked to ongoing theta oscillations. In support of this hypothesis we provide evidence that (1 perceptual switching during binocular rivalry is time-locked to gamma-band synchronizations which recur at a theta rate, indicating that the onset of new conscious percepts coincides with the emergence of a new gamma-synchronous assembly that is locked to an ongoing theta rhythm; (2 localization of the generators of these gamma rhythms reveals recurrent prefrontal and parietal sources; (3 theta modulation of gamma-band synchronization is observed between and within the activated brain regions. These results suggest that ongoing theta-modulated-gamma mechanisms periodically reintegrate a large-scale prefrontal-parietal network critical for perceptual experience. Moreover, activation and network inclusion of inferior temporal cortex and motor cortex uniquely occurs on the cycle immediately preceding responses signaling perceptual switching. This suggests that the essential prefrontal-parietal oscillatory network is expanded to include additional cortical regions relevant to tasks and perceptions furnishing consciousness at that moment, in this case image processing and response initiation, and that these activations occur within a time frame consistent with the notion that conscious processes directly affect behaviour.

  1. Auditory cortical deactivation during speech production and following speech perception: an EEG investigation of the temporal dynamics of the auditory alpha rhythm.

    Science.gov (United States)

    Jenson, David; Harkrider, Ashley W; Thornton, David; Bowers, Andrew L; Saltuklaroglu, Tim

    2015-01-01

    Sensorimotor integration (SMI) across the dorsal stream enables online monitoring of speech. Jenson et al. (2014) used independent component analysis (ICA) and event related spectral perturbation (ERSP) analysis of electroencephalography (EEG) data to describe anterior sensorimotor (e.g., premotor cortex, PMC) activity during speech perception and production. The purpose of the current study was to identify and temporally map neural activity from posterior (i.e., auditory) regions of the dorsal stream in the same tasks. Perception tasks required "active" discrimination of syllable pairs (/ba/ and /da/) in quiet and noisy conditions. Production conditions required overt production of syllable pairs and nouns. ICA performed on concatenated raw 68 channel EEG data from all tasks identified bilateral "auditory" alpha (α) components in 15 of 29 participants localized to pSTG (left) and pMTG (right). ERSP analyses were performed to reveal fluctuations in the spectral power of the α rhythm clusters across time. Production conditions were characterized by significant α event related synchronization (ERS; pFDR covert replay, and that covert replay provides one source of the motor activity previously observed in some speech perception tasks. To our knowledge, this is the first time that inhibition of auditory regions by speech has been observed in real-time with the ICA/ERSP technique.

  2. Auditory Cortical Deactivation during Speech Production and following Speech Perception: An EEG investigation of the temporal dynamics of the auditory alpha rhythm

    Directory of Open Access Journals (Sweden)

    David E Jenson

    2015-10-01

    Full Text Available Sensorimotor integration within the dorsal stream enables online monitoring of speech. Jenson et al. (2014 used independent component analysis (ICA and event related spectral perturbation (ERSP analysis of EEG data to describe anterior sensorimotor (e.g., premotor cortex; PMC activity during speech perception and production. The purpose of the current study was to identify and temporally map neural activity from posterior (i.e., auditory regions of the dorsal stream in the same tasks. Perception tasks required ‘active’ discrimination of syllable pairs (/ba/ and /da/ in quiet and noisy conditions. Production conditions required overt production of syllable pairs and nouns. ICA performed on concatenated raw 68 channel EEG data from all tasks identified bilateral ‘auditory’ alpha (α components in 15 of 29 participants localized to pSTG (left and pMTG (right. ERSP analyses were performed to reveal fluctuations in the spectral power of the α rhythm clusters across time. Production conditions were characterized by significant α event related synchronization (ERS; pFDR < .05 concurrent with EMG activity from speech production, consistent with speech-induced auditory inhibition. Discrimination conditions were also characterized by α ERS following stimulus offset. Auditory α ERS in all conditions also temporally aligned with PMC activity reported in Jenson et al. (2014. These findings are indicative of speech-induced suppression of auditory regions, possibly via efference copy. The presence of the same pattern following stimulus offset in discrimination conditions suggests that sensorimotor contributions following speech perception reflect covert replay, and that covert replay provides one source of the motor activity previously observed in some speech perception tasks. To our knowledge, this is the first time that inhibition of auditory regions by speech has been observed in real-time with the ICA/ERSP technique.

  3. Biological Rhythms Workshop IC: sleep and rhythms

    National Research Council Canada - National Science Library

    Münch, M Y; Cain, S W; Duffy, J F

    2007-01-01

    Rhythms of sleep and wakefulness (typically measured as rest/activity rhythms) are among the most prominent of biological rhythms and therefore were among the first to be recorded in early chronobiological studies...

  4. Distinguishing mechanisms of gamma frequency oscillations in human current source signals using a computational model of a laminar neocortical network

    Directory of Open Access Journals (Sweden)

    Shane eLee

    2013-12-01

    Full Text Available Gamma frequency rhythms have been implicated in numerous studies for their role in healthy and abnormal brain function. The frequency band has been described to encompass as broad a range as 30–150 Hz. Crucial to understanding the role of gamma in brain function is an identification of the underlying neural mechanisms, which is particularly difficult in the absence of invasive recordings in macroscopic human signals such as those from magnetoencephalography (MEG and electroencephalography (EEG. Here, we studied features of current dipole (CD signals from two distinct mechanisms of gamma generation, using a computational model of a laminar cortical circuit designed specifically to simulate CDs in a biophysically principled manner (Jones et al., 2007; Jones et al., 2009. We simulated spiking pyramidal interneuronal gamma (PING whose period is regulated by the decay time constant of GABAA-mediated synaptic inhibition and also subthreshold gamma driven by gamma-periodic exogenous excitatory synaptic drive. Our model predicts distinguishable CD features created by spiking PING compared to subthreshold driven gamma that can help to disambiguate mechanisms of gamma oscillations in human signals. We found that gamma rhythms in neocortical layer 5 can obscure a simultaneous, independent gamma in layer 2/3. Further, we arrived at a novel interpretation of the origin of high gamma frequency rhythms (100–150 Hz, showing that they emerged from a specific temporal feature of CDs associated with single cycles of PING activity and did not reflect a separate rhythmic process. Last we show that the emergence of observable subthreshold gamma required highly coherent exogenous drive. Our results are the first to demonstrate features of gamma oscillations in human current source signals that distinguish cellular and circuit level mechanisms of these rhythms and may help guide understanding of their functional role.

  5. Multi-dimensional modulations of alpha and gamma cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder

    NARCIS (Netherlands)

    Schoenberg, P.L.; Speckens, A.E.M.

    2015-01-01

    To illuminate candidate neural working mechanisms of Mindfulness-Based Cognitive Therapy (MBCT) in the treatment of recurrent depressive disorder, parallel to the potential interplays between modulations in electro-cortical dynamics and depressive symptom severity and self-compassionate experience.

  6. Silencing gamma-aminobutyric acid A receptor alpha 1 subunit expression and outward potassium current in developing cortical neurons

    Institute of Scientific and Technical Information of China (English)

    Tao Bo; Jiang Li; Jian Li; Xingfang Li; Kaihui Xing

    2011-01-01

    We used RNA interference (RNAi) to disrupt synthesis of the cortical neuronal γ-aminobutyric acid A receptor (GABAAR) α1 in rats during development, and measured outward K+ currents during neuronal electrical activity using whole-cell patch-clamp techniques. Three pairs of small interfering RNA (siRNA) for GABAAR α1 subunit were designed using OligoEngine RNAi software. This siRNA was found to effectively inhibited GABAAR α1 mRNA expression in cortical neuronal culture in vitro, but did not significantly affect neuronal survival. Outward K+ currents were decreased, indicating that GABAAR α1 subunits in developing neurons participate in neuronal function by regulating outward K+ current.

  7. ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song.

    Science.gov (United States)

    Sturm, Irene; Blankertz, Benjamin; Potes, Cristhian; Schalk, Gerwin; Curio, Gabriel

    2014-01-01

    Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

  8. ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song

    Directory of Open Access Journals (Sweden)

    Irene eSturm

    2014-10-01

    Full Text Available Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently within the subject group identified as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song overlaid on instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

  9. Synchronization of firing in cortical fast-spiking interneurons at gamma frequencies: a phase-resetting analysis.

    Directory of Open Access Journals (Sweden)

    Nathan W Gouwens

    Full Text Available Fast-spiking (FS cells in the neocortex are interconnected both by inhibitory chemical synapses and by electrical synapses, or gap-junctions. Synchronized firing of FS neurons is important in the generation of gamma oscillations, at frequencies between 30 and 80 Hz. To understand how these synaptic interactions control synchronization, artificial synaptic conductances were injected in FS cells, and the synaptic phase-resetting function (SPRF, describing how the compound synaptic input perturbs the phase of gamma-frequency spiking as a function of the phase at which it is applied, was measured. GABAergic and gap junctional conductances made distinct contributions to the SPRF, which had a surprisingly simple piecewise linear form, with a sharp midcycle break between phase delay and advance. Analysis of the SPRF showed how the intrinsic biophysical properties of FS neurons and their interconnections allow entrainment of firing over a wide gamma frequency band, whose upper and lower frequency limits are controlled by electrical synapses and GABAergic inhibition respectively.

  10. Cortical Motor Rhythms, Auditory Processing, and Plasticity

    OpenAIRE

    Schalles, Matt

    2014-01-01

    Synchronizing our movements to rhythmic sounds is a complex behavior, but easy for many humans, whether in the form of playing an instrument, dancing, or simply nodding/ tapping along to a musical beat. How is this feat accomplished? A Hebbian hypothesis would argue that when sounds and movements co-occur, the systems become strongly associated, however many children exhibit a rhythmic sensitivity and do not seem to require training to move in time with music. An alternate explanation is that...

  11. Voiced Reading and Rhythm

    Institute of Scientific and Technical Information of China (English)

    詹艳萍

    2007-01-01

    Since voiced reading is an important way in learning English,rhythm is the most critical factor that enables to read beautifully.This article illustrates the relationship between rhythm and voiced reading,the importance of rhythm,and the methods to develop the sense of rhythm.

  12. 1-aminocyclopropane-1-carboxylic acid (ACC)-induced reorientation of cortical microtubules is accompanied by a transient increase in the transcript levels of gamma-tubulin complex and katanin genes in azuki bean epicotyls.

    Science.gov (United States)

    Soga, Kouichi; Yamaguchi, Aya; Kotake, Toshihisa; Wakabayashi, Kazuyuki; Hoson, Takayuki

    2010-09-15

    The effects of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, on growth, orientation of cortical microtubules, and the transcript levels of gamma-tubulin complex (VaTUG and VaGCP3) and katanin (VaKTN1) genes in azuki bean (Vigna angularis) epicotyls were examined. ACC inhibited elongation growth and stimulated lateral growth of epicotyls dose dependently. It also reduced the percentage of cells with transverse microtubules and increased the percentage of cells with longitudinal microtubules. A significant change in elongation and lateral growth was detected within 1 and 1.5 h after the start of 10(-5) M ACC treatment, respectively. On the other hand, the reorientation of cortical microtubules from transverse to longitudinal direction began within 0.5 h, and continued until 2 h after the start of ACC treatment. ACC at 10(-5) M increased the transcript level of VaTUG, VaGCP3 and VaKTN1 within 0.5 h, and the levels of VaTUG and VaGCP3 became maximum at 1h and that of VaKTN1 at 1.5 h, followed by a decrease to the control level. These results suggest that ACC transiently increases the transcript levels of gamma-tubulin complex and katanin genes, which may facilitate reorientation of cortical microtubules and modification of growth anisotropy from elongation to lateral growth in azuki bean epicotyls.

  13. Off beat: pluralizing rhythm

    NARCIS (Netherlands)

    Hoogstad, J.H.; Stougaard Pedersen, B.

    2013-01-01

    Off Beat: Pluralizing Rhythm draws attention to rhythm as a tool for analyzing various cultural objects. In fields as diverse as music, culture, nature, and economy, rhythm can be seen as a phenomenon that both connects and divides. It suggests a certain measure with which people, practices, and cul

  14. Broadband cortical desynchronization underlies the human psychedelic state.

    Science.gov (United States)

    Muthukumaraswamy, Suresh D; Carhart-Harris, Robin L; Moran, Rosalyn J; Brookes, Matthew J; Williams, Tim M; Errtizoe, David; Sessa, Ben; Papadopoulos, Andreas; Bolstridge, Mark; Singh, Krish D; Feilding, Amanda; Friston, Karl J; Nutt, David J

    2013-09-18

    Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin--prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices. Large decreases in oscillatory power were seen in areas of the default-mode network. Independent component analysis was used to identify a number of resting-state networks, and activity in these was similarly decreased after psilocybin. Psilocybin had no effect on low-level visually induced and motor-induced gamma-band oscillations, suggesting that some basic elements of oscillatory brain activity are relatively preserved during the psychedelic experience. Dynamic causal modeling revealed that posterior cingulate cortex desynchronization can be explained by increased excitability of deep-layer pyramidal neurons, which are known to be rich in 5-HT2A receptors. These findings suggest that the subjective effects of psychedelics result from a desynchronization of ongoing oscillatory rhythms in the cortex, likely triggered by 5-HT2A receptor-mediated excitation of deep pyramidal cells.

  15. Circadian Rhythm Sleep Disorders

    Directory of Open Access Journals (Sweden)

    Erhan Akinci

    2016-06-01

    Full Text Available The circadian rhythm sleep disorders define the clinical conditions where sleep and ndash;wake rhythm is disrupted despite optimum environmental and social conditions. They occur as a result of the changes in endogenous circadian hours or non-compatibility of environmental factors or social life with endogenous circadian rhythm. The sleep and ndash;wake rhythm is disrupted continuously or in repeating phases depending on lack of balance between internal and external cycles. This condition leads to functional impairments which cause insomnia, excessive sleepiness or both in people. Application of detailed sleep anamnesis and sleep diary with actigraphy record, if possible, will be sufficient for diagnosis. The treatment aims to align endogenous circadian rhythm with environmental conditions. The purpose of this article is to review pathology, clinical characteristics, diagnosis and treatment of circadian rhythm disorder. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 178-189

  16. Level of participation in robotic-assisted treadmill walking modulates midline sensorimotor EEG rhythms in able-bodied subjects.

    Science.gov (United States)

    Wagner, Johanna; Solis-Escalante, Teodoro; Grieshofer, Peter; Neuper, Christa; Müller-Putz, Gernot; Scherer, Reinhold

    2012-11-15

    In robot assisted gait training, a pattern of human locomotion is executed repetitively with the intention to restore the motor programs associated with walking. Several studies showed that active contribution to the movement is critical for the encoding of motor memory. We propose to use brain monitoring techniques during gait training to encourage active participation in the movement. We investigated the spectral patterns in the electroencephalogram (EEG) that are related to active and passive robot assisted gait. Fourteen healthy participants were considered. Infomax independent component analysis separated the EEG into independent components representing brain, muscle, and eye movement activity, as well as other artifacts. An equivalent current dipole was calculated for each independent component. Independent components were clustered across participants based on their anatomical position and frequency spectra. Four clusters were identified in the sensorimotor cortices that accounted for differences between active and passive walking or showed activity related to the gait cycle. We show that in central midline areas the mu (8-12 Hz) and beta (18-21 Hz) rhythms are suppressed during active compared to passive walking. These changes are statistically significant: mu (F(1, 13)=11.2 p ≤ 0.01) and beta (F(1, 13)=7.7, p ≤ 0.05). We also show that these differences depend on the gait cycle phases. We provide first evidence of modulations of the gamma rhythm in the band 25 to 40 Hz, localized in central midline areas related to the phases of the gait cycle. We observed a trend (F(1, 8)=11.03, p ≤ 0.06) for suppressed low gamma rhythm when comparing active and passive walking. Additionally we found significant suppressions of the mu (F(1, 11)=20.1 p ≤ 0.01), beta (F(1, 11)=11.3 p ≤ 0.05) and gamma (F(1, 11)=4.9 p ≤ 0.05) rhythms near C3 (in the right hand area of the primary motor cortex) during phases of active vs. passive robot assisted walking. To our

  17. Cross-approximate entropy of cortical local field potentials quantifies effects of anesthesia - a pilot study in rats

    Directory of Open Access Journals (Sweden)

    Schwarz Cornelius

    2010-09-01

    Full Text Available Abstract Background Anesthetics dose-dependently shift electroencephalographic (EEG activity towards high-amplitude, slow rhythms, indicative of a synchronization of neuronal activity in thalamocortical networks. Additionally, they uncouple brain areas in higher (gamma frequency ranges possibly underlying conscious perception. It is currently thought that both effects may impair brain function by impeding proper information exchange between cortical areas. But what happens at the local network level? Local networks with strong excitatory interconnections may be more resilient towards global changes in brain rhythms, but depend heavily on locally projecting, inhibitory interneurons. As anesthetics bias cortical networks towards inhibition, we hypothesized that they may cause excessive synchrony and compromise information processing already on a small spatial scale. Using a recently introduced measure of signal independence, cross-approximate entropy (XApEn, we investigated to what degree anesthetics synchronized local cortical network activity. We recorded local field potentials (LFP from the somatosensory cortex of three rats chronically implanted with multielectrode arrays and compared activity patterns under control (awake state with those at increasing concentrations of isoflurane, enflurane and halothane. Results Cortical LFP signals were more synchronous, as expressed by XApEn, in the presence of anesthetics. Specifically, XApEn was a monotonously declining function of anesthetic concentration. Isoflurane and enflurane were indistinguishable; at a concentration of 1 MAC (the minimum alveolar concentration required to suppress movement in response to noxious stimuli in 50% of subjects both volatile agents reduced XApEn by about 70%, whereas halothane was less potent (50% reduction. Conclusions The results suggest that anesthetics strongly diminish the independence of operation of local cortical neuronal populations, and that the

  18. Dissociable systems of working memory for rhythm and melody.

    Science.gov (United States)

    Jerde, Trenton A; Childs, Stephanie K; Handy, Sarah T; Nagode, Jennifer C; Pardo, José V

    2011-08-15

    Specialized neural systems are engaged by the rhythmic and melodic components of music. Here, we used PET to measure regional cerebral blood flow (rCBF) in a working memory task for sequences of rhythms and melodies, which were presented in separate blocks. Healthy subjects, without musical training, judged whether a target rhythm or melody was identical to a series of subsequently presented rhythms or melodies. When contrasted with passive listening to rhythms, working memory for rhythm activated the cerebellar hemispheres and vermis, right anterior insular cortex, and left anterior cingulate gyrus. These areas were not activated in a contrast between passive listening to rhythms and a non-auditory control, indicating their role in the temporal processing that was specific to working memory for rhythm. The contrast between working memory for melody and passive listening to melodies activated mainly a right-hemisphere network of frontal, parietal, and temporal cortices: areas involved in pitch processing and auditory working memory. Overall, these results demonstrate that rhythm and melody have unique neural signatures not only in the early stages of auditory processing, but also at the higher cognitive level of working memory.

  19. Markets, Bodies, Rhythms

    DEFF Research Database (Denmark)

    Borch, Christian; Bondo Hansen, Kristian; Lange, Ann-Christina

    2015-01-01

    This article explores the relationship between bodily rhythms and market rhythms in two distinctly different financial market configurations, namely the open-outcry pit (prevalent especially in the early 20th century) and present-day high-frequency trading. Drawing on Henri Lefebvre's rhythmanaly......This article explores the relationship between bodily rhythms and market rhythms in two distinctly different financial market configurations, namely the open-outcry pit (prevalent especially in the early 20th century) and present-day high-frequency trading. Drawing on Henri Lefebvre...... of financial markets, it also suggests that high-frequency trading in particular might produce new types of market rhythms that, contra Lefebvre, do not revolve around traders' bodies....

  20. Endogenous control of waking brain rhythms induces neuroplasticity in humans.

    NARCIS (Netherlands)

    Ros, T.; Munneke, M.; Ruge, D.; Gruzelier, J.H.; Rothwell, J.C.

    2010-01-01

    This study explores the possibility of noninvasively inducing long-term changes in human corticomotor excitability by means of a brain-computer interface, which enables users to exert internal control over the cortical rhythms recorded from the scalp. We demonstrate that self-regulation of electroen

  1. Hippocampal and cortical expression of gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein in pentylenetetrazol-induced chronic epileptic rats

    Institute of Scientific and Technical Information of China (English)

    Yi Zeng; Zhong Yang; Xiaodong Long; Chao You

    2009-01-01

    BACKGROUND: Gamma-aminobutyric acid transporter plays an important role in gamma-aminobutyric acid metabolism, and is highly associated with epilepsy seizures.Pathologically, astrocytes release active substances that alter neuronal excitability, and it has been demonstrated that astrocytes play a role in epileptic seizures.OBJECTIVE: To observe changes in gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression in the hippocampus and cortex of the temporal lobe in rats with pentylenetetrazol-induced chronic epilepsy.DESIGN, TIME AND SETTING: Randomized, controlled, animal experiment was performed at the Department of Neurobiology, Third Military University of Chinese PLA between January 2006 and December 2007.MATERIALS: Pentylenetetrazol was purchased from Sigma, USA; rabbit anti-rat gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein were from Chemicon, USA.METHODS; A total of 40 Sprague Dawley rats were divided into model and control groups. Rat models of chronic epilepsy were created by pentylenetetrazol kindling, and were subdivided into 3-, 7-, and 14-day kindling subgroups.MAIN OUTCOME MEASURES: Gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression, as well as the number of positive cells in the hippocampus and cortex of temporal lobe of rats, were determined by immunohistochemistry and Western blot analyses.RESULTS: Compared with the control group, the number of gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein -positive cells in the hippocampus and cortex of rats with pentylenetetrazol-induced epilepsy significantly increased, gamma-aminobutyric acid transporter 1 and glial fibrillary acidic protein expression increased after 3 days of kindling, reached a peak on day 7, and remained at elevated levels at day 14 (P < 0.05).CONCLUSION: Astrocytic activation and gamma-aminobutyric acid transporter 1 overexpression may contribute to pentylenetetrazol

  2. Rhythm in language acquisition.

    Science.gov (United States)

    Langus, Alan; Mehler, Jacques; Nespor, Marina

    2016-12-16

    Spoken language is governed by rhythm. Linguistic rhythm is hierarchical and the rhythmic hierarchy partially mimics the prosodic as well as the morpho-syntactic hierarchy of spoken language. It can thus provide learners with cues about the structure of the language they are acquiring. We identify three universal levels of linguistic rhythm - the segmental level, the level of the metrical feet and the phonological phrase level - and discuss why primary lexical stress is not rhythmic. We survey experimental evidence on rhythm perception in young infants and native speakers of various languages to determine the properties of linguistic rhythm that are present at birth, those that mature during the first year of life and those that are shaped by the linguistic environment of language learners. We conclude with a discussion of the major gaps in current knowledge on linguistic rhythm and highlight areas of interest for future research that are most likely to yield significant insights into the nature, the perception, and the usefulness of linguistic rhythm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Gamma event-related synchronization analysis: a new method for cortical function mapping%通过Gamma频段能量分析进行大脑皮层功能区定位

    Institute of Scientific and Technical Information of China (English)

    潘鑫; 钱天翼; 韩宏彦; 周文静; 孙朝晖; 王东明; 左焕琮

    2012-01-01

    目的 通过分析颅内脑电中Gamma频段能量变化来实现大脑皮层感觉运动区定位.方法 利用Gamma频段能量分析法、诱发电位(SEP)和皮层电刺激(CES)等电生理检查对8例因难治性癫痫而行颅内电极植入术的患者进行大脑皮层感觉运动区定位,以减少术后功能缺失等并发症.将Gamma频段能量分析方法的定位结果与SEP与CES进行比较.结果 通过统计对比,Gamma频段能量分析所得上肢感觉运动区电极编号与CES和SEP所得感觉运动区电极编号完全重合的占80.7%,完全重合或者紧邻的达92.3%.结论 Gamma频段能量分析方法是一种敏感性高、结果准确的大脑皮层功能区定位的新方法.%Objective To localize the sensory motor cortex of human brain by analyzing the power change in Gamma band ( > 60 Hz ) of electrocorticography (ECoG) data.Methods Eight patients with intractable epilepsy underwent temporary placement of subdural electrodes. After surgery,scnsory cvokcd potential (SEP),electrocortical stimulation (CES) and event-related synchronization analysis of Gamma band ( Gamma ERS analysis) were performed to reduce the risk of complications.The results of Gamma ERS analysis were compared with those of SEP and CES.Results The results of Gamma ERS analysis had 80.7% electrodes fitting perfectly those of CES and SEP.And the percentage reached 92.3% if electrodes were superimposed or added adjacently.Conclusion The Gamma ERS analysis is a new sensitive and precise method for cortical function mapping.

  4. Other Rhythm Disorders

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Other Heart Rhythm Disorders Updated:Dec 21,2016 In ... page to further explore diagnosis, treatment options, and other information about conditions associated with atrial flutter. SICK ...

  5. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system.

  6. Transient increase in the levels of gamma-tubulin complex in reorientation of cortical microtubules by gravity in azuki bean epicotyls

    Science.gov (United States)

    Soga, Kouichi; Kotake, Toshihisa; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    Azuki bean (Vigna angularis Ohwi et Ohashi) seedlings were exposed to centrifugal hypergravity, and the changes in the orientation of cortical microtubules and the expression of genes cording γ-tubulin complex (VaTUBG and VaSpc98p) were examined. By 300 g treatment, the percentage of cells with transverse microtubules was decreased, while that with longitudinal microtubules was increased in epicotyls. Hypergravity increased the expression of VaTUBG and VaSpc98p transiently. Also, the expression of both genes was increased transiently by removal of hypergravity stimulus. Lanthanum and gadolinium ions, potential blockers of mechanosensitive calcium ion-permeable channels (mechanoreceptors), nullified reorientation of microtubules as well as up-regulation of expression of VaTUBG and VaSpc98p by hypergravity. These results suggest that mechanoreceptors on the plasma membrane may perceive the gravity signal, which leads to reorientation of cortical microtubules by transiently stimulating the formation of γ-tubulin complex.

  7. Neural networks for beat perception in musical rhythm

    Directory of Open Access Journals (Sweden)

    Edward W Large

    2015-11-01

    Full Text Available Entrainment of cortical rhythms to acoustic rhythms has been hypothesized to be the neural correlate of pulse and meter perception in music. Dynamic attending theory first proposed synchronization of endogenous perceptual rhythms nearly forty years ago, but only recently has the pivotal role of neural synchrony been demonstrated. Significant progress has since been made in understanding the role of neural oscillations and the neural structures that support synchronized responses to musical rhythm. Synchronized neural activity has been observed in auditory and motor networks, and has been linked with attentional allocation and movement coordination. Here we describe a neurodynamic model that shows how self-organization of oscillations in interacting sensory and motor networks could be responsible for the formation of the pulse percept in complex rhythms. We test the model's prediction that pulse can be perceived at a frequency for which no spectral energy is present in the amplitude envelope of the acoustic rhythm. The result provides a theoretical link between oscillatory neurodynamics and the induction of pulse and meter in musical rhythm.

  8. Neural Networks for Beat Perception in Musical Rhythm

    Science.gov (United States)

    Large, Edward W.; Herrera, Jorge A.; Velasco, Marc J.

    2015-01-01

    Entrainment of cortical rhythms to acoustic rhythms has been hypothesized to be the neural correlate of pulse and meter perception in music. Dynamic attending theory first proposed synchronization of endogenous perceptual rhythms nearly 40 years ago, but only recently has the pivotal role of neural synchrony been demonstrated. Significant progress has since been made in understanding the role of neural oscillations and the neural structures that support synchronized responses to musical rhythm. Synchronized neural activity has been observed in auditory and motor networks, and has been linked with attentional allocation and movement coordination. Here we describe a neurodynamic model that shows how self-organization of oscillations in interacting sensory and motor networks could be responsible for the formation of the pulse percept in complex rhythms. In a pulse synchronization study, we test the model's key prediction that pulse can be perceived at a frequency for which no spectral energy is present in the amplitude envelope of the acoustic rhythm. The result shows that participants perceive the pulse at the theoretically predicted frequency. This model is one of the few consistent with neurophysiological evidence on the role of neural oscillation, and it explains a phenomenon that other computational models fail to explain. Because it is based on a canonical model, the predictions hold for an entire family of dynamical systems, not only a specific one. Thus, this model provides a theoretical link between oscillatory neurodynamics and the induction of pulse and meter in musical rhythm. PMID:26635549

  9. Neural Networks for Beat Perception in Musical Rhythm.

    Science.gov (United States)

    Large, Edward W; Herrera, Jorge A; Velasco, Marc J

    2015-01-01

    Entrainment of cortical rhythms to acoustic rhythms has been hypothesized to be the neural correlate of pulse and meter perception in music. Dynamic attending theory first proposed synchronization of endogenous perceptual rhythms nearly 40 years ago, but only recently has the pivotal role of neural synchrony been demonstrated. Significant progress has since been made in understanding the role of neural oscillations and the neural structures that support synchronized responses to musical rhythm. Synchronized neural activity has been observed in auditory and motor networks, and has been linked with attentional allocation and movement coordination. Here we describe a neurodynamic model that shows how self-organization of oscillations in interacting sensory and motor networks could be responsible for the formation of the pulse percept in complex rhythms. In a pulse synchronization study, we test the model's key prediction that pulse can be perceived at a frequency for which no spectral energy is present in the amplitude envelope of the acoustic rhythm. The result shows that participants perceive the pulse at the theoretically predicted frequency. This model is one of the few consistent with neurophysiological evidence on the role of neural oscillation, and it explains a phenomenon that other computational models fail to explain. Because it is based on a canonical model, the predictions hold for an entire family of dynamical systems, not only a specific one. Thus, this model provides a theoretical link between oscillatory neurodynamics and the induction of pulse and meter in musical rhythm.

  10. Rhythms, rhythmicity and aggression.

    Science.gov (United States)

    Bronsard, Guillaume; Bartolomei, Fabrice

    2013-09-01

    The relationships between biological rhythms and human aggressive behavior are addressed and discussed in this article: First, circadian rhythms and aggression are considered. Studies of sleep/waking cycle disturbances in aggression are reported. Severe aggression is associated with profound changes in sleep architecture. Causal link is difficult to establish given that sleep disturbance and aggressive behavior could be the symptoms of the same disorder. Specific aggressive behavior developed during sleep is also described. In addition, hormonal circadian rhythm studies are reported. Thus, low cortisol levels, in particular low cortisol variability, are associated with aggressive behavior, suggesting an inhibitory role of cortisol. Testosterone has daily and seasonal fluctuations, but no link with aggression has been established. Neurophysiological underlying mechanisms are discussed in the last part of this article, with a focus on the relationship between brain rhythm and aggression. Increase of slow-wave EEG activities is observed in individuals with aggressive behavior. Epilepsy, as a disease of brain rhythm could be associated with aggressive behavior, in pre, post and inter ictal periodes. Incidence of aggression is not likely more prevalent in epileptic individuals compared to those with other neurological conditions. Ictal changes take the form of profound behavioral changes, including aggressive behavior which has been interpreted as the emergence of "archeical" or innate motor patterns. In this multidisciplinary approach, the main difficulty is the categorization of the differents types of aggression. Finally, taken together, these studies suggest that biological rhythms, especially circadian rhythms, could provide therapeutic benefits to human aggressive behavior. Biological rhythymicity seems to be a necessary permanent training offering interesting perspectives for the adaptation to changes in the field of aggression. Copyright © 2013 Elsevier Ltd

  11. Rhythm on Your Lips

    Science.gov (United States)

    Peña, Marcela; Langus, Alan; Gutiérrez, César; Huepe-Artigas, Daniela; Nespor, Marina

    2016-01-01

    The Iambic-Trochaic Law (ITL) accounts for speech rhythm, grouping of sounds as either Iambs—if alternating in duration—or Trochees—if alternating in pitch and/or intensity. The two different rhythms signal word order, one of the basic syntactic properties of language. We investigated the extent to which Iambic and Trochaic phrases could be auditorily and visually recognized, when visual stimuli engage lip reading. Our results show both rhythmic patterns were recognized from both, auditory and visual stimuli, suggesting that speech rhythm has a multimodal representation. We further explored whether participants could match Iambic and Trochaic phrases across the two modalities. We found that participants auditorily familiarized with Trochees, but not with Iambs, were more accurate in recognizing visual targets, while participants visually familiarized with Iambs, but not with Trochees, were more accurate in recognizing auditory targets. The latter results suggest an asymmetric processing of speech rhythm: in auditory domain, the changes in either pitch or intensity are better perceived and represented than changes in duration, while in the visual domain the changes in duration are better processed and represented than changes in pitch, raising important questions about domain general and specialized mechanisms for speech rhythm processing. PMID:27877144

  12. Rhythm on your lips

    Directory of Open Access Journals (Sweden)

    Marcela Pena

    2016-11-01

    Full Text Available The Iambic-Trochaic Law (ITL accounts for speech rhythm, grouping of sounds as either Iambs – if alternating in duration – or Trochees – if alternating in pitch and/or intensity. The two different rhythms signal word order, one of the basic syntactic properties of language. We investigated the extent to which Iambic and Trochaic phrases could be auditorily and visually recognized, when visual stimuli engage lip reading. Our results show both rhythmic patterns were recognized from both, auditory and visual stimuli, suggesting that speech rhythm has a multimodal representation. We further explored whether participants could match Iambic and Trochaic phrases across the two modalities. We found that participants auditorily familiarized with Trochees, but not with Iambs, were more accurate in recognizing visual targets, while participants visually familiarized with Iambs, but not with Trochees, were more accurate in recognizing auditory targets. The latter results suggest an asymmetric processing of speech rhythm: in auditory domain, the changes in either pitch or intensity are better perceived and represented than changes in duration, while in the visual domain the changes in duration are better processed and represented than changes in pitch, raising important questions about domain general and specialized mechanisms for speech rhythm processing.

  13. Circadian rhythm sleep disorders

    Directory of Open Access Journals (Sweden)

    Morgenthaler TI

    2012-05-01

    Full Text Available Bhanu P Kolla,1,2 R Robert Auger,1,2 Timothy I Morgenthaler11Mayo Center for Sleep Medicine, 2Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, MN, USAAbstract: Misalignment between endogenous circadian rhythms and the light/dark cycle can result in pathological disturbances in the form of erratic sleep timing (irregular sleep–wake rhythm, complete dissociation from the light/dark cycle (circadian rhythm sleep disorder, free-running type, delayed sleep timing (delayed sleep phase disorder, or advanced sleep timing (advanced sleep phase disorder. Whereas these four conditions are thought to involve predominantly intrinsic mechanisms, circadian dysrhythmias can also be induced by exogenous challenges, such as those imposed by extreme work schedules or rapid transmeridian travel, which overwhelm the ability of the master clock to entrain with commensurate rapidity, and in turn impair approximation to a desired sleep schedule, as evidenced by the shift work and jet lag sleep disorders. This review will focus on etiological underpinnings, clinical assessments, and evidence-based treatment options for circadian rhythm sleep disorders. Topics are subcategorized when applicable, and if sufficient data exist. The length of text associated with each disorder reflects the abundance of associated literature, complexity of management, overlap of methods for assessment and treatment, and the expected prevalence of each condition within general medical practice.Keywords: circadian rhythm sleep disorders, assessment, treatment

  14. Cerebrospinal fluid sodium rhythms

    Directory of Open Access Journals (Sweden)

    Johnson Benjamin

    2010-01-01

    Full Text Available Abstract Background Cerebrospinal fluid (CSF sodium levels have been reported to rise during episodic migraine. Since migraine frequently starts in early morning or late afternoon, we hypothesized that natural sodium chronobiology may predispose susceptible persons when extracellular CSF sodium increases. Since no mammalian brain sodium rhythms are known, we designed a study of healthy humans to test if cation rhythms exist in CSF. Methods Lumbar CSF was collected every ten minutes at 0.1 mL/min for 24 h from six healthy participants. CSF sodium and potassium concentrations were measured by ion chromatography, total protein by fluorescent spectrometry, and osmolarity by freezing point depression. We analyzed cation and protein distributions over the 24 h period and spectral and permutation tests to identify significant rhythms. We applied the False Discovery Rate method to adjust significance levels for multiple tests and Spearman correlations to compare sodium fluctuations with potassium, protein, and osmolarity. Results The distribution of sodium varied much more than potassium, and there were statistically significant rhythms at 12 and 1.65 h periods. Curve fitting to the average time course of the mean sodium of all six subjects revealed the lowest sodium levels at 03.20 h and highest at 08.00 h, a second nadir at 09.50 h and a second peak at 18.10 h. Sodium levels were not correlated with potassium or protein concentration, or with osmolarity. Conclusion These CSF rhythms are the first reports of sodium chronobiology in the human nervous system. The results are consistent with our hypothesis that rising levels of extracellular sodium may contribute to the timing of migraine onset. The physiological importance of sodium in the nervous system suggests that these rhythms may have additional repercussions on ultradian functions.

  15. Rhythm quantization for transcription

    NARCIS (Netherlands)

    Cemgil, A.T.; Desain, P.W.M.; Kappen, H.J.

    1999-01-01

    Automatic Music Transcription is the extraction of an acceptable notation from performed music. One important task in this problem is rhythm quantization which refers to categorization of note durations. Although quantization of a pure mechanical performance is rather straightforward, the task becom

  16. Measuring Child Rhythm

    Science.gov (United States)

    Payne, Elinor; Post, Brechtje; Astruc, Lluisa; Prieto, Pilar; Vanrell, Maria del Mar

    2012-01-01

    Interval-based rhythm metrics were applied to the speech of English, Catalan and Spanish 2, 4 and 6 year-olds, and compared with the (adult-directed) speech of their mothers. Results reveal that child speech does not fall into a well-defined rhythmic class: for all three languages, it is more "vocalic" (higher %V) than adult speech and has a…

  17. A Causal Rhythm Grouping

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    This paper presents a method to identify segment boundaries in music. The method is based on a multi-step model; first a features is measured from the audio, then a measure of rhythm is calculated from the feature, the diagonal of a self-similarity matrix is calculated, and finally the segment bo...

  18. Stimulating forebrain communications: Slow sinusoidal electric fields over frontal cortices dynamically modulate hippocampal activity and cortico-hippocampal interplay during slow-wave states.

    Science.gov (United States)

    Greenberg, Anastasia; Whitten, Tara A; Dickson, Clayton T

    2016-06-01

    Slow-wave states are characterized by the most global physiological phenomenon in the mammalian brain, the large-amplitude slow oscillation (SO; ~1Hz) composed of alternating states of activity (ON/UP states) and silence (OFF/DOWN states) at the network and single cell levels. The SO is cortically generated and appears as a traveling wave that can propagate across the cortical surface and can invade the hippocampus. This cortical rhythm is thought to be imperative for sleep-dependent memory consolidation, potentially through increased interactions with the hippocampus. The SO is correlated with learning and its presumed enhancement via slow rhythmic electrical field stimulation improves subsequent mnemonic performance. However, the mechanism by which such field stimulation influences the dynamics of ongoing cortico-hippocampal communication is unknown. Here we show - using multi-site recordings in urethane-anesthetized rats - that sinusoidal electrical field stimulation applied to the frontal region of the cerebral cortex creates a platform for improved cortico-hippocampal communication. Moderate-intensity field stimulation entrained hippocampal slow activity (likely by way of the temporoammonic pathway) and also increased sharp-wave ripples, the signature memory replay events of the hippocampus, and further increased cortical spindles. Following cessation of high-intensity stimulation, SO interactions in the cortical-to-hippocampal direction were reduced, while the reversed hippocampal-to-cortical communication at both SO and gamma bandwidths was enhanced. Taken together, these findings suggest that cortical field stimulation may function to boost memory consolidation by strengthening cortico-hippocampal and hippocampo-cortical interplay at multiple nested frequencies in an intensity-dependent fashion.

  19. Delta and gamma oscillations in operculo-insular cortex underlie innocuous cold thermosensation.

    Science.gov (United States)

    Fardo, Francesca; Vinding, Mikkel C; Allen, Micah; Jensen, Troels Staehelin; Finnerup, Nanna Brix

    2017-05-01

    Cold-sensitive and nociceptive neural pathways interact to shape the quality and intensity of thermal and pain perception. Yet the central processing of cold thermosensation in the human brain has not been extensively studied. Here, we used magnetoencephalography and EEG in healthy volunteers to investigate the time course (evoked fields and potentials) and oscillatory activity associated with the perception of cold temperature changes. Nonnoxious cold stimuli consisting of Δ3°C and Δ5°C decrements from an adapting temperature of 35°C were delivered on the dorsum of the left hand via a contact thermode. Cold-evoked fields peaked at around 240 and 500 ms, at peak latencies similar to the N1 and P2 cold-evoked potentials. Importantly, cold-related changes in oscillatory power indicated that innocuous thermosensation is mediated by oscillatory activity in the range of delta (1-4 Hz) and gamma (55-90 Hz) rhythms, originating in operculo-insular cortical regions. We suggest that delta rhythms coordinate functional integration between operculo-insular and frontoparietal regions, while gamma rhythms reflect local sensory processing in operculo-insular areas.NEW & NOTEWORTHY Using magnetoencephalography, we identified spatiotemporal features of central cold processing, with respect to the time course, oscillatory profile, and neural generators of cold-evoked responses in healthy human volunteers. Cold thermosensation was associated with low- and high-frequency oscillatory rhythms, both originating in operculo-insular regions. These results support further investigations of central cold processing using magnetoencephalography or EEG and the clinical utility of cold-evoked potentials for neurophysiological assessment of cold-related small-fiber function and damage. Copyright © 2017 the American Physiological Society.

  20. [Circadian rhythm sleep disorder].

    Science.gov (United States)

    Mishima, Kazuo

    2013-12-01

    Primary pathophysiology of circadian rhythm sleep disorders(CRSDs) is a misalignment between the endogenous circadian rhythm phase and the desired or socially required sleep-wake schedule, or dysfunction of the circadian pacemaker and its afferent/efferent pathways. CRSDs consist of delayed sleep phase type, advanced sleep phase type, free-running type, irregular sleep-wake type, shift work type and jet lag type. Chronotherapy using strong zeitgebers (time cues), such as bright light and melatonin/ melatonin type 2 receptor agonist, is effective when administered with proper timing. Bright light is the strongest entraining agent of circadian rhythms. Bright light therapy (appropriately-timed exposure to bright light) for CRSDs is an effective treatment option, and can shift the sleep-wake cycle to earlier or later times, in order to correct for misalignment between the circadian system and the desired sleep-wake schedule. Timed administration of melatonin, either alone or in combination with light therapy has also been shown to be useful in the treatment of CRSDs.

  1. Neurobiology of circadian rhythms.

    Science.gov (United States)

    Kumar, V

    1997-09-01

    Adaptation in the temporal environment is key to survival. This is achieved by the manifestation of periodicity in occurrence of vital behavioural and physiological processes at regular intervals--the biological rhythms. Biological rhythms (= biological clocks) are ubiquitous, can be demonstrated persisting at any level of organization in the living world, and are generated and controlled by some central pacemaker(s), mostly located in the brain. In mammals, the suprachiasmatic nucleus (SCN) of the anterior hypothalamus is the principal site of the endogenous circadian pacemaker, regulating many daily physiological and behavioural functions, although other neural structures could also be contributing to the circadian timekeeping system. In other vertebrates, the neural site(s) of the circadian pacemaker is(are) still unclear. An organism without brain can have the biological clock, as well, for fully functional 24-hour temporal organization has been identified in several invertebrates, including unicellular Paramecium and Gonyaulax as well as filamentous fungus, Neurospora. This article attempts to provide an update of the informations which have accumulated over the past decade about understanding of the neurophysiological and molecular bases of circadian rhythms in animals.

  2. Neural rhythmic symphony of human walking observation: Upside-down and Uncoordinated condition on cortical theta, alpha, beta and gamma oscillations.

    Directory of Open Access Journals (Sweden)

    David eZarka

    2014-09-01

    Full Text Available Biological motion observation has been recognized to produce dynamic change in sensorimotor activation according to the observed kinematics. Physical plausibility of the spatial-kinematic relationship of human movement may play a major role in the top-down processing of human motion recognition. Here, we investigated the time course of scalp activation during observation of human gait in order to extract and use it on future integrated brain-computer interface using virtual reality (VR. We analyzed event related potentials (ERP, the event related spectral perturbation (ERSP and the inter-trial coherence (ITC from high-density EEG recording during video display onset (-200 to 600 ms and the steady state visual evoked potentials (SSVEP inside the video of human walking 3D-animation in three conditions: Normal; Upside-down (inverted images; and Uncoordinated (pseudo-randomly mixed images. We found that early visual evoked response P120 was decreased in Upside-down condition. The N170 and P300b amplitudes were decreased in Uncoordinated condition. In Upside-down and Uncoordinated conditions, we found decreased alpha power and theta phase-locking. As regards gamma oscillation, power was increased during the Upside-down animation and decreased during the Uncoordinated animation. An SSVEP-like response oscillating at about 10 Hz was also described showing that the oscillating pattern is enhanced 300 ms after the heel strike event only in the Normal but not in the Upside-down condition. Our results are consistent with most of previous point-light display studies, further supporting possible use of virtual reality for neurofeedback applications.

  3. Do unresponsive wakefulness syndrome patients feel pain? Role of laser-evoked potential-induced gamma-band oscillations in detecting cortical pain processing.

    Science.gov (United States)

    Naro, A; Leo, A; Cannavò, A; Buda, A; Bramanti, P; Calabrò, R S

    2016-03-11

    It has been proposed that a neural signature of aware pain perception could be represented by the modulation of gamma-band oscillation (GBO) power induced by nociceptive repetitive laser stimulation (RLS). The aim of our study was to correlate the RLS-induced GBO modulation with the Nociception Coma Scale-Revised (NCS-R) scores (a validated scale assessing possible aware pain perception in patients with chronic disorders of consciousness), in an attempt to differentiate unresponsive wakefulness syndrome (UWS) patients from minimally conscious state (MCS) ones (both of them are awake but exhibit no or limited and fluctuant behavioral signs of awareness and mentation, and low and high NCS-R scores, respectively). In addition, we attempted to identify those among UWS patients who probably experienced pain at covert level (i.e. being aware but unable to show pain-related purposeful behaviors, which are those sustained, reproducible, and voluntary behavioral responses to nociceptive stimuli). Notably, the possibility of clearly differentiating UWS from MCS patients has outmost consequences concerning prognosis (worse in UWS) and adequate pain treatment. RLS consisted in 80 trains of three laser stimuli (delivered at 1Hz), at four different energies, able to evoke Aδ-fiber related laser evoked potentials. After each train, we assessed the NCS-R score. EEG was divided into epochs according to the laser trains, and the obtained epochs were classified in four categories according to the NCS-R score magnitude. We quantified the GBO absolute power for each category. RLS protocol induced a strongly correlated increase in GBO power and NCS-R score (the higher the laser stimulation intensity, the higher the NCS-R, independently of stimulus repetition) in all the MCS patients, thus confirming the presence of aware pain processing. Nonetheless, such findings were present even in five UWS individuals. This could suggest the presence of covert pain processing in such subjects

  4. Properties of precise firing synchrony between synaptically coupled cortical interneurons depend on their mode of coupling.

    Science.gov (United States)

    Hu, Hang; Agmon, Ariel

    2015-07-01

    Precise spike synchrony has been widely reported in the central nervous system, but its functional role in encoding, processing, and transmitting information is yet unresolved. Of particular interest is firing synchrony between inhibitory cortical interneurons, thought to drive various cortical rhythms such as gamma oscillations, the hallmark of cognitive states. Precise synchrony can arise between two interneurons connected electrically, through gap junctions, chemically, through fast inhibitory synapses, or dually, through both types of connections, but the properties of synchrony generated by these different modes of connectivity have never been compared in the same data set. In the present study we recorded in vitro from 152 homotypic pairs of two major subtypes of mouse neocortical interneurons: parvalbumin-containing, fast-spiking (FS) interneurons and somatostatin-containing (SOM) interneurons. We tested firing synchrony when the two neurons were driven to fire by long, depolarizing current steps and used a novel synchrony index to quantify the strength of synchrony, its temporal precision, and its dependence on firing rate. We found that SOM-SOM synchrony, driven solely by electrical coupling, was less precise than FS-FS synchrony, driven by inhibitory or dual coupling. Unlike SOM-SOM synchrony, FS-FS synchrony was strongly firing rate dependent and was not evident at the prototypical 40-Hz gamma frequency. Computer simulations reproduced these differences in synchrony without assuming any differences in intrinsic properties, suggesting that the mode of coupling is more important than the interneuron subtype. Our results provide novel insights into the mechanisms and properties of interneuron synchrony and point out important caveats in current models of cortical oscillations.

  5. Modelling Complexity in Musical Rhythm

    OpenAIRE

    Liou, Cheng-Yuan; Wu, Tai-Hei; Lee, Chia-Ying

    2007-01-01

    This paper constructs a tree structure for the music rhythm using the L-system. It models the structure as an automata and derives its complexity. It also solves the complexity for the L-system. This complexity can resolve the similarity between trees. This complexity serves as a measure of psychological complexity for rhythms. It resolves the music complexity of various compositions including the Mozart effect K488. Keyword: music perception, psychological complexity, rhythm, L-system, autom...

  6. [Fundamentals of chronobiology: nyctohemeral rhythms].

    Science.gov (United States)

    Bourdon, L; Buguet, A

    2004-09-01

    Most biological activities fluctuate throughout the day and contribute to a better adaptation to the organism's daily activity. During the last 30 Years, chronobiology has aimed at studying these biological rhythms, explaining most of the biological mechanisms of i) the endogenous circadian rhythmicity, ii) the neurophysiological mechanisms of the photic system that allows its external resetting, and iii) the neuroendocrine mechanisms of internal rhythm synchronization. Moreover, the description of specific biological rhythm disorders and rhythm problems at the cellular and even the molecular level have prompted the emerging fields of chronopharmacology and chronotherapeutics. Copyright 2004 Masson

  7. Circadian rhythms and cognition.

    Science.gov (United States)

    Waterhouse, Jim

    2010-01-01

    Like all circadian (near-24-h) rhythms, those of cognition have endogenous and exogenous components. The origins of these components, together with effects of time awake upon cognitive performance, are described in subjects living conventionally (sleeping at night and active during the daytime). Based on these considerations, predictions can be made about changes that might be expected in the days after a time-zone transition and during night work. The relevant literature on these circumstances is then reviewed. The last section of the chapter deals with sleep-wake schedules where both regular and irregular sleeps are taken (anchor sleep). Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Light Rhythms in Architecture

    DEFF Research Database (Denmark)

    Bülow, Katja

    2013-01-01

    On one hand, urban lighting expresses itself in a complex visual environment made by the interplay by between many separate lighting schemes, as street lighting, shop lighting, luminous commercials etc. On the other, a noticeable order of patterns occurs, when lighting is observed as luminous...... formation and rhythm. When integrated into an architectural concept, electrical lighting non-intended for poetic composition has the ability to contribute to place, time, and function-telling aspects of places in urban contexts. Urban environments are information wise challenging to pre-historic human...... instincts, but they can be met by careful selection and adjustment of existing light situations....

  9. Light Rhythms in Architecture

    DEFF Research Database (Denmark)

    Bülow, Katja

    2013-01-01

    On one hand, urban lighting expresses itself in a complex visual environment made by the interplay by between many separate lighting schemes, as street lighting, shop lighting, luminous commercials etc. On the other, a noticeable order of patterns occurs, when lighting is observed as luminous...... formation and rhythm. When integrated into an architectural concept, electrical lighting non-intended for poetic composition has the ability to contribute to place, time, and function-telling aspects of places in urban contexts. Urban environments are information wise challenging to pre-historic human...... instincts, but they can be met by careful selection and adjustment of existing light situations....

  10. Circadian rhythms regulate amelogenesis.

    Science.gov (United States)

    Zheng, Li; Seon, Yoon Ji; Mourão, Marcio A; Schnell, Santiago; Kim, Doohak; Harada, Hidemitsu; Papagerakis, Silvana; Papagerakis, Petros

    2013-07-01

    Ameloblasts, the cells responsible for making enamel, modify their morphological features in response to specialized functions necessary for synchronized ameloblast differentiation and enamel formation. Secretory and maturation ameloblasts are characterized by the expression of stage-specific genes which follows strictly controlled repetitive patterns. Circadian rhythms are recognized as key regulators of the development and diseases of many tissues including bone. Our aim was to gain novel insights on the role of clock genes in enamel formation and to explore the potential links between circadian rhythms and amelogenesis. Our data shows definitive evidence that the main clock genes (Bmal1, Clock, Per1 and Per2) oscillate in ameloblasts at regular circadian (24 h) intervals both at RNA and protein levels. This study also reveals that the two markers of ameloblast differentiation i.e. amelogenin (Amelx; a marker of secretory stage ameloblasts) and kallikrein-related peptidase 4 (Klk4, a marker of maturation stage ameloblasts) are downstream targets of clock genes. Both, Amelx and Klk4 show 24h oscillatory expression patterns and their expression levels are up-regulated after Bmal1 over-expression in HAT-7 ameloblast cells. Taken together, these data suggest that both the secretory and the maturation stages of amelogenesis might be under circadian control. Changes in clock gene expression patterns might result in significant alterations of enamel apposition and mineralization.

  11. Biological rhythms and preeclampsia

    Directory of Open Access Journals (Sweden)

    Agnès eDitisheim

    2013-04-01

    Full Text Available The impact of impaired circadian rhythm on health has been widely studied in shift workers and trans-meridian travelers. A part from its correlation with sleep and mood disorders, biological rhythm impairment is a recognized risk factor for cardiovascular diseases and breast cancer.Preeclampsia is a major public health issue, associated with a significant maternal and fetal morbidity and mortality worldwide. While the risks factors for this condition such as obesity, diabetes, pre-existing hypertension have been identified, the underlying mechanism of this multi-factorial disease is yet not fully understood.The disruption of the light/dark cycle in pregnancy has been associated with adverse outcomes. Slightly increased risk for small for gestational age babies, low birth weight babies and preterm deliveries has been reported in shift working women. Whether altered circadian cycle represents a risk factor for preeclampsia or preeclampsia is itself linked with an abnormal circadian cycle is less clear. There are only few reports available, showing conflicting results. In this review, we will discuss recent observations concerning circadian pattern of blood pressure in normotensive and hypertensive pregnancies. We explore the hypothesis that circadian misalignments may represent a risk factor for preeclampsia. Unraveling potential link between circadian clock gene and preeclampsia could offer a novel approach to our understanding of this multi-system disease specific to pregnancy.

  12. Fast (mainly 30-100 Hz) oscillations in the cat cerebellothalamic pathway and their synchronization with cortical potentials.

    Science.gov (United States)

    Timofeev, I; Steriade, M

    1997-01-01

    1. Intracellular recordings from 216 thalamocortical (TC) neurones in the ventrolateral (VL) nucleus of intact-cortex and decorticated cats under ketamine-xylazine anaesthesia revealed spontaneously occurring fast oscillations (mainly 30-100 Hz) in 86% of investigated cells. The fast depolarizing events consisted of excitatory postsynaptic potentials (EPSPs), giving rise to fast prepotentials (FPPs) in 22% of neurones, which eventually lead to full-blown action potentials. The frequency of fast events changed by factors of 2-5 in periods as short as 0.3-1.0 s. 2. The spontaneous oscillations were similar to responses evoked in VL relay neurones by stimuli to the afferent cerebellofugal axons in brachium conjunctivum (BC) and were strikingly reduced or abolished after electrolytic lesion of BC axons. 3. The amplitude and duration of fast depolarizing events were significantly reduced during the descending phase of the inhibitory postsynaptic potentials (IPSPs) in TC cells, related to spontaneous spindles or evoked by local thalamic stimulation. 4. Averaged field potentials recorded from motor cortex and triggered by EPSPs and/or action potentials of intracellularly recorded VL cells demonstrated that both spontaneous and BC-evoked fast depolarizations in VL relay neurones were coherent with fast rhythms in cortical area 4. 5. These results show that, in addition to the thalamic and cortical generation sites of the fast (so-called gamma) oscillations, prethalamic relay stations, such as deep cerebellar nuclei, are major contributors to the induction of fast rhythms which depend on the depolarization of thalamic and cortical neurones and which represent a hallmark of brain activation patterns. PMID:9350626

  13. Motor Cortex Theta and Gamma Architecture in Young Adult APPswePS1dE9 Alzheimer Mice

    Science.gov (United States)

    Lundt, Andreas; Wormuth, Carola; Ginde, Varun Raj; Müller, Ralf; Henseler, Christina; Broich, Karl; Xie, Kan; Haenisch, Britta; Ehninger, Dan; Weiergräber, Marco

    2017-01-01

    Alzheimer’s disease (AD) is a multifactorial disorder leading to progressive memory loss and eventually death. In this study, an APPswePS1dE9 AD mouse model has been analyzed for motor cortex theta, beta and gamma frequency alterations using computerized 3D stereotaxic electrode positioning and implantable video-EEG radiotelemetry to perform long-term M1 recordings from both genders considering age, circadian rhythm and activity status of experimental animals. We previously demonstrated that APPswePS1dE9 mice exibit complex alterations in hippocampal frequency power and another recent investigation reported a global increase of alpha, beta and gamma power in APPswePS1dE9 in females of 16–17 weeks of age. In this cortical study in APPswePS1dE9 mice we did not observe any changes in theta, beta and particularly gamma power in both genders at the age of 14, 15, 18 and 19 weeks. Importantly, no activity dependence of theta, beta and gamma activity could be detected. These findings clearly point to the fact that EEG activity, particularly gamma power exhibits developmental changes and spatial distinctiveness in the APPswePS1dE9 mouse model of Alzheimer’s disease. PMID:28072877

  14. Dissipative structures and biological rhythms

    Science.gov (United States)

    Goldbeter, Albert

    2017-10-01

    Sustained oscillations abound in biological systems. They occur at all levels of biological organization over a wide range of periods, from a fraction of a second to years, and with a variety of underlying mechanisms. They control major physiological functions, and their dysfunction is associated with a variety of physiological disorders. The goal of this review is (i) to give an overview of the main rhythms observed at the cellular and supracellular levels, (ii) to briefly describe how the study of biological rhythms unfolded in the course of time, in parallel with studies on chemical oscillations, (iii) to present the major roles of biological rhythms in the control of physiological functions, and (iv) the pathologies associated with the alteration, disappearance, or spurious occurrence of biological rhythms. Two tables present the main examples of cellular and supracellular rhythms ordered according to their period, and their role in physiology and pathophysiology. Among the rhythms discussed are neural and cardiac rhythms, metabolic oscillations such as those occurring in glycolysis in yeast, intracellular Ca++ oscillations, cyclic AMP oscillations in Dictyostelium amoebae, the segmentation clock that controls somitogenesis, pulsatile hormone secretion, circadian rhythms which occur in all eukaryotes and some bacteria with a period close to 24 h, the oscillatory dynamics of the enzymatic network driving the cell cycle, and oscillations in transcription factors such as NF-ΚB and tumor suppressors such as p53. Ilya Prigogine's concept of dissipative structures applies to temporal oscillations and allows us to unify within a common framework the various rhythms observed at different levels of biological organization, regardless of their period and underlying mechanism.

  15. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased visual ...

  16. Biophysical Modeling of Alpha Rhythms During Halothane-Induced Unconsciousness.

    Science.gov (United States)

    Vijayan, Sujith; Ching, ShiNung; Purdon, Patrick L; Brown, Emery N; Kopell, Nancy J

    2013-01-01

    During the induction of general anesthesia there is a shift in power from the posterior regions of the brain to the frontal cortices; this shift in power is called anteriorization. For many anesthetics, a prominent feature of anteriorization is a shift specifically in the alpha band (8-13 Hz) from posterior to frontal cortices. Here we present a biophysical computational model that describes thalamocortical circuit-level dynamics underlying anteriorization of the alpha rhythm in the case of halothane. Halothane potentiates GABAA and increases potassium leak conductances. According to our model, an increase in potassium leak conductances hyperpolarizes and silences the high-threshold thalamocortical (HTC) cells, a specialized subset of thalamocortical cells that fire at the alpha frequency at relatively depolarized membrane potentials (>-60 mV) and are thought to be the generators of quiet awake occipital alpha. At the same time the potentiation of GABAA imposes an alpha time scale on both the cortical and the thalamic component of the frontal portion of our model. The alpha activity in the frontal component is further strengthened by reciprocal thalamocortical feedback. Thus, we argue that the dual molecular targets of halothane induce the anteriorization of the alpha rhythm by increasing potassium leak conductances, which abolishes occipital alpha, and by potentiating GABAA, which induces frontal alpha. These results provide a computational modeling formulation for studying highly detailed biophysical mechanisms of anesthetic action in silico.

  17. Stress Assessment by Prefrontal Relative Gamma

    Science.gov (United States)

    Minguillon, Jesus; Lopez-Gordo, Miguel A.; Pelayo, Francisco

    2016-01-01

    Stress assessment has been under study in the last years. Both biochemical and physiological markers have been used to measure stress level. In neuroscience, several studies have related modification of stress level to brain activity changes in limbic system and frontal regions, by using non-invasive techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). In particular, previous studies suggested that the exhibition or inhibition of certain brain rhythms in frontal cortical areas indicates stress. However, there is no established marker to measure stress level by EEG. In this work, we aimed to prove the usefulness of the prefrontal relative gamma power (RG) for stress assessment. We conducted a study based on stress and relaxation periods. Six healthy subjects performed the Montreal Imaging Stress Task (MIST) followed by a stay within a relaxation room while EEG and electrocardiographic signals were recorded. Our results showed that the prefrontal RG correlated with the expected stress level and with the heart rate (HR; 0.8). In addition, the difference in prefrontal RG between time periods of different stress level was statistically significant (p < 0.01). Moreover, the RG was more discriminative between stress levels than alpha asymmetry, theta, alpha, beta, and gamma power in prefrontal cortex. We propose the prefrontal RG as a marker for stress assessment. Compared with other established markers such as the HR or the cortisol, it has higher temporal resolution. Additionally, it needs few electrodes located at non-hairy head positions, thus facilitating the use of non-invasive dry wearable real-time devices for ubiquitous assessment of stress. PMID:27713698

  18. Effect of melatonin on endogenous circadian rhythm

    Institute of Scientific and Technical Information of China (English)

    XU Feng; WANG Min; ZANG Ling-he

    2008-01-01

    Objective To further authenticate the role of melatonin on endogenous biologic clock system. Methods Pinealectomized mice were used in the experiments, a series of circadian rhythm of physiology index, such as glucocorticoid, amino acid neurotransmitter, immune function, sensitivity of algesia and body temperature were measured. Results Effects of melatonin on endogenous circadian rhythm roughly appeared four forms: 1) The model of inherent rhythm was invariant, but midvalue was removed. 2) Pacing function: pinealectomy and melatonin administration changed amplitude of the circadian vibration of aspartate, peripheral blood WBC and serum hemolysin. 3) Phase of rhythm changed, such as the effects on percentage of lymphocyte and sensitivity of algesia. 4) No effect, the circadian rhythm of body temperature belong to this form Conclusions Melatonin has effects some circadian rhythm, and it can adjust endogenous inherent rhythm and make the rhythm keep step with environmental cycle. Melatonin may be a kind of Zeitgeber, Pineal gland might being a rhythm bearing organ to some circadian rhythm.

  19. [Circadian rhythm in myocardial infarct].

    Science.gov (United States)

    Enciso, R; Ramos, M A; Badui, E; Hurtado, R

    1988-01-01

    In order to determine if the beginning of the Myocardial Infarction (MI) is at random along the day or if it follows a circadian rhythm, we analyzed the clinical charts of 819 patients admitted to the Coronary Care Unite. Among them, 645 were male and 174 female. It was established that the beginning of the MI follows a circadian rhythm with maximal frequency between 8 and 9 a.m. and minimal at 0 hours (p greater than 0.01). This rhythm is sex independent. In patients younger than 45 years as well as those who received beta-block agents in less than 24 hours previous the MI no circadian rhythm was observed.

  20. Substances and Heart Rhythm Disorders

    Science.gov (United States)

    ... drink coffee or tea or eat chocolate. Red wine and eating too much can bring about symptoms ... Rhythm Society 2017 Privacy Policy | Linking Policy | Patient Education Disclaimer You are about to exit the Heart ...

  1. Circadian Rhythm Management System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The value of measuring sleep-wake cycles is significantly enhanced by measuring other physiological signals that depend on circadian rhythms (such as heart rate and...

  2. Cortical Neural Computation by Discrete Results Hypothesis

    Science.gov (United States)

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  3. Biological rhythms and vector insects

    Directory of Open Access Journals (Sweden)

    Mirian David Marques

    2013-01-01

    Full Text Available The adjustment of all species, animals and plants, to the Earth’s cyclic environments is ensured by their temporal organisation. The relationships between parasites, vectors and hosts rely greatly upon the synchronisation of their biological rhythms, especially circadian rhythms. In this short note, parasitic infections by Protozoa and by microfilariae have been chosen as examples of the dependence of successful transmission mechanisms on temporal components.

  4. Gamma Oscillations and Visual Binding

    Science.gov (United States)

    Robinson, Peter A.; Kim, Jong Won

    2006-03-01

    At the root of visual perception is the mechanism the brain uses to analyze features in a scene and bind related ones together. Experiments show this process is linked to oscillations of brain activity in the 30-100 Hz gamma band. Oscillations at different sites have correlation functions (CFs) that often peak at zero lag, implying simultaneous firing, even when conduction delays are large. CFs are strongest between cells stimulated by related features. Gamma oscillations are studied here by modeling mm-scale patchy interconnections in the visual cortex. Resulting predictions for gamma responses to stimuli account for numerous experimental findings, including why oscillations and zero-lag synchrony are associated, observed connections with feature preferences, the shape of the zero-lag peak, and variations of CFs with attention. Gamma waves are found to obey the Schroedinger equation, opening the possibility of cortical analogs of quantum phenomena. Gamma instabilities are tied to observations of gamma activity linked to seizures and hallucinations.

  5. Endogenous rhythms influence interpersonal synchrony.

    Science.gov (United States)

    Zamm, Anna; Wellman, Chelsea; Palmer, Caroline

    2016-05-01

    Interpersonal synchrony, the temporal coordination of actions between individuals, is fundamental to social behaviors from conversational speech to dance and music-making. Animal models indicate constraints on synchrony that arise from endogenous rhythms: Intrinsic periodic behaviors or processes that continue in the absence of change in external stimulus conditions. We report evidence for a direct causal link between endogenous rhythms and interpersonal synchrony in a music performance task, which places high demands on temporal coordination. We first establish that endogenous rhythms, measured by spontaneous rates of individual performance, are stable within individuals across stimulus materials, limb movements, and time points. We then test a causal link between endogenous rhythms and interpersonal synchrony by pairing each musician with a partner who is either matched or mismatched in spontaneous rate and by measuring their joint behavior up to 1 year later. Partners performed melodies together, using either the same or different hands. Partners who were matched for spontaneous rate showed greater interpersonal synchrony in joint performance than mismatched partners, regardless of hand used. Endogenous rhythms offer potential to predict optimal group membership in joint behaviors that require temporal coordination.

  6. Modeling analysis of the relationship between EEG rhythms and connectivity among different neural populations.

    Science.gov (United States)

    Ursino, Mauro; Zavaglia, Melissa

    2007-12-01

    In our research, a neural mass model consisting of four interconnected neural groups (pyramidal neurons, excitatory interneurons, inhibitory interneurons with slow synaptic kinetics, and inhibitory interneurons with fast synaptic kinetics) is used to investigate the mechanisms which cause the appearance of multiple rhythms in EEG spectra, and to assess how these rhythms can be affected by connectivity among different populations. First, we showed that a single neural population, stimulated with white noise, can oscillate with its intrinsic rhythm, and that the position of this rhythm can be finely tuned (in the alpha, beta or gamma frequency ranges), acting on the population synaptic kinetics. Subsequently, we analyzed more complex circuits, composed of two or three interconnected populations, each with a different synaptic kinetics between neural groups within a population (hence, with a different intrinsic rhythm). The results demonstrates apex that a single population can exhibit many different simultaneous rhythms, provided that some of these come from external sources (for instance, from remote regions). The analysis of coherence, and of the position of the peaks in power spectral density, reveals important information on the possible connections among populations, and is especially useful to follow temporal changes in connectivity. In perspective, the results may be of value for a deeper comprehension of the mechanisms causing EEGs rhythms, for the study of connectivity among different neural populations and for the test of neurophysiological hypotheses.

  7. Comparison of English Language Rhythm and Kalhori Kurdish Language Rhythm

    Directory of Open Access Journals (Sweden)

    Nafiseh Taghva

    2016-04-01

    Full Text Available Investigating on quantitative features of languages rhythm is a recent issue that attracts the attention of linguists. Interval-based method is a method of studying the rhythmic quantitative features of languages. This method use Pairwise Variability Index (PVI to consider the variability of vocalic duration and inter-vocalic duration of sentences which leads to classification of languages rhythm into stress-timed languages and syllable-timed ones. This study aims to consider the rhythm of British English and Kalhori Kurdish, which is spoken in some part of west of Iran, based on interval-based method. In order to reach this aim the duration variability of vocalic interval and inter-vocalic interval of English and Kalhori Kurdish are measured by PVI. Afterward the outcomes of this study were compared to the existed results of other languages. The results of this research demonstrated that the rhythmic quantitative features of these two languages are placed among stress-timed languages.   Keywords: Rhythm, interval-based method, syllable-timed, stress-timed

  8. Mu and beta rhythm topographies during motor imagery and actual movements.

    Science.gov (United States)

    McFarland, D J; Miner, L A; Vaughan, T M; Wolpaw, J R

    2000-01-01

    People can learn to control the 8-12 Hz mu rhythm and/or the 18-25 Hz beta rhythm in the EEG recorded over sensorimotor cortex and use it to control a cursor on a video screen. Subjects often report using motor imagery to control cursor movement, particularly early in training. We compared in untrained subjects the EEG topographies associated with actual hand movement to those associated with imagined hand movement. Sixty-four EEG channels were recorded while each of 33 adults moved left- or right-hand or imagined doing so. Frequency-specific differences between movement or imagery and rest, and between right- and left-hand movement or imagery, were evaluated by scalp topographies of voltage and r spectra, and principal component analysis. Both movement and imagery were associated with mu and beta rhythm desynchronization. The mu topographies showed bilateral foci of desynchronization over sensorimotor cortices, while the beta topographies showed peak desynchronization over the vertex. Both mu and beta rhythm left/right differences showed bilateral central foci that were stronger on the right side. The independence of mu and beta rhythms was demonstrated by differences for movement and imagery for the subjects as a group and by principal components analysis. The results indicated that the effects of imagery were not simply an attenuated version of the effects of movement. They supply evidence that motor imagery could play an important role in EEG-based communication, and suggest that mu and beta rhythms might provide independent control signals.

  9. Ultradian rhythms in walking gastric activity.

    Science.gov (United States)

    Hiatt, J F; Kripke, D F

    1975-01-01

    Ninety to 120 min ultradian rhythms have been described in physiologic and behavioral functions relating to biologic drives. Gastric contractility rhythms were examined in isolated fasting volunteers to supplement behavioral observations of "oral" drives. A clear ultradian rhythms was observed, indicating inherent physiologic oscillation in stomach contractions.

  10. Circadian rhythms in microalgae production

    NARCIS (Netherlands)

    Winter, de L.

    2015-01-01

    Abstract Thesis: Circadian rhythms in microalgae production Lenneke de Winter The sun imposes a daily cycle of light and dark on nearly all organisms. The circadian clock evolved to help organisms program their activities at an appropriate time during this daily cycle. For example,

  11. ADHD, circadian rhythms and seasonality

    NARCIS (Netherlands)

    Wynchank, Dora S.; Bijlenga, Denise; Lamers, Femke; Bron, Tannetje I.; Winthorst, Wim H.; Vogel, Suzan W.; Penninx, Brenda W.; Beekman, Aartjan T.; Kooij, J. Sandra

    2016-01-01

    Objective: We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm. Method: Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups we

  12. ADHD, circadian rhythms and seasonality

    NARCIS (Netherlands)

    Wynchank, Dora S.; Bijlenga, Denise; Lamers, Femke; Bron, Tannetje I.; Winthorst, Wim H.; Vogel, Suzan W.; Penninx, Brenda W.; Beekman, Aartjan T.; Kooij, J. Sandra

    2016-01-01

    Objective: We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm. Method: Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups we

  13. ADHD, circadian rhythms and seasonality

    NARCIS (Netherlands)

    Wynchank, Dora S.; Bijlenga, Denise; Lamers, Femke; Bron, Tannetje I.; Winthorst, Wim H.; Vogel, Suzan W.; Penninx, Brenda W.; Beekman, Aartjan T.; Kooij, J. Sandra

    2016-01-01

    Objective: We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm. Method: Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups

  14. Circadian rhythms in microalgae production

    NARCIS (Netherlands)

    Winter, de L.

    2015-01-01

    Abstract Thesis: Circadian rhythms in microalgae production Lenneke de Winter The sun imposes a daily cycle of light and dark on nearly all organisms. The circadian clock evolved to help organisms program their activities at an appropriate time during this daily cycle. For example,

  15. PHASE INTERACTION BETWEEN EEG RHYTHMS IN THE STUDY OF PROCESSES OF TIME PERCEPTION

    Directory of Open Access Journals (Sweden)

    Yu. V. Bushov

    2014-01-01

    Full Text Available The present study pursued to investigate the role of phase interactions between EEG rhythms in the process of the perception of time. The purpose of the study was to analyse the dependence of these interactions on the type and stage of the activity being performed, as well as on the individual characteristics of a human. For this purpose, 27 boys and 29 girls, all university students, were asked to reproduce and measure short intervals of time (200 and 800 ms, during which their EEG was recorded in frontal, central, parietal, temporal, and occipital lobes, according to the system 10–20%. While studying phase interactions between EEG rhythms, we used wavelet bispectral analysis and calculated the bicoherence function. As it follows from the conducted research, most often close phase interactions are observed between the gamma-rhythm and other rhythms of EEG or between different frequencies of the gamma-rhythm. It was established that the phase interactions under study were influenced by the factors of “sex”, “activity type”, and “activity stage”. The study showed correlations of phase interactions with the levels of intellect, extraversion, neuroticism, with the particularities of the lateral organisation of brain, and the accuracy of time perception.

  16. Increased gamma- and decreased delta-oscillations in a mouse deficient for a potassium channel expressed in fast-spiking interneurons.

    Science.gov (United States)

    Joho, R H; Ho, C S; Marks, G A

    1999-10-01

    Kv3.1 is a voltage-gated, fast activating/deactivating potassium (K(+)) channel with a high-threshold of activation and a large unit conductance. Kv3.1 K(+) channels are expressed in fast-spiking, parvalbumin-containing interneurons in cortex, hippocampus, striatum, the thalamic reticular nucleus (TRN), and in several nuclei of the brain stem. A high density of Kv3.1 channels contributes to short-duration action potentials, fast afterhyperpolarizations, and brief refractory periods enhancing the capability in these neurons for high-frequency firing. Kv3.1 K(+) channel expression in the TRN and cortex also suggests a role in thalamocortical and cortical function. Here we show that fast gamma and slow delta oscillations recorded from the somatomotor cortex are altered in the freely behaving Kv3.1 mutant mouse. Electroencephalographic (EEG) recordings from homozygous Kv3.1(-/-) mice show a three- to fourfold increase in both absolute and relative spectral power in the gamma frequency range (20-60 Hz). In contrast, Kv3.1-deficient mice have a 20-50% reduction of power in the slow delta range (2-3 Hz). The increase in gamma power is most prominent during waking in the 40- to 55-Hz range, whereas the decrease in delta power occurs equally across all states of arousal. Our findings suggest that Kv3. 1-expressing neurons are involved in the generation and maintenance of cortical fast gamma and slow delta oscillations. Hence the Kv3. 1-mutant mouse could serve as a model to study the generation and maintenance of fast gamma and slow delta rhythms and their involvement in behavior and cognition.

  17. How Two Players Negotiate Rhythm in a Shared Rhythm Game

    DEFF Research Database (Denmark)

    Hansen, Anne-Marie; Andersen, Hans Jørgen; Raudaskoski, Pirkko Liisa

    2012-01-01

    In a design and working prototype of a shared music interface eleven teams of two people were to collaborate about filling in holes with tones and beats in an evolving ground rhythm. The hypothesis was that users would tune into each other and have sections of characteristic rhythmical relationsh......In a design and working prototype of a shared music interface eleven teams of two people were to collaborate about filling in holes with tones and beats in an evolving ground rhythm. The hypothesis was that users would tune into each other and have sections of characteristic rhythmical...... from each other. Video analysis of user interaction shines light upon how users engaged in a rhythmical relationship, and interviews give information about the user experience in terms of the game play and user collaboration. Based on the findings in this paper we propose design guidelines...... for collaborative rhythmical game play....

  18. Rhythm sequence through the olfactory bulb layers during the time window of a respiratory cycle.

    Science.gov (United States)

    Buonviso, Nathalie; Amat, Corine; Litaudon, Philippe; Roux, Stephane; Royet, Jean-Pierre; Farget, Vincent; Sicard, Gilles

    2003-05-01

    The mammalian olfactory bulb is characterized by prominent oscillatory activity of its local field potentials. Breathing imposes the most important rhythm. Other rhythms have been described in the beta- and gamma-frequency ranges. We recorded unitary activities in different bulbar layers simultaneously with local field potentials in order to examine the different relationships existing between (i) breathing and field potential oscillations, and (ii) breathing and spiking activity of different cell types. We show that, whatever the layer, odour-induced gamma oscillations always occur around the transition point between inhalation and exhalation while beta oscillations appear during early exhalation and may extend up to the end of inhalation. By contrast, unitary activities exhibit different characteristics according to the layer. They vary in (i) their temporal relationship with respect to the respiratory cycle; (ii) their spike rates; (iii) their temporal patterns defined according to the respiratory cycle. The time window of a respiratory cycle might thus be split into three main epochs based on the deceleration of field potential rhythms (from gamma to beta oscillations) and a simultaneous gradient of spike discharge frequencies ranging from 180 to 30 Hz. We discuss the possibility that each rhythm could serve different functions as priming, gating or tuning for the bulbar network.

  19. Cortical control of anticipatory postural adjustments prior to stepping.

    Science.gov (United States)

    Varghese, J P; Merino, D M; Beyer, K B; McIlroy, W E

    2016-01-28

    Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. This study also examined whether the preparatory cortical activations related to a specific movement is dependent on the context of control (postural component vs. focal component). Ground reaction forces and electroencephalographic (EEG) data were recorded from 14 healthy adults while they performed lateral weight shift and lateral stepping with and without initially preloading their weight to the stance leg. EEG analysis revealed that there were distinct movement-related potentials (MRPs) with concurrent event-related desynchronization (ERD) of mu and beta rhythms prior to the onset of APA and also to the onset of foot-off during lateral stepping in the fronto-central cortical areas. Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.

  20. Cortical Brain Connectivity and B-Type Natriuretic Peptide in Patients With Congestive Heart Failure.

    Science.gov (United States)

    Vecchio, Fabrizio; Miraglia, Francesca; Valeriani, Lavinia; Scarpellini, Maria Gabriella; Bramanti, Placido; Mecarelli, Oriano; Rossini, Paolo M

    2015-07-01

    The brain has a high level of complexity and needs continuous oxygen supply. So it is clear that any pathological condition, or physiological (aging) change, in the cardiovascular system affects functioning of the central nervous system. We evaluated linear aspects of the relationship between the slowness of cortical rhythms, as revealed by the modulation of a graph connectivity parameter, and congestive heart failure (CHF), as a reflection of neurodegenerative processes. Eyes-closed resting electroencephalographic (EEG) data of 10 patients with CHF were recorded by 19 electrodes positioned according the international 10-20 system. Graph theory function (normalized characteristic path length λ) was applied to the undirected and weighted networks obtained by lagged linear coherence evaluated by eLORETA software, therefore getting rid of volumetric propagation influences. The EEG frequency bands of interest were: delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), beta 2 (20-30 Hz), and gamma (30-40 Hz). The analysis between B-type natriuretic peptide (BNP) values and λ showed positive correlation in delta, associated with a negative correlation in alpha 2 band. Namely, the higher the severity of the disease (as revealed by the BNP vales), the higher the λ in delta, and lower in alpha 2 band. Results suggest that delta and alpha λ indices are good markers of the severity of CHF.

  1. Oscillatory Hierarchy Controlling Cortical Excitability and Stimulus Integration

    Science.gov (United States)

    Shah, A. S.; Lakatos, P.; McGinnis, T.; O'Connell, N.; Mills, A.; Knuth, K. H.; Chen, C.; Karmos, G.; Schroeder, C. E.

    2004-01-01

    Cortical gamma band oscillations have been recorded in sensory cortices of cats and monkeys, and are thought to aid in perceptual binding. Gamma activity has also been recorded in the rat hippocampus and entorhinal cortex, where it has been shown, that field gamma power is modulated at theta frequency. Since the power of gamma activity in the sensory cortices is not constant (gamma-bursts). we decided to examine the relationship between gamma power and the phase of low frequency oscillation in the auditory cortex of the awake macaque. Macaque monkeys were surgically prepared for chronic awake electrophysiological recording. During the time of the experiments. linear array multielectrodes were inserted in area AI to obtain laminar current source density (CSD) and multiunit activity profiles. Instantaneous theta and gamma power and phase was extracted by applying the Morlet wavelet transformation to the CSD. Gamma power was averaged for every 1 degree of low frequency oscillations to calculate power-phase relation. Both gamma and theta-delta power are largest in the supragranular layers. Power modulation of gamma activity is phase locked to spontaneous, as well as stimulus-related local theta and delta field oscillations. Our analysis also revealed that the power of theta oscillations is always largest at a certain phase of delta oscillation. Auditory stimuli produce evoked responses in the theta band (Le., there is pre- to post-stimulus addition of theta power), but there is also indication that stimuli may cause partial phase re-setting of spontaneous delta (and thus also theta and gamma) oscillations. We also show that spontaneous oscillations might play a role in the processing of incoming sensory signals by 'preparing' the cortex.

  2. Circadian Rhythm Control: Neurophysiological Investigations

    Science.gov (United States)

    Glotzbach, S. F.

    1985-01-01

    The suprachiasmatic nucleus (SCN) was implicated as a primary component in central nervous system mechanisms governing circadian rhythms. Disruption of the normal synchronization of temperature, activity, and other rhythms is detrimental to health. Sleep wake disorders, decreases in vigilance and performance, and certain affective disorders may result from or be exacerbated by such desynchronization. To study the basic neurophysiological mechanisms involved in entrainment of circadian systems by the environment, Parylene-coated, etched microwire electrode bundles were used to record extracellular action potentials from the small somata of the SCN and neighboring hypothalamic nuclei in unanesthetized, behaving animals. Male Wistar rats were anesthetized and chronically prepared with EEG ane EMG electrodes in addition to a moveable microdrive assembly. The majority of cells had firing rates 10 Hz and distinct populations of cells which had either the highest firing rate or lowest firing rate during sleep were seen.

  3. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  4. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  5. Egg-laying rhythm in Drosophila melanogaster

    Indian Academy of Sciences (India)

    T. Manjunatha; Shantala Hari Dass; Vijay Kumar Sharma

    2008-12-01

    Extensive research has been carried out to understand how circadian clocks regulate various physiological processes in organisms. The discovery of clock genes and the molecular clockwork has helped researchers to understand the possible role of these genes in regulating various metabolic processes. In Drosophila melanogaster, many studies have shown that the basic architecture of circadian clocks is multi-oscillatory. In nature, different neuronal subgroups in the brain of D. melanogaster have been demonstrated to control different circadian behavioural rhythms or different aspects of the same circadian rhythm. Among the circadian phenomena that have been studied so far in Drosophila, the egg-laying rhythm is unique, and relatively less explored. Unlike most other circadian rhythms, the egg-laying rhythm is rhythmic under constant light conditions, and the endogenous or free-running period of the rhythm is greater than those of most other rhythms. Although the clock genes and neurons required for the persistence of adult emergence and activity/rest rhythms have been studied extensively, those underlying the circadian egg-laying rhythm still remain largely unknown. In this review, we discuss our current understanding of the circadian egg-laying rhythm in D. melanogaster, and the possible molecular and physiological mechanisms that control the rhythmic output of the egg-laying process.

  6. Learning alters theta amplitude, theta-gamma coupling and neuronal synchronization in inferotemporal cortex

    Directory of Open Access Journals (Sweden)

    Nicol Alister U

    2011-06-01

    Full Text Available Abstract Background How oscillatory brain rhythms alone, or in combination, influence cortical information processing to support learning has yet to be fully established. Local field potential and multi-unit neuronal activity recordings were made from 64-electrode arrays in the inferotemporal cortex of conscious sheep during and after visual discrimination learning of face or object pairs. A neural network model has been developed to simulate and aid functional interpretation of learning-evoked changes. Results Following learning the amplitude of theta (4-8 Hz, but not gamma (30-70 Hz oscillations was increased, as was the ratio of theta to gamma. Over 75% of electrodes showed significant coupling between theta phase and gamma amplitude (theta-nested gamma. The strength of this coupling was also increased following learning and this was not simply a consequence of increased theta amplitude. Actual discrimination performance was significantly correlated with theta and theta-gamma coupling changes. Neuronal activity was phase-locked with theta but learning had no effect on firing rates or the magnitude or latencies of visual evoked potentials during stimuli. The neural network model developed showed that a combination of fast and slow inhibitory interneurons could generate theta-nested gamma. By increasing N-methyl-D-aspartate receptor sensitivity in the model similar changes were produced as in inferotemporal cortex after learning. The model showed that these changes could potentiate the firing of downstream neurons by a temporal desynchronization of excitatory neuron output without increasing the firing frequencies of the latter. This desynchronization effect was confirmed in IT neuronal activity following learning and its magnitude was correlated with discrimination performance. Conclusions Face discrimination learning produces significant increases in both theta amplitude and the strength of theta-gamma coupling in the inferotemporal cortex

  7. Investigating the role of alpha and beta rhythms in functional motor networks.

    Science.gov (United States)

    Athanasiou, Alkinoos; Klados, Manousos A; Styliadis, Charis; Foroglou, Nicolas; Polyzoidis, Konstantinos; Bamidis, Panagiotis D

    2016-05-27

    It is recognized that lower electroencephalography (EEG) frequencies correspond to distributed brain activity over larger spatial regions than higher frequencies and are associated with coordination. In motor processes it has been suggested that this is not always the case. Our objective was to explore this contradiction. In our study, seven healthy subjects performed four motor tasks (execution and imagery of right hand and foot) under EEG recording. Two cortical source models were defined, model «A» with 16 regions of interest (ROIs) and model «B» with 20 ROIs over the sensorimotor cortex. Functional connectivity was calculated by Directed Transfer Function for alpha and beta rhythm networks. Four graph properties were calculated for each network: characteristic path length (CPL), clustering coefficient (CC), density (D) and small-world-ness (SW). Different network modules and in-degrees of nodes were also calculated and depicted in connectivity maps. Analysis of variance was used to determine statistical significance of observed differences in the network properties between tasks, between rhythms and between ROI models. Consistently on both models, CPL and CC were lower and D was higher in beta rhythm networks. No statistically significant difference was observed for SW between rhythms or for any property between tasks on any model. Comparing the models we observed lower CPL for both rhythms, lower CC in alpha and higher CC in beta when the number of ROIs increased. Also, denser networks with higher SW were correlated with higher number of ROIs. We propose a non-exclusive model where alpha rhythm uses greater wiring costs to engage in local information progression while beta rhythm coordinates the neurophysiological processes in sensorimotor tasks. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Reduced GABAergic inhibition explains cortical hyperexcitability in the wobbler mouse model of ALS

    DEFF Research Database (Denmark)

    Nieto-Gonzalez, Jose Luis; Moser, Jakob; Lauritzen, Martin

    2011-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of the central nervous system. Symptomatic and presymptomatic ALS patients demonstrate cortical hyperexcitability, which raises the possibility that alterations in inhibitory gamma-aminobutyric acid (GABA)ergic system could...

  9. [Specificity of spatial organization of evoked EEG rhythms in patients with paranoid schizophrenia].

    Science.gov (United States)

    Bochkarev, V K; Kirenskaya, A V; Solnceva, S V; Tkachenko, A A

    The study aimed at analyzing the spatial patterns of evoked event-related oscillations in patients with paranoid schizophrenia and their relationship with clinical symptoms of disease. Evoked delta, theta, alpha, beta, and gamma rhythms in response to target auditory stimulus in an oddball paradigm were studied in 21 schizophrenic patients and 22 healthy subjects. The independent spatial patterns were revealed within each of the frequency range using the principal component analysis. Each spatial pattern was characterized by the specificity of intra- and inter-hemispheric relations. The schizophrenic patients were characterized by a decrease in the evoked activity in the theta range with the most pronounced changes in the frontal-central areas of the right hemisphere and parietal-occipital areas bilaterally. Associations of the evoked rhythms with PANSS positive and negative symptoms were identified. The study demonstrated the high functional significance of evoked EEG rhythms changes for neurophysiological characteristics of patients with paranoid schizophrenia.

  10. Acquisition of speech rhythm in first language.

    Science.gov (United States)

    Polyanskaya, Leona; Ordin, Mikhail

    2015-09-01

    Analysis of English rhythm in speech produced by children and adults revealed that speech rhythm becomes increasingly more stress-timed as language acquisition progresses. Children reach the adult-like target by 11 to 12 years. The employed speech elicitation paradigm ensured that the sentences produced by adults and children at different ages were comparable in terms of lexical content, segmental composition, and phonotactic complexity. Detected differences between child and adult rhythm and between rhythm in child speech at various ages cannot be attributed to acquisition of phonotactic language features or vocabulary, and indicate the development of language-specific phonetic timing in the course of acquisition.

  11. Human gamma oscillations during slow wave sleep.

    Directory of Open Access Journals (Sweden)

    Mario Valderrama

    Full Text Available Neocortical local field potentials have shown that gamma oscillations occur spontaneously during slow-wave sleep (SWS. At the macroscopic EEG level in the human brain, no evidences were reported so far. In this study, by using simultaneous scalp and intracranial EEG recordings in 20 epileptic subjects, we examined gamma oscillations in cerebral cortex during SWS. We report that gamma oscillations in low (30-50 Hz and high (60-120 Hz frequency bands recurrently emerged in all investigated regions and their amplitudes coincided with specific phases of the cortical slow wave. In most of the cases, multiple oscillatory bursts in different frequency bands from 30 to 120 Hz were correlated with positive peaks of scalp slow waves ("IN-phase" pattern, confirming previous animal findings. In addition, we report another gamma pattern that appears preferentially during the negative phase of the slow wave ("ANTI-phase" pattern. This new pattern presented dominant peaks in the high gamma range and was preferentially expressed in the temporal cortex. Finally, we found that the spatial coherence between cortical sites exhibiting gamma activities was local and fell off quickly when computed between distant sites. Overall, these results provide the first human evidences that gamma oscillations can be observed in macroscopic EEG recordings during sleep. They support the concept that these high-frequency activities might be associated with phasic increases of neural activity during slow oscillations. Such patterned activity in the sleeping brain could play a role in off-line processing of cortical networks.

  12. Learning by joining the rhythm

    DEFF Research Database (Denmark)

    Lund, Ole; Ravn, Susanne; Christensen, Mette Krogh

    2012-01-01

    This article aims to explore how a joint rhythm is learned. The exploration is based on a combination of a case study of training in elite rowing and theoretical considerations concerning mutual incorporation of skills in learning. In 2009 Juliane and Anne start to row the double sculler together...... and mutually affecting process rather than as unidirectional exchanges of information. This means that not only the inexperienced athlete is learning: the experienced athlete is also learning by compensating for the inexperienced athlete’s inadequacy....

  13. Gamma Knife

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Gamma Knife Gamma Knife® is a radiation therapy that uses computerized treatment planning software to help ... sparing surrounding tissue. If you're scheduled for radiation therapy using Gamma Knife®, a treatment team consisting of a radiation ...

  14. Gamma Knife

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Gamma Knife Gamma Knife® is a radiation therapy that uses computerized treatment ... If you're scheduled for radiation therapy using Gamma Knife®, a treatment team consisting of a radiation oncologist, ...

  15. Rhythms essential to logical communication

    Science.gov (United States)

    Myers, John M.; Madjid, F. Hadi

    2011-05-01

    In the context of quantum theory, recently we distinguished mathematics for expressing evidence from mathematics for explaining evidence. Here this distinction is made in spacetime physics. We offer a system of mathematical thought-or as termed in geodesy a reference system-for evidence, separated out from additional assumptions of a geometry in terms of which to explain that evidence. The offered reference system for evidence, free of any assumption of a particular explanatory geometry, whether Euclidean or general relativistic, amounts to a (theoretical) "assemblage of histories accumulated in the memories of parties to a synchronous communications network." The assemblage of histories gives voice to the known experimental finding, sometimes forgotten by theorists, that any memory device for recording logical symbols must be insensitive to variations in signals in which those symbols are carried. Out of acknowledging this insensitivity comes an appreciation of rhythms essential to the communication of digital symbols and of the need for analog measurements to maintain these rhythms. The separate reference system for evidence reconciles what otherwise is a conflict between the demand in quantum mechanics for repeatable experiments and the lack in spacetime metrics appropriate to the Global Positioning System of any exact symmetry, a lack that rules out an isometry between two spacetime regions for two occurrences of an experiment.

  16. Detecting and Correcting Speech Rhythm Errors

    Science.gov (United States)

    Yurtbasi, Metin

    2015-01-01

    Every language has its own rhythm. Unlike many other languages in the world, English depends on the correct pronunciation of stressed and unstressed or weakened syllables recurring in the same phrase or sentence. Mastering the rhythm of English makes speaking more effective. Experiments have shown that we tend to hear speech as more rhythmical…

  17. Development of cortisol circadian rhythm in infancy.

    NARCIS (Netherlands)

    Weerth, C. de; Zijl, R.H.

    2003-01-01

    BACKGROUND AND AIMS: Cortisol is the final product of the hypothalamus-pituitary-adrenal (HPA) axis. It is secreted in a pulsatile fashion that displays a circadian rhythm. Infants are born without a circadian rhythm in cortisol and they acquire it during their first year of life. Studies do not agr

  18. The Incarnate Rhythm of Geometrical Knowing

    Science.gov (United States)

    Bautista, Alfredo; Roth, Wolff-Michael

    2012-01-01

    Rhythm is a fundamental dimension of human nature at both biological and social levels. However, existing research literature has not sufficiently investigated its role in mathematical cognition and behavior. The purpose of this article is to bring the concept of "incarnate rhythm" into current discourses in the field of mathematical learning and…

  19. Quantifying Speech Rhythm Abnormalities in the Dysarthrias

    Science.gov (United States)

    Liss, Julie M.; White, Laurence; Mattys, Sven L.; Lansford, Kaitlin; Lotto, Andrew J.; Spitzer, Stephanie M.; Caviness, John N.

    2009-01-01

    Purpose: In this study, the authors examined whether rhythm metrics capable of distinguishing languages with high and low temporal stress contrast also can distinguish among control and dysarthric speakers of American English with perceptually distinct rhythm patterns. Methods: Acoustic measures of vocalic and consonantal segment durations were…

  20. Analysis of Handwriting based on Rhythm Perception

    Science.gov (United States)

    Saito, Kazuya; Uchida, Masafumi; Nozawa, Akio

    Humanity fluctuation was reported in some fields. In handwriting process, fluctuation appears on handwriting-velocity. In this report, we focused attention on human rhythm perception and analyzed fluctuation in handwriting process. As a result, 1/f noise related to rhythm perception and features may caused by Kahneman's capacity model were measured on handwriting process.

  1. A Variation on Kodaly's Rhythm Syllable System.

    Science.gov (United States)

    McGuire, Kenneth

    2003-01-01

    Discusses the rhythm syllable system within Zoltan Kodaly's method that is often used to teach elementary students in general music classes. Offers background information about this method as well as an alternative technique for teaching students about the single sixteenth-note rhythm. (CMK)

  2. Measurement of the occipital alpha rhythm and temporal tau rhythm by using magnetoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. E.; Gohel, Bakul; Kim, K.; Kwon, H.; An, Kyung Min [Center for Biosignals, Korea Research Institute of Standards and Science(KRISS), Daejeon (Korea, Republic of)

    2015-12-15

    Developing Magnetoencephalography (MEG) based on Superconducting Quantum Interference Device (SQUID) facilitates to observe the human brain functions in non-invasively and high temporal and high spatial resolution. By using this MEG, we studied alpha rhythm (8-13 Hz) that is one of the most predominant spontaneous rhythm in human brain. The 8–13 Hz rhythm is observed in several sensory region in the brain. In visual related region of occipital, we call to alpha rhythm, and auditory related region of temporal call to tau rhythm, sensorimotor related region of parietal call to mu rhythm. These rhythms are decreased in task related region and increased in task irrelevant regions. This means that these rhythms play a pivotal role of inhibition in task irrelevant region. It may be helpful to attention to the task. In several literature about the alpha-band inhibition in multi-sensory modality experiment, they observed this effect in the occipital and somatosensory region. In this study, we hypothesized that we can also observe the alpha-band inhibition in the auditory cortex, mediated by the tau rhythm. Before that, we first investigated the existence of the alpha and tau rhythm in occipital and temporal region, respectively. To see these rhythms, we applied the visual and auditory stimulation, in turns, suppressed in task relevant regions, respectively.

  3. Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus.

    Science.gov (United States)

    Enoki, Ryosuke; Oda, Yoshiaki; Mieda, Michihiro; Ono, Daisuke; Honma, Sato; Honma, Ken-Ichi

    2017-03-07

    The suprachiasmatic nucleus (SCN), the master circadian clock, contains a network composed of multiple types of neurons which are thought to form a hierarchical and multioscillator system. The molecular clock machinery in SCN neurons drives membrane excitability and sends time cue signals to various brain regions and peripheral organs. However, how and at what time of the day these neurons transmit output signals remain largely unknown. Here, we successfully visualized circadian voltage rhythms optically for many days using a genetically encoded voltage sensor, ArcLightD. Unexpectedly, the voltage rhythms are synchronized across the entire SCN network of cultured slices, whereas simultaneously recorded Ca(2+) rhythms are topologically specific to the dorsal and ventral regions. We further found that the temporal order of these two rhythms is cell-type specific: The Ca(2+) rhythms phase-lead the voltage rhythms in AVP neurons but Ca(2+) and voltage rhythms are nearly in phase in VIP neurons. We confirmed that circadian firing rhythms are also synchronous and are coupled with the voltage rhythms. These results indicate that SCN networks with asynchronous Ca(2+) rhythms produce coherent voltage rhythms.

  4. Evolution of cortical neurogenesis.

    Science.gov (United States)

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  5. Cortical Lewy Body Dementia

    Directory of Open Access Journals (Sweden)

    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  6. The Psychophysics of Brain Rhythms

    Directory of Open Access Journals (Sweden)

    Rufin eVanrullen

    2011-08-01

    Full Text Available It is becoming increasingly apparent that brain oscillations in various frequency bands play important roles in perceptual and attentional processes. Understandably, most of the associated experimental evidence comes from human or animal electrophysiological studies, allowing direct access to the oscillatory activities. However, such periodicities in perception and attention should, in theory, also be observable using the proper psychophysical tools. Here, we review a number of psychophysical techniques that have been used by us and other authors, in successful and sometimes unsuccessful attempts, to reveal the rhythmic nature of perceptual and attentional processes. We argue that the two existing and largely distinct debates about discrete vs. continuous perception and parallel vs. sequential attention should in fact be regarded as two facets of the same question: how do brain rhythms shape the psychological operations of perception and attention?

  7. Rhythms dysregulation: A new perspective for understanding PTSD?

    Science.gov (United States)

    Dayan, Jacques; Rauchs, Géraldine; Guillery-Girard, Bérengère

    2017-02-01

    Post-traumatic stress disorder (PTSD) is a complex syndrome that may occur after exposure to one or more traumatic events. It associates physiological, emotional, and cognitive changes Brain and hormonal modifications contribute to some impairments in learning, memory, and emotion regulation. Some of these biological dysfunctions may be analyzed in terms of rhythms dysregulation that would be expressed through endocrine rhythmicity, sleep organization, and temporal synchrony in brain activity. In the first part of this article, we report studies on endocrine rhythmicity revealing that some rhythms abnormalities are frequently observed, although not constantly, for both cortisol and sympathetic nervous system (SNS) activity. The most typical changes are a flattening of the diurnal secretion of cortisol and the hyperactivation of the SNS. These results may explain why cognitive functioning, in particular consolidation of emotional memories, attention, learning, vigilance and arousal, is altered in patients with PTSD. The second part of this article focuses on sleep disturbances, one of the core features of PTSD. Abnormal REM sleep reported in various studies may have a pathophysiological role in PTSD and may exacerbate some symptoms such as emotional regulation and memory. In addition, sleep disorders, such as paradoxical insomnia, increase the risk of developing PTSD. We also discuss the potential impact of sleep disturbances on cognition. Finally, temporal synchrony of brain activity and functional connectivity, explored using electroencephalography and functional magnetic resonance imaging, are addressed. Several studies reported abnormalities in alpha, beta and gamma frequency bands that may affect both attentional and memory processes. Other studies confirmed abnormalities in connectivity and recent fMRI data suggest that this could limit top-down control and may be associated with flashback intrusive memories. These data illustrate that a better knowledge of

  8. ADHD, circadian rhythms and seasonality.

    Science.gov (United States)

    Wynchank, Dora S; Bijlenga, Denise; Lamers, Femke; Bron, Tannetje I; Winthorst, Wim H; Vogel, Suzan W; Penninx, Brenda W; Beekman, Aartjan T; Kooij, J Sandra

    2016-10-01

    We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm. Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups were compared: with clinically significant ADHD symptoms (N = 175) and with No ADHD symptoms (N = 2064). Sleep parameters were sleep-onset and offset times, mid sleep and sleep duration from the Munich Chronotype Questionnaire. We identified the prevalence of probable SAD and subsyndromal SAD using the Seasonal Pattern Assessment Questionnaire (SPAQ). Clinically significant ADHD symptoms were identified by using a T score>65 on the Conners Adult ADHD Rating Scale. The prevalence of probable SAD was estimated at 9.9% in the ADHD group (vs. 3.3% in the No ADHD group) and of probable s-SAD at 12.5% in the ADHD group (vs 4.6% in the No ADHD group). Regression analyses showed consistently significant associations between ADHD symptoms and probable SAD, even after adjustment for current depression and anxiety, age, sex, education, use of antidepressants and benzodiazepines (B = 1.81, p < 0.001). Late self-reported sleep onset was an important mediator in the significant relationship between ADHD symptoms and probable SAD, even after correction for confounders (total model effects: B = 0.14, p ≤ 0.001). Both seasonal and circadian rhythm disturbances are significantly associated with ADHD symptoms. Delayed sleep onset time in ADHD may explain the increase in SAD symptoms. Treating patients with SAD for possible ADHD and delayed sleep onset time may reduce symptom severity in these complex patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Focal cortical dysplasia - review.

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-04-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types

  10. Vestibular loss disrupts daily rhythm in rats.

    Science.gov (United States)

    Martin, T; Mauvieux, B; Bulla, J; Quarck, G; Davenne, D; Denise, P; Philoxène, B; Besnard, S

    2015-02-01

    Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period (τ <20 h) for 115.8 ± 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans. Copyright © 2015 the American Physiological Society.

  11. Postpartum cortical blindness.

    Science.gov (United States)

    Faiz, Shakeel Ahmed

    2008-09-01

    A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.

  12. Circadian rhythms, sleep, and the menstrual cycle.

    Science.gov (United States)

    Baker, Fiona C; Driver, Helen S

    2007-09-01

    Women with ovulatory menstrual cycles have a circadian rhythm superimposed on the menstrual-associated rhythm; in turn, menstrual events affect the circadian rhythm. In this paper, we review circadian rhythms in temperature, selected hormone profiles, and sleep-wake behavior in healthy women at different phases of the menstrual cycle. The effects on menstrual cycle rhythmicity of disrupted circadian rhythms, for example, with shiftwork and altered circadian rhythms in women with menstrual-related mood disturbances, are discussed. Compared to the follicular phase, in the post-ovulation luteal phase, body temperature is elevated, but the amplitude of the temperature rhythm is reduced. Evidence indicates that the amplitude of other rhythms, such as melatonin and cortisol, may also be blunted in the luteal phase. Subjective sleep quality is lowest around menses, but the timing and composition of sleep remains relatively stable across the menstrual cycle in healthy women, apart from an increase in spindle frequency activity and a minor decrease in rapid eye movement (REM) sleep during the luteal phase. Disruption of circadian rhythms is associated with disturbances in menstrual function. Female shiftworkers compared to non-shiftworkers are more likely to report menstrual irregularity and longer menstrual cycles. There also is accumulating evidence that circadian disruption increases the risk of breast cancer in women, possibly due to altered light exposure and reduced melatonin secretion. Further investigations into the biological consequences of circadian disruption in women will offer insight into some menstrual-associated disorders, including mood changes, as well as reproductive function and possible links with breast cancer.

  13. Leading role of thalamic over cortical neurons during postinhibitory rebound excitation

    Science.gov (United States)

    Grenier, F.; Timofeev, I.; Steriade, M.

    1998-01-01

    The postinhibitory rebound excitation is an intrinsic property of thalamic and cortical neurons that is implicated in a variety of normal and abnormal operations of neuronal networks, such as slow or fast brain rhythms during different states of vigilance as well as seizures. We used dual simultaneous intracellular recordings of thalamocortical neurons from the ventrolateral nucleus and neurons from the motor cortex, together with thalamic and cortical field potentials, to investigate the temporal relations between thalamic and cortical events during the rebound excitation that follows prolonged periods of stimulus-induced inhibition. Invariably, the rebound spike-bursts in thalamocortical cells occurred before the rebound depolarization in cortical neurons and preceded the peak of the depth-negative, rebound field potential in cortical areas. Also, the inhibitory-rebound sequences were more pronounced and prolonged in cortical neurons when elicited by thalamic stimuli, compared with cortical stimuli. The role of thalamocortical loops in the rebound excitation of cortical neurons was shown further by the absence of rebound activity in isolated cortical slabs. However, whereas thalamocortical neurons remained hyperpolarized after rebound excitation, because of the prolonged spike-bursts in inhibitory thalamic reticular neurons, the rebound depolarization in cortical neurons was prolonged, suggesting the role of intracortical excitatory circuits in this sustained activity. The role of intrathalamic events in triggering rebound cortical activity should be taken into consideration when analyzing information processes at the cortical level; at each step, corticothalamic volleys can set into action thalamic inhibitory neurons, leading to rebound spike-bursts that are transferred back to the cortex, thus modifying cortical activities. PMID:9811903

  14. Hiperactivacion cortical y deterioro cognitivo en esquizofrenia

    OpenAIRE

    Suazo Bonnelly, Vanessa Johanna

    2014-01-01

    [ES] En este trabajo se estudió la actividad cerebral desorganizada y el deterioro cognitivo adjudicado a pacientes con esquizofrenia. Para estudiar la actividad cerebral se empleó una medida electroencefalográfica de ruido cortical (actividad promediada de fondo no ligada a la tarea) durante el desarrollo de una tarea sencilla (P300) en dos de las bandas oscilatorias (gamma y theta) más asociadas a la organización de la actividad cerebral según la literatura. Se utilizó una medida estructura...

  15. Musical alexia for rhythm notation: a discrepancy between pitch and rhythm.

    Science.gov (United States)

    Midorikawa, Akira; Kawamura, Mitsuru; Kezuka, Machiko

    2003-06-01

    In the process of reading music, the reading of rhythm and pitch might be differentiated, although there is no evidence of this to date. There have been cases of disorders restricted to the reading of pitch, but none in which the disorder has been restricted to the reading of rhythm. We present a case of musical alexia and agraphia with Wernicke's aphasia. An in-depth assessment of the subject's musical reading ability showed that her musical alexia was restricted to unfamiliar melodies. When a melody was divided into rhythm elements and pitch elements, pitch reading was preserved, but rhythm reading was severely disturbed. This is the first case reported of a disorder restricted to rhythm reading, and suggests the independence of rhythm reading and pitch reading.

  16. A New Perspective on Teaching English Pronunciation: Rhythm.

    Science.gov (United States)

    Chen, Chi-Fen; And Others

    This paper explores the features of rhythm that make English difficult for speakers of Chinese and suggests some techniques for helping students speak English with an English rhythm. The focus is on information obtained during a workshop: the rhythmic differences between Chinese and English, word rhythm in English, and sentence rhythm in English.…

  17. [Circadian rhythms in body temperature and sleep].

    Science.gov (United States)

    Honma, Ken-ichi

    2013-12-01

    A 24 hour variation of core body temperature in humans is primarily regulated by the endogenous circadian pacemaker located in the suprachiasmatic nucleus. And the expression of circadian rhythm is modified by the thermoregulatory mechanism controlling heat production and heat loss, which also show circadian rhythms. On the other hand, circadian rhythms in sleep-wakefulness are expressed by two independent but mutually coupled oscillators, the circadian pacemaker and the oscillator specific to sleep-wakefulness. However, neither the mechanism nor the site of oscillation of the latter is known. The time cues for these two oscillators are different. They are usually but frequently uncoupled under free-running conditions. Body temperature and sleep-wakefulness influence the counterpart in various extents, exerting masking effects on either circadian rhythm.

  18. Daily rhythms in mobile telephone communication

    CERN Document Server

    Aledavood, Talayeh; Roberts, Sam G B; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I M; Saramäki, Jari

    2015-01-01

    Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls wer...

  19. "Ritual Rhythms" - a collaborative WebDocumentary

    DEFF Research Database (Denmark)

    Møhl, Perle

    2014-01-01

    A collaborative web-based filmproject in 11 vignettes about the rituals and rhythms of daily life in various locations & settings in the city of Copenhagen. Created by Perle Møhl and the students on the 2014 courses in Visual Anthropology in Practice. We use the concepts of Ritual and Rhythm......, tuning in with all our senses to the details of daily life that often elude the attention of a wordy anthropology....

  20. Circadian rhythm and its role in malignancy

    OpenAIRE

    Rana, Sobia; Mahmood, Saqib

    2010-01-01

    Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circ...

  1. Cortical activity influences geniculocortical spike efficacy in the macaque monkey

    Directory of Open Access Journals (Sweden)

    Farran Briggs

    2007-11-01

    Full Text Available Thalamocortical communication is a dynamic process influenced by both presynaptic and postsynaptic mechanisms. In this study, we recorded single-unit responses from cortical neurons that received direct input from the lateral geniculate nucleus (LGN to address the question of whether prior patterns of cortical activity affect the ability of LGN inputs to drive cortical responses. By examining the ongoing activity that preceded the arrival of electrically evoked spikes from the LGN, we identified a number of activity patterns that were predictive of suprathreshold communication. Namely, cortical neurons were more likely to respond to LGN stimulation when their activity levels increased to 30-40Hz and/or their activity displayed rhythmic patterns (30 ms intervals with increased power in the gamma frequency band. Cortical neurons were also more likely to respond to LGN stimulation when their activity increased 30-40 ms prior to stimulation, suggesting that the phase of gamma activity also contributes to geniculocortical communication. Based on these results, we conclude that ongoing activity in the cortex is not random, but rather organized in a manner that can influence the dynamics of thalamocortical communication.

  2. Neural Oscillations Carry Speech Rhythm through to Comprehension.

    Science.gov (United States)

    Peelle, Jonathan E; Davis, Matthew H

    2012-01-01

    A key feature of speech is the quasi-regular rhythmic information contained in its slow amplitude modulations. In this article we review the information conveyed by speech rhythm, and the role of ongoing brain oscillations in listeners' processing of this content. Our starting point is the fact that speech is inherently temporal, and that rhythmic information conveyed by the amplitude envelope contains important markers for place and manner of articulation, segmental information, and speech rate. Behavioral studies demonstrate that amplitude envelope information is relied upon by listeners and plays a key role in speech intelligibility. Extending behavioral findings, data from neuroimaging - particularly electroencephalography (EEG) and magnetoencephalography (MEG) - point to phase locking by ongoing cortical oscillations to low-frequency information (~4-8 Hz) in the speech envelope. This phase modulation effectively encodes a prediction of when important events (such as stressed syllables) are likely to occur, and acts to increase sensitivity to these relevant acoustic cues. We suggest a framework through which such neural entrainment to speech rhythm can explain effects of speech rate on word and segment perception (i.e., that the perception of phonemes and words in connected speech is influenced by preceding speech rate). Neuroanatomically, acoustic amplitude modulations are processed largely bilaterally in auditory cortex, with intelligible speech resulting in differential recruitment of left-hemisphere regions. Notable among these is lateral anterior temporal cortex, which we propose functions in a domain-general fashion to support ongoing memory and integration of meaningful input. Together, the reviewed evidence suggests that low-frequency oscillations in the acoustic speech signal form the foundation of a rhythmic hierarchy supporting spoken language, mirrored by phase-locked oscillations in the human brain.

  3. Neural oscillations carry speech rhythm through to comprehension

    Directory of Open Access Journals (Sweden)

    Jonathan E Peelle

    2012-09-01

    Full Text Available A key feature of speech is the quasi-regular rhythmic information contained in its slow amplitude modulations. In this article we review the information conveyed by speech rhythm, and the role of ongoing brain oscillations in listeners’ processing of this content. Our starting point is the fact that speech is inherently temporal, and that rhythmic information conveyed by the amplitude envelope contains important markers for place and manner of articulation, segmental information, and speech rate. Behavioral studies demonstrate that amplitude envelope information is relied upon by listeners and plays a key role in speech intelligibility. Extending behavioral findings, data from neuroimaging—particularly electroencephalography (EEG and magnetoencephalography (MEG—point to phase locking by ongoing cortical oscillations to low-frequency information (~4–8 Hz in the speech envelope. This phase modulation effectively encodes a prediction of when important events (such as stressed syllables are likely to occur, and acts to increase sensitivity to these relevant acoustic cues. We suggest a framework through which such neural entrainment to speech rhythm can explain effects of speech rate on word and on segment perception (i.e., that the perception of phonemes and words in connected speech are influenced by preceding speech rate. Neuroanatomically, acoustic amplitude modulations are processed largely bilaterally in auditory cortex, with intelligible speech resulting in additional recruitment of left hemisphere regions. Notable among these is lateral anterior temporal cortex, which we propose functions in a domain-general fashion to support ongoing memory and integration of meaningful input. Together, the reviewed evidence suggests that low frequency oscillations in the acoustic speech signal form the foundation of a rhythmic hierarchy supporting spoken language, mirrored by phase-locked oscillations in the human brain.

  4. Alpha Rhythms in Audition: Cognitive and Clinical Perspectives

    Directory of Open Access Journals (Sweden)

    Nathan eWeisz

    2011-04-01

    Full Text Available Like the visual and the sensorimotor systems, the auditory system exhibits pronounced alpha-like resting oscillatory activity. Due to the relatively small spatial extent of auditory cortical areas, this rhythmic activity is less obvious and frequently masked by non-auditory alpha-generators when recording noninvasively using MEG or EEG. Following stimulation with sounds, marked desynchronizations can be observed between 6-12 Hz, which can be localized to the auditory cortex. However knowledge about the functional relevance of the auditory alpha rhythm has remained scarce so far. Results from the visual and sensorimotor system have fueled the hypothesis of alpha activity reflecting a state of functional inhibition. The current article pursues several intentions: 1 Firstly we review and present own evidence (MEG, EEG, sEEG for the existence of an auditory alpha-like rhythm independent of visual or motor generators, something that is occasionally met with scepticism. 2 In a second part we will discuss tinnitus and how this audiological symptom may relate to reduced background alpha. The clinical part will give an introduction into a method which aims to modulate neurophysiological activity hypothesized to underlie this distressing disorder. Using neurofeedback, one is able to directly target relevant oscillatory activity. Preliminary data point to a high potential of this approach for treating tinnitus. 3 Finally, in a cognitive neuroscientific part we will show that auditory alpha is modulated by anticipation / expectations with and without auditory stimulation. We will also introduce ideas and initial evidence that alpha oscillations are involved in the most complex capability of the auditory system, namely speech perception. The evidence presented in this article corroborates findings from other modalities, indicating that alpha-like activity functionally has an universal inhibitory role across sensory modalities.

  5. Alpha rhythms in audition: cognitive and clinical perspectives.

    Science.gov (United States)

    Weisz, Nathan; Hartmann, Thomas; Müller, Nadia; Lorenz, Isabel; Obleser, Jonas

    2011-01-01

    Like the visual and the sensorimotor systems, the auditory system exhibits pronounced alpha-like resting oscillatory activity. Due to the relatively small spatial extent of auditory cortical areas, this rhythmic activity is less obvious and frequently masked by non-auditory alpha-generators when recording non-invasively using magnetoencephalography (MEG) or electroencephalography (EEG). Following stimulation with sounds, marked desynchronizations can be observed between 6 and 12 Hz, which can be localized to the auditory cortex. However knowledge about the functional relevance of the auditory alpha rhythm has remained scarce so far. Results from the visual and sensorimotor system have fuelled the hypothesis of alpha activity reflecting a state of functional inhibition. The current article pursues several intentions: (1) Firstly we review and present own evidence (MEG, EEG, sEEG) for the existence of an auditory alpha-like rhythm independent of visual or motor generators, something that is occasionally met with skepticism. (2) In a second part we will discuss tinnitus and how this audiological symptom may relate to reduced background alpha. The clinical part will give an introduction into a method which aims to modulate neurophysiological activity hypothesized to underlie this distressing disorder. Using neurofeedback, one is able to directly target relevant oscillatory activity. Preliminary data point to a high potential of this approach for treating tinnitus. (3) Finally, in a cognitive neuroscientific part we will show that auditory alpha is modulated by anticipation/expectations with and without auditory stimulation. We will also introduce ideas and initial evidence that alpha oscillations are involved in the most complex capability of the auditory system, namely speech perception. The evidence presented in this article corroborates findings from other modalities, indicating that alpha-like activity functionally has an universal inhibitory role across sensory

  6. Circadian Rhythm in Cytokines Administration.

    Science.gov (United States)

    Trufakin, Valery A; Shurlygina, Anna V

    2016-01-01

    In recent times, a number of diseases involving immune system dysfunction have appeared. This increases the importance of research aimed at finding and developing optimized methods for immune system correction. Numerous studies have found a positive effect in using cytokines to treat a variety of diseases, yet the clinical use of cytokines is limited by their toxicity. Research in the field of chronotherapy, aimed at designing schedules of medicine intake using circadian biorhythms of endogenous production of factors, and receptors' expression to the factors on the target cells, as well as chronopharmacodynamics and chronopharmacokinetics of medicines may contribute to the solution of this problem. Advantages of chronotherapy include a greater effectiveness of treatment, reduced dose of required drugs, and minimized adverse effects. This review presents data on the presence of circadian rhythms of spontaneous and induced cytokine production, as well as the expression of cytokine receptors in the healthy body and in a number of diseases. The article reviews various effects of cytokines, used at different times of the day in humans and experimental animals, as well as possible mechanisms underlying the chronodependent effects of cytokines. The article presents the results of chronotherapeutic modes of administering IL-2, interferons, G-CSF, and GM-CSF in treatment of various types of cancer as well as in experimental models of immune suppression and inflammation, which lead to a greater effectiveness of therapy, the possibility of reducing or increasing the dosage, and reduced drug toxicity. Further research in this field will contribute to the effectiveness and safety of cytokine therapy.

  7. Laminar Profile and Physiology of the α Rhythm in Primary Visual, Auditory, and Somatosensory Regions of Neocortex

    Science.gov (United States)

    Barczak, Annamaria; Musacchia, Gabriella; Lipton, Michael L.; Mehta, Ashesh D.; Lakatos, Peter; Schroeder, Charles E.

    2015-01-01

    The functional significance of the α rhythm is widely debated. It has been proposed that α reflects sensory inhibition and/or a temporal sampling or “parsing” mechanism. There is also continuing disagreement over the more fundamental questions of which cortical layers generate α rhythms and whether the generation of α is equivalent across sensory systems. To address these latter questions, we analyzed laminar profiles of local field potentials (LFPs) and concomitant multiunit activity (MUA) from macaque V1, S1, and A1 during both spontaneous activity and sensory stimulation. Current source density (CSD) analysis of laminar LFP profiles revealed α current generators in the supragranular, granular, and infragranular layers. MUA phase-locked to local current source/sink configurations confirmed that α rhythms index local neuronal excitability fluctuations. CSD-defined α generators were strongest in the supragranular layers, whereas LFP α power was greatest in the infragranular layers, consistent with some of the previous reports. The discrepancy between LFP and CSD findings appears to be attributable to contamination of the infragranular LFP signal by activity that is volume-conducted from the stronger supragranular α generators. The presence of α generators across cortical depth in V1, S1, and A1 suggests the involvement of α in feedforward as well as feedback processes and is consistent with the view that α rhythms, perhaps in addition to a role in sensory inhibition, may parse sensory input streams in a way that facilitates communication across cortical areas. SIGNIFICANCE STATEMENT The α rhythm is thought to reflect sensory inhibition and/or a temporal parsing mechanism. Here, we address two outstanding issues: (1) whether α is a general mechanism across sensory systems and (2) which cortical layers generate α oscillations. Using intracranial recordings from macaque V1, S1, and A1, we show α band activity with a similar spectral and laminar

  8. Episodic multiregional cortical coherence at multiple frequencies during visual task performance

    Science.gov (United States)

    Bressler, Steven L.; Coppola, Richard; Nakamura, Richard

    1993-11-01

    THE way in which the brain integrates fragmentary neural events at multiple locations to produce unified perceptual experience and behaviour is called the binding problem1,2. Binding has been proposed to involve correlated activity at different cortical sites during perceptuomotor behaviour3& ndash;5, particularly by synchronization of narrow-band oscillations in the & gamma;-frequency range (30& ndash;80 Hz)6,7. In the rabbit olfactory system, inhalation induces increased & gamma;-cor-relation between sites in olfactory bulb and cortex8. In the cat visual system, coherent visual stimuli increase & gamma;-correlation between sites in both the same and different visual cortical areas9& ndash;12. In monkeys, some groups have found that & gamma;-oscillations transiently synchronize within striate cortex13, superior temporal sulcus14 and somatosensorimotor cortex15,16. Others have reported that visual stimuli produce increased broad-band power, but not & gamma;-oscillations, in several visual cortical areas17,18. But the absence of narrow-band oscillations in itself does not disprove interregional synchronization, which may be a broad-band phenomenon. We now describe episodes of increased broad-band coherence among local field potentials from sensory, motor and higher-order cortical sites of macaque monkeys performing a visual discrimination task. Widely distributed sites become coherent without involving other intervening sites. Spatially selective multiregional cortical binding, in the form of broad-band synchronization, may thus play a role in primate perceptuomotor behaviour.

  9. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, MAJ; Thom, M; Ellison, DW; Wilkins, P; Barnes, D; Thompson, PD; Brown, P

    2000-01-01

    Objective To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. Background: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  10. Cortical Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-12-01

    Full Text Available Grey-matter abnormalities at the cortical surface and regional brain size were mapped by high-resolution MRI and surface-based, computational image analytical techniques in a group of 27 children and adolescents with attention deficit hyperactivity disorder (ADHD and 46 controls, matched by age and sex, at the University of California at Los Angeles.

  11. Drugs of Abuse Can Entrain Circadian Rhythms

    Directory of Open Access Journals (Sweden)

    Ann E. K. Kosobud

    2007-01-01

    Full Text Available Circadian rhythms prepare organisms for predictable events during the Earth's 24-h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

  12. Drugs of abuse can entrain circadian rhythms.

    Science.gov (United States)

    Kosobud, Ann E K; Gillman, Andrea G; Leffel, Joseph K; Pecoraro, Norman C; Rebec, G V; Timberlake, William

    2007-11-02

    Circadian rhythms prepare organisms for predictable events in the 24 h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

  13. Mu rhythm desynchronization by tongue thrust observation.

    Science.gov (United States)

    Sakihara, Kotoe; Inagaki, Masumi

    2015-01-01

    We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram (EEG) was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD) and event-related synchronization (ERS) for the mu rhythm (8-13 Hz) and beta (13-25 Hz) bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance.

  14. Daily rhythms of benzodiazepine receptor numbers in frontal lobe and cerebellum of the rat

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, M.J.W.; Volicer, L.; Moore-Ede, M.C.; Borsook, D.

    1985-06-17

    Behavioral, biochemical and neurophysiological evidence suggests that gamma-aminobutyric acid (GABA) may play an important role in the neural control of circadian rhythms. Central receptors for benzodiazepines are functionally coupled to GABA receptors and appear to mediate behavioral effects of exogenous benzodiazepines. The binding of /sup 3/H-flunitrazepam to synaptic plasma membranes prepared from various regions of rat brain was examined at 6-hour intervals over a 36-hour period. Prominent daily rhythms in receptor number (Bmax) were observed in the frontal lobe and the cerebellum but not in the temporoparietal regions, hypothalamus or medulla/pons. Binding was highest during periods of sleep/low activity with a significant decrease occurring just prior to waking. These results suggest that daily fluctuations in benzodiazepine receptor numbers may be related to the temporal control of sleep/wake and muscle activity cycles. 23 references, 1 figure, 1 table.

  15. The dynamics of sensorimotor cortical oscillations during the observation of hand movements: an EEG study.

    Directory of Open Access Journals (Sweden)

    Pietro Avanzini

    Full Text Available BACKGROUND: The observation of action done by others determines a desynchronization of the rhythms recorded from cortical central regions. Here, we examined whether the observation of different types of hand movements (target directed, non-target directed, cyclic and non-cyclic elicits different EEG cortical temporal patterns. METHODOLOGY: Video-clips of four types of hand movements were shown to right-handed healthy participants. Two were target directed (grasping and pointing motor acts; two were non-target directed (supinating and clenching movements. Grasping and supinating were performed once, while pointing and clenching twice (cyclic movements. High-density EEG was recorded and analyzed by means of wavelet transform, subdividing the time course in time bins of 200 ms. The observation of all presented movements produced a desynchronization of alpha and beta rhythms in central and parietal regions. The rhythms desynchronized as soon as the hand movement started, the nadir being reached around 700 ms after movement onset. At the end of the movement, a large power rebound occurred for all bands. Target and non-target directed movements produced an alpha band desynchronization in the central electrodes at the same time, but with a stronger desynchronization and a prolonged rebound for target directed motor acts. Most interestingly, there was a clear correlation between the velocity profile of the observed movements and beta band modulation. SIGNIFICANCE: Our data show that the observation of motor acts determines a modulation of cortical rhythm analogous to that occurring during motor act execution. In particular, the cortical motor system closely follows the velocity of the observed movements. This finding provides strong evidence for the presence in humans of a mechanism (mirror mechanism mapping action observation on action execution motor programs.

  16. Subcortical substrates of TMS induced modulation of the cortico-cortical connectivity

    DEFF Research Database (Denmark)

    Groppa, Sergiu; Muthuraman, Muthuraman; Otto, Birte

    2013-01-01

    of oscillatory interaction between corresponding central regions of both hemispheres in the alpha band. The contralateral thalamus, transcallosal fibres and the contralateral thalamocortical pathways may constitute critical brain structures mediating the TMS induced change in oscillatory coupling.......BACKGROUND: Transcranial magnetic stimulation (TMS) can modulate transiently the physiological brain oscillations, e.g. the alpha rhythm. It has been hypothesized that this effect is not limited to the stimulated region but involves subcortical and distant cortical areas. METHODS: We applied single...

  17. Stochastic Amplification of Fluctuations in Cortical Up-States

    Science.gov (United States)

    Hidalgo, Jorge; Seoane, Luís F.; Cortés, Jesús M.; Muñoz, Miguel A.

    2012-01-01

    Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the Hz band). Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum) do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of “stochastic amplification of fluctuations” – previously described in other contexts such as Ecology and Epidemiology – explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs. PMID:22879879

  18. Stochastic amplification of fluctuations in cortical up-states.

    Directory of Open Access Journals (Sweden)

    Jorge Hidalgo

    Full Text Available Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow 0.5 2 Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around 20 Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the 30-90 Hz band. Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of "stochastic amplification of fluctuations"--previously described in other contexts such as Ecology and Epidemiology--explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs.

  19. Abstract Art and Cortical Motor Activation: an EEG study.

    Directory of Open Access Journals (Sweden)

    Maria Alessandra eUmilta'

    2012-11-01

    Full Text Available The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al 2007, Redies, 2007, and Taylor et al, 2011, neglected the question, while the field of neuroesthetics (Zeki, 1999; Ramachandran and Hirstein, 1999 mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder’s brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works. Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works.

  20. Abstract art and cortical motor activation: an EEG study.

    Science.gov (United States)

    Umilta', M Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works.

  1. Abstract art and cortical motor activation: an EEG study

    Science.gov (United States)

    Umilta', M. Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works. PMID:23162456

  2. Sensorimotor and cognitive involvement of the beta-gamma oscillation in the frontal N30 component of somatosensory evoked potentials.

    Science.gov (United States)

    Cebolla, A M; Cheron, G

    2015-12-01

    The most consistent negative cortical component of somatosensory evoked potentials (SEPs), namely the frontal N30, can be considered more multidimensional than a strict item of standard somatosensory investigation, dedicated to tracking the afferent volley from the peripheral sensory nerve potentials to the primary somatosensory cortex. In this review, we revisited its classical sensorimotor implication within the framework of the recent oscillatory model of ongoing electroencephalogram (EEG) rhythms. Recently, the N30 component was demonstrated to be related to an increase in the power of beta-gamma EEG oscillation and a phase reorganization of the ongoing EEG oscillations (phase locking) in this frequency band. Thanks to high density EEG recordings and the inverse modeling method (swLORETA), it was shown that different overlapping areas of the motor and premotor cortex are specifically involved in generating the N30 in the form of a beta gamma oscillatory phase locking and power increase. This oscillatory approach has allowed a re-investigation of the movement gating behavior of the N30. It was demonstrated that the concomitant execution of finger movements by a stimulated hand impinges the temporal concentration of the ongoing beta/gamma EEG oscillations and abolished the N30 component. It was hypothesized that the involvement of neuronal populations in both the sensorimotor cortex and other related areas were unable to respond to the phasic sensory activation so could not phase-lock their oscillatory signals to the external sensory input during the movement. In this case, the actual movement has primacy over the artificial somatosensory input. The contribution of the ongoing oscillatory activity in the N30 emergence calls for a reappraisal of fundamental and clinical interpretations of the frontal N30 component. An absent or reduced amplitude of the N30 can now be viewed not only as a deficit in the activation of the somatosensory synaptic network in response

  3. Daily rhythm of cerebral blood flow velocity

    Directory of Open Access Journals (Sweden)

    Spielman Arthur J

    2005-03-01

    Full Text Available Abstract Background CBFV (cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler (TCD ultrasonography. Other variables included core body temperature (CBT, end-tidal carbon dioxide (EtCO2, blood pressure, and heart rate. Salivary dim light melatonin onset (DLMO served as a measure of endogenous circadian phase position. Results A non-linear multiple regression, cosine fit analysis revealed that both the CBT and CBFV rhythm fit a 24 hour rhythm (R2 = 0.62 and R2 = 0.68, respectively. Circadian phase position of CBT occurred at 6:05 am while CBFV occurred at 12:02 pm, revealing a six hour, or 90 degree difference between these two rhythms (t = 4.9, df = 10, p Conclusion In conclusion, time of day variations in CBFV have an approximately 24 hour rhythm under constant conditions, suggesting regulation by a circadian oscillator. The 90 degree-phase angle difference between the CBT and CBFV rhythms may help explain previous findings of lower CBFV values in the morning. The phase difference occurs at a time period during which cognitive performance decrements have been observed and when both cardiovascular and cerebrovascular events occur more frequently. The mechanisms underlying this phase angle difference require further exploration.

  4. Improvement of pedestrian flow by slow rhythm

    Science.gov (United States)

    Yanagisawa, Daichi; Tomoeda, Akiyasu; Nishinari, Katsuhiro

    2012-01-01

    We have developed a simple model for pedestrians by dividing walking velocity into two parts, which are step size and pace of walking (number of steps per unit time). Theoretical analysis on pace indicates that rhythm that is slower than normal-walking pace in a low-density regime increases flow if the flow-density diagram is convex downward in a high-density regime. In order to verify this result, we have performed an experiment with real pedestrians and observed the improvement of flow in a congested situation using slow rhythm.

  5. "Ritual Rhythms" - a collaborative WebDocumentary

    DEFF Research Database (Denmark)

    Møhl, Perle

    2014-01-01

    A collaborative web-based filmproject in 11 vignettes about the rituals and rhythms of daily life in various locations & settings in the city of Copenhagen. Created by Perle Møhl and the students on the 2014 courses in Visual Anthropology in Practice. We use the concepts of Ritual and Rhythm...... to investigate how various forms of daily life may be analysed as ritual events, how they order, unite or transform people, places & objects, installing particular social aesthetics that make them familiar to those who know and obscure to those who don't. We perform our analysis with a camera and a microphone...

  6. Circadian rhythm asynchrony in man during hypokinesis.

    Science.gov (United States)

    Winget, C. M.; Vernikos-Danellis, J.; Cronin, S. E.; Leach, C. S.; Rambaut, P. C.; Mack, P. B.

    1972-01-01

    Posture and exercise were investigated as synchronizers of certain physiologic rhythms in eight healthy male subjects in a defined environment. Four subjects exercised during bed rest. Body temperature (BT), heart rate, plasma thyroid hormone, and plasma steroid data were obtained from the subjects for a 6-day ambulatory equilibration period before bed rest, 56 days of bed rest, and a 10-day recovery period after bed rest. The results indicate that the mechanism regulating the circadian rhythmicity of the cardiovascular system is rigorously controlled and independent of the endocrine system, while the BT rhythm is more closely aligned to the endocrine system.

  7. Apolipoprotein E and alpha brain rhythms in mild cognitive impairment: a multicentric electroencephalogram study.

    Science.gov (United States)

    Babiloni, Claudio; Benussi, Luisa; Binetti, Giuliano; Cassetta, Emanuele; Dal Forno, Gloria; Del Percio, Claudio; Ferreri, Florinda; Ferri, Raffaele; Frisoni, Giovanni; Ghidoni, Roberta; Miniussi, Carlo; Rodriguez, Guido; Romani, Gian Luca; Squitti, Rosanna; Ventriglia, Maria Carla; Rossini, Paolo M

    2006-02-01

    Relationships between the apolipoprotein E epsilon4 allele and electroencephalographic (EEG) rhythmicity have been demonstrated in Alzheimer's disease (AD) patients but not in the preclinical stage prodromic to it, namely, mild cognitive impairment (MCI). The present multicentric EEG study tested the hypothesis that presence of epsilon4 affects sources of resting EEG rhythms in both MCI and AD subjects. We enrolled 89 MCI subjects (34.8% with epsilon4) and 103 AD patients (50.4% with epsilon4). Resting eyes-closed EEG data were recorded for all subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed that amplitude of alpha 1 and 2 sources in occipital, temporal, and limbic areas was lower in subjects carrying the epsilon4 allele than in those not carrying the epsilon4 allele (p neurophysiological phenotype (ie, cortical alpha rhythmicity) in a preclinical AD condition, MCI, in addition to clinically manifest AD. Such a demonstration motivates future genotype-EEG phenotype studies for the early prediction of AD conversion in individual MCI subjects.

  8. Purely Cortical Anaplastic Ependymoma

    Directory of Open Access Journals (Sweden)

    Flávio Ramalho Romero

    2012-01-01

    Full Text Available Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma.

  9. [Posterior cortical atrophy].

    Science.gov (United States)

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  10. Interaction among cardiac, respiratory, and locomotor rhythms during cardiolocomotor synchronization.

    Science.gov (United States)

    Niizeki, K; Kawahara, K; Miyamoto, Y

    1993-10-01

    The nature of entrainment between cardiac and locomotor rhythms was investigated while normal human subjects walked or ran on a treadmill. To detect the incidence of entrainment occurrence, the phase relationships among cardiac, respiratory, and locomotor rhythms were analyzed. The phase relationship between heartbeats and gait signals showed that entrainment of cardiac rhythm to locomotor rhythm occurred in all subjects at one or more treadmill speeds. To elucidate interactions among cardiac, respiratory, and locomotor rhythms during the cardiolocomotor synchronization, spectral and coherence analyses were done for these three rhythms. Spectral and coherence analyses on fluctuations in the heart period and respiratory rhythms revealed that the strength of coupling between cardiac and respiratory rhythms decreased in the presence of cardiolocomotor synchronization. In addition, the coupling of cardiac and locomotor rhythms appeared to induce dissociation of coupling between respiratory and locomotor rhythms. These results were similar to those observed when stepping was voluntarily synchronized with cardiac rhythm. Possible mechanisms to explain coordination and interaction among the neural oscillators innervating these three rhythms are discussed.

  11. Monkey Lipsmacking Develops Like the Human Speech Rhythm

    Science.gov (United States)

    Morrill, Ryan J.; Paukner, Annika; Ferrari, Pier F.; Ghazanfar, Asif A.

    2012-01-01

    Across all languages studied to date, audiovisual speech exhibits a consistent rhythmic structure. This rhythm is critical to speech perception. Some have suggested that the speech rhythm evolved "de novo" in humans. An alternative account--the one we explored here--is that the rhythm of speech evolved through the modification of rhythmic facial…

  12. Neural dynamics in a model of the thalamocortical system. I. Layers, loops and the emergence of fast synchronous rhythms.

    Science.gov (United States)

    Lumer, E D; Edelman, G M; Tononi, G

    1997-01-01

    A large-scale computer model was constructed to gain insight into the structural basis for the generation of fast synchronous rhythms (20-60 Hz) in the thalamocortical system. The model consisted of 65,000 spiking neurons organized topographically to represent sectors of a primary and secondary area of mammalian visual cortex, and two associated regions of the dorsal thalamus and the thalamic reticular nucleus. Cortical neurons, both excitatory and inhibitory, were organized in supragranular layers, infraganular layers and layer IV. Reciprocal intra- and interlaminar, interareal, thalamocortical, corticothalamic and thalamoreticular connections were set up based on known anatomical constraints. Simulations of neuronal responses to visual input revealed sporadic epochs of synchronous oscillations involving all levels of the model, similar to the fast rhythms recorded in vivo. By systematically modifying physiological and structural parameters in the model, specific network properties were found to play a major role in the generation of this rhythmic activity. For example, fast synchronous rhythms could be sustained autonomously by lateral and interlaminar interactions within and among local cortical circuits. In addition, these oscillations were propagated to the thalamus and amplified by corticothalamocortical loops, including the thalamic reticular complex. Finally, synchronous oscillations were differentially affected by lesioning forward and backward interareal connections.

  13. Gamma watermarking

    Science.gov (United States)

    Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

    2004-05-25

    A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

  14. Gamma watermarking

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

    2004-05-25

    A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

  15. Case study of psychophysiological diary: infradian rhythms.

    Science.gov (United States)

    Slover, G P; Morris, R W; Stroebel, C F; Patel, M K

    1987-01-01

    A 4-year case study was made of a 42-year-old white woman as seen through the psychophysiological diary. There was an awakening diary and a bedtime diary composed of 125 variables. The data are divided into two series: series I containing a manic episode, and series II as a control. Spectral analysis shows infradian rhythms in hypoglycemia and fear (11 days) and time to fall asleep (5 days). Depressed feelings showed a circatrigintan (28-day) rhythm, which was not correlated with menses. Mania had an annual rhythm (spring) but no circatrigintan or less rhythm. The following correlations have a P value less than or equal to 0.01: mania was directly correlated with number of sleeping pills, time to really wake up, need for rest, moodiness, and helplessness, and indirectly with expectations, pressure at work, sense of time, and emotional state. Interestingly, awakening pulse is directly correlated with awakening temperature, number of sleeping pills, bedtime pulse, tiredness at bedtime, hypoglycemia, and fear. Bedtime pulse is directly correlated with awakening pulse and awakening temperature. Both pulse and temperature at bedtime are directly correlated with negative variables such as tiredness, moodiness, helplessness, and depression, and inversely correlated with positive variables such as happiness, loving, performance at work, and thinking efficiency. This study demonstrates a significant correlation between physiological variables.

  16. [Circadian rhythm of human lymphocyte subpopulations].

    Science.gov (United States)

    Pasqualetti, P; Colantonio, D; Casale, R; Colangeli, S; Natali, G

    1988-01-01

    Circadian rhythm of lymphocyte subsets was investigated in four healthy subjects, males, aged 35-58 years old. After a period of ambiental synchronization, venous blood samples were taken during a span of a day at 0.00 a.m., 4.00 a.m., 8.00 a.m., noon, 4.00 p.m. and 8.00 p.m. Lymphocyte subsets (OKT3, OKT4, OKT8, OKB7, OKJa1) were determined by monoclonal antibodies method, and serum level of cortisol by radioimmunoassay method. The OKT4/OKT8 ratio was also calculated. Data were analyzed by chronograms (mean +/- 1SD) and by cosinor method. Results show a significant circadian rhythm for each lymphocyte subset and for serum cortisol levels. The lowest levels of all circulating subsets were seen between noon and 4.00 p.m. and the highest levels around midnight, inversely related with the circadian rhythm of serum cortisol. The OKT4/OKT8 ratio, on the contrary, was relatively constant during the day, without a significant circadian rhythm. These observations have laboratoristic, clinical, and therapeutic implications and should be considered in the course of immunological studies.

  17. Structure and interpretation of rhythm and timing

    NARCIS (Netherlands)

    Honing, H.J.

    2002-01-01

    Rhythm, as it is performed and perceived, is only sparingly addressed in music theory. Existing theories of rhythmic structure are often restricted to music as notated in a score, and as a result are bound to refrain from making statements about music as it is perceived and appreciated by listeners.

  18. Structure and interpretation of rhythm and timing

    NARCIS (Netherlands)

    Honing, H.J.

    2002-01-01

    Rhythm, as it is performed and perceived, is only sparingly addressed in music theory. Existing theories of rhythmic structure are often restricted to music as notated in a score, and as a result are bound to refrain from making statements about music as it is perceived and appreciated by listeners.

  19. Biologic rhythms derived from Siberian mammoths' hairs.

    Directory of Open Access Journals (Sweden)

    Mike Spilde

    Full Text Available Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was ∼31 cms/year and ∼16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios, which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

  20. Changes in sleep-waking rhythms of rats following a single injection of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Nakagagi, K.; Arito, H.; Tsuruta, H.

    1983-01-01

    The acute effects of toluene on sleep-waking rhythms were investigated in rats. In order to determine the characteristics of sleep-waking rhythms in rats quantitatively, polygraphic recordings of cortical EEG activity and neck EMG were made under a 12:12 light-dark schedule. Toluene was injected intraperitoneally at three dosages, i.e., 200, 400, and 600 mg/kg of body weight. The toluene concentration in the blood was determined in rats implanted with a jugular catheter to collect the blood. The circadian sleep-waking rhythms were still entrained to the environmental light-dark cycle following the administration of toluene. On the day of administration, wakefulness (W) increased immediately after toluene administration at the lower two doses, and an abnormal EEG pattern was observed, transiently at the highest dose. The initial increase in W at 200 and 400 mg/kg, and the appearance of the abnormal EEG pattern at 600 mg/kg were observed for 32, 79 and 83 min. after the administration of toluene, respectively. The toluene concentration in the blood of rats given 600 mg/kg was about 70 ..mu..g/ml when the abnormal EEG disappeared. Slow wave sleep (SWS) and paradoxical sleep (PS) increased during the period when blood toluene levels decreased. On the second day, when almost all of the toluene was eliminated from the blood, the lowest dose produced an increase in PS during the dark period, and the higher two doses produced a decrease in PS during the light period. At the highest dose, the amount of SES during the light period was still higher than control. Toluene-induced changes in the sleep-waking rhythms returned to the control by the third day.

  1. Effect of Synaptic Connectivity on Long-Range Synchronization of Fast Cortical Oscillations

    Science.gov (United States)

    Bazhenov, M.; Rulkov, N. F.; Timofeev, I.

    2008-01-01

    Cortical gamma oscillations in the 20- to 80-Hz range are associated with attentiveness and sensory perception and have strong connections to both cognitive processing and temporal binding of sensory stimuli. These gamma oscillations become synchronized within a few milliseconds over distances spanning a few millimeters in spite of synaptic delays. In this study using in vivo recordings and large-scale cortical network models, we reveal a critical role played by the network geometry in achieving precise long-range synchronization in the gamma frequency band. Our results indicate that the presence of many independent synaptic pathways in a two-dimensional network facilitate precise phase synchronization of fast gamma band oscillations with nearly zero phase delays between remote network sites. These findings predict a common mechanism of precise oscillatory synchronization in neuronal networks. PMID:18632897

  2. A Prototype-Based Resonance Model of Rhythm Categorization

    Directory of Open Access Journals (Sweden)

    Rasmus Bååth

    2014-10-01

    Full Text Available Categorization of rhythmic patterns is prevalent in musical practice, an example of this being the transcription of (possibly not strictly metrical music into musical notation. In this article we implement a dynamical systems' model of rhythm categorization based on the resonance theory of rhythm perception developed by Large (2010. This model is used to simulate the categorical choices of participants in two experiments of Desain and Honing (2003. The model accurately replicates the experimental data. Our results support resonance theory as a viable model of rhythm perception and show that by viewing rhythm perception as a dynamical system it is possible to model central properties of rhythm categorization.

  3. A prototype-based resonance model of rhythm categorization.

    Science.gov (United States)

    Bååth, Rasmus; Lagerstedt, Erik; Gärdenfors, Peter

    2014-01-01

    Categorization of rhythmic patterns is prevalent in musical practice, an example of this being the transcription of (possibly not strictly metrical) music into musical notation. In this article we implement a dynamical systems' model of rhythm categorization based on the resonance theory of rhythm perception developed by Large (2010). This model is used to simulate the categorical choices of participants in two experiments of Desain and Honing (2003). The model accurately replicates the experimental data. Our results support resonance theory as a viable model of rhythm perception and show that by viewing rhythm perception as a dynamical system it is possible to model central properties of rhythm categorization.

  4. Chronotherapeutic strategy: Rhythm monitoring, manipulation and disruption.

    Science.gov (United States)

    Ohdo, Shigehiro

    2010-07-31

    Mammalians circadian pacemaker resides in the paired suprachiasmatic nuclei (SCN) and influences a multitude of biological processes, including the sleep-wake rhythm. Clock genes are the genes that control the circadian rhythms in physiology and behavior. 24h rhythm is demonstrated for the function of physiology and the pathophysiology of diseases. The effectiveness and toxicity of many drugs vary depending on dosing time. Such chronopharmacological phenomena are influenced by not only the pharmacodynamics but also pharmacokinetics of medications. The underlying mechanisms are associated with 24h rhythms of biochemical, physiological and behavioral processes under the control of circadian clock. Thus, the knowledge of 24h rhythm in the risk of disease plus evidence of 24h rhythm dependencies of drug pharmacokinetics, effects, and safety constitutes the rationale for pharmacotherapy. Chronotherapy is especially relevant, when the risk and/or intensity of the symptoms of disease vary predictably over time as exemplified by allergic rhinitis, arthritis, asthma, myocardial infarction, congestive heart failure, stroke, and peptic ulcer disease. Morning once-daily administration of corticosteroid tablet medications results in little adrenocortical suppression, while the same daily dose split into four equal administrations to coincide with daily meals and bedtime results in significant hypothalamus-pituitary-adrenal (HPA) axis suppression. However, the drugs for several diseases are still given without regard to the time of day. Identification of a rhythmic marker for selecting dosing time will lead to improved progress and diffusion of chronopharmacotherapy. To monitor the rhythmic marker such as clock genes it may be useful to choose the most appropriate time of day for administration of drugs that may increase their therapeutic effects and/or reduce their side effects. Furthermore, to produce new rhythmicity by manipulating the conditions of living organs by using

  5. Gamma oscillations in human primary somatosensory cortex reflect pain perception.

    Directory of Open Access Journals (Sweden)

    Joachim Gross

    2007-05-01

    Full Text Available Successful behavior requires selection and preferred processing of relevant sensory information. The cortical representation of relevant sensory information has been related to neuronal oscillations in the gamma frequency band. Pain is of invariably high behavioral relevance and, thus, nociceptive stimuli receive preferred processing. Here, by using magnetoencephalography, we show that selective nociceptive stimuli induce gamma oscillations between 60 and 95 Hz in primary somatosensory cortex. Amplitudes of pain-induced gamma oscillations vary with objective stimulus intensity and subjective pain intensity. However, around pain threshold, perceived stimuli yielded stronger gamma oscillations than unperceived stimuli of equal stimulus intensity. These results show that pain induces gamma oscillations in primary somatosensory cortex that are particularly related to the subjective perception of pain. Our findings support the hypothesis that gamma oscillations are related to the internal representation of behaviorally relevant stimuli that should receive preferred processing.

  6. Interactive effect of 5-HTTLPR genotype and age on sources of cortical rhythms in healthy women.

    Science.gov (United States)

    Volf, Nina V; Belousova, Ludmila V; Knyazev, Gennady G; Kulikov, Alexander V

    2016-11-01

    This study was aimed to localize the effects of 5-HTTLPR (serotonin-transporter-linked polymorphic region) on the age differences of spontaneous EEG activity in women using neuroimaging analysis sLORETA (Standardized Low Resolution brain Electromagnetic Tomography). DNA samples extracted from cheek swabs and resting-state EEG recorded at 60 standard leads were collected from young (YW, N=86, 18-35years) and older (OW, N=45; 55-80years) healthy women. We have shown that advanced age was associated with increased posterior EEG desynchronization in S'/S'. S' (LG allele was grouped with S alleles owing to its functional equivalence and this group was labeled as S') genotype carriers denoted by decrease of delta - beta1 current source density, and to a lesser extent in L/L homozygotes denoted by decrease in delta activity. In heterozygotes OW, as compared with heterozygotes YW, higher source density estimates of beta1 in frontal and temporal cortex were observed. Age differences were more pronounced in the right hemisphere in S'/S' and L/L carriers and in the left hemisphere in heterozygotes. We also found that in OW, current source density estimates of theta, alpha1, alpha2, alpha3 and beta1 sources in the right occipital lobe were higher in S'/L than in S'/S' carriers. These results may have implications for understanding 5-HTT-dependent variation in the effect of aging on brain activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Seizure-like thalamocortical rhythms initiate in the deep layers of the cortex in a co-culture model.

    Science.gov (United States)

    Adams, Brendan E L; Kyi, Mervyn; Reid, Christopher A; Myers, Damian E; Xu, Shenghong; Williams, David A; O'Brien, Terence J

    2011-01-01

    The oscillatory rhythms underlying many physiological and pathological states, including absence seizures, require both the thalamus and cortices for full expression. A co-culture preparation combining cortical and thalamic explants provides a unique model for investigating how such oscillations initiate and spread. Here we investigated the dynamics of synchronized thalamocortical activity by simultaneous measurement of field-potential recordings and rapid imaging of Ca(2+) transients by fluorescence methods. Spontaneous sustained hypersynchronized "seizure-like" oscillations required reciprocal cortico-thalamocortical connections. Isolated cortical explants can independently develop brief discharges, while thalamic explants alone were unable to do so. Rapid imaging of Ca(2+) transients demonstrated deep-layer cortical initiation of oscillatory network activity in both connected and isolated explants. Further, cortical explants derived from a rat model of genetic absence epilepsy showed increased bursting duration consistent with an excitable cortex. We propose that thalamocortical oscillatory network activity initiates in deep layers of the cortex with reciprocal thalamic interconnections enabling sustained hyper-synchronization.

  8. Hippocampal, amygdala, and neocortical synchronization of theta rhythms is related to an immediate recall during rey auditory verbal learning test.

    Science.gov (United States)

    Babiloni, Claudio; Vecchio, Fabrizio; Mirabella, Giovanni; Buttiglione, Maura; Sebastiano, Fabio; Picardi, Angelo; Di Gennaro, Giancarlo; Quarato, Pier P; Grammaldo, Liliana G; Buffo, Paola; Esposito, Vincenzo; Manfredi, Mario; Cantore, Giampaolo; Eusebi, Fabrizio

    2009-07-01

    It is well known that theta rhythms (3-8 Hz) are the fingerprint of hippocampus, and that neural activity accompanying encoding of words differs according to whether the items are later remembered or forgotten ["subsequent memory effect" (SME)]. Here, we tested the hypothesis that temporal synchronization of theta rhythms among hippocampus, amygdala, and neocortex is related to immediate memorization of repeated words. To address this issue, intracerebral electroencephalographic (EEG) activity was recorded in five subjects with drug-resistant temporal lobe epilepsy (TLE), under presurgical monitoring routine. During the recording of the intracerebral EEG activity, the subjects performed a computerized version of Rey auditory verbal learning test (RAVLT), a popular test for the clinical evaluation of the immediate and delayed memory. They heard the same list of 15 common words for five times. Each time, immediately after listening the list, the subjects were required to repeat as many words as they could recall. Spectral coherence of the intracerebral EEG activity was computed in order to assess the temporal synchronization of the theta (about 3-8 Hz) rhythms among hippocampus, amygdala, and temporal-occipital neocortex. We found that theta coherence values between amygdala and hippocampus, and between hippocampus and occipital-temporal cortex, were higher in amplitude during successful than unsuccessful immediate recall. A control analysis showed that this was true also for a gamma band (40-45 Hz). Furthermore, these theta and gamma effects were not observed in an additional (control) subject with drug-resistant TLE and a wide lesion to hippocampus. In conclusion, a successful immediate recall to the RAVLT was associated to the enhancement of temporal synchronization of the theta (gamma) rhythms within a cerebral network including hippocampus, amygdala, and temporal-occipital neocortex. Copyright 2009 Wiley-Liss, Inc

  9. Clinical skills: cardiac rhythm recognition and monitoring.

    Science.gov (United States)

    Sharman, Joanna

    With technological advances, changes in provision of healthcare services and increasing pressure on critical care services, ward patients' severity of illness is ever increasing. As such, nurses need to develop their skills and knowledge to care for their client group. Competency in cardiac rhythm monitoring is beneficial to identify changes in cardiac status, assess response to treatment, diagnosis and post-surgical monitoring. This paper describes the basic anatomy and physiology of the heart and its conduction system, and explains a simple and easy to remember process of analysing cardiac rhythms (Resuscitation Council UK, 2000) that can be used in first-line assessment to assist healthcare practitioners in providing care to their patients.

  10. Rhythm R3710:DSP系统

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    安森美半导体推出预配置数字信号处理(DSP)系统RhythmR3710,专为用于耳道内不可见(IIC)助听器设备而设计。RhythmR3710混合系统集成先进的语音及音频信号处理算法,采用安森美半导体先进的微型封装技术,使助听器制造商能够开发置于深耳道的极分立产品。

  11. Working night shifts affects surgeons' biological rhythm

    DEFF Research Database (Denmark)

    Amirian, Ilda; Andersen, Lærke T; Rosenberg, Jacob

    2015-01-01

    BACKGROUND: Chronic sleep deprivation combined with work during the night is known to affect performance and compromise residents' own safety. The aim of this study was to examine markers of circadian rhythm and the sleep-wake cycle in surgeons working night shifts. METHODS: Surgeons were monitored...... prospectively for 4 days: pre call, on call, post call day 1 (PC1), and post call day 2 (PC2). The urinary metabolite of melatonin and cortisol in saliva were measured to assess the circadian rhythm. Sleep and activity were measured by actigraphy. Subjective measures were assessed by the Karolinska Sleepiness...... Scale and Visual Analog Scale of fatigue, general well-being, and sleep quality. RESULTS: For both metabolite of melatonin and cortisol, a significant difference (P sleep time during the day on call...

  12. Circadian rhythm and cell population growth

    CERN Document Server

    Clairambault, Jean; Lepoutre, Thomas

    2010-01-01

    Molecular circadian clocks, that are found in all nucleated cells of mammals, are known to dictate rhythms of approximately 24 hours (circa diem) to many physiological processes. This includes metabolism (e.g., temperature, hormonal blood levels) and cell proliferation. It has been observed in tumor-bearing laboratory rodents that a severe disruption of these physiological rhythms results in accelerated tumor growth. The question of accurately representing the control exerted by circadian clocks on healthy and tumour tissue proliferation to explain this phenomenon has given rise to mathematical developments, which we review. The main goal of these previous works was to examine the influence of a periodic control on the cell division cycle in physiologically structured cell populations, comparing the effects of periodic control with no control, and of different periodic controls between them. We state here a general convexity result that may give a theoretical justification to the concept of cancer chronothera...

  13. Circadian rhythms of women with fibromyalgia

    Science.gov (United States)

    Klerman, E. B.; Goldenberg, D. L.; Brown, E. N.; Maliszewski, A. M.; Adler, G. K.

    2001-01-01

    Fibromyalgia syndrome is a chronic and debilitating disorder characterized by widespread nonarticular musculoskeletal pain whose etiology is unknown. Many of the symptoms of this syndrome, including difficulty sleeping, fatigue, malaise, myalgias, gastrointestinal complaints, and decreased cognitive function, are similar to those observed in individuals whose circadian pacemaker is abnormally aligned with their sleep-wake schedule or with local environmental time. Abnormalities in melatonin and cortisol, two hormones whose secretion is strongly influenced by the circadian pacemaker, have been reported in women with fibromyalgia. We studied the circadian rhythms of 10 women with fibromyalgia and 12 control healthy women. The protocol controlled factors known to affect markers of the circadian system, including light levels, posture, sleep-wake state, meals, and activity. The timing of the events in the protocol were calculated relative to the habitual sleep-wake schedule of each individual subject. Under these conditions, we found no significant difference between the women with fibromyalgia and control women in the circadian amplitude or phase of rhythms of melatonin, cortisol, and core body temperature. The average circadian phases expressed in hours posthabitual bedtime for women with and without fibromyalgia were 3:43 +/- 0:19 and 3:46 +/- 0:13, respectively, for melatonin; 10:13 +/- 0:23 and 10:32 +/- 0:20, respectively for cortisol; and 5:19 +/- 0:19 and 4:57 +/- 0:33, respectively, for core body temperature phases. Both groups of women had similar circadian rhythms in self-reported alertness. Although pain and stiffness were significantly increased in women with fibromyalgia compared with healthy women, there were no circadian rhythms in either parameter. We suggest that abnormalities in circadian rhythmicity are not a primary cause of fibromyalgia or its symptoms.

  14. Modeling biological rhythms in failure time data

    Directory of Open Access Journals (Sweden)

    Myles James D

    2006-11-01

    Full Text Available Abstract Background The human body exhibits a variety of biological rhythms. There are patterns that correspond, among others, to the daily wake/sleep cycle, a yearly seasonal cycle and, in women, the menstrual cycle. Sine/cosine functions are often used to model biological patterns for continuous data, but this model is not appropriate for analysis of biological rhythms in failure time data. Methods We adapt the cosinor method to the proportional hazards model and present a method to provide an estimate and confidence interval of the time when the minimum hazard is achieved. We then apply this model to data taken from a clinical trial of adjuvant of pre-menopausal breast cancer patients. Results The application of this technique to the breast cancer data revealed that the optimal day for pre-resection incisional or excisional biopsy of 28-day cycle (i. e. the day associated with the lowest recurrence rate is day 8 with 95% confidence interval of 4–12 days. We found that older age, fewer positive nodes, smaller tumor size, and experimental treatment were predictive of longer relapse-free survival. Conclusion In this paper we have described a method for modeling failure time data with an underlying biological rhythm. The advantage of adapting a cosinor model to proportional hazards model is its ability to model right censored data. We have presented a method to provide an estimate and confidence interval of the day in the menstrual cycle where the minimum hazard is achieved. This method is not limited to breast cancer data, and may be applied to any biological rhythms linked to right censored data.

  15. Significance of Circadian Rhythms in Aerospace Operations,

    Science.gov (United States)

    1980-12-01

    impression that the endogenous circadian component of this hormone is weak or even lacking, and variation might reflect merely responses to changes of the...on vigilance and in- formation procefsing. In: R.R. Mackie (Ed.): Vigilance. Theory, Operational Performance, and Physio- logical Correlates. New York...ntrainmVn’>--ui cirpatan rhythms after phase- shifts of the Zeitgeber. Chropsyi,:ologia 2:23-78 (197))..-. 26. ASCH -OFF, J., U.v. SAINT PAUL, and R

  16. Circadian rhythms synchronize mitosis in Neurospora crassa

    OpenAIRE

    Hong, Christian I.; Zámborszky, Judit; Baek, Mokryun; Labiscsak, Laszlo; Ju, Kyungsu; Lee, Hyeyeong; Luis F. Larrondo; Goity, Alejandra; Chong, Hin Siong; Belden, William J.; Csikász-Nagy, Attila

    2014-01-01

    Circadian rhythms provide temporal information to other cellular processes, such as metabolism. We investigate the coupling between the cell cycle and the circadian clock using mathematical modeling and experimentally validate model-driven predictions with a model filamentous fungus, Neurospora crassa. We demonstrate a conserved coupling mechanism between the cell cycle and the circadian clock in Neurospora as in mammals, which results in circadian clock-gated mitotic cycles. Furthermore, we ...

  17. Tonic neuromodulation of the inspiratory rhythm generator

    Directory of Open Access Journals (Sweden)

    Fernando ePeña-Ortega

    2012-07-01

    Full Text Available The generation of neural network dynamics relies on the interactions between the intrinsic and synaptic properties of their neural components. Moreover, neuromodulators allow networks to change these properties and adjust their activity to specific challenges. Endogenous continuous (tonic neuromodulation can regulate and sometimes be indispensible for networks to produce basal activity. This seems to be the case for the inspiratory rhythm generator located in the pre-Bötzinger complex (preBötC. This neural network is necessary and sufficient for generating inspiratory rhythms. The preBötC produces normal respiratory activity (eupnea as well as sighs under normoxic conditions, and it generates gasping under hypoxic conditions after a reconfiguration process. The reconfiguration leading to gasping generation involves changes of synaptic and intrinsic properties that can be mediated by several neuromodulators. Over the past years, it has been shown that endogenous continuous neuromodulation of the preBötC may involve the continuous action of amines and peptides on extrasynaptic receptors. I will summarize the findings supporting the role of endogenous continuous neuromodulation in the generation and regulation of different inspiratory rhythms, exploring the possibility that these neuromodulatory actions involve extrasynaptic receptors along with evidence of glial modulation of preBötC activity.

  18. Subjective alertness rhythms in elderly people

    Science.gov (United States)

    Monk, T. H.; Buysse, D. J.; Reynolds, C. F. 3rd; Kupfer, D. J.; Houck, P. R.

    1996-01-01

    The aim of this study was to evaluate age-related changes in the circadian rhythm of subjective alertness and to explore the circadian mechanisms underlying such changes. Using a visual analogue scale (VAS) instrument, 25 older men and women (71 y and older; 15 female, 10 male) rated their subjective alertness about 7 times per day during 5 baseline days of temporal isolation during which habitual bedtimes and waketimes were enforced. Comparisons were made with 13 middle-aged men (37-52 y) experiencing the same protocol. Advancing age (particularly in the men) resulted in less rhythmic alertness patterns, as indicated by lower amplitudes and less reliability of fitted 24-h sinusoids. This appeared in spite of the absence of any reliable age-related diminution in circadian temperature rhythm amplitude, thus suggesting the effect was not due to SCN weakness per se, but to weakened transduction of SCN output. In a further experiment, involving 36 h of constant wakeful bedrest, differences in the amplitude of the alertness rhythm were observed between 9 older men (79 y+), 7 older women (79 y+), and 17 young controls (9 males, 8 females, 19-28 y) suggesting that with advancing age (particularly in men) there is less rhythmic input into subjective alertness from the endogenous circadian pacemaker. These results may explain some of the nocturnal insomnia and daytime hypersomnia that afflict many elderly people.

  19. Brain networks for integrative rhythm formation.

    Directory of Open Access Journals (Sweden)

    Michael H Thaut

    Full Text Available BACKGROUND: Performance of externally paced rhythmic movements requires brain and behavioral integration of sensory stimuli with motor commands. The underlying brain mechanisms to elaborate beat-synchronized rhythm and polyrhythms that musicians readily perform may differ. Given known roles in perceiving time and repetitive movements, we hypothesized that basal ganglia and cerebellar structures would have greater activation for polyrhythms than for on-the-beat rhythms. METHODOLOGY/PRINCIPAL FINDINGS: Using functional MRI methods, we investigated brain networks for performing rhythmic movements paced by auditory cues. Musically trained participants performed rhythmic movements at 2 and 3 Hz either at a 1:1 on-the-beat or with a 3:2 or a 2:3 stimulus-movement structure. Due to their prior musical experience, participants performed the 3:2 or 2:3 rhythmic movements automatically. Both the isorhythmic 1:1 and the polyrhythmic 3:2 or 2:3 movements yielded the expected activation in contralateral primary motor cortex and related motor areas and ipsilateral cerebellum. Direct comparison of functional MRI signals obtained during 3:2 or 2:3 and on-the-beat rhythms indicated activation differences bilaterally in the supplementary motor area, ipsilaterally in the supramarginal gyrus and caudate-putamen and contralaterally in the cerebellum. CONCLUSIONS/SIGNIFICANCE: The activated brain areas suggest the existence of an interconnected brain network specific for complex sensory-motor rhythmic integration that might have specificity for elaboration of musical abilities.

  20. Evaluating mandibular cortical index quantitatively.

    Science.gov (United States)

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  1. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

    Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

  2. Basic Principles of Interpersonal Social Rhythm Therapy in Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Gokben Hizli Sayar

    2014-08-01

    Full Text Available Interpersonal Social Rhythm Therapy is a psychotherapy modality that helps the patient recognize the relationship between disruptions in social rhythms and the onset of previous episodes of psychiatric disorders. It uses psychoeducation and behavioral techniques to maintain social rhythm and sleep/wake regularity. It is closely related to and ldquo;social zeitgeber theory and rdquo; that emphasizes the importance that social rhythm regularity may play in synchronization of circadian rhythms in individuals with or at risk for bipolar spectrum disorders. Interpersonal and social rhythm therapy have been shown to stabilize social rhythms and enhance course and outcome in bipolar disorder. This review focuses on the theoretical principles and the basic steps of interpersonal and social rhythm therapy as a psychotherapy approach in bipolar disorder. PubMed, Scopus, Google Scholar databases were searched without temporal restriction. Search terms included interpersonal social rhythm therapy, bipolar, mood disorders. Abstracts were reviewed for relevance, and randomized controlled trials of interpersonal and social rhythm therapy in bipolar disorder selected. These researches also summarized on the final part of this review. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 438-446

  3. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  4. Cortical and spinal assessment

    DEFF Research Database (Denmark)

    Fischer, I W; Gram, Mikkel; Hansen, T M

    2017-01-01

    BACKGROUND: Standardized objective methods to assess the analgesic effects of opioids, enable identification of underlying mechanisms of drug actions in the central nervous system. Opioids may exert their effect on both cortical and spinal levels. In this study actions of morphine at both levels...... subjects was included in the data analysis. There was no change in the activity in resting EEG (P>0.05) after morphine administration as compared to placebo. During cold pressor stimulation, morphine significantly lowered the relative activity in the delta (1-4Hz) band (P=0.03) and increased the activity...... morphine administration (P>0.05). CONCLUSIONS: Cold pressor EEG and the nociceptive reflex were more sensitive to morphine analgesia than resting EEG and can be used as standardized objective methods to assess opioid effects. However, no correlation between the analgesic effect of morphine on the spinal...

  5. Hiperostosis cortical infantil

    OpenAIRE

    Salvador Javier Santos Medina; Orelvis Pérez Duerto

    2015-01-01

    La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco mes...

  6. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  7. Cortical plasticity and rehabilitation.

    Science.gov (United States)

    Moucha, Raluca; Kilgard, Michael P

    2006-01-01

    The brain is constantly adapting to environmental and endogenous changes (including injury) that occur at every stage of life. The mechanisms that regulate neural plasticity have been refined over millions of years. Motivation and sensory experience directly shape the rewiring that makes learning and neurological recovery possible. Guiding neural reorganization in a manner that facilitates recovery of function is a primary goal of neurological rehabilitation. As the rules that govern neural plasticity become better understood, it will be possible to manipulate the sensory and motor experience of patients to induce specific forms of plasticity. This review summarizes our current knowledge regarding factors that regulate cortical plasticity, illustrates specific forms of reorganization induced by control of each factor, and suggests how to exploit these factors for clinical benefit.

  8. Distribution of gamma-aminobutyric and nitrogen monoxide-coexisting neurons in cortical amygdaloid nucleus in rats and its modulation effect on pain transmission%大鼠杏仁皮质核内γ-氨基丁酸与一氧化氮共存神经元分布及对痛觉信息传递的调控

    Institute of Scientific and Technical Information of China (English)

    倪晶晶; 凌树才; 朱晞

    2005-01-01

    BACKGROUND: Quite a few deoxidized reduced form of nicotinamide-adenime dinucleotide phosphate (NADPH-d) -positive neurons distribute in amygdala complex (AMC) and gamma-aminobutyric acid(GABA)is an important inhibitory neurotransmitter that also widely distributes in the central nervous system (CNS) of mammals. Whether there is coexistence of GABA and nitricoxide synthase (NOS) in AMC is unknown at present.OBJECTIVE: To observe whether there is GABA and NADPH-d-eoexist neuron in cortical nucleus of amygdala (Co) with the combination of NADPH-d hischemical and immunohistochemical double staining.DESIGN: A verifying controlled study based on the experimental animals.SETTING: Department of anatomy of two universities MATERIALS: The study was conducted in the department of Anatomy,Medical College of Zhejiang University between May 2004 and June 2004. Six SD rats in either gender with a body mass between 250 g and 300 g were selected.INTERVENTIONS: Coronary serial frozen slices of brain tissue were prepared. 4 sets of slices were selected for Nissl staining, NADPH-d histochemical staining, NADPH-d histochemical and GABA immunohistochemical double staining, and control experiment for the test of antibody specificity. GABA-labeled neurons, NADPH-d-positive neurons, and NADPH-d/GABA double-labeled neurons were counted in Co nucleus for the calculation of the percentage of double-labeled positive neurons to single-labeled positive neurons.MAIN OUTCOME MEASURES: Distribution of NADPH-d/GABA double labeled neuron; distribution of NADPH-d or GABA single labeled neuron.RESULTS: Most of GABA-positive neurons distributed in posteromed cortical amygdaloid nucleus (PMCo), posterolateral cortical amygdaloid nucleus (PLCo), which were mainly small types but few middle types. Most of NADPH-d-positive neurons distributed in PMCo, PLCo and anterior cortical amygdaloid nucleus (Aco), which were mainly middle sized and small sized neurons. The ratio of NADPH-d/GABA double-labeled neurons

  9. Circadian Rhythms and Sleep in Drosophila melanogaster.

    Science.gov (United States)

    Dubowy, Christine; Sehgal, Amita

    2017-04-01

    The advantages of the model organism Drosophila melanogaster, including low genetic redundancy, functional simplicity, and the ability to conduct large-scale genetic screens, have been essential for understanding the molecular nature of circadian (∼24 hr) rhythms, and continue to be valuable in discovering novel regulators of circadian rhythms and sleep. In this review, we discuss the current understanding of these interrelated biological processes in Drosophila and the wider implications of this research. Clock genes period and timeless were first discovered in large-scale Drosophila genetic screens developed in the 1970s. Feedback of period and timeless on their own transcription forms the core of the molecular clock, and accurately timed expression, localization, post-transcriptional modification, and function of these genes is thought to be critical for maintaining the circadian cycle. Regulators, including several phosphatases and kinases, act on different steps of this feedback loop to ensure strong and accurately timed rhythms. Approximately 150 neurons in the fly brain that contain the core components of the molecular clock act together to translate this intracellular cycling into rhythmic behavior. We discuss how different groups of clock neurons serve different functions in allowing clocks to entrain to environmental cues, driving behavioral outputs at different times of day, and allowing flexible behavioral responses in different environmental conditions. The neuropeptide PDF provides an important signal thought to synchronize clock neurons, although the details of how PDF accomplishes this function are still being explored. Secreted signals from clock neurons also influence rhythms in other tissues. SLEEP is, in part, regulated by the circadian clock, which ensures appropriate timing of sleep, but the amount and quality of sleep are also determined by other mechanisms that ensure a homeostatic balance between sleep and wake. Flies have been useful

  10. Biologic Rhythms Derived from Siberian Mammoths Hairs

    Energy Technology Data Exchange (ETDEWEB)

    M Spilde; A Lanzirotti; C Qualls; G Phillips; A Ali; L Agenbroad; O Appenzeller

    2011-12-31

    Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was {approx}31 cms/year and {approx}16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios), which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

  11. Human cortical responses to slow and fast binaural beats reveal multiple mechanisms of binaural hearing.

    Science.gov (United States)

    Ross, Bernhard; Miyazaki, Takahiro; Thompson, Jessica; Jamali, Shahab; Fujioka, Takako

    2014-10-15

    When two tones with slightly different frequencies are presented to both ears, they interact in the central auditory system and induce the sensation of a beating sound. At low difference frequencies, we perceive a single sound, which is moving across the head between the left and right ears. The percept changes to loudness fluctuation, roughness, and pitch with increasing beat rate. To examine the neural representations underlying these different perceptions, we recorded neuromagnetic cortical responses while participants listened to binaural beats at a continuously varying rate between 3 Hz and 60 Hz. Binaural beat responses were analyzed as neuromagnetic oscillations following the trajectory of the stimulus rate. Responses were largest in the 40-Hz gamma range and at low frequencies. Binaural beat responses at 3 Hz showed opposite polarity in the left and right auditory cortices. We suggest that this difference in polarity reflects the opponent neural population code for representing sound location. Binaural beats at any rate induced gamma oscillations. However, the responses were largest at 40-Hz stimulation. We propose that the neuromagnetic gamma oscillations reflect postsynaptic modulation that allows for precise timing of cortical neural firing. Systematic phase differences between bilateral responses suggest that separate sound representations of a sound object exist in the left and right auditory cortices. We conclude that binaural processing at the cortical level occurs with the same temporal acuity as monaural processing whereas the identification of sound location requires further interpretation and is limited by the rate of object representations. Copyright © 2014 the American Physiological Society.

  12. Investigating repetition and change in musical rhythm by functional MRI.

    Science.gov (United States)

    Danielsen, A; Otnæss, M K; Jensen, J; Williams, S C R; Ostberg, B C

    2014-09-05

    Groove-based rhythm is a basic and much appreciated feature of Western popular music. It is commonly associated with dance, movement and pleasure and is characterized by the repetition of a basic rhythmic pattern. At various points in the musical course, drum breaks occur, representing a change compared to the repeated pattern of the groove. In the present experiment, we investigated the brain response to such drum breaks in a repetitive groove. Participants were scanned with functional magnetic resonance imaging (fMRI) while listening to a previously unheard naturalistic groove with drum breaks at uneven intervals. The rhythmic pattern and the timing of its different parts as performed were the only aspects that changed from the repetitive sections to the breaks. Differences in blood oxygen level-dependent activation were analyzed. In contrast to the repetitive parts, the drum breaks activated the left cerebellum, the right inferior frontal gyrus (RIFG), and the superior temporal gyri (STG) bilaterally. A tapping test using the same stimulus showed an increase in the standard deviation of inter-tap-intervals in the breaks versus the repetitive parts, indicating extra challenges for auditory-motor integration in the drum breaks. Both the RIFG and STG have been associated with structural irregularity and increase in musical-syntactical complexity in several earlier studies, whereas the left cerebellum is known to play a part in timing. Together these areas may be recruited in the breaks due to a prediction error process whereby the internal model is being updated. This concurs with previous research suggesting a network for predictive feed-forward control that comprises the cerebellum and the cortical areas that were activated in the breaks.

  13. Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography.

    Science.gov (United States)

    Lega, Bradley; Dionisio, Sasha; Flanigan, Patrick; Bingaman, William; Najm, Imad; Nair, Dileep; Gonzalez-Martinez, Jorge

    2015-09-01

    Cortico-cortical evoked potentials offer the possibility of understanding connectivity within seizure networks to improve diagnosis and more accurately identify candidates for seizure surgery. We sought to determine if cortico-cortical evoked potentials and post-stimulation oscillatory changes differ for sites of EARLY versus LATE ictal spread. 37 patients undergoing stereoelectroencephalography were tested using a cortico-cortical evoked potential paradigm. All electrodes were classified according to the speed of ictal spread. EARLY spread sites were matched to a LATE spread site equidistant from the onset zone. Root-mean-square was used to quantify evoked responses and post-stimulation gamma band power and coherence were extracted and compared. Sites of EARLY spread exhibited significantly greater evoked responses after stimulation across all patients (t(36)=2.973, p=0.004). Stimulation elicited enhanced gamma band activity at EARLY spread sites (t(36)=2.61, p=0.03, FDR corrected); this gamma band oscillation was highly coherent with the onset zone. Cortico-cortical evoked potentials and post-stimulation changes in gamma band activity differ between sites of EARLY versus LATE ictal spread. The oscillatory changes can help visualize connectivity within the seizure network.

  14. Nonlinear neurodynamics in representation of a rhythm of speech.

    Science.gov (United States)

    Skljarov, O P

    1999-06-01

    The mathematical model is offered to describe an algorithm for functioning of a speech rhythm. The duration of a speech signal is divided into the numbered sequence of durations of voice and voiceless segments. All elements of this sequence will be considered as values normalized on the maximum element. We determine this sequence of the elements as a speech rhythm. 1) The model describes a speech rhythm as the recurrent relations between elements of a rhythm. 2) The model permits use of the concept of information entropy. 3) The model explains experimental findings obtained by our research group during comparative investigation of a rhythm in normal speech and stuttering. In particular, the model explains the existence of two classes of stutterers with various rhythms of speech.

  15. Evidence for a rhythm perception deficit in children who stutter.

    Science.gov (United States)

    Wieland, Elizabeth A; McAuley, J Devin; Dilley, Laura C; Chang, Soo-Eun

    2015-05-01

    Stuttering is a neurodevelopmental disorder that affects the timing and rhythmic flow of speech production. When speech is synchronized with an external rhythmic pacing signal (e.g., a metronome), even severe stuttering can be markedly alleviated, suggesting that people who stutter may have difficulty generating an internal rhythm to pace their speech. To investigate this possibility, children who stutter and typically-developing children (n=17 per group, aged 6-11 years) were compared in terms of their auditory rhythm discrimination abilities of simple and complex rhythms. Children who stutter showed worse rhythm discrimination than typically-developing children. These findings provide the first evidence of impaired rhythm perception in children who stutter, supporting the conclusion that developmental stuttering may be associated with a deficit in rhythm processing.

  16. Mechanisms by which circadian rhythm disruption may lead to cancer

    Directory of Open Access Journals (Sweden)

    L. C. Roden

    2010-02-01

    Full Text Available Humans have evolved in a rhythmic environment and display daily (circadian rhythms in physiology, metabolism and behaviour that are in synchrony with the solar day. Modern lifestyles have compromised the exposure to bright light during the day and dark nights, resulting in the desynchronisation of endogenously generated circadian rhythms from the external environment and loss of coordination between rhythms within the body. This has detrimental effects on physical and mental health, due to the misregulation and uncoupling of important cellular and physiological processes. Long-term shift workers who are exposed to bright light at night experience the greatest disruption of their circadian rhythms. Studies have shown an association between exposure to light at night, circadian rhythm disruption and an increased risk of cancer. Previous reviews have explored the relevance of light and melatonin in cancer, but here we explore the correlation of circadian rhythm disruption and cancer in terms of molecular mechanisms affecting circadian gene expression and melatonin secretion.

  17. Conventional rhythms enhance infants' and adults' perception of musical patterns.

    Science.gov (United States)

    Trehub, Sandra E; Hannon, Erin E

    2009-01-01

    Listeners may favour particular rhythms because of their degree of conformity to culture-specific expectations or because of perceptual constraints that are apparent early in development. In two experiments we examined adults' and 6-month-old infants' detection of subtle rhythmic and melodic changes to two sequences of tones, a conventional rhythm that musically untrained adults rated as rhythmically good and an unconventional rhythm that was rated as poor. Detection of the changes was above chance in all conditions, but adults and infants performed more accurately in the context of the conventional rhythm. Unlike adults, who benefited from rhythmic conventionality only when detecting rhythmic changes, infants benefited when detecting melodic as well as rhythmic changes. The findings point to infant and adult parallels for some aspects of rhythm processing and to integrated perception of rhythm and melody early in life.

  18. Activity in the ferret: oestradiol effects and circadian rhythms

    Science.gov (United States)

    Stockman, E. R.; Albers, H. E.; Baum, M. J.; Wurtman, R. J. (Principal Investigator)

    1985-01-01

    The present study was conducted to determine whether oestradiol increases activity in the European ferret (Mustela furo), whether this effect is sexually dimorphic, and whether a 24-h rhythm is present in the ferret's daily activity. The activity of male and female adult, postpubertally gonadectomized ferrets was monitored while they were maintained singly on a 13:11 light-dark cycle, before and after implantation with oestradiol-17 beta. Gonadectomized male and female ferrets exhibited equal levels of activity, and neither sex exhibited a significant change in activity following oestradiol implantation. None of the ferrets exhibited a strong circadian rhythm, although weak 24-h rhythms and shorter harmonic rhythms were present. Golden hamsters (Mesocricetus auratus), monitored in an identical manner, exhibited strong circadian rhythms. It was concluded that oestradiol administration may not cause an increase in activity in the ferret, and that this species lacks a strong circadian activity rhythm.

  19. Random curds as mathematical models of fractal rhythm in architecture

    Directory of Open Access Journals (Sweden)

    Ćirović Ivana

    2014-01-01

    Full Text Available The author Carl Bovill has suggested and described a method for generating rhythm in architecture with the help of random curds, as they are the mathematical models of unpredictable and uneven groupings which he recognizes in natural shapes and in natural processes. He specified the rhythm generated in this way as the fractal rhythm. Random curds can be generated by a simple process of curdling, as suggested by B. Mandelbrot. This paper examines the way in which the choice of probability for every stage or level of the curdling process, and the number of stages in the procedure of curdling, affect the characteristics of the obtained fractal object as a potential mathematical model of rhythm in the design process. At the same time, this paper examines the characteristics of rhythm in architecture which determine whether the obtained fractal object will be accepted as an appropriate mathematical model of the observed rhythm.

  20. Cortical Network Dynamics of Perceptual Decision-Making in the Human Brain

    Directory of Open Access Journals (Sweden)

    Markus eSiegel

    2011-02-01

    Full Text Available Goal-directed behavior requires the flexible transformation of sensory evidence about our environment into motor actions. Studies of perceptual decision-making have shown that this transformation is distributed across several widely separated brain regions. Yet, little is known about how decision-making emerges from the dynamic interactions among these regions. Here, we review a series of studies, in which we characterized the cortical network interactions underlying a perceptual decision process in the human brain. We used magnetoencephalography (MEG to measure the large-scale cortical population dynamics underlying each of the sub-processes involved in this decision: the encoding of sensory evidence and action plan, the mapping between the two, and the attentional selection of task-relevant evidence. We found that these sub-processes are mediated by neuronal oscillations within specific frequency ranges. Localized gamma-band oscillations in sensory and motor cortices reflect the encoding of the sensory evidence and motor plan. Large-scale oscillations across widespread cortical networks mediate the integrative processes connecting these local networks: Gamma- and beta-band oscillations across frontal, parietal and sensory cortices serve the selection of relevant sensory evidence and its flexible mapping onto action plans. In sum, our results suggest that perceptual decisions are mediated by oscillatory interactions within overlapping local and large-scale cortical networks.

  1. Relationships between circadian rhythms and ethanol intake in mice

    OpenAIRE

    Trujillo, Jennifer L.

    2009-01-01

    This dissertation integrates methods from alcohol and circadian rhythms research to explore relationships between ethanol and circadian rhythms in mice. Ingesting alcohol at certain times of day differentially affects the body; circadian rhythms also impact preference for drinking alcohol at different times of day. The influence of circadian timing on development and maintenance of ethanol drinking patterns was studied in Chapter 2. This showed how establishing a history of ethanol exposure a...

  2. Perceptual tests of rhythmic similarity: I. Mora Rhythm

    OpenAIRE

    Murty, L.; Otake, T; Cutler, A.

    2007-01-01

    Listeners rely on native-language rhythm in segmenting speech; in different languages, stress-, syllable- or mora-based rhythm is exploited. The rhythmic similarity hypothesis holds that where two languages have similar rhythm, listeners of each language should segment their own and the other language similarly. Such similarity in listening was previously observed only for related languages (English-Dutch; French-Spanish). We now report three experiments in which speakers of Telugu, a Dravidi...

  3. gamma-gamma Interactions from Real to Virtual Photons

    CERN Document Server

    Sjöstrand, Torbjörn

    2000-01-01

    A `complete' framework for gamma-gamma / gamma*-gamma / gamma*-gamma* interactions is presented. The emphasis is on providing a model for gamma-gamma physics at all photon virtualities, including the difficult transition region around the rho meson mass.

  4. Electrophysiological Data and the Biophysical Modelling of Local Cortical Circuits

    Directory of Open Access Journals (Sweden)

    Dimitris Pinotsis

    2014-03-01

    Full Text Available This paper shows how recordings of gamma oscillations – under different experimental conditions or from different subjects – can be combined with a class of population models called neural fields and dynamic causal modeling (DCM to distinguish among alternative hypotheses regarding cortical structure and function. This approach exploits inter-subject variability and trial-specific effects associated with modulations in the peak frequency of gamma oscillations. It draws on the computational power of Bayesian model inversion, when applied to neural field models of cortical dynamics. Bayesian model comparison allows one to adjudicate among different mechanistic hypotheses about cortical excitability, synaptic kinetics and the cardinal topographic features of local cortical circuits. It also provides optimal parameter estimates that quantify neuromodulation and the spatial dispersion of axonal connections or summation of receptive fields in the visual cortex. This paper provides an overview of a family of neural field models that have been recently implemented using the DCM toolbox of the academic freeware Statistical Parametric Mapping (SPM. The SPM software is a popular platform for analyzing neuroimaging data, used by several neuroscience communities worldwide. DCM allows for a formal (Bayesian statistical analysis of cortical network connectivity, based upon realistic biophysical models of brain responses. It is this particular feature of DCM – the unique combination of generative models with optimization techniques based upon (variational Bayesian principles – that furnishes a novel way to characterize functional brain architectures. In particular, it provides answers to questions about how the brain is wired and how it responds to different experimental manipulations. For a review of the general role of neural fields in SPM the reader can consult e.g. see [1]. Neural fields have a long and illustrious history in mathematical

  5. [Sensory processing could be temporally organized by ultradian brain rhythms].

    Science.gov (United States)

    Pedemonte, M; Velluti, R A

    Neuronal activity of sensory systems depends on input from the environment, the body and the brain itself. Various rhythms have been shown to affect sensory processing, such as the waking-sleep cycle and hippocampal theta waves, our aim in this revision. The hippocampus, known as a structure involved in learning and memory processing, has the theta rhythm (4-10 Hz), present in all behavioural states. This rhythm has been temporally related to automatic, reflex and voluntary movements, both during wakefulness and sleep, and in the autonomic control of the heart rate. On the other hand theta rhythm has been considered as a novelty detector expressing different level of attention, selecting the information and protecting from interference. Our research is based on the hypothesis that sensory processing needs a timer to be processed and stored, and hippocampal theta rhythm could contribute to the temporal organization of these events. We have demonstrated that auditory and visual unitary discharges in guinea pigs show phase-locking to the hippocampal theta rhythm. This temporal correlation appears during both spontaneous and specific sensory stimulation evoked discharges. Neuronal discharges fluctuate between phase-locked and uncorrelated firing modes relative to the theta rhythm. This changing state depends on known and unknown situations. We have provoked, changing the visual stimuli, a power theta rhythm increment and the phase-locking between this rhythm and the lateral geniculate neurone discharge during wakefulness. In slow wave sleep results were different demonstrating that the ways of the inputs processing have changed.

  6. GAMMA-400 gamma-ray observatory

    CERN Document Server

    Topchiev, N P; Bonvicini, V; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bakaldin, A V; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, L; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Cumani, P; Dalkarov, O D; Dedenko, G L; De Donato, C; Dogiel, V A; Finetti, N; Gascon, D; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Leonov, A A; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Martinez, M; Menshenin, A L; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Paredes, J M; Pearce, M; Picozza, P; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Stozhkov, Yu I; Suchkov, S I; Taraskin, A A; Tavani, M; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Ward, J E; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2015-01-01

    The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons + positrons. Precision investigations of gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well as diffuse gamma-ray emission, along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will study gamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The energy range of GAMMA-400 is expected to be from ~20 MeV up to TeV energies for gamma rays, up to 20 TeV for electrons + positrons, and up to 10E15 eV for cosmic-ray nuclei. For high-energy gamma rays with energy from 10 to 100 GeV, the GAMMA-400 angular resolution improves from 0.1{\\deg} to ~0.01{\\deg} and energy resolution from 3% to ~1%; the proton rejection factor is ~5x10E5. GAMMA-400 will be installed onboard the Russian space observatory.

  7. Circadian modulation of gene expression, but not glutamate uptake, in mouse and rat cortical astrocytes.

    Directory of Open Access Journals (Sweden)

    Christian Beaulé

    Full Text Available BACKGROUND: Circadian clocks control daily rhythms including sleep-wake, hormone secretion, and metabolism. These clocks are based on intracellular transcription-translation feedback loops that sustain daily oscillations of gene expression in many cell types. Mammalian astrocytes display circadian rhythms in the expression of the clock genes Period1 (Per1 and Period2 (Per2. However, a functional role for circadian oscillations in astrocytes is unknown. Because uptake of extrasynaptic glutamate depends on the presence of Per2 in astrocytes, we asked whether glutamate uptake by glia is circadian. METHODOLOGY/PRINCIPAL FINDINGS: We measured glutamate uptake, transcript and protein levels of the astrocyte-specific glutamate transporter, Glast, and the expression of Per1 and Per2 from cultured cortical astrocytes and from explants of somatosensory cortex. We found that glutamate uptake and Glast mRNA and protein expression were significantly reduced in Clock/Clock, Per2- or NPAS2-deficient glia. Uptake was augmented when the medium was supplemented with dibutyryl-cAMP or B27. Critically, glutamate uptake was not circadian in cortical astrocytes cultured from rats or mice or in cortical slices from mice. CONCLUSION/SIGNIFICANCE: We conclude that glutamate uptake levels are modulated by CLOCK, PER2, NPAS2, and the composition of the culture medium, and that uptake does not show circadian variations.

  8. Musical rhythms in heart period dynamics: a cross-cultural and interdisciplinary approach to cardiac rhythms.

    Science.gov (United States)

    Bettermann, H; Amponsah, D; Cysarz, D; van Leeuwen, P

    1999-11-01

    The purpose of this study was to expand classic heart period analysis methods by techniques from ethnomusicology that explicitly take complex musical rhythm principles into consideration. The methods used are based on the theory of African music, the theory of symbolic dynamics, and combinatorial theory. Heart period tachograms from 192 24-h electrocardiograms of 96 healthy subjects were transformed into binary symbol sequences that were interpretable as elementary rhythmic (percussive) patterns, the time lines in African music. Using a hierarchical rhythm pattern scheme closely related to the Derler Rhythm Classification (from jazz theory), we calculated the predominance and stability of pattern classes. The results show that during sleep certain classes, specific to individuals, occurred in a cyclically recurrent manner and many times more often than expected. Simultaneously, other classes disappeared more or less completely. Moreover, the most frequent classes obviously originate from phase-locking processes in autonomic regulation (e.g., between respiratory and cardiac cycles). In conclusion, the new interdisciplinary method presented here demonstrates that heart period patterns, in particular those occurring during night sleep, can be interpreted as musical rhythms. This method may be of great potential use in music therapy research.

  9. Demand-feeding rhythms and feeding-entrainment of locomotor activity rhythms in tench (Tinca tinca).

    Science.gov (United States)

    Herrero, M J; Pascual, M; Madrid, J A; Sánchez-Vázquez, F J

    2005-03-31

    Tench (Tinca tinca) has been described as a strictly nocturnal species whose locomotor activity rhythms, albeit strongly synchronised by light, have an endogenous nature. Aside from light, a number of other environmental factors, such as mealtime, can act as circadian system synchronisers in fish; however, there is a scarcity of information on tench feeding rhythms. This study describes daily self-feeding rhythms in tench, and analyses the role of feeding time on synchronisation of locomotor activity rhythms. Tench were able to operate string sensor-activated self-feeders, and they displayed a strictly nocturnal behavior, both under indoor and outdoor conditions. Locomotor activity remained strictly nocturnal irrespective of whether tench were fed only during the scotophase (D-feeding) or the photophase (L-feeding). However, no statistically significant differences were detected between both groups in terms of food intake or growth performance. Furthermore, unlike L-feeding, D-feeding elicited a clear anticipatory activity (FAA). When tench were given the possibility of feeding at both times of the day, they showed a clear preference for D-feeding. Finally, in fish exposed to constant darkness (DD), feeding time acted as a true zeitgeber and FAA was observed. When animals were fasted under DD conditions, locomotor activity free-run and 6 out of 12 individuals yielded significant results in the periodogram analysis. Under DD, fish resynchronised when regular food was resumed, with some tench displaying FAA. The obtained results indicated the existence of a feeding-entrainable oscillator (FEO) in tench.

  10. Rhythm & Blues de sans papiers parisiens

    OpenAIRE

    Fogel, Frederique

    2014-01-01

    Le sans papiers (ici parisien) est l’une des figures, plurielles, du migrant immobilisé. Le temps qui passe lui ouvre des possibilités de régulariser sa situation. Il lui faut donc patienter, s’adapter dans la contrainte au "rhythm" défini par l’administration, tantôt lent, tantôt rapide. Et trouver aussi son propre rythme en posant des actes. Il lui faut faire avec le blues, qui survient souvent par la prise de conscience du décalage entre l’espoir d’une vie meilleure qui avait déclenché le ...

  11. Abnormal resting-state cortical coupling in chronic tinnitus

    Directory of Open Access Journals (Sweden)

    Langguth Berthold

    2009-02-01

    Full Text Available Abstract Background Subjective tinnitus is characterized by an auditory phantom perception in the absence of any physical sound source. Consequently, in a quiet environment, tinnitus patients differ from control participants because they constantly perceive a sound whereas controls do not. We hypothesized that this difference is expressed by differential activation of distributed cortical networks. Results The analysis was based on a sample of 41 participants: 21 patients with chronic tinnitus and 20 healthy control participants. To investigate the architecture of these networks, we used phase locking analysis in the 1–90 Hz frequency range of a minute of resting-state MEG recording. We found: 1 For tinnitus patients: A significant decrease of inter-areal coupling in the alpha (9–12 Hz band and an increase of inter-areal coupling in the 48–54 Hz gamma frequency range relative to the control group. 2 For both groups: an inverse relationship (r = -.71 of the alpha and gamma network coupling. 3 A discrimination of 83% between the patient and the control group based on the alpha and gamma networks. 4 An effect of manifestation on the distribution of the gamma network: In patients with a tinnitus history of less than 4 years, the left temporal cortex was predominant in the gamma network whereas in patients with tinnitus duration of more than 4 years, the gamma network was more widely distributed including more frontal and parietal regions. Conclusion In the here presented data set we found strong support for an alteration of long-range coupling in tinnitus. Long-range coupling in the alpha frequency band was decreased for tinnitus patients while long-range gamma coupling was increased. These changes discriminate well between tinnitus and control participants. We propose a tinnitus model that integrates this finding in the current knowledge about tinnitus. Furthermore we discuss the impact of this finding to tinnitus therapies using Transcranial

  12. Focal cortical dysplasia – review

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-01-01

    Summary Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed – from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized. Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe. Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes. New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life. Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias. The most common findings on MRI imaging include: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy. However, in type I cortical dysplasia, MR imaging is often normal, and also

  13. Thalamocortical mechanisms for the anteriorization of α rhythms during propofol-induced unconsciousness.

    Science.gov (United States)

    Vijayan, Sujith; Ching, Shinung; Purdon, Patrick L; Brown, Emery N; Kopell, Nancy J

    2013-07-01

    As humans are induced into a state of general anesthesia via propofol, the normal alpha rhythm (8-13 Hz) in the occipital cortex disappears and a frontal alpha rhythm emerges. This spatial shift in alpha activity is called anteriorization. We present a thalamocortical model that suggests mechanisms underlying anteriorization. Our model captures the neural dynamics of anteriorization when we adjust it to reflect two key actions of propofol: its potentiation of GABA and its reduction of the hyperpolarization-activated current Ih. The reduction in Ih abolishes the occipital alpha by silencing a specialized subset of thalamocortical cells, thought to generate occipital alpha at depolarized membrane potentials (>-60 mV). The increase in GABA inhibition imposes an alpha timescale on both the cortical and thalamic portions of the frontal component that are reinforced by reciprocal thalamocortical feedback. Anteriorization can thus be understood as a differential effect of anesthetic drugs on thalamic nuclei with disparate spatial projections, i.e.: (1) they disrupt the normal, depolarized alpha in posterior-projecting thalamic nuclei while (2) they engage a new, hyperpolarized alpha in frontothalamic nuclei. Our model generalizes to other anesthetics that include GABA as a target, since the molecular targets of many such anesthetics alter the model dynamics in a manner similar to that of propofol.

  14. Dynamics of Electrocorticographic (ECoG) Activity in Human Temporal and Frontal Cortical Areas During Music Listening

    Science.gov (United States)

    2012-04-14

    REPORT Dynamics of electrocorticographic (ECoG) activity in human temporal and frontal cortical areas during music listening 14. ABSTRACT 16. SECURITY...information about the sound intensity of music . ECoG activity in the high gamma band recorded from the posterior part of the superior temporal 1. REPORT...ECoG) activity in human temporal and frontal cortical areas during music listening Report Title ABSTRACT Previous studies demonstrated that brain

  15. Analysis of Cortical Flow Models In Vivo

    Science.gov (United States)

    Benink, Hélène A.; Mandato, Craig A.; Bement, William M.

    2000-01-01

    Cortical flow, the directed movement of cortical F-actin and cortical organelles, is a basic cellular motility process. Microtubules are thought to somehow direct cortical flow, but whether they do so by stimulating or inhibiting contraction of the cortical actin cytoskeleton is the subject of debate. Treatment of Xenopus oocytes with phorbol 12-myristate 13-acetate (PMA) triggers cortical flow toward the animal pole of the oocyte; this flow is suppressed by microtubules. To determine how this suppression occurs and whether it can control the direction of cortical flow, oocytes were subjected to localized manipulation of either the contractile stimulus (PMA) or microtubules. Localized PMA application resulted in redirection of cortical flow toward the site of application, as judged by movement of cortical pigment granules, cortical F-actin, and cortical myosin-2A. Such redirected flow was accelerated by microtubule depolymerization, showing that the suppression of cortical flow by microtubules is independent of the direction of flow. Direct observation of cortical F-actin by time-lapse confocal analysis in combination with photobleaching showed that cortical flow is driven by contraction of the cortical F-actin network and that microtubules suppress this contraction. The oocyte germinal vesicle serves as a microtubule organizing center in Xenopus oocytes; experimental displacement of the germinal vesicle toward the animal pole resulted in localized flow away from the animal pole. The results show that 1) cortical flow is directed toward areas of localized contraction of the cortical F-actin cytoskeleton; 2) microtubules suppress cortical flow by inhibiting contraction of the cortical F-actin cytoskeleton; and 3) localized, microtubule-dependent suppression of actomyosin-based contraction can control the direction of cortical flow. We discuss these findings in light of current models of cortical flow. PMID:10930453

  16. The effects of rhythm training on tennis performance.

    Science.gov (United States)

    Söğüt, Mustafa; Kirazci, Sadettin; Korkusuz, Feza

    2012-06-01

    Rhythm training is an integral part of sports. The purposes of the study were to analyze the effects of rhythm training on tennis performance and rhytmic competence of tennis players, to compare the improvement levels of tennis specific and general rhythm training and to examine the effects of shorter and longer tempos on rhythmic competence. Thirty university students whose mean score of International Tennis Number (ITN) was 7.3 (±0.9) were divided randomly into three sub-groups: Tennis Group, General Rhythm Training Group and Tennis-Specific Rhythm Training Group. The experimental procedure lasted 8 weeks. During this period, all groups had the same tennis training twice a week. The Tennis Group had regular tennis training sessions. In addition to regular tennis training sessions, the General Rhythm Training Group followed the general rhythm training sessions and the Tennis-Specific Rhythm Training Group had tennis-specific rhythm training. The measurement instruments were ITN, Rhythmic Competence Analysis Test and Untimed Consecutive Rally Test. The results indicated that participation in tennis-specific or general rhythm training resulted in progress in tennis playing levels, forehand consistency performance and rhythmic competence of the participants. On the other hand, attendance to the regular 8-week tennis training was enough to solely increase the tennis playing level but not sufficient to develop forehand consistency performance and rhythmic competence. Although the participants in the TRTG had better improvement scores than the ones in the GRTG, no significant difference was found between the rhythm training groups. The results also revealed that participants exhibited higher rhythmic competence scores on fast tempo compared to slow tempo.

  17. Fragmentation and stability of circadian activity rhythms predict mortality : the rotterdam study

    NARCIS (Netherlands)

    Zuurbier, Lisette A; Luik, Annemarie I; Hofman, Albert; Franco, Oscar H; Van Someren, Eus J W; Tiemeier, Henning

    2015-01-01

    Circadian rhythms and sleep patterns change as people age. Little is known about the associations between circadian rhythms and mortality rates. We investigated whether 24-hour activity rhythms and sleep characteristics independently predicted mortality. Actigraphy was used to determine the

  18. Core curriculum for the heart rhythm specialist.

    Science.gov (United States)

    Merino, Jose L; Arribas, Fernando; Botto, Giovanni Luca; Huikuri, Heikki; Kraemer, Lars I; Linde, Cecilia; Morgan, John M; Schalij, Martin; Simantirakis, Emmanuel; Wolpert, Christian; Villard, Marie-Christine; Poirey, Julie; Karaim-Fanchon, Svya; Deront, Keren

    2009-08-01

    Heart rhythm (HR) management is rapidly developing as a subspecialty within cardiology and it is imperative to promote and ensure sufficient and homogeneous training and qualification among professionals in Europe. This encouraged the European Society of Cardiology, through the European Heart Rhythm Association (EHRA), to organize a European Core Curriculum for the HR specialist through the following: definition of the scope of the HR speciality (Syllabus), development of minimum standards and objectives for training in HR management (Curriculum), development of a model to certify HR professionals and teaching units (Accreditation), and development of a Registry for European HR accredited professionals and teaching units and their activity (Registries). The duration of the training period should be of a minimum of 2 years following general cardiology training. During this period, the trainee must develop the required knowledge, practical skills, behaviours, and attitudes to manage HR patients. The trainee must be involved in a minimum number of different procedures and achieve specified levels of competence. The training centre should be integrated within a full-service cardiology department. Assessment of the trainee and the training programmes should include reports by the training programme supervisor and the national society HR organizations, a logbook of procedures, written examinations, and assessment of professionalism. The EHRA presently requires the trainee to pass the EHRA accreditation exams (invasive EP and cardiac pacing and ICDs). Continuous learning and practice are required to maintain standards and practice because substantial changes may occur in clinical practice or the health-care environment.

  19. Rhythms of EEG and cognitive processes

    Directory of Open Access Journals (Sweden)

    Novikova S.I.

    2015-06-01

    Full Text Available The study of cognitive processes is regarded to be more effective if it combines a psychological approach with a neurophysiological one. This approach makes it possible to come closer to understanding of the basic mechanisms of different cognitive processes, to describe the patterns of forming these mechanisms in ontogenesis, to investigate the origin of cognitive impairments, and to develop intervention techniques. The promising way of investigating the mechanisms of cognitive functions is the electroencephalography (EEG. This is a non-invasive, safe, and relatively cheap method of research of the functional condition of the brain. The characteristics of EEG rhythms, recorded with different cognitive loads, reflect the processes of functional modulation of neural network activity of the cortex, which serves the neurophysiologic basis for attention, memory and other cognitive processes. The article provides an overview of works containing the analysis of the alpha and theta rhythms’ dynamics in various states of wakefulness. It also introduces the substantiation of methodology of functional regulatory approach to the interpretation of behaviors of EEG rhythms.

  20. Circadian Rhythms, Sleep Deprivation, and Human Performance

    Science.gov (United States)

    Goel, Namni; Basner, Mathias; Rao, Hengyi; Dinges, David F.

    2014-01-01

    Much of the current science on, and mathematical modeling of, dynamic changes in human performance within and between days is dominated by the two-process model of sleep–wake regulation, which posits a neurobiological drive for sleep that varies homeostatically (increasing as a saturating exponential during wakefulness and decreasing in a like manner during sleep), and a circadian process that neurobiologically modulates both the homeostatic drive for sleep and waking alertness and performance. Endogenous circadian rhythms in neurobehavioral functions, including physiological alertness and cognitive performance, have been demonstrated using special laboratory protocols that reveal the interaction of the biological clock with the sleep homeostatic drive. Individual differences in circadian rhythms and genetic and other components underlying such differences also influence waking neurobehavioral functions. Both acute total sleep deprivation and chronic sleep restriction increase homeostatic sleep drive and degrade waking neurobehavioral functions as reflected in sleepiness, attention, cognitive speed, and memory. Recent evidence indicating a high degree of stability in neurobehavioral responses to sleep loss suggests that these trait-like individual differences are phenotypic and likely involve genetic components, including circadian genes. Recent experiments have revealed both sleep homeostatic and circadian effects on brain metabolism and neural activation. Investigation of the neural and genetic mechanisms underlying the dynamically complex interaction between sleep homeostasis and circadian systems is beginning. A key goal of this work is to identify biomarkers that accurately predict human performance in situations in which the circadian and sleep homeostatic systems are perturbed. PMID:23899598

  1. Temperature compensation and entrainment in circadian rhythms

    Science.gov (United States)

    Bodenstein, C.; Heiland, I.; Schuster, S.

    2012-06-01

    To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24 h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

  2. Chaos control applied to heart rhythm dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Borem Ferreira, Bianca, E-mail: biaborem@gmail.com [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil); Souza de Paula, Aline, E-mail: alinedepaula@unb.br [Universidade de Brasi' lia, Department of Mechanical Engineering, 70.910.900 Brasilia, DF (Brazil); Amorim Savi, Marcelo, E-mail: savi@mecanica.ufrj.br [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil)

    2011-08-15

    Highlights: > A natural cardiac pacemaker is modeled by a modified Van der Pol oscillator. > Responses related to normal and chaotic, pathological functioning of the heart are investigated. > Chaos control methods are applied to avoid pathological behaviors of heart dynamics. > Different approaches are treated: stabilization of unstable periodic orbits and chaos suppression. - Abstract: The dynamics of cardiovascular rhythms have been widely studied due to the key aspects of the heart in the physiology of living beings. Cardiac rhythms can be either periodic or chaotic, being respectively related to normal and pathological physiological functioning. In this regard, chaos control methods may be useful to promote the stabilization of unstable periodic orbits using small perturbations. In this article, the extended time-delayed feedback control method is applied to a natural cardiac pacemaker described by a mathematical model. The model consists of a modified Van der Pol equation that reproduces the behavior of this pacemaker. Results show the ability of the chaos control strategy to control the system response performing either the stabilization of unstable periodic orbits or the suppression of chaotic response, avoiding behaviors associated with critical cardiac pathologies.

  3. Hiperostosis cortical infantil

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-04-01

    Full Text Available La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco meses de edad, atendido en el Hospital Pediátrico Provincial “Mártires de Las Tunas” con este diagnóstico, quien ingresó en el servicio de miscelánea B por una celulitis facial. Presentaba aumento de volumen en la región geniana izquierda, febrícola e inapetencia. Se impuso tratamiento con cefazolina y se egresó a los siete días. Acudió nuevamente con tumefacción blanda y difusa de ambas hemicaras, irritabilidad y fiebre. Se interconsultó con cirugía maxilofacial, se indicaron estudios sanguíneos y radiológicos. Se diagnosticó como enfermedad de Caffey, basado en la edad del niño, tumefacción facial sin signos inflamatorios agudos e hiperostosis en ambas corticales mandibulares a la radiografía AP mandíbula; unido a anemia ligera, leucocitosis y eritrosedimentación acelerada. El paciente se trató sintomáticamente y con antinflamatorios no esteroideos. Esta rara entidad se debe tener presente en casos de niños y lactantes con irritabilidad y fiebre inespecífica

  4. A circadian rhythm regulating hyphal melanization in Cercospora kikuchii.

    Science.gov (United States)

    Bluhm, Burton H; Burnham, A Michele; Dunkle, Larry D

    2010-01-01

    Many metabolic and developmental processes in fungi are controlled by biological rhythms. Circadian rhythms approximate a daily (24 h) cycle and have been thoroughly studied in the model fungus, Neurospora crassa. However relatively few examples of true circadian rhythms have been documented among other filamentous fungi. In this study we describe a circadian rhythm underlying hyphal melanization in Cercospora kikuchii, an important pathogen of soybean. After growth in light or light : dark cycles, colonies transferred to darkness produced zonate bands of melanized hyphae interspersed with bands of hyaline hyphae. Rhythmic production of bands was remarkably persistent in the absence of external cues, lasting at least 7 d after transfer to darkness, and was compensated over a range of temperatures. As in N. crassa, blue light but not red light was sufficient to entrain the circadian rhythm in C. kikuchii, and a putative ortholog of white collar-1, one of the genes required for light responses in N. crassa, was identified in C. kikuchii. Circadian regulation of melanization is conserved in other members of the genus: Similar rhythms were identified in another field isolate of C. kikuchii as well as field isolates of C. beticola and C. sorghi, but not in wild-type strains of C. zeae-maydis or C. zeina. This report represents the first documented circadian rhythm among Dothideomycete fungi and provides a new opportunity to dissect the molecular basis of circadian rhythms among filamentous fungi.

  5. Effects of tempo and timing of simple musical rhythms

    NARCIS (Netherlands)

    Repp, B.H.; Windsor, W.L.; Desain, P.W.M.

    2002-01-01

    In this study we investigated whether and how the timing of musical rhythms changes with tempo. Twelve skilled pianists played a monophonic 8-bar melody in 21 different rhythmic versions at 4 different tempi. Within bars, the rhythms represented all possible ordered pairs and triplets of note values

  6. Capturing daily urban rhythms: the use of location aware technologies

    CSIR Research Space (South Africa)

    Krygsman, S

    2007-07-01

    Full Text Available that activities and travel behaviour are believed to be habitual and recurring. Aggregating such individual behaviour leads to so-called daily urban rhythms. Knowledge of these daily urban rhythms is important as they are indicative of temporal and spatial user...

  7. Unexpected diversity in socially synchronized rhythms of shorebirds

    NARCIS (Netherlands)

    Bulla, Martin; Valcu, Mihai; Dokter, Adriaan M; Dondua, Alexei G; Kosztolányi, András; Helm, Barbara; Sandercock, Brett K; Casler, Bruce; Ens, Bruno J.; Spiegel, Caleb S; Hassell, Chris J; Küpper, Clemens; Minton, Clive; Burgas, Daniel; Lank, David B; Payer, David C; Loktionov, Egor Y; Nol, Erica; Kwon, Eunbi; Smith, Fletcher; Gates, H River; Vitnerová, Hana; Prüter, Hanna; Johnson, James A; St Clair, James J H; Lamarre, Jean-François; Rausch, Jennie; Reneerkens, Jeroen; Conklin, Jesse R; Burger, Joanna; Liebezeit, Joe; Bêty, Joël; Coleman, Jonathan T; Figuerola, Jordi; Hooijmeijer, Joslyn; Alves, José A; Smith, Joseph A M; Weidinger, Karel; Koivula, Kari; Gosbell, Ken; Exo, Klaus-Michael; Niles, Larry; Koloski, Laura; McKinnon, Laura; Praus, Libor; Klaassen, Marcel; Giroux, Marie-Andrée; Sládeček, Martin; Boldenow, Megan L; Goldstein, Michael I; Šálek, Miroslav; Senner, Nathan; Rönkä, Nelli; Lecomte, Nicolas; Gilg, Olivier; Vincze, Orsolya; Johnson, Oscar W; Smith, Paul A; Woodard, Paul F; Tomkovich, Pavel S; Battley, Phil F; Bentzen, Rebecca; Lanctot, Richard B; Porter, Ron; Saalfeld, Sarah T; Freeman, Scott; Brown, Stephen C; Yezerinac, Stephen; Székely, Tamás; Montalvo, Tomás; Piersma, Theunis; Loverti, Vanessa; Pakanen, Veli-Matti; Tijsen, Wim; Kempenaers, Bart

    2016-01-01

    The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities

  8. A Rhythm Recognition Computer Program to Advocate Interactivist Perception

    Science.gov (United States)

    Buisson, Jean-Christophe

    2004-01-01

    This paper advocates the main ideas of the interactive model of representation of Mark Bickhard and the assimilation/accommodation framework of Jean Piaget, through a rhythm recognition demonstration program. Although completely unsupervised, the program progressively learns to recognize more and more complex rhythms struck on the user's keyboard.…

  9. Interactive Rhythm Learning System by Combining Tablet Computers and Robots

    Directory of Open Access Journals (Sweden)

    Chien-Hsing Chou

    2017-03-01

    Full Text Available This study proposes a percussion learning device that combines tablet computers and robots. This device comprises two systems: a rhythm teaching system, in which users can compose and practice rhythms by using a tablet computer, and a robot performance system. First, teachers compose the rhythm training contents on the tablet computer. Then, the learners practice these percussion exercises by using the tablet computer and a small drum set. The teaching system provides a new and user-friendly score editing interface for composing a rhythm exercise. It also provides a rhythm rating function to facilitate percussion training for children and improve the stability of rhythmic beating. To encourage children to practice percussion exercises, a robotic performance system is used to interact with the children; this system can perform percussion exercises for students to listen to and then help them practice the exercise. This interaction enhances children’s interest and motivation to learn and practice rhythm exercises. The results of experimental course and field trials reveal that the proposed system not only increases students’ interest and efficiency in learning but also helps them in understanding musical rhythms through interaction and composing simple rhythms.

  10. Unexpected diversity in socially synchronized rhythms of shorebirds

    NARCIS (Netherlands)

    Bulla, Martin; Valcu, Mihai; Dokter, Adriaan M; Dondua, Alexei G; Kosztolányi, András; Helm, Barbara; Sandercock, Brett K; Casler, Bruce; Ens, Bruno J; Spiegel, Caleb S; Hassell, Chris J; Küpper, Clemens; Minton, Clive; Burgas, Daniel; Lank, David B; Payer, David C; Loktionov, Egor Y; Nol, Erica; Kwon, Eunbi; Smith, Fletcher; Gates, H River; Vitnerová, Hana; Prüter, Hanna; Johnson, James A; St Clair, James J H; Lamarre, Jean-François; Rausch, Jennie; Reneerkens, Jeroen; Conklin, Jesse R; Burger, Joanna; Liebezeit, Joe; Bêty, Joël; Coleman, Jonathan T; Figuerola, Jordi; Hooijmeijer, Joslyn; Alves, José A; Smith, Joseph A M; Weidinger, Karel; Koivula, Kari; Gosbell, Ken; Exo, Klaus-Michael; Niles, Larry; Koloski, Laura; McKinnon, Laura; Praus, Libor; Klaassen, Marcel; Giroux, Marie-Andrée; Sládeček, Martin; Boldenow, Megan L; Goldstein, Michael I; Šálek, Miroslav; Senner, Nathan; Rönkä, Nelli; Lecomte, Nicolas; Gilg, Olivier; Vincze, Orsolya; Johnson, Oscar W; Smith, Paul A; Woodard, Paul F; Tomkovich, Pavel S; Battley, Phil F; Bentzen, Rebecca; Lanctot, Richard B; Porter, Ron; Saalfeld, Sarah T; Freeman, Scott; Brown, Stephen C; Yezerinac, Stephen; Székely, Tamás; Montalvo, Tomás; Piersma, Theunis; Loverti, Vanessa; Pakanen, Veli-Matti; Tijsen, Wim; Kempenaers, Bart

    2016-01-01

    The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities

  11. Time-frequency representation of musical rhythm by continuous wavelets

    NARCIS (Netherlands)

    Smith, L.M.; Honing, H.

    2008-01-01

    A method is described that exhaustively represents the periodicities created by a musical rhythm. The continuous wavelet transform is used to decompose an interval representation of a musical rhythm into a hierarchy of short-term frequencies. This reveals the temporal relationships between events ov

  12. A Rhythm Recognition Computer Program to Advocate Interactivist Perception

    Science.gov (United States)

    Buisson, Jean-Christophe

    2004-01-01

    This paper advocates the main ideas of the interactive model of representation of Mark Bickhard and the assimilation/accommodation framework of Jean Piaget, through a rhythm recognition demonstration program. Although completely unsupervised, the program progressively learns to recognize more and more complex rhythms struck on the user's keyboard.…

  13. Perceptual tests of rhythmic similarity: II. Syllable rhythm

    NARCIS (Netherlands)

    Kim, J.; Davis, C.; Cutler, A.

    2008-01-01

    To segment continuous speech into its component words, listeners make use of language rhythm; because rhythm differs across languages, so do the segmentation procedures which listeners use. For each of stress-, syllable-and mora-based rhythmic structure, perceptual experiments have led to the discov

  14. Interaction with Mass Media: The Importance of Rhythm and Tempo.

    Science.gov (United States)

    Snow, Robert P.

    1987-01-01

    Stresses that understanding the impact of interaction with mass media requires conceptualizing media as an institutionalized social form. A critical feature of this process is the grammatical character of media interaction in the form of rhythm and tempo, because these rhythms and tempos become established in everyday routine. (SKC)

  15. Human Brain Basis of Musical Rhythm Perception: Common and Distinct Neural Substrates for Meter, Tempo, and Pattern

    Directory of Open Access Journals (Sweden)

    Michael H. Thaut

    2014-06-01

    Full Text Available Rhythm as the time structure of music is composed of distinct temporal components such as pattern, meter, and tempo. Each feature requires different computational processes: meter involves representing repeating cycles of strong and weak beats; pattern involves representing intervals at each local time point which vary in length across segments and are linked hierarchically; and tempo requires representing frequency rates of underlying pulse structures. We explored whether distinct rhythmic elements engage different neural mechanisms by recording brain activity of adult musicians and non-musicians with positron emission tomography (PET as they made covert same-different discriminations of (a pairs of rhythmic, monotonic tone sequences representing changes in pattern, tempo, and meter, and (b pairs of isochronous melodies. Common to pattern, meter, and tempo tasks were focal activities in right, or bilateral, areas of frontal, cingulate, parietal, prefrontal, temporal, and cerebellar cortices. Meter processing alone activated areas in right prefrontal and inferior frontal cortex associated with more cognitive and abstract representations. Pattern processing alone recruited right cortical areas involved in different kinds of auditory processing. Tempo processing alone engaged mechanisms subserving somatosensory and premotor information (e.g., posterior insula, postcentral gyrus. Melody produced activity different from the rhythm conditions (e.g., right anterior insula and various cerebellar areas. These exploratory findings suggest the outlines of some distinct neural components underlying the components of rhythmic structure.

  16. Human brain basis of musical rhythm perception: common and distinct neural substrates for meter, tempo, and pattern.

    Science.gov (United States)

    Thaut, Michael H; Trimarchi, Pietro Davide; Parsons, Lawrence M

    2014-06-17

    Rhythm as the time structure of music is composed of distinct temporal components such as pattern, meter, and tempo. Each feature requires different computational processes: meter involves representing repeating cycles of strong and weak beats; pattern involves representing intervals at each local time point which vary in length across segments and are linked hierarchically; and tempo requires representing frequency rates of underlying pulse structures. We explored whether distinct rhythmic elements engage different neural mechanisms by recording brain activity of adult musicians and non-musicians with positron emission tomography (PET) as they made covert same-different discriminations of (a) pairs of rhythmic, monotonic tone sequences representing changes in pattern, tempo, and meter, and (b) pairs of isochronous melodies. Common to pattern, meter, and tempo tasks were focal activities in right, or bilateral, areas of frontal, cingulate, parietal, prefrontal, temporal, and cerebellar cortices. Meter processing alone activated areas in right prefrontal and inferior frontal cortex associated with more cognitive and abstract representations. Pattern processing alone recruited right cortical areas involved in different kinds of auditory processing. Tempo processing alone engaged mechanisms subserving somatosensory and premotor information (e.g., posterior insula, postcentral gyrus). Melody produced activity different from the rhythm conditions (e.g., right anterior insula and various cerebellar areas). These exploratory findings suggest the outlines of some distinct neural components underlying the components of rhythmic structure.

  17. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

    Science.gov (United States)

    Houdayer, Elise; Cursi, Marco; Nuara, Arturo; Zanini, Sonia; Gatti, Roberto; Comi, Giancarlo; Leocani, Letizia

    2016-01-01

    The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS). Twelve subjects (experimental group) underwent, before and after a two week-piano training: (1) hand-motor function tests: Jamar, grip and nine-hole peg tests; (2) electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD) during keyboard performance; and (3) TMS, targeting bilateral abductor pollicis brevis (APB) and abductor digiti minimi (ADM), to obtain duration and area of ipsilateral silent period (ISP) during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  18. The impact of cortical deafferentation on the neocortical slow oscillation.

    Science.gov (United States)

    Lemieux, Maxime; Chen, Jen-Yung; Lonjers, Peter; Bazhenov, Maxim; Timofeev, Igor

    2014-04-16

    Slow oscillation is the main brain rhythm observed during deep sleep in mammals. Although several studies have demonstrated its neocortical origin, the extent of the thalamic contribution is still a matter of discussion. Using electrophysiological recordings in vivo on cats and computational modeling, we found that the local thalamic inactivation or the complete isolation of the neocortical slabs maintained within the brain dramatically reduced the expression of slow and fast oscillations in affected cortical areas. The slow oscillation began to recover 12 h after thalamic inactivation. The slow oscillation, but not faster activities, nearly recovered after 30 h and persisted for weeks in the isolated slabs. We also observed an increase of the membrane potential fluctuations recorded in vivo several hours after thalamic inactivation. Mimicking this enhancement in a network computational model with an increased postsynaptic activity of long-range intracortical afferents or scaling K(+) leak current, but not several other Na(+) and K(+) intrinsic currents was sufficient for recovering the slow oscillation. We conclude that, in the intact brain, the thalamus contributes to the generation of cortical active states of the slow oscillation and mediates its large-scale synchronization. Our study also suggests that the deafferentation-induced alterations of the sleep slow oscillation can be counteracted by compensatory intracortical mechanisms and that the sleep slow oscillation is a fundamental and intrinsic state of the neocortex.

  19. ‘Ragged Time’ in Intra-panel Comics Rhythms

    Directory of Open Access Journals (Sweden)

    Corry Shores

    2016-07-01

    Full Text Available A phenomenological method of comics analysis can be useful when we need to uncover the structural features of the comics experience itself. One fruitful application would be in the study of irregular intra-panel rhythms, where the temporalized divisions are not visibly indicated but rather are only experienced. By means of Gilles Deleuze’s notion of rhythmic repetition and his elaboration of it through Olivier Messiaen’s theory of ‘kinetic’ rhythm, we will formulate a conception of visual rhythm as being based on metrical irregularity. We further explicate this concept of irregular rhythm by drawing upon the notion of ‘ragged time’ in the early jazz musical form, ragtime. We finally test its usefulness by examining how the ‘jazzy’ rhythms of Cubist-styled panels by Art Spiegelman and Mary Fleener generate an experience of ragged time.

  20. Chronobiology: biological clocks and rhythms of the skin.

    Science.gov (United States)

    Mehling, A; Fluhr, J W

    2006-01-01

    The cyclicity of time affects virtually all aspects of our being and is the basis of the underlying rhythmicity which is typical of our lives. To 'tell time', most living organisms use internal timing mechanisms known as 'biological clocks'. These 'clocks' coordinate our physiological and behavioral functions and interactions with our environment. One of the strongest influences on rhythmicity is the solar day. The study of these temporal rhythms in biological systems has been coined chronobiology. With the present article we aim to give an overview on chronobiology. Examples of chronobiological effects on skin will be described. Particular emphasis will be placed on circadian rhythms (including rhythms that take place within a 24-hour period, including so-called infradian and/or diurnal rhythms) but also on seasonal variations (circaannual rhythms).

  1. Daily Rhythms in Mosquitoes and Their Consequences for Malaria Transmission

    Directory of Open Access Journals (Sweden)

    Samuel S. C. Rund

    2016-04-01

    Full Text Available The 24-h day involves cycles in environmental factors that impact organismal fitness. This is thought to select for organisms to regulate their temporal biology accordingly, through circadian and diel rhythms. In addition to rhythms in abiotic factors (such as light and temperature, biotic factors, including ecological interactions, also follow daily cycles. How daily rhythms shape, and are shaped by, interactions between organisms is poorly understood. Here, we review an emerging area, namely the causes and consequences of daily rhythms in the interactions between vectors, their hosts and the parasites they transmit. We focus on mosquitoes, malaria parasites and vertebrate hosts, because this system offers the opportunity to integrate from genetic and molecular mechanisms to population dynamics and because disrupting rhythms offers a novel avenue for disease control.

  2. 24-h activity rhythm and sleep in depressed outpatients.

    Science.gov (United States)

    Hori, Hiroaki; Koga, Norie; Hidese, Shinsuke; Nagashima, Anna; Kim, Yoshiharu; Higuchi, Teruhiko; Kunugi, Hiroshi

    2016-06-01

    Disturbances in sleep and circadian rest-activity rhythms are key features of depression. Actigraphy, a non-invasive method for monitoring motor activity, can be used to objectively assess circadian rest-activity rhythms and sleep patterns. While recent studies have measured sleep and daytime activity of depressed patients using wrist-worn actigraphy, the actigraphic 24-h rest-activity rhythm in depression has not been well documented. We aimed to examine actigraphically measured sleep and circadian rest-activity rhythms in depressed outpatients. Twenty patients with DSM-IV major depressive episode and 20 age- and sex-matched healthy controls participated in this study. Participants completed 7 consecutive days of all-day actigraphic activity monitoring while engaging in usual activities. For sleep parameters, total sleep time, wake after sleep onset, and sleep fragmentation index were determined. Circadian rhythms were estimated by fitting individual actigraphy data to a cosine curve of a 24-h activity rhythm using the cosinor method, which generated three circadian activity rhythm parameters, i.e., MESOR (rhythm-adjusted mean), amplitude, and acrophase. Subjective sleep was also assessed using a sleep diary and the Pittsburgh Sleep Quality Index. Patients showed significantly lower MESOR and more dampened amplitude along with significant sleep disturbances. Logistic regression analysis revealed that lower MESOR and more fragmented sleep emerged as the significant predictors of depression. Correlations between subjectively and actigraphically measured parameters demonstrated the validity of actigraphic measurements. These results indicate marked disturbances in sleep and circadian rest-activity rhythms of depression. By simultaneously measuring sleep and rest-activity rhythm parameters, actigraphy might serve as an objective diagnostic aid for depression.

  3. Continuity of visual and auditory rhythms influences sensorimotor coordination.

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    Manuel Varlet

    Full Text Available People often coordinate their movement with visual and auditory environmental rhythms. Previous research showed better performances when coordinating with auditory compared to visual stimuli, and with bimodal compared to unimodal stimuli. However, these results have been demonstrated with discrete rhythms and it is possible that such effects depend on the continuity of the stimulus rhythms (i.e., whether they are discrete or continuous. The aim of the current study was to investigate the influence of the continuity of visual and auditory rhythms on sensorimotor coordination. We examined the dynamics of synchronized oscillations of a wrist pendulum with auditory and visual rhythms at different frequencies, which were either unimodal or bimodal and discrete or continuous. Specifically, the stimuli used were a light flash, a fading light, a short tone and a frequency-modulated tone. The results demonstrate that the continuity of the stimulus rhythms strongly influences visual and auditory motor coordination. Participants' movement led continuous stimuli and followed discrete stimuli. Asymmetries between the half-cycles of the movement in term of duration and nonlinearity of the trajectory occurred with slower discrete rhythms. Furthermore, the results show that the differences of performance between visual and auditory modalities depend on the continuity of the stimulus rhythms as indicated by movements closer to the instructed coordination for the auditory modality when coordinating with discrete stimuli. The results also indicate that visual and auditory rhythms are integrated together in order to better coordinate irrespective of their continuity, as indicated by less variable coordination closer to the instructed pattern. Generally, the findings have important implications for understanding how we coordinate our movements with visual and auditory environmental rhythms in everyday life.

  4. Cross-cultural influences on rhythm processing: reproduction, discrimination, and beat tapping.

    Science.gov (United States)

    Cameron, Daniel J; Bentley, Jocelyn; Grahn, Jessica A

    2015-01-01

    The structures of musical rhythm differ between cultures, despite the fact that the ability to entrain movement to musical rhythm occurs in virtually all individuals across cultures. To measure the influence of culture on rhythm processing, we tested East African and North American adults on perception, production, and beat tapping for rhythms derived from East African and Western music. To assess rhythm perception, participants identified whether pairs of rhythms were the same or different. To assess rhythm production, participants reproduced rhythms after hearing them. To assess beat tapping, participants tapped the beat along with repeated rhythms. We expected that performance in all three tasks would be influenced by the culture of the participant and the culture of the rhythm. Specifically, we predicted that a participant's ability to discriminate, reproduce, and accurately tap the beat would be better for rhythms from their own culture than for rhythms from another culture. In the rhythm discrimination task, there were no differences in discriminating culturally familiar and unfamiliar rhythms. In the rhythm reproduction task, both groups reproduced East African rhythms more accurately than Western rhythms, but East African participants also showed an effect of cultural familiarity, leading to a significant interaction. In the beat tapping task, participants in both groups tapped the beat more accurately for culturally familiar than for unfamiliar rhythms. Moreover, there were differences between the two participant groups, and between the two types of rhythms, in the metrical level selected for beat tapping. The results demonstrate that culture does influence the processing of musical rhythm. In terms of the function of musical rhythm, our results are consistent with theories that musical rhythm enables synchronization. Musical rhythm may foster musical cultural identity by enabling within-group synchronization to music, perhaps supporting social cohesion.

  5. Short-Latency Median-Nerve Somatosensory-Evoked Potentials and Induced Gamma-Oscillations in Humans

    Science.gov (United States)

    Fukuda, Miho; Nishida, Masaaki; Juhasz, Csaba; Muzik, Otto; Sood, Sandeep; Chugani, Harry T.; Asano, Eishi

    2008-01-01

    Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the…

  6. Cortical Correlates of Fitts’ Law

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    Peter eIfft

    2011-12-01

    Full Text Available Fitts' law describes the fundamental trade-off between movement accuracy and speed: It states that the duration of reaching movements is a function of target size and distance. While Fitts' law has been extensively studied in ergonomics and has guided the design of human-computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1 and primary somatosensory (S1 cortices. The monkeys performed reaches with a joystick-controlled cursor towards targets of different size. The reaction time, movement time and movement velocity changed with target size, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required target size as an additional parameter. Neuronal representation of target size was especially prominent during the early reaction time period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was mostly correlated with movement velocity. Neural decoders were applied to simultaneously decode target size and motor parameters from cortical modulations. We suggest using such classifiers to improve neuroprosthetic control.

  7. Beta rhythm modulation by speech sounds: somatotopic mapping in somatosensory cortex.

    Science.gov (United States)

    Bartoli, Eleonora; Maffongelli, Laura; Campus, Claudio; D'Ausilio, Alessandro

    2016-08-08

    During speech listening motor regions are somatotopically activated, resembling the activity that subtends actual speech production, suggesting that motor commands can be retrieved from sensory inputs. Crucially, the efficient motor control of the articulators relies on the accurate anticipation of the somatosensory reafference. Nevertheless, evidence about somatosensory activities elicited by auditory speech processing is sparse. The present work looked for specific interactions between auditory speech presentation and somatosensory cortical information processing. We used an auditory speech identification task with sounds having different place of articulation (bilabials and dentals). We tested whether coupling the auditory task with a peripheral electrical stimulation of the lips would affect the pattern of sensorimotor electroencephalographic rhythms. Peripheral electrical stimulation elicits a series of spectral perturbations of which the beta rebound reflects the return-to-baseline stage of somatosensory processing. We show a left-lateralized and selective reduction in the beta rebound following lip somatosensory stimulation when listening to speech sounds produced with the lips (i.e. bilabials). Thus, the somatosensory processing could not return to baseline due to the recruitment of the same neural resources by speech stimuli. Our results are a clear demonstration that heard speech sounds are somatotopically mapped onto somatosensory cortices, according to place of articulation.

  8. Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

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    Kimura Akio

    2010-06-01

    Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

  9. Beta rhythm modulation by speech sounds: somatotopic mapping in somatosensory cortex

    Science.gov (United States)

    Bartoli, Eleonora; Maffongelli, Laura; Campus, Claudio; D’Ausilio, Alessandro

    2016-01-01

    During speech listening motor regions are somatotopically activated, resembling the activity that subtends actual speech production, suggesting that motor commands can be retrieved from sensory inputs. Crucially, the efficient motor control of the articulators relies on the accurate anticipation of the somatosensory reafference. Nevertheless, evidence about somatosensory activities elicited by auditory speech processing is sparse. The present work looked for specific interactions between auditory speech presentation and somatosensory cortical information processing. We used an auditory speech identification task with sounds having different place of articulation (bilabials and dentals). We tested whether coupling the auditory task with a peripheral electrical stimulation of the lips would affect the pattern of sensorimotor electroencephalographic rhythms. Peripheral electrical stimulation elicits a series of spectral perturbations of which the beta rebound reflects the return-to-baseline stage of somatosensory processing. We show a left-lateralized and selective reduction in the beta rebound following lip somatosensory stimulation when listening to speech sounds produced with the lips (i.e. bilabials). Thus, the somatosensory processing could not return to baseline due to the recruitment of the same neural resources by speech stimuli. Our results are a clear demonstration that heard speech sounds are somatotopically mapped onto somatosensory cortices, according to place of articulation. PMID:27499204

  10. Abnormal interictal gamma activity may manifest a seizure onset zone in temporal lobe epilepsy.

    Science.gov (United States)

    Medvedev, Andrei V; Murro, Anthony M; Meador, Kimford J

    2011-04-01

    Even though recent studies have suggested that seizures do not occur suddenly and that before a seizure there is a period with an increased probability of seizure occurrence, neurophysiological mechanisms of interictal and pre-seizure states are unknown. The ability of mathematical methods to provide much more sensitive tools for the detection of subtle changes in the electrical activity of the brain gives promise that electrophysiological markers of enhanced seizure susceptibility can be found even during interictal periods when EEG of epilepsy patients often looks 'normal'. Previously, we demonstrated in animals that hippocampal and neocortical gamma-band rhythms (30-100 Hz) intensify long before seizures caused by systemic infusion of kainic acid. Other studies in recent years have also drawn attention to the fast activity (>30 Hz) as a possible marker of epileptogenic tissue. The current study quantified gamma-band activity during interictal periods and seizures in intracranial EEG (iEEG) in 5 patients implanted with subdural grids/intracranial electrodes during their pre-surgical evaluation. In all our patients, we found distinctive (abnormal) bursts of gamma activity with a 3 to 100 fold increase in power at gamma frequencies with respect to selected by clinicians, quiescent, artifact-free, 7-20 min "normal" background (interictal) iEEG epochs 1 to 14 hours prior to seizures. Increases in gamma activity were largest in those channels which later displayed the most intensive electrographic seizure discharges. Moreover, location of gamma-band bursts correlated (with high specificity, 96.4% and sensitivity, 83.8%) with seizure onset zone (SOZ) determined by clinicians. Spatial localization of interictal gamma rhythms within SOZ suggests that the persistent presence of abnormally intensified gamma rhythms in the EEG may be an important tool for focus localization and possibly a determinant of epileptogenesis.

  11. Effect of Pilates Training on Alpha Rhythm

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    Zhijie Bian

    2013-01-01

    Full Text Available In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI. It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation.

  12. Effect of Pilates Training on Alpha Rhythm

    Science.gov (United States)

    Bian, Zhijie; Sun, Hongmin; Lu, Chengbiao; Yao, Li; Chen, Shengyong; Li, Xiaoli

    2013-01-01

    In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI). It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation. PMID:23861723

  13. Rhythm and Randomness in Human Contact

    CERN Document Server

    Freeman, Mervyn P; Yoneki, Eiko; Crowcroft, Jon

    2010-01-01

    There is substantial interest in the effect of human mobility patterns on opportunistic communications. Inspired by recent work revisiting some of the early evidence for a L\\'evy flight foraging strategy in animals, we analyse datasets on human contact from real world traces. By analysing the distribution of inter-contact times on different time scales and using different graphical forms, we find not only the highly skewed distributions of waiting times highlighted in previous studies but also clear circadian rhythm. The relative visibility of these two components depends strongly on which graphical form is adopted and the range of time scales. We use a simple model to reconstruct the observed behaviour and discuss the implications of this for forwarding efficiency.

  14. Circadian Rhythms, Sleep, and Disorders of Aging.

    Science.gov (United States)

    Mattis, Joanna; Sehgal, Amita

    2016-04-01

    Sleep-wake cycles are known to be disrupted in people with neurodegenerative disorders. These findings are now supported by data from animal models for some of these disorders, raising the question of whether the disrupted sleep/circadian regulation contributes to the loss of neural function. As circadian rhythms and sleep consolidation also break down with normal aging, changes in these may be part of what makes aging a risk factor for disorders like Alzheimer's disease (AD). Mechanisms underlying the connection between circadian/sleep dysregulation and neurodegeneration remain unclear, but several recent studies provide interesting possibilities. While mechanistic analysis is under way, it is worth considering treatment of circadian/sleep disruption as a means to alleviate symptoms of neurodegenerative disorders.

  15. Copula-based analysis of rhythm

    Science.gov (United States)

    García, J. E.; González-López, V. A.; Viola, M. L. Lanfredi

    2016-06-01

    In this paper we establish stochastic profiles of the rhythm for three languages: English, Japanese and Spanish. We model the increase or decrease of the acoustical energy, collected into three bands coming from the acoustic signal. The number of parameters needed to specify a discrete multivariate Markov chain grows exponentially with the order and dimension of the chain. In this case the size of the database is not large enough for a consistent estimation of the model. We apply a strategy to estimate a multivariate process with an order greater than the order achieved using standard procedures. The new strategy consist on obtaining a partition of the state space which is constructed from a combination of the partitions corresponding to the three marginal processes, one for each band of energy, and the partition coming from to the multivariate Markov chain. Then, all the partitions are linked using a copula, in order to estimate the transition probabilities.

  16. Circadian Rhythms in Diet-Induced Obesity.

    Science.gov (United States)

    Engin, Atilla

    2017-01-01

    The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in

  17. Biological and psychological rhythms: an integrative approach to rhythm disturbances in autistic disorder.

    Science.gov (United States)

    Botbol, Michel; Cabon, Philippe; Kermarrec, Solenn; Tordjman, Sylvie

    2013-09-01

    Biological rhythms are crucial phenomena that are perfect examples of the adaptation of organisms to their environment. A considerable amount of work has described different types of biological rhythms (from circadian to ultradian), individual differences in their patterns and the complexity of their regulation. In particular, the regulation and maturation of the sleep-wake cycle have been thoroughly studied. Its desynchronization, both endogenous and exogenous, is now well understood, as are its consequences for cognitive impairments and health problems. From a completely different perspective, psychoanalysts have shown a growing interest in the rhythms of psychic life. This interest extends beyond the original focus of psychoanalysis on dreams and the sleep-wake cycle, incorporating central theoretical and practical psychoanalytic issues related to the core functioning of the psychic life: the rhythmic structures of drive dynamics, intersubjective developmental processes and psychic containment functions. Psychopathological and biological approaches to the study of infantile autism reveal the importance of specific biological and psychological rhythmic disturbances in this disorder. Considering data and hypotheses from both perspectives, this paper proposes an integrative approach to the study of these rhythmic disturbances and offers an etiopathogenic hypothesis based on this integrative approach.

  18. Cortical myoclonus in Huntington's disease.

    Science.gov (United States)

    Thompson, P D; Bhatia, K P; Brown, P; Davis, M B; Pires, M; Quinn, N P; Luthert, P; Honovar, M; O'Brien, M D; Marsden, C D

    1994-11-01

    We describe three patients with Huntington's disease, from two families, in whom myoclonus was the predominant clinical feature. The diagnosis was confirmed at autopsy in two cases and by DNA analysis in all three. These patients all presented before the age of 30 years and were the offspring of affected fathers. Neurophysiological studies documented generalised and multifocal action myoclonus of cortical origin that was strikingly stimulus sensitive, without enlargement of the cortical somatosensory evoked potential. The myoclonus improved with piracetam therapy in one patient and a combination of sodium valproate and clonazepam in the other two. Cortical reflex myoclonus is a rare but disabling component of the complex movement disorder of Huntington's disease, which may lead to substantial diagnostic difficulties.

  19. Cross-Cultural Influences on Rhythm Processing: Reproduction, Discrimination, and Beat Tapping

    Directory of Open Access Journals (Sweden)

    Daniel J Cameron

    2015-04-01

    Full Text Available The structures of musical rhythm differ between cultures, despite the fact that the ability to synchronize one’s movements to musical rhythms appears to be universal. To measure the influence of culture on rhythm processing, we tested East African and North American adults on the perception, production, and beat tapping of rhythms derived from East African and Western music. To assess rhythm perception, participants identified whether pairs of rhythms were same or different. To assess rhythm production, participants reproduced rhythms after hearing them. To assess beat tapping, participants tapped the beat along with repeated rhythms. We expected that performance in all three tasks would be influenced both by the culture of the participant and by the culture of the rhythm. Specifically, we predicted that a participant’s ability to discriminate, reproduce, and accurately tap the beat would be better for rhythms from their own culture than for rhythms from another culture. In the rhythm discrimination task, there were no differences in discriminating culturally familiar and unfamiliar rhythms. In the rhythm reproduction task, both groups reproduced East African rhythms more accurately than Western rhythms, but East African participants also showed an effect of cultural familiarity, leading to a significant interaction. In the beat tapping task, participants in both groups tapped the beat more accurately for culturally familiar than unfamiliar rhythms. The results demonstrate that culture does influence the processing of musical rhythm. In terms of the function of musical rhythm, our results are consistent with theories that musical rhythm enables synchronization. Musical rhythm may foster musical cultural identity by enabling within-group synchronization to music, perhaps supporting social cohesion.

  20. A Reliable Method for Rhythm Analysis during Cardiopulmonary Resuscitation

    Directory of Open Access Journals (Sweden)

    U. Ayala

    2014-01-01

    Full Text Available Interruptions in cardiopulmonary resuscitation (CPR compromise defibrillation success. However, CPR must be interrupted to analyze the rhythm because although current methods for rhythm analysis during CPR have high sensitivity for shockable rhythms, the specificity for nonshockable rhythms is still too low. This paper introduces a new approach to rhythm analysis during CPR that combines two strategies: a state-of-the-art CPR artifact suppression filter and a shock advice algorithm (SAA designed to optimally classify the filtered signal. Emphasis is on designing an algorithm with high specificity. The SAA includes a detector for low electrical activity rhythms to increase the specificity, and a shock/no-shock decision algorithm based on a support vector machine classifier using slope and frequency features. For this study, 1185 shockable and 6482 nonshockable 9-s segments corrupted by CPR artifacts were obtained from 247 patients suffering out-of-hospital cardiac arrest. The segments were split into a training and a test set. For the test set, the sensitivity and specificity for rhythm analysis during CPR were 91.0% and 96.6%, respectively. This new approach shows an important increase in specificity without compromising the sensitivity when compared to previous studies.

  1. A Reliable Method for Rhythm Analysis during Cardiopulmonary Resuscitation

    Science.gov (United States)

    Ayala, U.; Irusta, U.; Ruiz, J.; Eftestøl, T.; Kramer-Johansen, J.; Alonso-Atienza, F.; Alonso, E.; González-Otero, D.

    2014-01-01

    Interruptions in cardiopulmonary resuscitation (CPR) compromise defibrillation success. However, CPR must be interrupted to analyze the rhythm because although current methods for rhythm analysis during CPR have high sensitivity for shockable rhythms, the specificity for nonshockable rhythms is still too low. This paper introduces a new approach to rhythm analysis during CPR that combines two strategies: a state-of-the-art CPR artifact suppression filter and a shock advice algorithm (SAA) designed to optimally classify the filtered signal. Emphasis is on designing an algorithm with high specificity. The SAA includes a detector for low electrical activity rhythms to increase the specificity, and a shock/no-shock decision algorithm based on a support vector machine classifier using slope and frequency features. For this study, 1185 shockable and 6482 nonshockable 9-s segments corrupted by CPR artifacts were obtained from 247 patients suffering out-of-hospital cardiac arrest. The segments were split into a training and a test set. For the test set, the sensitivity and specificity for rhythm analysis during CPR were 91.0% and 96.6%, respectively. This new approach shows an important increase in specificity without compromising the sensitivity when compared to previous studies. PMID:24895621

  2. Development and use of a biological rhythm interview.

    Science.gov (United States)

    Giglio, Larriany Maria Falsin; Magalhães, Pedro Vieira da Silva; Andreazza, Ana Cristina; Walz, Julio Cesar; Jakobson, Lourenço; Rucci, Paola; Rosa, Adriane Ribeiro; Hidalgo, Maria Paz; Vieta, Eduard; Kapczinski, Flávio

    2009-11-01

    As several lines of evidence point to irregular biological rhythms in bipolar disorder, and its disruption may lead to new illness episodes, having an instrument that measures biological rhythms is critical. This report describes the validation of a new instrument, the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), designed to assess biological rhythms in the clinical setting. Eighty-one outpatients with a diagnosis of bipolar disorder and 79 control subjects matched for type of health service used, sex, age and educational level were consecutively recruited. After a pilot study, 18 items evaluating sleep, activities, social rhythm and eating pattern were probed for discriminant, content and construct validity, concurrent validity with the Pittsburgh Sleep Quality Index (PSQI), internal consistency and test-retest reliability. A three-factor solution, termed sleep/social rhythm factor, activity factor and feeding factor, provided the best theoretical and most parsimonious account of the data; items essentially loaded in factors as theoretically intended, with the exception of the sleep and social scales, which formed a single factor. Test-retest reliability and internal consistency were excellent. Highly significant differences between the two groups were found for the whole scale and for each BRIAN factor. Total BRIAN scores were highly correlated with the global PSQI score. The BRIAN scale presents a consistent profile of validity and reliability. Its use may help clinicians to better assess their patients and researchers to improve the evaluation of the impact of novel therapies targeting biological rhythm pathways.

  3. Grid cells and cortical representation.

    Science.gov (United States)

    Moser, Edvard I; Roudi, Yasser; Witter, Menno P; Kentros, Clifford; Bonhoeffer, Tobias; Moser, May-Britt

    2014-07-01

    One of the grand challenges in neuroscience is to comprehend neural computation in the association cortices, the parts of the cortex that have shown the largest expansion and differentiation during mammalian evolution and that are thought to contribute profoundly to the emergence of advanced cognition in humans. In this Review, we use grid cells in the medial entorhinal cortex as a gateway to understand network computation at a stage of cortical processing in which firing patterns are shaped not primarily by incoming sensory signals but to a large extent by the intrinsic properties of the local circuit.

  4. Paroxysmal kinesigenic dyskinesia : Cortical or non-cortical origin

    NARCIS (Netherlands)

    van Strien, Teun W.; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A. J.; Linssen, Wim H. J. P.; Groffen, Alexander J. A.; Tijssen, Marina A. J.

    2012-01-01

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or non-co

  5. Focal electroencephalography rhythm asymmetry due to focal skull fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Michael A. Meyer

    2014-06-01

    Full Text Available An unusual pervasive and persistent asymmetry in background rhythm was found on surface electroencephalography (EEG recordings in a 22 year old with new onset of generalized seizure activity. Radiographic correlation with computed tomography, positron emission tomography and bone scan imaging uncovered that the higher amplitude left frontal-parietal background activity was related to a circumscribed area of left frontal-parietal fibrous dysplasia affecting the skull. This case report emphasizes that the presumed higher electrical conductance of fibrous dysplasia lead to a greater transparency of normal background rhythms, and must be taken into account as a form of breach rhythm for accurate EEG interpretation.

  6. Rhythm as an affordance for the entrainment of movement.

    Science.gov (United States)

    Cummins, Fred

    2009-01-01

    A general account of rhythm in human behaviour is provided, according to which rhythm inheres in the affordance that a signal provides for the entrainment of movement on the part of a perceiver. This generic account is supported by an explication of the central concepts of affordance and entrainment. When viewed in this light, rhythm appears as the correct explanandum to account for coordinated behaviour in a wide variety of situations, including such core senses as dance and the production of music. Speech may appear to be only marginally rhythmical under such an account, but several experimental studies reveal that speech, too, has the potential to entrain movement.

  7. Gamma Oscillations of Spiking Neural Populations Enhance Signal Discrimination

    Science.gov (United States)

    Masuda, Naoki; Doiron, Brent

    2007-01-01

    Selective attention is an important filter for complex environments where distractions compete with signals. Attention increases both the gamma-band power of cortical local field potentials and the spike-field coherence within the receptive field of an attended object. However, the mechanisms by which gamma-band activity enhances, if at all, the encoding of input signals are not well understood. We propose that gamma oscillations induce binomial-like spike-count statistics across noisy neural populations. Using simplified models of spiking neurons, we show how the discrimination of static signals based on the population spike-count response is improved with gamma induced binomial statistics. These results give an important mechanistic link between the neural correlates of attention and the discrimination tasks where attention is known to enhance performance. Further, they show how a rhythmicity of spike responses can enhance coding schemes that are not temporally sensitive. PMID:18052541

  8. Gamma oscillations of spiking neural populations enhance signal discrimination.

    Directory of Open Access Journals (Sweden)

    Naoki Masuda

    2007-11-01

    Full Text Available Selective attention is an important filter for complex environments where distractions compete with signals. Attention increases both the gamma-band power of cortical local field potentials and the spike-field coherence within the receptive field of an attended object. However, the mechanisms by which gamma-band activity enhances, if at all, the encoding of input signals are not well understood. We propose that gamma oscillations induce binomial-like spike-count statistics across noisy neural populations. Using simplified models of spiking neurons, we show how the discrimination of static signals based on the population spike-count response is improved with gamma induced binomial statistics. These results give an important mechanistic link between the neural correlates of attention and the discrimination tasks where attention is known to enhance performance. Further, they show how a rhythmicity of spike responses can enhance coding schemes that are not temporally sensitive.

  9. Face activated neurodynamic cortical networks.

    Science.gov (United States)

    Susac, Ana; Ilmoniemi, Risto J; Ranken, Doug; Supek, Selma

    2011-05-01

    Previous neuroimaging studies have shown that complex visual stimuli, such as faces, activate multiple brain regions, yet little is known on the dynamics and complexity of the activated cortical networks during the entire measurable evoked response. In this study, we used simulated and face-evoked empirical MEG data from an oddball study to investigate the feasibility of accurate, efficient, and reliable spatio-temporal tracking of cortical pathways over prolonged time intervals. We applied a data-driven, semiautomated approach to spatio-temporal source localization with no prior assumptions on active cortical regions to explore non-invasively face-processing dynamics and their modulation by task. Simulations demonstrated that the use of multi-start downhill simplex and data-driven selections of time intervals submitted to the Calibrated Start Spatio-Temporal (CSST) algorithm resulted in improved accuracy of the source localization and the estimation of the onset of their activity. Locations and dynamics of the identified sources indicated a distributed cortical network involved in face processing whose complexity was task dependent. This MEG study provided the first non-invasive demonstration, agreeing with intracranial recordings, of an early onset of the activity in the fusiform face gyrus (FFG), and that frontal activation preceded parietal for responses elicited by target faces.

  10. Speech rhythms and multiplexed oscillatory sensory coding in the human brain.

    Directory of Open Access Journals (Sweden)

    Joachim Gross

    2013-12-01

    Full Text Available Cortical oscillations are likely candidates for segmentation and coding of continuous speech. Here, we monitored continuous speech processing with magnetoencephalography (MEG to unravel the principles of speech segmentation and coding. We demonstrate that speech entrains the phase of low-frequency (delta, theta and the amplitude of high-frequency (gamma oscillations in the auditory cortex. Phase entrainment is stronger in the right and amplitude entrainment is stronger in the left auditory cortex. Furthermore, edges in the speech envelope phase reset auditory cortex oscillations thereby enhancing their entrainment to speech. This mechanism adapts to the changing physical features of the speech envelope and enables efficient, stimulus-specific speech sampling. Finally, we show that within the auditory cortex, coupling between delta, theta, and gamma oscillations increases following speech edges. Importantly, all couplings (i.e., brain-speech and also within the cortex attenuate for backward-presented speech, suggesting top-down control. We conclude that segmentation and coding of speech relies on a nested hierarchy of entrained cortical oscillations.

  11. Biological rhythms during residence in polar regions.

    Science.gov (United States)

    Arendt, Josephine

    2012-05-01

    At Arctic and Antarctic latitudes, personnel are deprived of natural sunlight in winter and have continuous daylight in summer: light of sufficient intensity and suitable spectral composition is the main factor that maintains the 24-h period of human circadian rhythms. Thus, the status of the circadian system is of interest. Moreover, the relatively controlled artificial light conditions in winter are conducive to experimentation with different types of light treatment. The hormone melatonin and/or its metabolite 6-sulfatoxymelatonin (aMT6s) provide probably the best index of circadian (and seasonal) timing. A frequent observation has been a delay of the circadian system in winter. A skeleton photoperiod (2 × 1-h, bright white light, morning and evening) can restore summer timing. A single 1-h pulse of light in the morning may be sufficient. A few people desynchronize from the 24-h day (free-run) and show their intrinsic circadian period, usually >24 h. With regard to general health in polar regions, intermittent reports describe abnormalities in various physiological processes from the point of view of daily and seasonal rhythms, but positive health outcomes are also published. True winter depression (SAD) appears to be rare, although subsyndromal SAD is reported. Probably of most concern are the numerous reports of sleep problems. These have prompted investigations of the underlying mechanisms and treatment interventions. A delay of the circadian system with "normal" working hours implies sleep is attempted at a suboptimal phase. Decrements in sleep efficiency, latency, duration, and quality are also seen in winter. Increasing the intensity of ambient light exposure throughout the day advanced circadian phase and was associated with benefits for sleep: blue-enriched light was slightly more effective than standard white light. Effects on performance remain to be fully investigated. At 75°S, base personnel adapt the circadian system to night work within a week

  12. GammaWorkshops Proceedings

    DEFF Research Database (Denmark)

    Strålberg, Elisabeth; Klemola, Seppo; Nielsen, Sven Poul;

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activitie...

  13. Analysis of Nonstationary Time Series for Biological Rhythms Research.

    Science.gov (United States)

    Leise, Tanya L

    2017-06-01

    This article is part of a Journal of Biological Rhythms series exploring analysis and statistics topics relevant to researchers in biological rhythms and sleep research. The goal is to provide an overview of the most common issues that arise in the analysis and interpretation of data in these fields. In this article on time series analysis for biological rhythms, we describe some methods for assessing the rhythmic properties of time series, including tests of whether a time series is indeed rhythmic. Because biological rhythms can exhibit significant fluctuations in their period, phase, and amplitude, their analysis may require methods appropriate for nonstationary time series, such as wavelet transforms, which can measure how these rhythmic parameters change over time. We illustrate these methods using simulated and real time series.

  14. Ultradian rhythm unmasked in the Pdf clock mutant of Drosophila.

    Science.gov (United States)

    Seki, Yuuichi; Tanimura, Teiichi

    2014-09-01

    A diverse range of organisms shows physiological and behavioural rhythms with various periods. Extensive studies have been performed to elucidate the molecular mechanisms of circadian rhythms with an approximately 24 h period in both Drosophila and mammals, while less attention has been paid to ultradian rhythms with shorter periods. We used a video-tracking method to monitor the movement of single flies, and clear ultradian rhythms were detected in the locomotor behaviour of wild type and clock mutant flies kept under constant dark conditions. In particular, the Pigment-dispersing factor mutant (Pdf 01) demonstrated a precise and robust ultradian rhythmicity, which was not temperature compensated. Our results suggest that Drosophila has an endogenous ultradian oscillator that is masked by circadian rhythmic behaviours.

  15. Rhythm dynamics of complex neuronal networks with mixed bursting neurons

    Institute of Scientific and Technical Information of China (English)

    Lü Yong-Bing; Shi Xia; Zheng Yan-Hong

    2013-01-01

    The spatiotemporal order and rhythm dynamics of a complex neuronal network with mixed bursting neurons are studied in this paper.A quantitative characteristic,the width factor,is introduced to describe the rhythm dynamics of an individual neuron,and the average width factor is used to characterize the rhythm dynamics of a neuronal network.An r parameter is introduced to denote the ratio of the short bursting neurons in the network.Then we investigate the effect of the ratio on the rhythm dynamics of the neuronal network.The critical value of r is derived,and the neurons in the network always remain short bursting when the r ratio is larger than the critical value.

  16. Ultradian rhythm unmasked in the Pdf clock mutant of Drosophila

    Indian Academy of Sciences (India)

    Yuuichi Seki; Teiichi Tanimura

    2014-09-01

    A diverse range of organisms shows physiological and behavioural rhythms with various periods. Extensive studies have been performed to elucidate the molecular mechanisms of circadian rhythms with an approximately 24 h period in both Drosophila and mammals, while less attention has been paid to ultradian rhythms with shorter periods. We used a video-tracking method to monitor the movement of single flies, and clear ultradian rhythms were detected in the locomotor behaviour of wild type and clock mutant flies kept under constant dark conditions. In particular, the Pigment-dispersing factor mutant (Pdf01) demonstrated a precise and robust ultradian rhythmicity, which was not temperature compensated. Our results suggest that Drosophila has an endogenous ultradian oscillator that is masked by circadian rhythmic behaviours.

  17. Chorusing, synchrony, and the evolutionary functions of rhythm

    National Research Council Canada - National Science Library

    Ravignani, Andrea; Bowling, Daniel L; Fitch, W Tecumseh

    2014-01-01

    .... Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony...

  18. Language familiarity, expectation, and novice musical rhythm production.

    Science.gov (United States)

    Neuhoff, John G; Lidji, Pascale

    2014-12-01

    The music of expert musicians reflects the speech rhythm of their native language. Here, we examine this effect in amateur and novice musicians. English- and French-speaking participants were both instructed to produce simple "English" and "French" tunes using only two keys on a keyboard. All participants later rated the rhythmic variability of English and French speech samples. The rhythmic variability of the "English" and "French" tunes that were produced reflected the perceived rhythmic variability in English and French speech samples. Yet, the pattern was different for English and French participants and did not correspond to the actual measured speech rhythm variability of the speech samples. Surprise recognition tests two weeks later confirmed that the music-speech relationship remained over time. The results show that the relationship between music and speech rhythm is more widespread than previously thought and that musical rhythm production by amateurs and novices is concordant with their rhythmic expectations in the perception of speech.

  19. Speech rhythm sensitivity and musical aptitude: ERPs and individual differences.

    Science.gov (United States)

    Magne, Cyrille; Jordan, Deanna K; Gordon, Reyna L

    2016-02-01

    This study investigated the electrophysiological markers of rhythmic expectancy during speech perception. In addition, given the large literature showing overlaps between cognitive and neural resources recruited for language and music, we considered a relation between musical aptitude and individual differences in speech rhythm sensitivity. Twenty adults were administered a standardized assessment of musical aptitude, and EEG was recorded as participants listened to sequences of four bisyllabic words for which the stress pattern of the final word either matched or mismatched the stress pattern of the preceding words. Words with unexpected stress patterns elicited an increased fronto-central mid-latency negativity. In addition, rhythm aptitude significantly correlated with the size of the negative effect elicited by unexpected iambic words, the least common type of stress pattern in English. The present results suggest shared neurocognitive resources for speech rhythm and musical rhythm.

  20. An empirical comparison of rhythm in language and music.

    Science.gov (United States)

    Patel, Aniruddh D; Daniele, Joseph R

    2003-02-01

    Musicologists and linguists have often suggested that the prosody of a culture's spoken language can influence the structure of its instrumental music. However, empirical data supporting this idea have been lacking. This has been partly due to the difficulty of developing and applying comparable quantitative measures to melody and rhythm in speech and music. This study uses a recently-developed measure for the study of speech rhythm to compare rhythmic patterns in English and French language and classical music. We find that English and French musical themes are significantly different in this measure of rhythm, which also differentiates the rhythm of spoken English and French. Thus, there is an empirical basis for the claim that spoken prosody leaves an imprint on the music of a culture.

  1. Melatonin in sleepless children : everything has a rhythm?

    NARCIS (Netherlands)

    van Geijlswijk, I.M.

    2011-01-01

    Every living organism has an biological clock regulating endogenous melatonin production, synchronized by exogenous impulses like daylight, temperature and feeding. Inappropriately applied bright light disturbs this melatonin rhythm. Some large swine producers apply artificial light three times a da

  2. In sync: gamma oscillations and emotional memory

    Directory of Open Access Journals (Sweden)

    Drew Battenfield Headley

    2013-11-01

    Full Text Available Emotional experiences leave vivid memories that can last a lifetime. The emotional facilitation of memory has been attributed to the engagement of diffusely projecting neuromodulatory systems that enhance the consolidation of synaptic plasticity in regions activated by the experience. This process requires the propagation of signals between brain regions, and for those signals to induce long-lasting synaptic plasticity. Both of these demands are met by gamma oscillations, which reflect synchronous population activity on a fast timescale (35-120 Hz. Regions known to participate in the formation of emotional memories, such as the basolateral amygdala, also promote gamma-band activation throughout cortical and subcortical circuits. Recent studies have demonstrated that gamma oscillations are enhanced during emotional situations, coherent between regions engaged by salient stimuli, and predict subsequent memory for cues associated with aversive stimuli. Furthermore, neutral stimuli that come to predict emotional events develop enhanced gamma oscillations, reflecting altered processing in the brain, which may underpin how past emotional experiences color future learning and memory.

  3. Cortical Alpha Oscillations Predict Speech Intelligibility

    Science.gov (United States)

    Dimitrijevic, Andrew; Smith, Michael L.; Kadis, Darren S.; Moore, David R.

    2017-01-01

    Understanding speech in noise (SiN) is a complex task involving sensory encoding and cognitive resources including working memory and attention. Previous work has shown that brain oscillations, particularly alpha rhythms (8–12 Hz) play important roles in sensory processes involving working memory and attention. However, no previous study has examined brain oscillations during performance of a continuous speech perception test. The aim of this study was to measure cortical alpha during attentive listening in a commonly used SiN task (digits-in-noise, DiN) to better understand the neural processes associated with “top-down” cognitive processing in adverse listening environments. We recruited 14 normal hearing (NH) young adults. DiN speech reception threshold (SRT) was measured in an initial behavioral experiment. EEG activity was then collected: (i) while performing the DiN near SRT; and (ii) while attending to a silent, close-caption video during presentation of identical digit stimuli that the participant was instructed to ignore. Three main results were obtained: (1) during attentive (“active”) listening to the DiN, a number of distinct neural oscillations were observed (mainly alpha with some beta; 15–30 Hz). No oscillations were observed during attention to the video (“passive” listening); (2) overall, alpha event-related synchronization (ERS) of central/parietal sources were observed during active listening when data were grand averaged across all participants. In some participants, a smaller magnitude alpha event-related desynchronization (ERD), originating in temporal regions, was observed; and (3) when individual EEG trials were sorted according to correct and incorrect digit identification, the temporal alpha ERD was consistently greater on correctly identified trials. No such consistency was observed with the central/parietal alpha ERS. These data demonstrate that changes in alpha activity are specific to listening conditions. To our

  4. Persistence, entrainment, and function of circadian rhythms in polar vertebrates.

    Science.gov (United States)

    Williams, Cory T; Barnes, Brian M; Buck, C Loren

    2015-03-01

    Polar organisms must cope with an environment that periodically lacks the strongest time-giver, or zeitgeber, of circadian organization-robust, cyclical oscillations between light and darkness. We review the factors influencing the persistence of circadian rhythms in polar vertebrates when the light-dark cycle is absent, the likely mechanisms of entrainment that allow some polar vertebrates to remain synchronized with geophysical time, and the adaptive function of maintaining circadian rhythms in such environments.

  5. Practical stepwise approach to rhythm disturbances in congenital heart diseases

    OpenAIRE

    Huh, June

    2010-01-01

    Patients with congenital heart diseases (CHD) are confronted with early- and late-onset complications, such as conduction disorders, arrhythmias, myocardial dysfunction, altered coronary flow, and ischemia, throughout their lifetime despite successful hemodynamic and/or anatomical correction. Rhythm disturbance is a well-known and increasingly frequent cause of morbidity and mortality in patients with CHD. Predisposing factors to rhythm disturbances include underlying cardiac defects, hemodyn...

  6. Human adipose tissue expresses intrinsic circadian rhythm in insulin sensitivity.

    Science.gov (United States)

    Carrasco-Benso, Maria P; Rivero-Gutierrez, Belen; Lopez-Minguez, Jesus; Anzola, Andrea; Diez-Noguera, Antoni; Madrid, Juan A; Lujan, Juan A; Martínez-Augustin, Olga; Scheer, Frank A J L; Garaulet, Marta

    2016-09-01

    In humans, insulin sensitivity varies according to time of day, with decreased values in the evening and at night. Mechanisms responsible for the diurnal variation in insulin sensitivity are unclear. We investigated whether human adipose tissue (AT) expresses intrinsic circadian rhythms in insulin sensitivity that could contribute to this phenomenon. Subcutaneous and visceral AT biopsies were obtained from extremely obese participants (body mass index, 41.8 ± 6.3 kg/m(2); 46 ± 11 y) during gastric-bypass surgery. To assess the rhythm in insulin signaling, AKT phosphorylation was determined every 4 h over 24 h in vitro in response to different insulin concentrations (0, 1, 10, and 100 nM). Data revealed that subcutaneous AT exhibited robust circadian rhythms in insulin signaling (P Insulin sensitivity reached its maximum (acrophase) around noon, being 54% higher than during midnight (P = 0.009). The amplitude of the rhythm was positively correlated with in vivo sleep duration (r = 0.53; P = 0.023) and negatively correlated with in vivo bedtime (r = -0.54; P = 0.020). No circadian rhythms were detected in visceral AT (P = 0.643). Here, we demonstrate the relevance of the time of the day for how sensitive AT is to the effects of insulin. Subcutaneous AT shows an endogenous circadian rhythm in insulin sensitivity that could provide an underlying mechanism for the daily rhythm in systemic insulin sensitivity.-Carrasco-Benso, M. P., Rivero-Gutierrez, B., Lopez-Minguez, J., Anzola, A., Diez-Noguera, A., Madrid, J. A., Lujan, J. A., Martínez-Augustin, O., Scheer, F. A. J. L., Garaulet, M. Human adipose tissue expresses intrinsic circadian rhythm in insulin sensitivity. © FASEB.

  7. Isochron-Based Phase Response Analysis of Circadian Rhythms

    OpenAIRE

    Gunawan, Rudiyanto; Doyle, Francis J.

    2006-01-01

    Circadian rhythms possess the ability to robustly entrain to the environmental cycles. This ability relies on the phase synchronization of circadian rhythm gene regulation to different environmental cues, of which light is the most obvious and important. The elucidation of the mechanism of circadian entrainment requires an understanding of circadian phase behavior. This article presents two phase analyses of oscillatory systems for infinitesimal and finite perturbations based on isochrons as ...

  8. Circadian rhythms of hedonic drinking behavior in mice.

    Science.gov (United States)

    Bainier, Claire; Mateo, Maria; Felder-Schmittbuhl, Marie-Paule; Mendoza, Jorge

    2017-05-04

    In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is the site of the main circadian clock, synchronized by the light-dark cycle, which generates behavioral rhythms like feeding, drinking and activity. Notwithstanding, the main role of the SCN clock on the control of all circadian rhythms has been questioned due to the presence of clock activity in many brain areas, including those implicated in the regulation of feeding and reward. Moreover, whether circadian rhythms of particular motivated behaviors exist is unknown. Here, we evaluated the spontaneous daily and circadian behavior of consumption of a sweet caloric solution (5-10% sucrose), and the effects of sucrose intake on the expression of clock genes in the mouse brain. Mice showed a daily (in a light-dark cycle) and a circadian (in constant darkness conditions) rhythm in the intake and sucrose preference with a rise for both parameters at night (or subjective night). In addition, we observed changes in the circadian day-night expression of the clock gene Per2 in the SCN, cortex and striatum of animals ingesting sucrose compared to control mice on pure water. Finally, daily rhythms of sucrose intake and preference were abolished in Per2(Brdm1)- and double Per1(-/-)Per2(Brdm1)-mutant animals. These data indicate that the expression of circadian rhythms of hedonic feeding behaviors may be controlled by brain circadian clocks and Per gene expression. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Educating the sense of rhythm in primary education students

    Directory of Open Access Journals (Sweden)

    Silvia GRĂDINARU

    2017-03-01

    Full Text Available Background: Rhythm as a core element of complex coordination is the key to efficient moulding of motor skills specific to sports activities in curricula. Practicing physical exercise in a varied rhythm and tempo in primary school students moulds the skill of achieving correct movement basics (direction, span, coordination, and expressivity. The use of music in sports classes improves kinetics and vestibular sensitivity. The sense of rhythm and tempo are imperative criteria in vocational schools. Purpose: This paper aims to describe a pattern of means selected to develop the sense of rhythm and to allow movements in different sports branches with increased efficiency. Methods: The test battery was applied on a sample of 15 students from the 4th grade of the “Ion Vidu” National Arts College in Timisoara, Romania, aged 9-10 years, over an entire school year, using different rhythms and tempos during sports classes, which were later used in gymnastics, athletic events, and basketball. Results: Data recorded after the application tests, processed and interpreted confirms the proposed assumption and validates the motor contents used. Conclusions: Sense of rhythm is a component of coordinative capacity that is required to be educated from an early age. Rhythmic movements are easier to automate saving energy and motivating students to an active and conscious participation.

  10. Using synchronous speech to facilitate acquisition of English rhythm

    Directory of Open Access Journals (Sweden)

    Elina Banzina

    2014-11-01

    Full Text Available While appropriate stress and rhythm is of importance for any speaker’s intelligibility, such properties are critical for international teaching assistants (ITA, who deliver new and complex information to native speaker audiences. Given the limited time available for ITA instruction and the need for a time-efficient rhythm teaching method, this article reports findings of a small-scale feasibility study that tested the effectiveness of a synchronous speech component introduced into conventional rhythm instruction. Synchronous speech involves teacher and learner speaking in unison continuously, which allows the L2 learner to learn rhythm implicitly and uninterruptedly, and provides rich auditory-visual input, ample motor speech practice and real-time feedback, thereby automatizing rhythm patterns. In a 6-week-long pre-post experimental feasibility study, blind listeners evaluated pretraining and post-training recordings of ITA-produced speech. Data revealed a trend towards more improvement in L2 rhythm working with the synchronous speech technique. Results establish feasibility in both instruction and research

  11. Effects of stressor controllability on diurnal physiological rhythms.

    Science.gov (United States)

    Thompson, Robert S; Christianson, John P; Maslanik, Thomas M; Maier, Steve F; Greenwood, Benjamin N; Fleshner, Monika

    2013-03-15

    Disruptions in circadian and diurnal rhythms are associated with stress-related psychiatric disorders and stressor exposure can disrupt these rhythms. The controllability of the stressor can modulate various behavioral and neurochemical responses to stress. Uncontrollable, but not controllable, stress produces behaviors in rats that resemble symptoms of anxiety and depression. Whether acute stress-induced disruptions in physiological rhythms are sensitive to controllability of the stressor, however, remains unknown. To examine the role of controllability in diurnal rhythm disruption, adult male Sprague-Dawley rats were implanted with Data Sciences International (DSI) biotelemetry devices. Real-time measurements were obtained before, during and after exposure to a controllable or yoked uncontrollable stressor. Controllable and uncontrollable stress equally disrupted diurnal rhythms of locomotor activity and body temperature but not heart rate. The diurnal heart rate the day following stressor exposure was flattened to a greater extent and was significantly higher in rats with control over stress suggesting a relationship between stressor controllability and the heart rate response. Our results are consistent with the conclusion that acute stress-induced disruptions in diurnal physiological rhythms likely contribute little to the behavioral and affective consequences of stress that are sensitive to stressor controllability.

  12. Neural mechanisms of rhythm perception: current findings and future perspectives.

    Science.gov (United States)

    Grahn, Jessica A

    2012-10-01

    Perception of temporal patterns is fundamental to normal hearing, speech, motor control, and music. Certain types of pattern understanding are unique to humans, such as musical rhythm. Although human responses to musical rhythm are universal, there is much we do not understand about how rhythm is processed in the brain. Here, I consider findings from research into basic timing mechanisms and models through to the neuroscience of rhythm and meter. A network of neural areas, including motor regions, is regularly implicated in basic timing as well as processing of musical rhythm. However, fractionating the specific roles of individual areas in this network has remained a challenge. Distinctions in activity patterns appear between "automatic" and "cognitively controlled" timing processes, but the perception of musical rhythm requires features of both automatic and controlled processes. In addition, many experimental manipulations rely on participants directing their attention toward or away from certain stimulus features, and measuring corresponding differences in neural activity. Many temporal features, however, are implicitly processed whether attended to or not, making it difficult to create controlled baseline conditions for experimental comparisons. The variety of stimuli, paradigms, and definitions can further complicate comparisons across domains or methodologies. Despite these challenges, the high level of interest and multitude of methodological approaches from different cognitive domains (including music, language, and motor learning) have yielded new insights and hold promise for future progress.

  13. Circadian rhythms in cognitive performance: implications for neuropsychological assessment

    Directory of Open Access Journals (Sweden)

    Valdez P

    2012-12-01

    Full Text Available Pablo Valdez, Candelaria Ramírez, Aída GarcíaLaboratory of Psychophysiology, School of Psychology, University of Nuevo León, Monterrey, Nuevo León, MéxicoAbstract: Circadian variations have been found in human performance, including the efficiency to execute many tasks, such as sensory, motor, reaction time, time estimation, memory, verbal, arithmetic calculations, and simulated driving tasks. Performance increases during the day and decreases during the night. Circadian rhythms have been found in three basic neuropsychological processes (attention, working memory, and executive functions, which may explain oscillations in the performance of many tasks. The time course of circadian rhythms in cognitive performance may be modified significantly in patients with brain disorders, due to chronotype, age, alterations of the circadian rhythm, sleep deprivation, type of disorder, and medication. This review analyzes the recent results on circadian rhythms in cognitive performance, as well as the implications of these rhythms for the neuropsychological assessment of patients with brain disorders such as traumatic head injury, stroke, dementia, developmental disorders, and psychiatric disorders.Keywords: human circadian rhythms, cognitive performance, neuropsychological assessment, attention, working memory, executive functions

  14. Music and speech prosody: A common rhythm

    Directory of Open Access Journals (Sweden)

    Maija eHausen

    2013-09-01

    Full Text Available Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61 using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress.

  15. Sleep-wake as a biological rhythm.

    Science.gov (United States)

    Lavie, P

    2001-01-01

    Evidence that the sleep-wake rhythm is generated endogenously has been provided by studies employing a variety of experimental paradigms such as sleep deprivation, sleep displacement, isolating subjects in environments free of time cues, or imposing on subjects sleep-wake schedules widely deviating from 24 hours. The initial observations obtained in isolated subjects revealed that the period of the endogenous circadian pacemaker regulating sleep is of approximately 25 hours. More recent studies, however, in which a more rigorous control of subjects' behavior was exerted, particularly over lighting conditions, have shown that the true periodicity of the endogenous pacemaker deviates from 24 hours by a few minutes only. Besides sleep propensity, the circadian pacemaker has been shown to regulate sleep consolidation, sleep stage structure, and electroencephalographic activities. The pattern of light exposure throughout the 24 hours appears to participate in the entrainment of the circadian pacemaker to the geophysical day-night cycle. Melatonin, the pineal hormone produced during the dark hours, participates in communicating both between the environmental light-dark cycle and the circadian pacemaker, and between the circadian pacemaker and the sleep-wake-generating mechanism. In contrast to prevailing views that have placed great emphasis on homeostatic sleep drive, recent data have revealed a potent circadian cycle in the drive for wakefulness, which is generated by the suprachiasmatic nucleus. This drive reaches a peak during the evening hours just before habitual bedtime.

  16. Music and speech prosody: a common rhythm

    Science.gov (United States)

    Hausen, Maija; Torppa, Ritva; Salmela, Viljami R.; Vainio, Martti; Särkämö, Teppo

    2013-01-01

    Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61) using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA) and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception, and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks) was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress). PMID:24032022

  17. Music and speech prosody: a common rhythm.

    Science.gov (United States)

    Hausen, Maija; Torppa, Ritva; Salmela, Viljami R; Vainio, Martti; Särkämö, Teppo

    2013-01-01

    Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61) using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA) and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception, and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks) was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress).

  18. [Circadian variations of performances and basic rhythms].

    Science.gov (United States)

    Querrioux-Coulombier, G; Rossi, J P

    1995-12-01

    Difficulties with chronopsychology studies include a masking effect of variables, the combination of different rhythms and variations of strategies. An experiment is conducted to analyze the role of circadian variations of elementary processes in the variations of performance for a complex task. Twenty-four subjects solved anagrams and tried to find the rule of anagram construction, during two sessions, at 10 am and 5 pm. Responses were classified in three groups: (a) discovery of the anagram construction rule (R2 responses); (b) resolution of anagram without discovery of rule (R1 responses); (c) failure, no resolution of anagram (R0 responses). During the second session, R2 performances were better at 10 am than at 5 pm. In contrast, R1 performances were better at 5 pm than at 10 am. Rule application was faster at 10 am than at 5 pm. Results are discussed in terms of variations of short-term memory capacity (Folkard and Monk, 1980). Using chronopsychology to analyze the role of elementary processes in a complex task is discussed.

  19. Rehabilitation of gamma

    Science.gov (United States)

    Poynton, Charles A.

    1998-07-01

    Gamma characterizes the reproduction of tone scale in an imaging system. Gamma summarizes, in a single numerical parameter, the nonlinear relationship between code value--in an 8-bit system, from 0 through 255--and physical intensity. Nearly all image coding systems are nonlinear, and so involve values of gamma different from unity. Owing to poor understanding of tone scale reproduction, and to misconceptions about nonlinear coding, gamma has acquired a terrible reputation in computer graphics and image processing. In addition, the world-wide web suffers from poor reproduction of grayscale and color images, due to poor handling of nonlinear image coding. This paper aims to make gamma respectable again.

  20. Motor cortical thresholds and cortical silent periods in epilepsy.

    Science.gov (United States)

    Tataroglu, Cengiz; Ozkiziltan, Safa; Baklan, Baris

    2004-10-01

    We studied motor cortical thresholds (TIs) and cortical silent periods (SPs) evoked by transcranial magnetic stimulation (TMS) in 110 epileptic patients. Sixty-two had primary generalised, 48 had partial type seizures. Fifteen out 110 patients were analysed both before and after anticonvulsant medication. Our aims were to evaluate the TI levels and the duration of SPs in patients with epilepsy and to determine the reliability of TMS in patients with epilepsy. There was no negative effect of TMS on the clinical status and EEG findings in patients with epilepsy. TIs obtained from patients with partial epilepsy were higher than those obtained from both controls and primary epileptics. The duration of SP in patients with primary epileptics was more prolonged than those obtained from controls. There was no correlation between EEG lateralisation and both SP duration and TI values. In de novo patient group, SP duration was significantly prolonged after anticonvulsant medication. We concluded that TMS is a reliable electrophysiological investigation in patients with epilepsy. The analysis of SP duration may be an appropriate investigation in monitoring the effect of anticonvulsant medication on the cortical inhibitory activity.

  1. Movement-related dynamics of cortical oscillations in Parkinson's disease and essential tremor.

    Science.gov (United States)

    Kondylis, Efstathios D; Randazzo, Michael J; Alhourani, Ahmad; Lipski, Witold J; Wozny, Thomas A; Pandya, Yash; Ghuman, Avniel S; Turner, Robert S; Crammond, Donald J; Richardson, R M

    2016-08-01

    Recent electrocorticography data have demonstrated excessive coupling of beta-phase to gamma-amplitude in primary motor cortex and that deep brain stimulation facilitates motor improvement by decreasing baseline phase-amplitude coupling. However, both the dynamic modulation of phase-amplitude coupling during movement and the general cortical neurophysiology of other movement disorders, such as essential tremor, are relatively unexplored. To clarify the relationship of these interactions in cortical oscillatory activity to movement and disease state, we recorded local field potentials from hand sensorimotor cortex using subdural electrocorticography during a visually cued, incentivized handgrip task in subjects with Parkinson's disease (n = 11), with essential tremor (n = 9) and without a movement disorder (n = 6). We demonstrate that abnormal coupling of the phase of low frequency oscillations to the amplitude of gamma oscillations is not specific to Parkinson's disease, but also occurs in essential tremor, most prominently for the coupling of alpha to gamma oscillations. Movement kinematics were not significantly different between these groups, allowing us to show for the first time that robust alpha and beta desynchronization is a shared feature of sensorimotor cortical activity in Parkinson's disease and essential tremor, with the greatest high-beta desynchronization occurring in Parkinson's disease and the greatest alpha desynchronization occurring in essential tremor. We also show that the spatial extent of cortical phase-amplitude decoupling during movement is much greater in subjects with Parkinson's disease and essential tremor than in subjects without a movement disorder. These findings suggest that subjects with Parkinson's disease and essential tremor can produce movements that are kinematically similar to those of subjects without a movement disorder by reducing excess sensorimotor cortical phase-amplitude coupling that is characteristic of these

  2. Changes in cortical activity when subjects scan memory for tones.

    Science.gov (United States)

    Kaufman, L; Curtis, S; Wang, J Z; Williamson, S J

    1992-04-01

    The magnetoencephalogram (MEG) was used to detect regional changes in spontaneous cortical activity accompanying short-term memory search. This method was chosen because magnetic fields are detectable only within a few centimeters of the projections of their sources onto the scalp. The specific hypothesis that auditory cortex is involved in scanning memory for tones was tested by sensing the field of the magnetic counterpart to N100 (N100m) which is known to originate in auditory cortex. N100m was measured at many different positions and the spontaneous cortical rhythms in the alpha bandwidth (8-12 Hz) were measured at the same places. These rhythms were found to be suppressed while subjects scanned memory for musical tones in a Sternberg paradigm. For 3 subjects, both the MEG suppression time (ST) and reaction time (RT) increased linearly with memory set size. The correlation between ST measured over the left hemisphere and set size was significant for two subjects but not significant for the third, and the slopes of the regression lines relating ST to set size were too shallow to be related to the time required to scan memory. However, the correlation between ST of the right hemisphere and set size was highly significant for all subjects, and the slopes of the regression lines were comparable to those relating RT to set size. The electroencephalogram (EEG) recorded with midline electrodes failed to reveal a significant relationship between suppression time and set size for 2 of the subjects, thus ruling out global alpha blockage and generalized arousal as the basis for the task-related suppression duration. The electric N100, measured at Cz, decreased significantly in amplitude with set size for 2 subjects, but it increased significantly in amplitude for the third subject. In contrast, RT increased with set size for all subjects. N100m measured over the right hemisphere was similar to the behavior of N100, while N100m measured over the left hemisphere showed

  3. Coherent delta-band oscillations between cortical areas correlate with decision making

    Science.gov (United States)

    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-01-01

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1–4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making. PMID:23980180

  4. Coherent delta-band oscillations between cortical areas correlate with decision making.

    Science.gov (United States)

    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-09-10

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1-4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making.

  5. Optogenetically evoked gamma oscillations are disturbed by cocaine administration

    Directory of Open Access Journals (Sweden)

    Jonathan E Dilgen

    2013-11-01

    Full Text Available Drugs of abuse have enormous societal impact by degrading the cognitive abilities, emotional state and social behavior of addicted individuals. Among other events involved in the addiction cycle, the study of a single exposure to cocaine, and the contribution of the effects of that event to the continuous and further use of drugs of abuse are fundamental. Gamma oscillations are thought to be important neural correlates of cognitive processing in the prefrontal cortex (PFC which include decision making, set shifting and working memory. It follows that cocaine exposure might modulate gamma oscillations, which could result in reduced cognitive ability. Parvalbumin-positive fast-spiking interneurons play an orchestrating role in gamma oscillation induction and it has been shown recently that gamma oscillations can be induced in an anesthetized animal using optogenetic techniques. We use a knock-in mouse model together with optogenetics and in vivo electrophysiology to study the effects of acute cocaine on PFC gamma oscillation as a step toward understanding the cortical changes that may underlie continuous use of stimulants. Our results show that acute cocaine administration increases entrainment of the gamma oscillation to the optogentically induced driving frequency. Our results also suggest that this modulation of gamma oscillations is driven trough activation of DAD1 receptors. The acute cocaine-mediated changes in mPFC may underlie the enhancement of attention and awareness commonly reported by cocaine users and may contribute to the further use and abuse of psychostimulants.

  6. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  7. Cortical sensorimotor integration: a hypothesis.

    Science.gov (United States)

    Batuev, A S

    1989-01-01

    A hypothesis is proposed that neocortex is constructed from structural neuronal modules (columns and rings). Each module is considered as unit for cortical sensorimotor integration. Complex functional relationships between modules can be arranged by intracortical inhibition participation. High pronounced neocortical plasticity ensures the process of continuous formation of various dominating operative constellations comprising stable neuronal modules whose component structure and distributive characteristic are determined by the dominant motivation and the central motor program.

  8. [Parietal Cortices and Body Information].

    Science.gov (United States)

    Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

    2016-11-01

    Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

  9. Gamma-range corticomuscular coherence during dynamic force output.

    Science.gov (United States)

    Omlor, Wolfgang; Patino, Luis; Hepp-Reymond, Marie-Claude; Kristeva, Rumyana

    2007-02-01

    The beta-range synchronization between cortical motor and muscular activity as revealed by EEG/MEG-EMG coherence has been extensively investigated for steady-state motor output. However, there is a lack of information on the modulation of the corticomuscular coherence in conjunction with dynamic force output. We addressed this question comparing the EEG-EMG coherence and the cortical motor spectral power in eight healthy subjects in a visuomotor task, in which the subjects exerted a steady-state or periodically modulated dynamic isometric force output with their right-index finger to keep a visual cursor within a target zone. In the static condition, significant coherence was confined to the beta-range. In the dynamic condition, the most distinct coherence occurred in the gamma-range and the significant beta-range coherence was strikingly reduced. The cortical motor power in the beta-range during dynamic force output was decreased, whereas the power in the gamma-range remained without significant change. We conclude that during dynamic force the corticospinal oscillation mode of the sensorimotor system shifts towards higher (principally gamma) frequencies for the rapid integration of the visual and somatosensory information required to produce the appropriate motor command.

  10. Brain rhythms reveal a hierarchical network organization.

    Directory of Open Access Journals (Sweden)

    G Karl Steinke

    2011-10-01

    Full Text Available Recordings of ongoing neural activity with EEG and MEG exhibit oscillations of specific frequencies over a non-oscillatory background. The oscillations appear in the power spectrum as a collection of frequency bands that are evenly spaced on a logarithmic scale, thereby preventing mutual entrainment and cross-talk. Over the last few years, experimental, computational and theoretical studies have made substantial progress on our understanding of the biophysical mechanisms underlying the generation of network oscillations and their interactions, with emphasis on the role of neuronal synchronization. In this paper we ask a very different question. Rather than investigating how brain rhythms emerge, or whether they are necessary for neural function, we focus on what they tell us about functional brain connectivity. We hypothesized that if we were able to construct abstract networks, or "virtual brains", whose dynamics were similar to EEG/MEG recordings, those networks would share structural features among themselves, and also with real brains. Applying mathematical techniques for inverse problems, we have reverse-engineered network architectures that generate characteristic dynamics of actual brains, including spindles and sharp waves, which appear in the power spectrum as frequency bands superimposed on a non-oscillatory background dominated by low frequencies. We show that all reconstructed networks display similar topological features (e.g. structural motifs and dynamics. We have also reverse-engineered putative diseased brains (epileptic and schizophrenic, in which the oscillatory activity is altered in different ways, as reported in clinical studies. These reconstructed networks show consistent alterations of functional connectivity and dynamics. In particular, we show that the complexity of the network, quantified as proposed by Tononi, Sporns and Edelman, is a good indicator of brain fitness, since virtual brains modeling diseased states

  11. Physiological basis for human autonomic rhythms

    Science.gov (United States)

    Eckberg, D. L.

    2000-01-01

    Oscillations of arterial pressures, heart periods, and muscle sympathetic nerve activity have been studied intensively in recent years to explore otherwise obscure human neurophysiological mechanisms. The best-studied rhythms are those occurring at breathing frequencies. Published evidence indicates that respiratory fluctuations of muscle sympathetic nerve activity and electrocardiographic R-R intervals result primarily from the action of a central 'gate' that opens during expiration and closes during inspiration. Parallel respiratory fluctuations of arterial pressures and R-R intervals are thought to be secondary to arterial baroreflex physiology: changes in systolic pressure provoke changes in the R-R interval. However, growing evidence suggests that these parallel oscillations result from the influence of respiration on sympathetic and vagal-cardiac motoneurones rather than from baroreflex physiology. There is a rapidly growing literature on the use of mathematical models of low- and high-frequency (respiratory) R-R interval fluctuations in characterizing instantaneous 'sympathovagal balance'. The case for this approach is based primarily on measurements made with patients in upright tilt. However, the strong linear relation between such measures as the ratio of low- to high-frequency R-R interval oscillations and the angle of the tilt reflects exclusively the reductions of the vagal (high-frequency) component. As the sympathetic component does not change in tilt, the low- to high-frequency R-R interval ratio provides no proof that sympathetic activity increases. Moreover, the validity of extrapolating from measurements performed during upright tilt to measurements during supine rest has not been established. Nonetheless, it is clear that measures of heart rate variability provide important prognostic information in patients with cardiovascular diseases. It is not known whether reduced heart rate variability is merely a marker for the severity of disease or a

  12. Circadian rhythms synchronize mitosis in Neurospora crassa.

    Science.gov (United States)

    Hong, Christian I; Zámborszky, Judit; Baek, Mokryun; Labiscsak, Laszlo; Ju, Kyungsu; Lee, Hyeyeong; Larrondo, Luis F; Goity, Alejandra; Chong, Hin Siong; Belden, William J; Csikász-Nagy, Attila

    2014-01-28

    The cell cycle and the circadian clock communicate with each other, resulting in circadian-gated cell division cycles. Alterations in this network may lead to diseases such as cancer. Therefore, it is critical to identify molecular components that connect these two oscillators. However, molecular mechanisms between the clock and the cell cycle remain largely unknown. A model filamentous fungus, Neurospora crassa, is a multinucleate system used to elucidate molecular mechanisms of circadian rhythms, but not used to investigate the molecular coupling between these two oscillators. In this report, we show that a conserved coupling between the circadian clock and the cell cycle exists via serine/threonine protein kinase-29 (STK-29), the Neurospora homolog of mammalian WEE1 kinase. Based on this finding, we established a mathematical model that predicts circadian oscillations of cell cycle components and circadian clock-dependent synchronized nuclear divisions. We experimentally demonstrate that G1 and G2 cyclins, CLN-1 and CLB-1, respectively, oscillate in a circadian manner with bioluminescence reporters. The oscillations of clb-1 and stk-29 gene expression are abolished in a circadian arrhythmic frq(ko) mutant. Additionally, we show the light-induced phase shifts of a core circadian component, frq, as well as the gene expression of the cell cycle components clb-1 and stk-29, which may alter the timing of divisions. We then used a histone hH1-GFP reporter to observe nuclear divisions over time, and show that a large number of nuclear divisions occur in the evening. Our findings demonstrate the circadian clock-dependent molecular dynamics of cell cycle components that result in synchronized nuclear divisions in Neurospora.

  13. Circadian rhythms in floral scent emission

    Directory of Open Access Journals (Sweden)

    Myles eFenske

    2016-04-01

    Full Text Available To successfully recruit pollinators, plants often release attractive floral scents at specific times of day to coincide with pollinator foraging. This timing of scent emission is thought to be evolutionarily beneficial to maximize resource efficiency while attracting only useful pollinators. Temporal regulation of scent emission is tied to the activity of the specific metabolic pathways responsible for scent production. Although floral volatile profiling in various plants indicated a contribution by the circadian clock, the mechanisms by which the circadian clock regulates timing of floral scent emission remained elusive. Recent studies using two species in the Solanaceae family provided initial insight into molecular clock regulation of scent emission timing. In Petunia hybrida, the benzenoid/phenylpropanoid (FVBP pathway is the major metabolic pathway that produces floral volatiles. Three MYB-type transcription factors, ODORANT1 (ODO1, EMISSION OF BENZENOIDS I (EOBI, and EOBII, all of which show diurnal rhythms in mRNA expression, act as positive regulators for several enzyme genes in the FVBP pathway. Recently, in P. hybrida and Nicotiana attenuata, homologs of the Arabidopsis clock gene LATE ELONGATED HYPOCOTYL (LHY have been shown to have a similar role in the circadian clock in these plants, and to also determine the timing of scent emission. In addition, in P. hybrida, PhLHY directly represses ODO1 and several enzyme genes in the FVBP pathway during the morning as an important negative regulator of scent emission. These findings facilitate our understanding of the relationship between a molecular timekeeper and the timing of scent emission, which may influence reproductive success.

  14. [Psychoeducation and interpersonal and social rhythm therapy for bipolar disorder].

    Science.gov (United States)

    Mizushima, Hiroko

    2011-01-01

    In treating bipolar disorder, specific psychotherapies in adjunct to pharmacotherapy have been shown to be effective in preventing new episodes and treating depressive episodes. Among those, interpersonal and social rhythm therapy (IPSRT) developed by Frank, amalgamation of interpersonal psychotherapy (IPT) with behavioral therapy focused on social rhythm has been shown to be an efficacious adjunct to mediation in preventing new episodes in bipolar I patients and in treating depression in bipolar I arid II disorder. IPSRT has also been shown to enhance total functioning, relationship functioning and life satisfaction among patients with bipolar disorder, even after pretreatment functioning and concurrent depression were covaried. IPSRT was designed to directly address the major pathways to recurrence in bipolar disorder, namely medication nonadherence, stressful life events, and disruptions in social rhythms. IPT, originated by Klerman et al., is a strategic time-limited psychotherapy focused on one or two of four current interpersonal problem areas (ie, grief, interpersonal role disputes, role transitions, and interpersonal dificits). In IPSRT, the fifth problem area "grief for the lost healthy self" has been added in order to promote acceptance of the diagnosis and the need for life-long treatment. Social rhythm therapy is a behavioral approach aiming at increasing regularity of social rhythms using the Social Rhythm Metric (SRM), a chart to record daily social activities including how stimulating they were, developed from observation that disruptions in social rhythms often trigger affective episodes in patients with bipolar disorder. IPSRT also appears to be a promising intervention for a subset of individuals with bipolar II depression as monotherapy for the acute treatment.

  15. Premature Trigger of ERI in Medtronic EnRhythm Devices.

    Science.gov (United States)

    Middeldorp, Melissa E; Mahajan, Rajiv; Elliott, Adrian D; Pathak, Rajeev K; Twomey, Darragh; Wilson, Lauren; Stolcman, Simon; Munawar, Dian A; Kumar, Sharath; Lau, Dennis H; Sanders, Prashanthan

    2017-06-01

    Medical technology has made significant advances over the last few decades with smaller and more dynamic pacemakers. However, technical failures leading to premature replacement is a cause of concern. We present a series of Medtronic EnRhythm devices that reached premature elective replacement indicator (ERI). The database of Centre of Heart Rhythm Disorders was searched for EnRhythm device implantation from 2006 to 2011. Battery depletion <8.5 years was considered premature considering the projected average longevity to be 8.5-10.5 years. An unexpected premature ERI was defined when it was reached within 3 months of last normal check. Device follow-up was conducted every 3 months after advisory. A total of 88 EnRhythm pacemakers were implanted. Over a median follow-up of 6.2 years (range: 0.3-9.2), 39 (44.3%) EnRhythm devices reached premature ERI. In 11 (28%), ERI was not recognized and patients were being investigated for other causes of unsteadiness or dyspnea prior to device check. Notably, three (7%) patients had premature ERI < 3.5 years. Ten (25.6%) had sudden and unexpected premature ERI. While asynchronous pacing was observed, there were no cases of absence of pacing. The rate of premature ERI for EnRhythm devices was 44.3%, significantly higher than reported by the manufacturer. Of concern, a sizeable proportion occurred unexpectedly, warranting more frequent reviews and empirical replacement in some patients. With the experience of the EnRhythm, appropriate monitoring strategies are recommended for future advisories. © 2017 Wiley Periodicals, Inc.

  16. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

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    Elise Houdayer

    Full Text Available The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS. Twelve subjects (experimental group underwent, before and after a two week-piano training: (1 hand-motor function tests: Jamar, grip and nine-hole peg tests; (2 electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD during keyboard performance; and (3 TMS, targeting bilateral abductor pollicis brevis (APB and abductor digiti minimi (ADM, to obtain duration and area of ipsilateral silent period (ISP during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  17. Metabolic cycles are linked to the cardiovascular diurnal rhythm in rats with essential hypertension.

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    He Cui

    Full Text Available BACKGROUND: The loss of diurnal rhythm in blood pressure (BP is an important predictor of end-organ damage in hypertensive and diabetic patients. Recent evidence has suggested that two major physiological circadian rhythms, the metabolic and cardiovascular rhythms, are subject to regulation by overlapping molecular pathways, indicating that dysregulation of metabolic cycles could desynchronize the normal diurnal rhythm of BP with the daily light/dark cycle. However, little is known about the impact of changes in metabolic cycles on BP diurnal rhythm. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis that feeding-fasting cycles could affect the diurnal pattern of BP, we used spontaneously hypertensive rats (SHR which develop essential hypertension with disrupted diurnal BP rhythms and examined whether abnormal BP rhythms in SHR were caused by alteration in the daily feeding rhythm. We found that SHR exhibit attenuated feeding rhythm which accompanies disrupted rhythms in metabolic gene expression not only in metabolic tissues but also in cardiovascular tissues. More importantly, the correction of abnormal feeding rhythms in SHR restored the daily BP rhythm and was accompanied by changes in the timing of expression of key circadian and metabolic genes in cardiovascular tissues. CONCLUSIONS/SIGNIFICANCE: These results indicate that the metabolic cycle is an important determinant of the cardiovascular diurnal rhythm and that disrupted BP rhythms in hypertensive patients can be normalized by manipulating feeding cycles.

  18. Measurement of. gamma. gamma. widths of charmonium states

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.Y.; McIlwain, R.L.; Miller, D.H.; Ng, C.R.; Schaffner, S.F.; Shibata, E.I.; Yao, W.M. (Purdue Univ., Lafayette, IN (USA)); Sparks, K.; Thorndike, E.H.; Wang, C.H. (Rochester Univ., NY (USA)); Alam, M.S.; Kim, I.J.; Li, W.C.; Lou, X.C.; Sun, C.R.; Wang, P.N.; Zoeller, M.I. (State Univ. of New York, Albany (USA)); Bortoletto, D.; Goldberg, M.; Horwitz, N.; Jain, V.; Mestayer, M.D.; Moneti, G.C.; Sharma, V.; Shipsey, I.P.J.; Skwarnicki, T.; Thulasidas, M. (Syracuse Univ., NY (USA)); Csorna, S.E.; Letson, T. (Vanderbilt Univ., Nashville, TN (USA)); Alexander, J.; Artuso, M.; Bebek, C.; Berkelman, K.; Cassel, D.G.; Cheu, E.; Coffman, D.M.; Crawford, G.; DeWire, J.W.; Dell, P.S.; Ehrlich, R.; Galik, R.S.; Gittelman, B.; Gray, S.W.; Halling, A.M.; Hartill, D.L.; Heltsley, B.K.; Kandaswamy, J.; Katayama, N.; Kreinick, D.L.; Lewis, J.D.; Mistry, N.B.; Mueller, J.; Namjoshi, R.; Nandi, S.; Nordberg, E.; O' Grady, C.; Peterson, D.; Pisharody, M.; Riley, D.; Sapper, M.; Silverman, A.

    1990-06-21

    Using the CLEO detector at the Cornell Electron Storage Ring, we have searched for two-phonon production of charmonium in four-track final states. We have measured {Gamma}{sub {gamma}{gamma}}({eta}{sub c})=5.9{sub -1.8}{sup +2.1}{plus minus}1.9 keV, and we have obtained 95% CL upper limits of {Gamma}{sub {gamma}{gamma}}({chi}{sub c0})<6.2 keV and {Gamma}{sub {gamma}{gamma}}({chi}{sub c2})<1.0 keV. (orig.).

  19. Relating Alpha Power and Phase to Population Firing and Hemodynamic Activity Using a Thalamo-cortical Neural Mass Model.

    Directory of Open Access Journals (Sweden)

    Robert Becker

    2015-09-01

    Full Text Available Oscillations are ubiquitous phenomena in the animal and human brain. Among them, the alpha rhythm in human EEG is one of the most prominent examples. However, its precise mechanisms of generation are still poorly understood. It was mainly this lack of knowledge that motivated a number of simultaneous electroencephalography (EEG - functional magnetic resonance imaging (fMRI studies. This approach revealed how oscillatory neuronal signatures such as the alpha rhythm are paralleled by changes of the blood oxygenation level dependent (BOLD signal. Several such studies revealed a negative correlation between the alpha rhythm and the hemodynamic BOLD signal in visual cortex and a positive correlation in the thalamus. In this study we explore the potential generative mechanisms that lead to those observations. We use a bursting capable Stefanescu-Jirsa 3D (SJ3D neural-mass model that reproduces a wide repertoire of prominent features of local neuronal-population dynamics. We construct a thalamo-cortical network of coupled SJ3D nodes considering excitatory and inhibitory directed connections. The model suggests that an inverse correlation between cortical multi-unit activity, i.e. the firing of neuronal populations, and narrow band local field potential oscillations in the alpha band underlies the empirically observed negative correlation between alpha-rhythm power and fMRI signal in visual cortex. Furthermore the model suggests that the interplay between tonic and bursting mode in thalamus and cortex is critical for this relation. This demonstrates how biophysically meaningful modelling can generate precise and testable hypotheses about the underpinnings of large-scale neuroimaging signals.

  20. Cortical surface alignment in multi-subject spatiotemporal independent EEG source imaging.

    Science.gov (United States)

    Tsai, Arthur C; Jung, Tzyy-Ping; Chien, Vincent S C; Savostyanov, Alexander N; Makeig, Scott

    2014-02-15

    Brain responses to stimulus presentations may vary widely across subjects in both time course and spatial origins. Multi-subject EEG source imaging studies that apply Independent Component Analysis (ICA) to data concatenated across subjects have overlooked the fact that projections to the scalp sensors from functionally equivalent cortical sources vary from subject to subject. This study demonstrates an approach to spatiotemporal independent component decomposition and alignment that spatially co-registers the MR-derived cortical topographies of individual subjects to a well-defined, shared spherical topology (Fischl et al., 1999). Its efficacy for identifying functionally equivalent EEG sources in multi-subject analysis is demonstrated by analyzing EEG and behavioral data from a stop-signal paradigm using two source-imaging approaches, both based on individual subject independent source decompositions. The first, two-stage approach uses temporal infomax ICA to separate each subject's data into temporally independent components (ICs), then estimates the source density distribution of each IC process from its scalp map and clusters similar sources across subjects (Makeig et al., 2002). The second approach, Electromagnetic Spatiotemporal Independent Component Analysis (EMSICA), combines ICA decomposition and source current density estimation of the artifact-rejected data into a single spatiotemporal ICA decomposition for each subject (Tsai et al., 2006), concurrently identifying both the spatial source distribution of each cortical source and its event-related dynamics. Applied to the stop-signal task data, both approaches gave IC clusters that separately accounted for EEG processes expected in stop-signal tasks, including pre/postcentral mu rhythms, anterior-cingulate theta rhythm, and right-inferior frontal responses, the EMSICA clusters exhibiting more tightly correlated source areas and time-frequency features.

  1. Attenuation of the gamma rays in tissues; Atenuacion de los rayos gamma en tejidos

    Energy Technology Data Exchange (ETDEWEB)

    Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R. [Unidad Academica de Estudios Nucleares, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2005-07-01

    The mass and lineal attenuation coefficient and of hepatic tissue, muscular, osseous and of brain before gamma rays of 10{sup -3} to 10{sup 5} MeV were calculated. For the case of the osseous tissue the calculation was made for the cartilage, the cortical tissue and the bone marrow. During the calculations the elementary composition of the tissues of human origin was used. The calculations include by separate the Photoelectric effect, the Compton scattering and the Pair production, as well as the total. For to establish a comparison with the attenuation capacities, the coefficients of the water, the aluminum and the lead also were calculated. The study was complemented measuring the attenuation coefficient of hepatic tissue of bovine before gamma rays of 0.662 MeV of a source of {sup 137} Cs. The measurement was made through of an experiment of photons transmission through samples frozen of hepatic tissue and with a Geiger-Mueller detector. (Author)

  2. Gamma Splines and Wavelets

    Directory of Open Access Journals (Sweden)

    Hannu Olkkonen

    2013-01-01

    Full Text Available In this work we introduce a new family of splines termed as gamma splines for continuous signal approximation and multiresolution analysis. The gamma splines are born by -times convolution of the exponential by itself. We study the properties of the discrete gamma splines in signal interpolation and approximation. We prove that the gamma splines obey the two-scale equation based on the polyphase decomposition. to introduce the shift invariant gamma spline wavelet transform for tree structured subscale analysis of asymmetric signal waveforms and for systems with asymmetric impulse response. Especially we consider the applications in biomedical signal analysis (EEG, ECG, and EMG. Finally, we discuss the suitability of the gamma spline signal processing in embedded VLSI environment.

  3. Genetic dissection of theta rhythm heterogeneity in mice.

    Science.gov (United States)

    Shin, Jonghan; Kim, Daesoo; Bianchi, Riccardo; Wong, Robert K S; Shin, Hee-Sup

    2005-12-13

    Rhythmic oscillatory activities at the theta frequency (4-12 Hz) in the hippocampus have long-attracted attention because they have been implicated in diverse brain functions, including spatial cognition. Although studies based on pharmacology and lesion experiments suggested heterogeneity of these rhythms and their behavioral correlates, controversies are abundant on these issues. Here we show that mice harboring a phospholipase C (PLC)-beta1(-/-) mutation (PLC-beta1(-/-) mice) lack one subset of theta rhythms normally observed during urethane anesthesia, alert immobility, and passive whole-body rotation. In contrast, the other subset of theta rhythms observed during walking or running was intact in these mutant mice. PLC-beta1(-/-) mice also have somewhat disrupted theta activity during paradoxical sleep but do have an atropine-resistant component of theta rhythm. In addition, carbachol-induced oscillations were obliterated in hippocampal slices of PLC-beta1(-/-) mice. Interestingly, PLC-beta1(-/-) mice showed deficits in a hidden platform version of the Morris water maze yet performed well in motor coordination tests and a visual platform version of the Morris water maze. The results genetically define the existence of at least two subtypes of theta rhythms and reveal their association with different behaviors.

  4. Social Rhythm and Mental Health: A Cross-Cultural Comparison.

    Directory of Open Access Journals (Sweden)

    Jürgen Margraf

    Full Text Available Social rhythm refers to the regularity with which one engages in social activities throughout the week, and has established links with bipolar disorder, as well as some links with depression and anxiety. The aim of the present study is to examine social rhythm and its relationship to various aspects of health, including physical health, negative mental health, and positive mental health.Questionnaire data were obtained from a large-scale multi-national sample of 8095 representative participants from the U.S., Russia, and Germany.Results indicated that social rhythm irregularity is related to increased reporting of health problems, depression, anxiety, and stress. In contrast, greater regularity is related to better overall health state, life satisfaction, and positive mental health. The effects are generally small in size, but hold even when controlling for gender, marital status, education, income, country, and social support. Further, social rhythm means differ across Russia, the U.S., and Germany. Relationships with mental health are present in all three countries, but differ in magnitude.Social rhythm irregularity is related to mental health in Russia, the U.S., and Germany.

  5. Glucocorticoids play a key role in circadian cell cycle rhythms.

    Directory of Open Access Journals (Sweden)

    Thomas Dickmeis

    2007-04-01

    Full Text Available Clock output pathways play a pivotal role by relaying timing information from the circadian clock to a diversity of physiological systems. Both cell-autonomous and systemic mechanisms have been implicated as clock outputs; however, the relative importance and interplay between these mechanisms are poorly understood. The cell cycle represents a highly conserved regulatory target of the circadian timing system. Previously, we have demonstrated that in zebrafish, the circadian clock has the capacity to generate daily rhythms of S phase by a cell-autonomous mechanism in vitro. Here, by studying a panel of zebrafish mutants, we reveal that the pituitary-adrenal axis also plays an essential role in establishing these rhythms in the whole animal. Mutants with a reduction or a complete absence of corticotrope pituitary cells show attenuated cell-proliferation rhythms, whereas expression of circadian clock genes is not affected. We show that the corticotrope deficiency is associated with reduced cortisol levels, implicating glucocorticoids as a component of a systemic signaling pathway required for circadian cell cycle rhythmicity. Strikingly, high-amplitude rhythms can be rescued by exposing mutant larvae to a tonic concentration of a glucocorticoid agonist. Our work suggests that cell-autonomous clock mechanisms are not sufficient to establish circadian cell cycle rhythms at the whole-animal level. Instead, they act in concert with a systemic signaling environment of which glucocorticoids are an essential part.

  6. Pathophysiology and pathogenesis of circadian rhythm sleep disorders

    Directory of Open Access Journals (Sweden)

    Hida Akiko

    2012-03-01

    Full Text Available Abstract Metabolic, physiological and behavioral processes exhibit 24-hour rhythms in most organisms, including humans. These rhythms are driven by a system of self-sustained clocks and are entrained by environmental cues such as light-dark cycles as well as food intake. In mammals, the circadian clock system is hierarchically organized such that the master clock in the suprachiasmatic nuclei of the hypothalamus integrates environmental information and synchronizes the phase of oscillators in peripheral tissues. The transcription and translation feedback loops of multiple clock genes are involved in the molecular mechanism of the circadian system. Disturbed circadian rhythms are known to be closely related to many diseases, including sleep disorders. Advanced sleep phase type, delayed sleep phase type and nonentrained type of circadian rhythm sleep disorders (CRSDs are thought to result from disorganization of the circadian system. Evaluation of circadian phenotypes is indispensable to understanding the pathophysiology of CRSD. It is laborious and costly to assess an individual's circadian properties precisely, however, because the subject is usually required to stay in a laboratory environment free from external cues and masking effects for a minimum of several weeks. More convenient measurements of circadian rhythms are therefore needed to reduce patients' burden. In this review, we discuss the pathophysiology and pathogenesis of CRSD as well as surrogate measurements for assessing an individual's circadian phenotype.

  7. Lateralized ultradian rhythms: evidence from tactile discrimination of either hand.

    Science.gov (United States)

    Meier-Koll, A

    1998-12-01

    Endogenous ultradian rhythms with periods of one or a few hours affect not only on physiological and behavioural functions but also perception and cognition. In particular, lateralized ultradian rhythms which seem to operate separately in the right and left hemispheres of the brain can be monitored by testing the tactile discrimination of the contralateral hand. The present paper is based on two subsequent studies: First, ultradian rhythms in tactile discrimination of either hand were examined in German subjects under laboratory conditions. Considerably different ultradian periods of right and left-handed tactile error rate were found in men but not in women. In a second study, a group of Kenyan Masai shepherds were tested while the subjects were leading herds on daily feeding routes through a savanna habitat. They showed ultradian periods of about 2 hours in tactile discrimination of either hand. Since the right hemisphere is specialized for visuospatial, the left for verbal processing lateralized ultradian rhythms may serve for a long-scale timing of neural processes underlying spatial and semantic mapping of the environment. Sex difference in German subjects and lateral differences found in left-handed (right-hemispheric) ultradian rhythms of German and Masai subjects are discussed from this point of view.

  8. Neuroimaging, cognition, light and circadian rhythms

    Directory of Open Access Journals (Sweden)

    Giulia eGaggioni

    2014-07-01

    Full Text Available In humans, sleep and wakefulness and the associated cognitive processes are regulated through interactions between sleep homeostasis and the circadian system. Chronic disruption of sleep and circadian rhythmicity is common in our society and there is a need for a better understanding of the brain mechanisms regulating sleep, wakefulness and associated cognitive processes. This review summarizes recent investigations which provide first neural correlates of the combined influence of sleep homeostasis and circadian rhythmicity on cognitive brain activity. Markers of interindividual variations in sleep-wake regulation, such as chronotype and polymorphisms in sleep and clock genes, are associated with changes in cognitive brain responses in subcortical and cortical areas in response to manipulations of the sleep-wake cycle. This review also includes recent data showing that cognitive brain activity is regulated by light, which is a powerful modulator of cognition and alertness and also directly impacts sleep and circadian rhythmicity. The effect of light varied with age, psychiatric status, PERIOD3 genotype and changes in sleep homeostasis and circadian phase. These data provide new insights into the contribution of demographic characteristics, the sleep-wake cycle, circadian rhythmicity and light to brain functioning.

  9. Beta and Gamma Gradients

    DEFF Research Database (Denmark)

    Løvborg, Leif; Gaffney, C. F.; Clark, P. A.;

    1985-01-01

    Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions...... of differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears...

  10. Sound identification in human auditory cortex: Differential contribution of local field potentials and high gamma power as revealed by direct intracranial recordings.

    Science.gov (United States)

    Nourski, Kirill V; Steinschneider, Mitchell; Rhone, Ariane E; Oya, Hiroyuki; Kawasaki, Hiroto; Howard, Matthew A; McMurray, Bob

    2015-09-01

    High gamma power has become the principal means of assessing auditory cortical activation in human intracranial studies, albeit at the expense of low frequency local field potentials (LFPs). It is unclear whether limiting analyses to high gamma impedes ability of clarifying auditory cortical organization. We compared the two measures obtained from posterolateral superior temporal gyrus (PLST) and evaluated their relative utility in sound categorization. Subjects were neurosurgical patients undergoing invasive monitoring for medically refractory epilepsy. Stimuli (consonant-vowel syllables varying in voicing and place of articulation and control tones) elicited robust evoked potentials and high gamma activity on PLST. LFPs had greater across-subject variability, yet yielded higher classification accuracy, relative to high gamma power. Classification was enhanced by including temporal detail of LFPs and combining LFP and high gamma. We conclude that future studies should consider utilizing both LFP and high gamma when investigating the functional organization of human auditory cortex. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Brain dynamics in the comprehension of action-related language. A time-frequency analysis of mu rhythms.

    Science.gov (United States)

    Moreno, Iván; de Vega, Manuel; León, Inmaculada; Bastiaansen, Marcel; Glen Lewis, Ashley; Magyari, Lilla

    2015-04-01

    EEG mu rhythms (8-13 Hz) recorded at fronto-central electrodes are generally considered as markers of motor cortical activity in humans, because they are modulated when participants perform an action, when they observe another's action or even when they imagine performing an action. In this study, we analyzed the time-frequency (TF) modulation of mu rhythms while participants read action language ("You will cut the strawberry cake"), abstract language ("You will doubt the patient's argument"), and perceptive language ("You will notice the bright day"). The results indicated that mu suppression at fronto-central sites is associated with action language rather than with abstract or perceptive language. Also, the largest difference between conditions occurred quite late in the sentence, while reading the first noun, (contrast Action vs. Abstract), or the second noun following the action verb (contrast Action vs. Perceptive). This suggests that motor activation is associated with the integration of words across the sentence beyond the lexical processing of the action verb. Source reconstruction localized mu suppression associated with action sentences in premotor cortex (BA 6). The present study suggests (1) that the understanding of action language activates motor networks in the human brain, and (2) that this activation occurs online based on semantic integration across multiple words in the sentence.

  12. Hamilton-Jacobi skeleton on cortical surfaces.

    Science.gov (United States)

    Shi, Y; Thompson, P M; Dinov, I; Toga, A W

    2008-05-01

    In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton [1] to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions.

  13. Disorders of cortical formation: MR imaging features.

    Science.gov (United States)

    Abdel Razek, A A K; Kandell, A Y; Elsorogy, L G; Elmongy, A; Basett, A A

    2009-01-01

    The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

  14. How the $\\gamma \\gamma$ Resonance Stole Christmas

    CERN Document Server

    Craig, Nathaniel; Kilic, Can; Thomas, Scott

    2015-01-01

    The experimental and theoretical implications of heavy di-gauge boson resonances that couple to, or are comprised of, new charged and strongly interacting matter are investigated. Observation and measurement of ratios of the resonant di-gauge boson channels $WW$, $ZZ$, $\\gamma \\gamma$, $Z \\gamma$, and $gg$ in the form of di-jets, provide a rather direct -- and for some ratios a rather robust -- probe of the gauge representations of the new matter. For a spin-zero resonance with the quantum numbers of the vacuum, the ratios of resonant $WW$ and $ZZ$ to $\\gamma \\gamma$ channels, as well as the longitudinal versus transverse polarization fractions in the $WW$ and $ZZ$ channels, provide extraordinarily sensitive probes for possible mixing with the Higgs boson, while di-Higgs and di-top resonant channels, $hh$ and $tt$, provide somewhat less sensitivity. We present a survey of possible underlying models for di-gauge boson resonances by considering various limits for the mass of the new charged and strongly interac...

  15. A study of free-running rhythms in sheep.

    Science.gov (United States)

    Hunsaker, W G; Wolynetz, M S

    1979-01-01

    Free-running rhythms for eating, drinking, standing and walking activities were studied in two experiments with four cross-bred rams. In the first experiment the rhythms were entrained to a LD (12:12) (300:0) regimen. Following a change to continuous dim light (less than 2 lux) there was a suggestion of free-running activity for about three days in some of the variables. By the fourth day, however, the previously entrained rhythms had been damped out and were replaced by random patterns of activity in all variables. In the second experiment, two entraining agents were used: LD (12:12) (300:0) and restriction of feed to the light period only. There was again some indication of free-running activity for the first few days of continuous dim light (less than 2 lux) but by the fourth day only random patterns of activity were evident.

  16. Current Conceptual Challenges in the Study of Rhythm Processing Deficits

    Directory of Open Access Journals (Sweden)

    Pauline eTranchant

    2015-06-01

    Full Text Available Interest in the study of rhythm processing deficits (RPD is currently growing in the cognitive neuroscience community, as this type of investigation constitutes a powerful tool for the understanding of normal rhythm processing. Because this field is in its infancy, it still lacks a common conceptual vocabulary to facilitate effective communication between different researchers and research groups. In this commentary, we provide a brief review of recent reports of RPD through the lens of one important empirical issue: the method by which beat perception is measured, and the consequences of method selection for the researcher’s ability to specify which mechanisms are impaired in RPD. This critical reading advocates for the importance of matching measurement tools to the putative neurocognitive mechanisms under study, and reveals the need for effective and specific assessments of the different aspects of rhythm perception and synchronization.

  17. Thalamocortical mechanisms for integrating musical tone and rhythm.

    Science.gov (United States)

    Musacchia, Gabriella; Large, Edward W; Schroeder, Charles E

    2014-02-01

    Studies over several decades have identified many of the neuronal substrates of music perception by pursuing pitch and rhythm perception separately. Here, we address the question of how these mechanisms interact, starting with the observation that the peripheral pathways of the so-called "Core" and "Matrix" thalamocortical system provide the anatomical bases for tone and rhythm channels. We then examine the hypothesis that these specialized inputs integrate acoustic content within rhythm context in auditory cortex using classical types of "driving" and "modulatory" mechanisms. This hypothesis provides a framework for deriving testable predictions about the early stages of music processing. Furthermore, because thalamocortical circuits are shared by speech and music processing, such a model provides concrete implications for how music experience contributes to the development of robust speech encoding mechanisms.

  18. Body movement selectively shapes the neural representation of musical rhythms.

    Science.gov (United States)

    Chemin, Baptiste; Mouraux, André; Nozaradan, Sylvie

    2014-12-01

    It is increasingly recognized that motor routines dynamically shape the processing of sensory inflow (e.g., when hand movements are used to feel a texture or identify an object). In the present research, we captured the shaping of auditory perception by movement in humans by taking advantage of a specific context: music. Participants listened to a repeated rhythmical sequence before and after moving their bodies to this rhythm in a specific meter. We found that the brain responses to the rhythm (as recorded with electroencephalography) after body movement were significantly enhanced at frequencies related to the meter to which the participants had moved. These results provide evidence that body movement can selectively shape the subsequent internal representation of auditory rhythms.

  19. Inositols affect the mating circadian rhythm of Drosophila melanogaster

    Science.gov (United States)

    Sakata, Kazuki; Kawasaki, Haruhisa; Suzuki, Takahiro; Ito, Kumpei; Negishi, Osamu; Tsuno, Takuo; Tsuno, Hiromi; Yamazaki, Youta; Ishida, Norio

    2015-01-01

    Accumulating evidence indicates that the molecular circadian clock underlies the mating behavior of Drosophila melanogaster. However, information about which food components affect circadian mating behavior is scant. The ice plant, Mesembryanthemum crystallinum has recently become a popular functional food. Here, we showed that the close-proximity (CP) rhythm of D. melanogaster courtship behavior was damped under low-nutrient conditions, but significantly enhanced by feeding the flies with powdered ice plant. Among various components of ice plants, we found that myo-inositol increased the amplitude and slightly shortened the period of the CP rhythm. Real-time reporter assays showed that myo-inositol and D-pinitol shortened the period of the circadian reporter gene Per2-luc in NIH 3T3 cells. These data suggest that the ice plant is a useful functional food and that the ability of inositols to shorten rhythms is a general phenomenon in insects as well as mammals. PMID:26097456

  20. Inositols affect the mating circadian rhythm of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Kazuki eSakata

    2015-06-01

    Full Text Available Accumulating evidence indicates that the molecular circadian clock underlies the mating behavior of D. melanogaster. However, information about which food components affect circadian mating behavior is scant. The ice plant, Mesembryanthemum crystallinum has recently become a popular functional food. Here, we showed that the close-proximity (CP rhythm of Drosophila melanogaster courtship behavior was damped under low-nutrient conditions, but significantly enhanced by feeding the flies with powdered ice plant. Among various components of ice plants, we found that myo-inositol increased the amplitude and slightly shortened the period of the CP rhythm. Real-time reporter assays showed that myo-inositol and D-pinitol shortened the period of the circadian reporter gene Per2-luc in NIH 3T3 cells. These data suggest that the ice plant is a useful functional food and that the ability of inositols to shorten rhythms is a general phenomenon in insects as well as mammals.

  1. Disruption of biological rhythms as a core problem and therapeutic target in mood disorders: the emerging concept of 'rhythm regulators'

    Directory of Open Access Journals (Sweden)

    Fountoulakis Konstantinos N

    2010-01-01

    Full Text Available Abstract Biological rhythms have always been considered to be disrupted in depression, with the predominant theory being that of hyperarousal. However, recent data suggest that it might be more appropriate to suggest that depressed patients are incapable of achieving and maintaining the particular level of internal homeostasis which permits them to function smoothly, to lower the level of arousal during sleep sufficiently so that quality of sleep is good, and to increase this level enough during the day so the person can function properly. Therefore, the transition from one state to another is somewhat problematic, delayed, incomplete and desynchronised. Thus, agents with a 'rhythm stabilising' effect could be beneficial in the treatment of mood disorders. Such an agent should have a beneficial effect on restoring and stabilising the rhythm of a physiological function while not pushing it towards a specific pole, or inducing the opposite pole; it should also allow response to internal and environmental stimuli and zeitgebers, and restore synchronisation of the various body rhythms while not inducing or worsening desynchronisation. Agomelatine could represent the first of a new class of 'rhythm stabilising antidepressants', but further research is necessary to support this theory.

  2. Broadband Macroscopic Cortical Oscillations Emerge from Intrinsic Neuronal Response Failures

    Directory of Open Access Journals (Sweden)

    Amir eGoldental

    2015-10-01

    Full Text Available Broadband spontaneous macroscopic neural oscillations are rhythmic cortical firing which was extensively examined during the last century, however, their possible origination is still controversial. In this work we show how macroscopic oscillations emerge in solely excitatory random networks and without topological constraints. We experimentally and theoretically show that these oscillations stem from the counterintuitive underlying mechanism - the intrinsic stochastic neuronal response failures. These neuronal response failures, which are characterized by short-term memory, lead to cooperation among neurons, resulting in sub- or several- Hertz macroscopic oscillations which coexist with high frequency gamma oscillations. A quantitative interplay between the statistical network properties and the emerging oscillations is supported by simulations of large networks based on single-neuron in-vitro experiments and a Langevin equation describing the network dynamics. Results call for the examination of these oscillations in the presence of inhibition and external drives.

  3. The roles of cortical oscillations in sustained attention.

    Science.gov (United States)

    Clayton, Michael S; Yeung, Nick; Cohen Kadosh, Roi

    2015-04-01

    We rely on sustained attention to protect task performance against fatigue and distraction. Time-related variations in attention correlate with amplitude changes of specific cortical oscillations. However, the ways in which these oscillations might support sustained attention, how these oscillations are controlled, and the extent to which they influence one another remain unclear. We address this issue by proposing an oscillatory model of sustained attention. Within this framework, sustained attention relies on frontomedial theta oscillations, inter-areal communication via low-frequency phase synchronisation, and selective excitation and inhibition of cognitive processing through gamma and alpha oscillations, respectively. Sustained attention also relies on interactions between these oscillations across attention-related brain networks.

  4. A Rare Hydrocephalus Complication: Cortical Blindness.

    Science.gov (United States)

    Ünal, Emre; Göçmen, Rahşan; Işıkay, Ayşe İlksen; Tekşam, Özlem

    2015-01-01

    Cortical blindness related to bilateral occipital lobe infarction is an extremely rare complication of hydrocephalus. Compression of the posterior cerebral artery, secondary to tentorial herniation, is the cause of occipital infarction. Particularly in children and mentally ill patients, cortical blindness may be missed. Therefore, early diagnosis and treatment of hydrocephalus is important. We present herein a child of ventricular shunt malfunction complicated by cortical blindness.

  5. Acute hepatic encephalopathy with diffuse cortical lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.M.; Spreer, J.; Schumacher, M. [Section of Neuroradiology, Univ. of Freiburg (Germany); Els, T. [Dept. of Neurology, University of Freiburg (Germany)

    2001-07-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  6. Membrane Potential Dynamics of Spontaneous and Visually Evoked Gamma Activity in V1 of Awake Mice

    NARCIS (Netherlands)

    Perrenoud, Q.; Pennartz, C.M.A.; Gentet, L.J.

    2016-01-01

    Cortical gamma activity (30-80 Hz) is believed to play important functions in neural computation and arises from the interplay of parvalbumin-expressing interneurons (PV) and pyramidal cells (PYRs). However, the subthreshold dynamics underlying its emergence in the cortex of awake animals remain unc

  7. Nursing students’ knowledge about arrest rhythms and their treatment

    Directory of Open Access Journals (Sweden)

    Aikaterini Kyrgianidou

    2014-04-01

    Full Text Available Cardiovascular diseases are one of the leading causes of death worldwide. Knowledge of health professionals for the arrest rhythms, is considered particularly important for the early recognition and proper treatment. Aim: The purpose of the present study was to assess the knowledge of nursing students on arrest rhythms and how to treat them. Material and Methods: The sample studied included 151 students from the Department of Nursing A' (n = 60, 40% and B' (n = 91, 60%, TEI of Athens, of whom 83% (n=125 were women and 17% (n=26 were men with a mean age of 23 years. Data collection was performed with specially designed questionnaire, that apart from demographics and students’ education level, it included ten questions about arrest rhythms’ knowledge and also self-assessment questions of their level of knowledge. The data were analyzed with the SPSS package v.19, using the criteria t-Test and χ2. Results: Of all the participants in the research, 95% (n = 144 did not answer correctly more than 6 questions from a total of 10. The students of the Department of Nursing A’ recognized with greater accuracy the arrest rhythms (p = 0.003. Those studying in lower semester acknowledged best the arrest rhythms (p = 0.002. Students who had recently attended course in basic or advanced resuscitation recognized best the arrest rhythms (p = 0.006. Older students knew better right treatment of the arrest rhythms (p = 0.037. Also, students who had attended the course of cardiac nursing in the last year, knew better the right treatment (p <0.001. Finally, the level of self-assessment was in line with the actual level of knowledge of students (p = 0.05. Conclusions: Continuous attendance of courses, education on certified programs and refresh courses help to maintain a good level of knowledge for longer periods.

  8. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  9. Negative Correlations in Visual Cortical Networks

    National Research Council Canada - National Science Library

    Chelaru, Mircea I; Dragoi, Valentin

    2016-01-01

    .... Whereas positive noise correlations have been extensively studied using experimental and theoretical tools, the functional role of negative correlations in cortical circuits has remained elusive...

  10. Functional localization of the cortical motor area in the brain Electrocorticogram analysis

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Xiaoming Wu; Binggang Ye; Sijuan Huang

    2010-01-01

    The method for rapidly,precisely and non-invasively localizing functional regions of the brain is a problem in neuromedicine research.Cortical electrostimulation is the optimal localization method during brain surgery,with a degree of accuracy of approximately 5 mm.However,electrostimulation can damage the cerebral cortex,trigger epilepsy,and extend the operation time.Studies are required to determine whether cortical motor regions can be localized by wavelet analysis from electrocorticograms.In this study,based on wavelet analysis of electrocorticograms,a selection of algorithms for classification of the mu rhythm in the motor regions utilizing experimental data was verified.Results demonstrated that a characteristic quantity of energy ratio in the reconstructed signal was filtered in the d6(7.81-15.62 Hz)band prior to and following motion events.A characteristic threshold was considered to be 40%.The accuracy of localization detection was 93%.The degree of accuracy was less than 5 mm.The present study avoided the problems of cerebral cortex injury and epilepsy onset,with an operation time of 60 seconds.Therefore,wavelet analysis on electrocorticogram is feasible for localizing cortical motor regions.Furthermore,this localization technique is accurate,safe and rapid.

  11. Recording Gamma Band Oscillations in Pedunculopontine Nucleus Neurons.

    Science.gov (United States)

    Urbano, Francisco J; Luster, Brennon R; D'Onofrio, Stasia; Mahaffey, Susan; Garcia-Rill, Edgar

    2016-09-14

    Synaptic efferents from the PPN are known to modulate the neuronal activity of several intralaminar thalamic regions (e.g., the centrolateral/parafascicular; Cl/Pf nucleus). The activation of either the PPN or Cl/Pf nuclei in vivo has been described to induce the arousal of the animal and an increment in gamma band activity in the cortical electroencephalogram (EEG). The cellular mechanisms for the generation of gamma band oscillations in Reticular Activating System (RAS) neurons are the same as those found to generate gamma band oscillations in other brains nuclei. During current-clamp recordings of PPN neurons (from parasagittal slices from 9 - 25 day-old rats), the use of depolarizing square steps rapidly activated voltage-dependent potassium channels that prevented PPN neurons from being depolarized beyond -25 mV. Injecting 1 - 2 sec long depolarizing current ramps gradually depolarized PPN membrane potential resting values towards 0 mV. However, injecting depolarizing square pulses generated gamma-band oscillations of membrane potential that showed to be smaller in amplitude compared to the oscillations generated by ramps. All experiments were performed in the presence of voltage-gated sodium channels and fast synaptic receptors blockers. It has been shown that the activation of high-threshold voltage-dependent calcium channels underlie gamma-band oscillatory activity in PPN neurons. Specific methodological and pharmacological interventions are described here, providing the necessary tools to induce and sustain PPN subthreshold gamma band oscillation in vitro.

  12. Stimulus Dependence of Gamma Oscillations in Human Visual Cortex.

    Science.gov (United States)

    Hermes, D; Miller, K J; Wandell, B A; Winawer, J

    2015-09-01

    A striking feature of some field potential recordings in visual cortex is a rhythmic oscillation within the gamma band (30-80 Hz). These oscillations have been proposed to underlie computations in perception, attention, and information transmission. Recent studies of cortical field potentials, including human electrocorticography (ECoG), have emphasized another signal within the gamma band, a nonoscillatory, broadband signal, spanning 80-200 Hz. It remains unclear under what conditions gamma oscillations are elicited in visual cortex, whether they are necessary and ubiquitous in visual encoding, and what relationship they have to nonoscillatory, broadband field potentials. We demonstrate that ECoG responses in human visual cortex (V1/V2/V3) can include robust narrowband gamma oscillations, and that these oscillations are reliably elicited by some spatial contrast patterns (luminance gratings) but not by others (noise patterns and many natural images). The gamma oscillations can be conspicuous and robust, but because they are absent for many stimuli, which observers can see and recognize, the oscillations are not necessary for seeing. In contrast, all visual stimuli induced broadband spectral changes in ECoG responses. Asynchronous neural signals in visual cortex, reflected in the broadband ECoG response, can support transmission of information for perception and recognition in the absence of pronounced gamma oscillations.

  13. Amplitude-Modulated Bursting: A Novel Class of Bursting Rhythms

    Science.gov (United States)

    Vo, Theodore; Kramer, Mark A.; Kaper, Tasso J.

    2016-12-01

    We report on the discovery of a novel class of bursting rhythms, called amplitude-modulated bursting (AMB), in a model for intracellular calcium dynamics. We find that these rhythms are robust and exist on open parameter sets. We develop a new mathematical framework with broad applicability to detect, classify, and rigorously analyze AMB. Here we illustrate this framework in the context of AMB in a model of intracellular calcium dynamics. In the process, we discover a novel family of singularities, called toral folded singularities, which are the organizing centers for the amplitude modulation and exist generically in slow-fast systems with two or more slow variables.

  14. Rhythm-based segmentation of Popular Chinese Music

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    We present a new method to segment popular music based on rhythm. By computing a shortest path based on the self-similarity matrix calculated from a model of rhythm, segmenting boundaries are found along the di- agonal of the matrix. The cost of a new segment is opti- mized by matching manual...... and automatic segment boundaries. We compile a small song database of 21 randomly selected popular Chinese songs which come from Chinese Mainland, Taiwan and Hong Kong. The segmenting results on the small corpus show that 78% manual segmentation points are detected and 74% auto- matic segmentation points...

  15. Circadian activity rhythms in the spiny mouse, Acomys cahirinus.

    Science.gov (United States)

    Weber, E T; Hohn, V M

    2005-11-15

    Circadian locomotor rhythms were examined in adult common spiny mice, Acomys cahirinus. Spiny mice demonstrated nocturnal activity, with onset of activity coinciding promptly with onset of darkness. Re-entrainment to 6-h delays of the light-dark cycle was accomplished faster than to 6-h advances. Access to running wheels yielded significant changes in period and duration of daily activity. Novelty-induced wheel running had no effect on phase of activity rhythms. Circadian responses to light at various times of the circadian cycle were temporally similar to those observed in other nocturnal rodent species. No gender differences were observed in any of the parameters measured.

  16.  Gap junction involvement in hippocampal theta rhythm generation

    Directory of Open Access Journals (Sweden)

    Renata Bocian

    2012-10-01

    Full Text Available  Hippocampal theta rhythm is probably the best example of oscillations and synchrony phenomena occurring in neuronal networks of the central nervous system. It is well known that intraneuronal communication via chemical and electrical synapses underlies these oscillatory processes. Despite well-documented knowledge concerning the participation of chemical transmission in production of theta activity, the role of much faster gap junction communication is still not fully understood. This paper provides an overview of current research data concerning the involvement of electrical transmission in generation of the best synchronized EEG pattern recorded from the mammalian brain – theta rhythm.

  17. Functional roles of 10 Hz alpha-band power modulating engagement and disengagement of cortical networks in a complex visual motion task.

    Directory of Open Access Journals (Sweden)

    Kunjan D Rana

    Full Text Available Alpha band power, particularly at the 10 Hz frequency, is significantly involved in sensory inhibition, attention modulation, and working memory. However, the interactions between cortical areas and their relationship to the different functional roles of the alpha band oscillations are still poorly understood. Here we examined alpha band power and the cortico-cortical interregional phase synchrony in a psychophysical task involving the detection of an object moving in depth by an observer in forward self-motion. Wavelet filtering at the 10 Hz frequency revealed differences in the profile of cortical activation in the visual processing regions (occipital and parietal lobes and in the frontoparietal regions. The alpha rhythm driving the visual processing areas was found to be asynchronous with the frontoparietal regions. These findings suggest a decoupling of the 10 Hz frequency into separate functional roles: sensory inhibition in the visual processing regions and spatial attention in the frontoparietal regions.

  18. Functional roles of 10 Hz alpha-band power modulating engagement and disengagement of cortical networks in a complex visual motion task.

    Science.gov (United States)

    Rana, Kunjan D; Vaina, Lucia M

    2014-01-01

    Alpha band power, particularly at the 10 Hz frequency, is significantly involved in sensory inhibition, attention modulation, and working memory. However, the interactions between cortical areas and their relationship to the different functional roles of the alpha band oscillations are still poorly understood. Here we examined alpha band power and the cortico-cortical interregional phase synchrony in a psychophysical task involving the detection of an object moving in depth by an observer in forward self-motion. Wavelet filtering at the 10 Hz frequency revealed differences in the profile of cortical activation in the visual processing regions (occipital and parietal lobes) and in the frontoparietal regions. The alpha rhythm driving the visual processing areas was found to be asynchronous with the frontoparietal regions. These findings suggest a decoupling of the 10 Hz frequency into separate functional roles: sensory inhibition in the visual processing regions and spatial attention in the frontoparietal regions.

  19. Transition Distribution Amplitudes for gamma* gamma collisions

    CERN Document Server

    Lansberg, J P; Szymanowski, L

    2008-01-01

    We study the exclusive production of pi-pi and rho-pi in hard gamma* gamma scattering in the forward kinematical region where the virtuality of one photon provides us with a hard scale in the process. The newly introduced concept of Transition Distribution Amplitudes (TDA) is used to perform a QCD calculation of these reactions thanks to two simple models for TDAs. The sizable cross sections for rho-pi and pi-pi production may be tested at intense electron-positron colliders such as CLEO and B factories (Belle and BaBar).

  20. Gamma-ray triangles

    DEFF Research Database (Denmark)

    Ibarra, Alejandro; Lopez-Gehler, Sergio; Molinaro, Emiliano

    2016-01-01

    We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight into another fermion and a photon. The r...

  1. Altered Cortical Ensembles in Mouse Models of Schizophrenia.

    Science.gov (United States)

    Hamm, Jordan P; Peterka, Darcy S; Gogos, Joseph A; Yuste, Rafael

    2017-04-05

    In schizophrenia, brain-wide alterations have been identified at the molecular and cellular levels, yet how these phenomena affect cortical circuit activity remains unclear. We studied two mouse models of schizophrenia-relevant disease processes: chronic ketamine (KET) administration and Df(16)A(+/-), modeling 22q11.2 microdeletions, a genetic variant highly penetrant for schizophrenia. Local field potential recordings in visual cortex confirmed gamma-band abnormalities similar to patient studies. Two-photon calcium imaging of local cortical populations revealed in both models a deficit in the reliability of neuronal coactivity patterns (ensembles), which was not a simple consequence of altered single-neuron activity. This effect was present in ongoing and sensory-evoked activity and was not replicated by acute ketamine administration or pharmacogenetic parvalbumin-interneuron suppression. These results are consistent with the hypothesis that schizophrenia is an "attractor" disease and demonstrate that degraded neuronal ensembles are a common consequence of diverse genetic, cellular, and synaptic alterations seen in chronic schizophrenia. Published by Elsevier Inc.

  2. Gyrification from constrained cortical expansion

    CERN Document Server

    Tallinen, Tuomas; Biggins, John S; Mahadevan, L

    2015-01-01

    The exterior of the mammalian brain - the cerebral cortex - has a conserved layered structure whose thickness varies little across species. However, selection pressures over evolutionary time scales have led to cortices that have a large surface area to volume ratio in some organisms, with the result that the brain is strongly convoluted into sulci and gyri. Here we show that the gyrification can arise as a nonlinear consequence of a simple mechanical instability driven by tangential expansion of the gray matter constrained by the white matter. A physical mimic of the process using a layered swelling gel captures the essence of the mechanism, and numerical simulations of the brain treated as a soft solid lead to the formation of cusped sulci and smooth gyri similar to those in the brain. The resulting gyrification patterns are a function of relative cortical expansion and relative thickness (compared with brain size), and are consistent with observations of a wide range of brains, ranging from smooth to highl...

  3. Cortical control of facial expression.

    Science.gov (United States)

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

  4. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  5. Rhythm and blues. Neurochemical, neuropharmacological and neuropsychological implications of a hypothesis of circadian rhythm dysfunction in the affective disorders.

    Science.gov (United States)

    Healy, D

    1987-01-01

    Current views on the organisation and functions of the circadian rhythm system are outlined. Evidence is presented supportive of the notion that the pathophysiology of the affective disorders involves a disruption of circadian rhythms and that the primary locus of action of agents effective in the affective disorders is on the circadian rhythm system. Potential disruptions of this system are enumerated. Such a hypothesis, it is argued, might potentially unite the disparate neurochemical and neuroendocrinological findings emerging in both depression and mania. There are in addition neuropsychological and nosological implications of such a framework, which may help bridge the divide between molecular and behavioural approaches to research on the affective disorders which are outlined.

  6. Cortical EEG oscillations and network connectivity as efficacy indices for assessing drugs with cognition enhancing potential.

    Science.gov (United States)

    Ahnaou, A; Huysmans, H; Jacobs, T; Drinkenburg, W H I M

    2014-11-01

    Synchronization of electroencephalographic (EEG) oscillations represents a core mechanism for cortical and subcortical networks, and disturbance in neural synchrony underlies cognitive processing deficits in neurological and neuropsychiatric disorders. Here, we investigated the effects of cognition enhancers (donepezil, rivastigmine, tacrine, galantamine and memantine), which are approved for symptomatic treatment of dementia, on EEG oscillations and network connectivity in conscious rats chronically instrumented with epidural electrodes in different cortical areas. Next, EEG network indices of cognitive impairments with the muscarinic receptor antagonist scopolamine were modeled. Lastly, we examined the efficacy of cognition enhancers to normalize those aberrant oscillations. Cognition enhancers elicited systematic ("fingerprint") enhancement of cortical slow theta (4.5-6 Hz) and gamma (30.5-50 Hz) oscillations correlated with lower activity levels. Principal component analysis (PCA) revealed a compact cluster that corresponds to shared underlying mechanisms as compared to different drug classes. Functional network connectivity revealed consistent elevated coherent slow theta activity in parieto-occipital and between interhemispheric cortical areas. In rats instrumented with depth hippocampal CA1-CA3 electrodes, donepezil elicited similar oscillatory and coherent activities in cortico-hippocampal networks. When combined with scopolamine, the cognition enhancers attenuated the leftward shift in coherent slow delta activity. Such a consistent shift in EEG coherence into slow oscillations associated with altered slow theta and gamma oscillations may underlie cognitive deficits in scopolamine-treated animals, whereas enhanced coherent slow theta and gamma activity may be a relevant mechanism by which cognition enhancers exert their beneficial effect on plasticity and cognitive processes. The findings underscore that PCA and network connectivity are valuable tools to

  7. Rhythm, movement, and autism: Using rhythmic rehabilitation research as a model for autism

    Directory of Open Access Journals (Sweden)

    A. Blythe eLaGasse

    2013-03-01

    Full Text Available Recently, there has been increased focus on movement and sensory abnormalities in autism spectrum disorders (ASD. This has come from research demonstrating cortical and cerebellar difference in autism, with suggestion of early cerebellar dysfunction. As evidence for an extended profile of ASD grows, there are vast implications for treatment and therapy for individuals with autism. Persons with autism are often provided behavioral or cognitive strategies for navigating their environment; however, these strategies do not consider differences in motor functioning. One accommodation that has not yet been explored in the literature is the use of auditory rhythmic cueing to improve motor functioning in ASD. The purpose of this paper is to illustrate the potential impact of auditory rhythmic cueing for motor functioning in persons with ASD. To this effect, we review research on rhythm in motor rehabilitation, draw parallels to motor dysfunction in ASD, and propose a rationale for how rhythmic input can improve sensorimotor functioning, thereby allowing individuals with autism to demonstrate their full cognitive, behavioral, social, and communicative potential.

  8. Rhythm, movement, and autism: using rhythmic rehabilitation research as a model for autism.

    Science.gov (United States)

    Hardy, Michelle W; Lagasse, A Blythe

    2013-01-01

    Recently, there has been increased focus on movement and sensory abnormalities in autism spectrum disorders (ASD). This has come from research demonstrating cortical and cerebellar differences in autism, with suggestion of early cerebellar dysfunction. As evidence for an extended profile of ASD grows, there are vast implications for treatment and therapy for individuals with autism. Persons with autism are often provided behavioral or cognitive strategies for navigating their environment; however, these strategies do not consider differences in motor functioning. One accommodation that has not yet been explored in the literature is the use of auditory rhythmic cueing to improve motor functioning in ASD. The purpose of this paper is to illustrate the potential impact of auditory rhythmic cueing for motor functioning in persons with ASD. To this effect, we review research on rhythm in motor rehabilitation, draw parallels to motor dysfunction in ASD, and propose a rationale for how rhythmic input can improve sensorimotor functioning, thereby allowing individuals with autism to demonstrate their full cognitive, behavioral, social, and communicative potential.

  9. Electroencephalographic sensorimotor rhythms are modulated in the acute phase following focal vibration in healthy subjects.

    Science.gov (United States)

    Lopez, Susanna; Bini, Fabiano; Del Percio, Claudio; Marinozzi, Franco; Celletti, Claudia; Suppa, Antonio; Ferri, Raffaele; Staltari, Emanuela; Camerota, Filippo; Babiloni, Claudio

    2017-06-03

    Few minutes of focal vibration (FV) on limb muscles can improve motor control in neurological (stroke, Parkinson) patients for unknown underlying neurophysiological mechanisms. Here we hypothesized that in healthy volunteers this FV would increase excitability in the primary sensorimotor cortex (S1-M1) during an isometric contraction of the stimulated muscle. The design included an initial control condition with no FV stimulation (Baseline) as well as three short experimental sessions of FV and a Sham (fake) session in a pseudo-random order. In the Baseline condition and immediately after those sessions, electroencephalographic (EEG) activity was recorded during a mild isometric muscle contraction of the right arm. Alpha and beta motor-related EEG power desynchronization (MRPD) at C4 and C3 electrodes overlying Rolandic regions were used as an index of the cortical excitation in S1-M1. Results showed that, compared to the Baseline (no FV) or Sham stimulation, the first two FV sessions showed a cumulative increase in alpha (but not beta) MRPD at C3 electrode, suggesting a specific effect of vibration on the excitability of contralateral S1-M1 generating EEG "mu" rhythms. FV over limb muscles modulates neurophysiological oscillations enhancing excitability of contralateral S1-M1 in healthy volunteers. The proposed mechanism may explain the clinical effects of vibratory rehabilitation in neurological patients with motor deficits. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  10. The role of alpha-rhythm states in perceptual learning: insights from experiments and computational models

    Science.gov (United States)

    Sigala, Rodrigo; Haufe, Sebastian; Roy, Dipanjan; Dinse, Hubert R.; Ritter, Petra

    2014-01-01

    During the past two decades growing evidence indicates that brain oscillations in the alpha band (~10 Hz) not only reflect an “idle” state of cortical activity, but also take a more active role in the generation of complex cognitive functions. A recent study shows that more than 60% of the observed inter-subject variability in perceptual learning can be ascribed to ongoing alpha activity. This evidence indicates a significant role of alpha oscillations for perceptual learning and hence motivates to explore the potential underlying mechanisms. Hence, it is the purpose of this review to highlight existent evidence that ascribes intrinsic alpha oscillations a role in shaping our ability to learn. In the review, we disentangle the alpha rhythm into different neural signatures that control information processing within individual functional building blocks of perceptual learning. We further highlight computational studies that shed light on potential mechanisms regarding how alpha oscillations may modulate information transfer and connectivity changes relevant for learning. To enable testing of those model based hypotheses, we emphasize the need for multidisciplinary approaches combining assessment of behavior and multi-scale neuronal activity, active modulation of ongoing brain states and computational modeling to reveal the mathematical principles of the complex neuronal interactions. In particular we highlight the relevance of multi-scale modeling frameworks such as the one currently being developed by “The Virtual Brain” project. PMID:24772077

  11. Demonstration of a day-night rhythm in human skeletal muscle oxidative capacity

    Directory of Open Access Journals (Sweden)

    Dirk van Moorsel

    2016-08-01

    Conclusions: Our results suggest that the biological clock drives robust rhythms in human skeletal muscle oxidative metabolism. It is tempting to speculate that disruption of these rhythms contribute to the deterioration of metabolic health associated with circadian misalignment.

  12. Cross-cultural influences on rhythm processing: reproduction, discrimination, and beat tapping

    National Research Council Canada - National Science Library

    Cameron, Daniel J; Bentley, Jocelyn; Grahn, Jessica A

    2015-01-01

    .... To measure the influence of culture on rhythm processing, we tested East African and North American adults on perception, production, and beat tapping for rhythms derived from East African and Western music...

  13. Galactic gamma ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, V.

    1982-05-01

    During the last decade the exploration of the sky in the light of gamma rays has begun by means of satellite-and balloon-borne instruments. Like in other ranges of the electromagnetic spectrum the Milky Way clearly stands out against the rest of the sphere. Part of the galactic ..gamma..-ray emission is due to discrete sources, part is diffuse in origin and is produced in interstellar space. Some of the discrete ..gamma..-ray sources are radio pulsars, the nature of the other sources is still unknown. The intensity distribution of the diffuse galactic ..gamma..-ray component is consistent with a decrease of the cosmic-ray intensity towards the outer part of the galaxy. The identification of the cosmic-ray sources will be one of the main objectives of the next generation of ..gamma..-ray telescopes.

  14. Momentum Dependent Vertices $\\sigma \\gamma \\gamma$, $\\sigma \\rho \\gamma$ and $\\sigma \\rho \\rho$ : The NJL Scalar Hidden by Chiral Symmetry

    OpenAIRE

    Bajc, B.; Blin, A. H.; Hiller, B.; Nemes, M. C.; Rosina, M.

    1994-01-01

    We calculate the momentum dependence of three particle vertices $\\sigma \\gamma \\gamma$, $\\sigma \\rho \\gamma$ and $\\sigma \\rho \\rho$ in the context of a Nambu Jona Lasinio type model. We show how they influence the processes $\\gamma \\gamma \\rightarrow \\sigma \\rightarrow \\pi \\pi$, $\\rho \\rightarrow \\gamma \\sigma$ and $\\gamma \\gamma \\rightarrow \\rho \\rho$ and how chiral symmetry shadows the presence of the $\\sigma$.

  15. Colliding. gamma. e- and. gamma gamma. -beams on the basis of electron-positron linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, I.F.; Kotkin, G.L.; Serbo, V.G.; Tel' nov, V.I.

    1983-08-01

    Main properties of the ..gamma..e and ..gamma gamma.. collisions are discussed in some detail with application to the generation of colliding ..gamma..e and ..gamma gamma.. beams basing on the designed linear accelerators with colliding e/sup +/e/sup -/ beams, VLEEP and SLC, as it was proposed in a previous work. Intensive ..gamma.. beams with the energy 50 GeV would be produced from scattering of the laser light focused to the electron beams of the accelerators. Laser radiation is focused to the electron beam in the conversion region at a distance of about 10 cm from the place of collision. After scattering on electrons high-energy photons move practically along the electron primary trajectories and are focused in the collision region. The electrons are deflected from the collision region by means of approximately 1 T magnetic field. Then the produced ..gamma..-beam collides with an electron beam or a similar ..gamma..-beam. In the case when the maximum luminosity (L) is attained, the luminosity distribution in the invariant mass of the ..gamma..e or ..gamma gamma.. systems is wide. A monochromatization of the collisions up to the level of 5-10% is possible. That will entail a decrease in the luminosity, the procedure is most effective if one uses the electrons and the laser photons with opposite helicities. Examples of physically interesting problems to be investigated with the proposed ..gamma..e and ..gamma gamma.. beams are suggested.

  16. Chronobiology applied to spawning and gamete withdrawal: importance of daily rhythms

    OpenAIRE

    2011-01-01

    Chronobiology is the field of science which studies the biological rhythms and the mechanisms by which the organisms adapt to a constantly changing environment. Animals synchronize their rhythms with environmental cycles choosing the most suitable moment to feed, reproduce or be active, thereby optimizing biological processes. In fish, the study of circadian activity and feeding rhythms has been profusely investigated lately; however, reproduction rhythms are often neglected. Fish species rep...

  17. Circadian Sleep-Wake Rhythm of Older Adults with Intellectual Disabilities

    Science.gov (United States)

    Maaskant, Marijke; van de Wouw, Ellen; van Wijck, Ruud; Evenhuis, Heleen M.; Echteld, Michael A.

    2013-01-01

    The circadian sleep-wake rhythm changes with aging, resulting in a more fragmented sleep-wake pattern. In individuals with intellectual disabilities (ID), brain structures regulating the sleep-wake rhythm might be affected. The aims of this study were to compare the sleep-wake rhythm of older adults with ID to that of older adults in the general…

  18. Development of the cortisol circadian rhythm in the light of stress early in life

    NARCIS (Netherlands)

    Simons, S.S.H.; Beijers, R.; Cillessen, A.H.N.; Weerth, C. de

    2015-01-01

    The secretion of the stress hormone cortisol follows a diurnal circadian rhythm. There are indications that this rhythm is affected by stress early in life. This paper addresses the development of the cortisol circadian rhythm between 1 and 6 years of age, and the role of maternal stress and anxiety

  19. Relation between functional connectivity and rhythm discrimination in children who do and do not stutter

    Directory of Open Access Journals (Sweden)

    Soo-Eun Chang

    2016-01-01

    Full Text Available Our ability to perceive and produce rhythmic patterns in the environment supports fundamental human capacities ranging from music and language processing to the coordination of action. This article considers whether spontaneous correlated brain activity within a basal ganglia-thalamocortical (rhythm network is associated with individual differences in auditory rhythm discrimination. Moreover, do children who stutter with demonstrated deficits in rhythm perception have weaker links between rhythm network functional connectivity and rhythm discrimination? All children in the study underwent a resting-state fMRI session, from which functional connectivity measures within the rhythm network were extracted from spontaneous brain activity. In a separate session, the same children completed an auditory rhythm-discrimination task, where behavioral performance was assessed using signal detection analysis. We hypothesized that in typically developing children, rhythm network functional connectivity would be associated with behavioral performance on the rhythm discrimination task, but that this relationship would be attenuated in children who stutter. Results supported our hypotheses, lending strong support for the view that (1 children who stutter have weaker rhythm network connectivity and (2 the lack of a relation between rhythm network connectivity and rhythm discrimination in children who stutter may be an important contributing factor to the etiology of stuttering.

  20. The Effect of Pitch and Rhythm Difficulty on Vocal Sight-Reading Performance

    Science.gov (United States)

    Henry, Michele L.

    2011-01-01

    Singing music at sight is a complex skill, requiring the singer to perform pitch and rhythm simultaneously. Previous research has identified difficulty levels for pitch and rhythm skills individually but not in combination. In this study, the author sought to determine the relationship between pitch and rhythm tasks occurring concurrently. High…

  1. Perceiving Speech Rhythm in Music: Listeners Classify Instrumental Songs According to Language of Origin

    Science.gov (United States)

    Hannon, Eric E.

    2009-01-01

    Recent evidence suggests that the musical rhythm of a particular culture may parallel the speech rhythm of that culture's language (Patel, A. D., & Daniele, J. R. (2003). "An empirical comparison of rhythm in language and music." "Cognition, 87," B35-B45). The present experiments aimed to determine whether listeners actually perceive such rhythmic…

  2. Exogenous melatonin entrains rhythm and reduces amplitude of endogenous melatonin : An in vivo microdialysis study

    NARCIS (Netherlands)

    Drijfhout, WJ; Homan, EJ; Brons, HF; Oakley, NR; Skingle, M; Grol, CJ; Westerink, BHC

    1996-01-01

    The circadian rhythm of melatonin production was studied using on-line, in vivo microdialysis in the rat pineal gland. With this technique it was possible to record a pronounced melatonin rhythm with very high time resolution. Three phase-markers of the rhythm were calculated from the data, indicati

  3. The Effect of Pitch and Rhythm Difficulty on Vocal Sight-Reading Performance

    Science.gov (United States)

    Henry, Michele L.

    2011-01-01

    Singing music at sight is a complex skill, requiring the singer to perform pitch and rhythm simultaneously. Previous research has identified difficulty levels for pitch and rhythm skills individually but not in combination. In this study, the author sought to determine the relationship between pitch and rhythm tasks occurring concurrently. High…

  4. A Qualitative Investigation of Early Childhood Teachers' Experiences of Rhythm as Pedagogy

    Science.gov (United States)

    Matthews, Douglas R; Ubbes, Valerie A; Freysinger, Valeria J

    2016-01-01

    Rhythm has been found to enhance not only biological functioning (e.g. balance, timing and coordination), but also to facilitate learning across sociocultural contexts. That is, rhythm may be a method of supporting child development and well-being. Hence, to the extent that children are not exposed to or engaged with rhythm, their development or…

  5. Forced desynchrony of circadian rhythms of body temperature and activity in rats

    NARCIS (Netherlands)

    Strijkstra, AM; Meerlo, P; Beersma, DGM

    1999-01-01

    The daily rhythm in body temperature is thought to be the result of the direct effects of activity and the effects of an endogenous circadian clock. Forced desynchrony (FD) is a tool used in human circadian rhythm research to disentangle endogenous and activity-related effects on daily rhythms. In t

  6. Sex differences in Siberian hamster ultradian locomotor rhythms.

    Science.gov (United States)

    Prendergast, Brian J; Stevenson, Tyler J; Zucker, Irving

    2013-02-17

    Sex differences in ultradian activity rhythms (URs) and circadian rhythms (CRs) were assessed in Siberian hamsters kept in long day (LD) or short day (SD) photoperiods for 40 weeks. For both sexes URs of locomotor activity were more prevalent, greater in amplitude and more robust in SDs. The UR period was longer in females than males in both day lengths. The reproductive system underwent regression and body mass declined during the initial 10 weeks of SD treatment, and in both sexes these traits spontaneously reverted to the LD phenotype at or before 40 weeks in SD, reflecting the development of neuroendocrine refractoriness to SD patterns of melatonin secretion. Hamsters of both sexes, however, continued to display SD-like URs at the 40 weeks time point. CRs were less prevalent and the waveform less robust and lower in amplitude in SDs than LDs; the SD circadian waveform also did not revert to the long-day phenotype after 40 weeks of SD treatment. Short day lengths enhanced ultradian and diminished circadian rhythms in both sexes. Day length controls several UR characteristics via gonadal steroid and melatonin-independent mechanisms. Sex differences in ultradian timing may contribute to sex diphenisms in rhythms of sleep, food intake and exercise.

  7. Auditory and Motor Rhythm Awareness in Adults with Dyslexia

    Science.gov (United States)

    Thomson, Jennifer M.; Fryer, Ben; Maltby, James; Goswami, Usha

    2006-01-01

    Children with developmental dyslexia appear to be insensitive to basic auditory cues to speech rhythm and stress. For example, they experience difficulties in processing duration and amplitude envelope onset cues. Here we explored the sensitivity of adults with developmental dyslexia to the same cues. In addition, relations with expressive and…

  8. Intersensory redundancy promotes visual rhythm discrimination in visually impaired infants.

    Science.gov (United States)

    Brenna, Viola; Nava, Elena; Turati, Chiara; Montirosso, Rosario; Cavallini, Anna; Borgatti, Renato

    2015-05-01

    Infants' attention is captured by the redundancy of amodal stimulation in multimodal objects and events. Evidence from this study demonstrates that intersensory redundancy can facilitate discrimination of rhythm changes presented in the visual modality alone in visually impaired infants, suggesting that multisensory rehabilitation strategies could prove helpful in this population.

  9. Rhythm perturbations in acoustically paced treadmill walking after stroke

    NARCIS (Netherlands)

    Roerdink, Melvyn; Lamoth, Claudine J. C.; Van Kordelaar, Joost; Elich, Peter; Konijnenbelt, Manin; Kwakkel, Gert; Beek, Peter J.

    2009-01-01

    Background. In rehabilitation, acoustic rhythms are often used to improve gait after stroke. Acoustic cueing may enhance gait coordination by creating a stable coupling between heel strikes and metronome beats and provide a means to train the adaptability of gait coordination to environmental change

  10. Speech rhythm in Kannada speaking adults who stutter.

    Science.gov (United States)

    Maruthy, Santosh; Venugopal, Sahana; Parakh, Priyanka

    2017-10-01

    A longstanding hypothesis about the underlying mechanisms of stuttering suggests that speech disfluencies may be associated with problems in timing and temporal patterning of speech events. Fifteen adults who do and do not stutter read five sentences, and from these, the vocalic and consonantal durations were measured. Using these, pairwise variability index (raw PVI for consonantal intervals and normalised PVI for vocalic intervals) and interval based rhythm metrics (PercV, DeltaC, DeltaV, VarcoC and VarcoV) were calculated for all the participants. Findings suggested higher mean values in adults who stutter when compared to adults who do not stutter for all the rhythm metrics except for VarcoV. Further, statistically significant difference between the two groups was found for all the rhythm metrics except for VarcoV. Combining the present results with consistent prior findings based on rhythm deficits in children and adults who stutter, there appears to be strong empirical support for the hypothesis that individuals who stutter may have deficits in generation of rhythmic speech patterns.

  11. Knowledge Representation of the Melody and Rhythm in Koto Songs

    Science.gov (United States)

    Deguchi, Sachiko; Shirai, Katsuhiko

    This paper describes the knowledge representation of the melody and rhythm in koto songs based on the structure of the domain: the scale, melisma (the melody in a syllable), and bar. We have encoded koto scores and extracted 2,3,4-note melodic patterns sequentially from the voice part of koto scores. The 2,3,4-note patterns used in the melisma are limited and the percentages of top patterns are high. The 3,4-note melodic patterns are examined at each scale degree. These patterns are more restricted than the patterns that are possible under the constraint of the scale. These typical patterns on the scale represent the knowledge of koto players. We have analyzed rhythms in two different ways. We have extracted rhythms depending on each melodic pattern, while we have extracted rhythms depending on each bar. The former are complicated and the latter are typical. This result indicates that koto players recognize melodic patterns and rhythmic patterns independently. Our analyses show the melodic patterns and rhythmic patterns that are acquired by koto players. These patterns will be applied to the description of variations of the melisma to build a score database. These patterns will also be applied to a composition and education. The melodic patterns can be extracted from other genres of Japanese traditional music, foreign old folk songs or chants by using this method.

  12. EEG Alpha Rhythm Frequency and Intelligence in Normal Adults.

    Science.gov (United States)

    Anokhin, Andrey; Vogel, Friedrich

    1996-01-01

    Scores on Raven's Progressive Matrices correlated positively with electroencephalogram-recorded alpha rhythm frequency (AF) in 101 healthy male adults, as did one test of verbal ability and one of mental performance. However, AF did not show significant relationships with general intelligence or spatial and arithmetic abilities. (SLD)

  13. [Electrovectorcardiographic manifestations of supraventricular ectopic rhythms (an interpretive hypothesis)].

    Science.gov (United States)

    de Micheli, A; Medrano, G A

    1989-01-01

    When a low right atrial rhythm is present, P waves are negative in the low leads, they are variable in a VR and positive in a VL and LI. The figure eighth PF loop is located in the first quadrant, the PH loop has a counterclockwise rotation, and the PS can rotate in either direction. In the presence of upper left atrial rhythms, P waves are positive in the low leads and negative in a VL and a VR. The PF and PH loops can be found in the third quadrant of both planes with a clockwise rotation. If the rhythm originates in low left atrial regions, negative P waves are recorded in left precordial leads and positive ones in a VR and a VL. The PF loop has counterclockwise rotation or its branches superimposed and is situated in the second quadrant; PH with clockwise rotation is registered in the third quadrant; PS with either counterclockwise or clockwise rotation develops above and slightly ahead of the E point. When a nodal rhythm exists, P waves are negative in the low leads. The P loops show a counterclockwise rotation or a figure eight morphology. In the absence of atrial enlargements, the PF loop can be recorded in the first quadrant and the PH in the first or the fourth quadrant.

  14. Auditory and Visual Cues for Spatiotemporal Rhythm Reproduction

    DEFF Research Database (Denmark)

    Maculewicz, Justyna; Serafin, Stefania; Kofoed, Lise B.

    2013-01-01

    The goal of this experiment is to investigate the role of au- ditory and visual feedback in a rhythmic tapping task. Subjects had to tap with the finger following presented rhythms, which were divided into easy and difficult patterns. Specificity of the task was that participants had to take...

  15. Nonlinear Dynamics in the Ultradian Rhythm of Desmodium motorium

    Science.gov (United States)

    Chen, Jyh-Phen; Engelmann, Wolfgang; Baier, Gerold

    1995-12-01

    The dynamics of the lateral leaflet movement of Desmodium motorium is studied. Simple periodic, quasiperiodic and aperiodic time series are observed. The long-scale dynamics may either be uniform or composed of several prototypic oscillations (one of them reminiscent of homoclinic chaos). Diffusively coupled nonlinear oscillators may account for the variety of ultradian rhythms.

  16. Circadian Rest-Activity Rhythm in Pediatric Type 1 Narcolepsy.

    Science.gov (United States)

    Filardi, Marco; Pizza, Fabio; Bruni, Oliviero; Natale, Vincenzo; Plazzi, Giuseppe

    2016-06-01

    Pediatric type 1 narcolepsy is often challenging to diagnose and remains largely undiagnosed. Excessive daytime sleepiness, disrupted nocturnal sleep, and a peculiar phenotype of cataplexy are the prominent features. The knowledge available about the regulation of circadian rhythms in affected children is scarce. This study compared circadian rest-activity rhythm and actigraphic estimated sleep measures of children with type 1 narcolepsy versus healthy controls. Twenty-two drug-naïve type 1 narcolepsy children and 21 age- and sex- matched controls were monitored for seven days during the school week by actigraphy. Circadian activity rhythms were analyzed through functional linear modeling; nocturnal and diurnal sleep measures were estimated from activity using a validated algorithm. Children with type 1 narcolepsy presented an altered rest-activity rhythm characterized by enhanced motor activity throughout the night and blunted activity in the first afternoon. No difference was found between children with type 1 narcolepsy and controls in the timing of the circadian phase. Actigraphic sleep measures showed good discriminant capabilities in assessing type 1 narcolepsy nycthemeral disruption. Actigraphy reliably renders the nycthemeral disruption typical of narcolepsy type 1 in drug-naïve children with recent disease onset, indicating the sensibility of actigraphic assessment in the diagnostic work-up of childhood narcolepsy type 1. © 2016 Associated Professional Sleep Societies, LLC.

  17. My Path from Chemistry to Phytochrome and Circadian Rhythms

    Science.gov (United States)

    Tobin, Elaine M.

    2016-01-01

    I summarize my scientific journey from my first interest in science to my career investigating how plants use the phytochrome photoreceptor to regulate what genes they express. I then describe how this work led to an understanding of how circadian rhythms function in plants and to the discovery of CCA1, a component of the plant central oscillator. PMID:27014288

  18. Visual Tracking and Entrainment to an Environmental Rhythm

    Science.gov (United States)

    Schmidt, R. C.; Richardson, Michael J.; Arsenault, Christine; Galantucci, Bruno

    2007-01-01

    This study investigated the role that visual tracking plays in coupling rhythmic limb movements to an environmental rhythm. Two experiments were conducted in which participants swung a hand-held pendulum while tracking an oscillating stimulus or while keeping their eyes fixed on a stationary location directly above an oscillating stimulus. It…

  19. Studies on circadian rhythm disturbances and melatonin in delirium

    NARCIS (Netherlands)

    de Jonghe, A.-M.

    2014-01-01

    The circadian sleep/wake rhythm disturbances that are seen in delirium and the role of melatonin supplementation provide a new angle in delirium research. More research is needed to determine the role of melatonin in the pathophysiological mechanisms of delirium and to determine whether the

  20. Perception of Timbre and Rhythm Similarity in Electronic Dance Music

    NARCIS (Netherlands)

    Honingh, A.; Panteli, M.; Brockmeier, T.; López Mejía, D.I.; Sadakata, M.

    2015-01-01

    Music similarity is known to be a multi-dimensional concept, depending among others on rhythm similarity and timbre similarity. The present study aims to investigate whether such sub-dimensions of similarity can be assessed independently and how they relate to general similarity. To this end, we per

  1. Circadian rhythms, metabolism, and chrononutrition in rodents and humans

    Science.gov (United States)

    Chrononutrition is an emerging discipline that builds on the intimate relation between endogenous circadian (24-h) rhythms and metabolism. Circadian regulation of metabolic function can be observed from the level of intracellular biochemistry to whole-organism physiology and even postprandial respon...

  2. A Preliminary Analysis of Early Rhythm and Blues Musical Practices.

    Science.gov (United States)

    Meadows, Eddie S.

    1983-01-01

    Presents background information on the evolution of rhythm and blues (R & B) from the 1940s to the 1960s: the origin and naming of selected R & B groups, role of instruments in R & B orchestras, soloist/group vocal practices, and the role that independent record labels played in artists' successes and failures. (Author/ML)

  3. Learning L2 Rhythm : Does the direction of acquisition matter?

    NARCIS (Netherlands)

    van Maastricht, Lieke; Krahmer, Emiel; Swerts, Marc; Prieto, Pilar

    2016-01-01

    This study investigates the acquisition of second language (L2) rhythm by speakers of Dutch and Spanish, two languages that traditionally are considered to be rhythmically different. Specifically, it investigates whether the direction in which the L2 is learned (from Dutch to Spanish, or vice versa)

  4. Learning L2 Rhythm : does the direction of acquisition matter?

    NARCIS (Netherlands)

    van Maastricht, Lieke; Krahmer, Emiel; Swerts, Marc; Prieto, Pilar

    2016-01-01

    This study investigates the acquisition of second language (L2) rhythm by speakers of Dutch and Spanish, two languages that traditionally are considered to be rhythmically different. Specifically, it investigates whether the direction in which the L2 is learned (from Dutch to Spanish, or vice versa)

  5. External stimuli mediate collective rhythms: artificial control strategies.

    Directory of Open Access Journals (Sweden)

    Tianshou Zhou

    Full Text Available The artificial intervention of biological rhythms remains an exciting challenge. Here, we proposed artificial control strategies that were developed to mediate the collective rhythms emerging in multicellular structures. Based on noisy repressilators and by injecting a periodic control amount to the extracellular medium, we introduced two typical kinds of control models. In one, there are information exchanges among cells, where signaling molecules receive the injected stimulus that freely diffuses toward/from the intercellular medium. In the other, there is no information exchange among cells, but signaling molecules also receive the stimulus that directionally diffuses into each cell from the common environment. We uncovered physical mechanisms for how the stimulus induces, enhances or ruins collective rhythms. We found that only when the extrinsic period is close to an integer multiplicity of the averaged intrinsic period can the collective behaviors be induced/enhanced; otherwise, the stimulus possibly ruins the achieved collective behaviors. Such entrainment properties of these oscillators to external signals would be exploited by realistic living cells to sense external signals. Our results not only provide a new perspective to the understanding of the interplays between extrinsic stimuli and intrinsic physiological rhythms, but also would lead to the development of medical therapies or devices.

  6. Atrial rate and rhythm abnormalities in a patient with hyperkalemia.

    Science.gov (United States)

    Rosman, Jonathan; Thiagarajah, Prashan; Schweitzer, Paul; Rachko, Maurice; Hanon, Sam

    2009-05-15

    A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

  7. Glutamate phase shifts circadian activity rhythms in hamsters

    NARCIS (Netherlands)

    Meijer, J.H.; van der Zee, E.A.; Dietz, M.

    1988-01-01

    The suprachiasmatic nuclei (SCN) have been identified as a pacemaker for many circadian rhythms in mammals. Photic entrainment of this pacemaker can be accomplished via the direct retino-hypothalamic tract (RHT). Glutamate is a putative transmitter of the RHT. In the present study it is demonstrated

  8. Circadian Rhythm Shapes the Gut Microbiota Affecting Host Radiosensitivity.

    Science.gov (United States)

    Cui, Ming; Xiao, Huiwen; Luo, Dan; Zhang, Xin; Zhao, Shuyi; Zheng, Qisheng; Li, Yuan; Zhao, Yu; Dong, Jiali; Li, Hang; Wang, Haichao; Fan, Saijun

    2016-10-26

    Modern lifestyles, such as shift work, nocturnal social activities, and jet lag, disturb the circadian rhythm. The interaction between mammals and the co-evolved intestinal microbiota modulates host physiopathological processes. Radiotherapy is a cornerstone of modern management of malignancies; however, it was previously unknown whether circadian rhythm disorder impairs prognosis after radiotherapy. To investigate the effect of circadian rhythm on radiotherapy, C57BL/6 mice were housed in different dark/light cycles, and their intestinal bacterial compositions were compared using high throughput sequencing. The survival rate, body weight, and food intake of mice in diverse cohorts were measured following irradiation exposure. Finally, the enteric bacterial composition of irradiated mice that experienced different dark/light cycles was assessed using 16S RNA sequencing. Intriguingly, mice housed in aberrant light cycles harbored a reduction of observed intestinal bacterial species and shifts of gut bacterial composition compared with those of the mice kept under 12 h dark/12 h light cycles, resulting in a decrease of host radioresistance. Moreover, the alteration of enteric bacterial composition of mice in different groups was dissimilar. Our findings provide novel insights into the effects of biological clocks on the gut bacterial composition, and underpin that the circadian rhythm influences the prognosis of patients after radiotherapy in a preclinical setting.

  9. Entrainment of circadian rhythm by ambient temperature cycles in mice.

    Science.gov (United States)

    Refinetti, Roberto

    2010-08-01

    Much is known about how environmental light-dark cycles synchronize circadian rhythms in animals. The ability of environmental cycles of ambient temperature to synchronize circadian rhythms has also been investigated extensively but mostly in ectotherms. In the present study, the synchronization of the circadian rhythm of running-wheel activity by environmental cycles of ambient temperature was studied in laboratory mice. Although all mice were successfully entrained by a light-dark cycle, only 60% to 80% of the mice were entrained by temperature cycles (24-32 degrees C or 24-12 degrees C), and attainment of stable entrainment seemed to take longer under temperature cycles than under a light-dark cycle. This suggests that ambient temperature cycles are weaker zeitgebers than light-dark cycles, which is consistent with the results of the few previous studies using mammalian species. Whereas 80% of the mice were entrained by 24-h temperature cycles, only 60% were entrained by 23-h cycles, and none was entrained by 25-h cycles. The results did not clarify whether entrainment by temperature cycles is caused directly by temperature or indirectly through a temperature effect on locomotor activity, but it is clear that the rhythm of running-wheel activity in mice can be entrained by ambient temperature cycles in the nonnoxious range.

  10. Studies on circadian rhythm disturbances and melatonin in delirium

    NARCIS (Netherlands)

    de Jonghe, A.-M.

    2014-01-01

    The circadian sleep/wake rhythm disturbances that are seen in delirium and the role of melatonin supplementation provide a new angle in delirium research. More research is needed to determine the role of melatonin in the pathophysiological mechanisms of delirium and to determine whether the restorat

  11. Spatial-temporal structures of human alpha rhythms: theory, microcurrent sources, multiscale measurements, and global binding of local networks.

    Science.gov (United States)

    Nunez, P L; Wingeier, B M; Silberstein, R B

    2001-07-01

    A theoretical framework supporting experimental measures of dynamic properties of human EEG is proposed with emphasis on distinct alpha rhythms. Robust relationships between measured dynamics and cognitive or behavioral conditions are reviewed, and proposed physiological bases for EEG at cellular levels are considered. Classical EEG data are interpreted in the context of a conceptual framework that distinguishes between locally and globally dominated dynamic processes, as estimated with coherence or other measures of phase synchronization. Macroscopic (scalp) potentials generated by cortical current sources are described at three spatial scales, taking advantage of the columnar structure of neocortex. New EEG data demonstrate that both globally coherent and locally dominated behavior can occur within the alpha band, depending on narrow band frequency, spatial measurement scale, and brain state. Quasi-stable alpha phase structures consistent with global standing waves are observed. At the same time, alpha and theta phase locking between cortical regions during mental calculations is demonstrated, consistent with neural network formation. The brain-binding problem is considered in the context of EEG dynamic behavior that generally exhibits both of these local and global aspects. But specific experimental designs and data analysis methods may severely bias physiological interpretations in either local or global directions.

  12. [Individual Types Reactivity of EEG Oscillations in Effective Heart Rhythm Biofeedback Parameters in Adolescents and Young People in the North].

    Science.gov (United States)

    Krivonogova, E V; Poskotinova, L V; Demin, D B

    2015-01-01

    A single session of heart rate variability (HRV) biofeedback in apparently healthy young people and adolescents aged 14-17 years in order to increase vagal effects on heart rhythm and also electroencephalograms were carried out. Different variants of EEG spectral power during the successful HRV biofeedback session were identified. In the case of I variant of EEG activity the increase of power spectrum of alpha-, betal-, theta-components takes place in all parts of the brain. In the case of II variant of EEG activity the reduction of power spectrum of alpha-, betal-, theta-activity in all parts of the brain was observed. I and II variants of EEG activity cause more intensive regime of cortical-subcortical interactions. During the III variant of EEG activity the successful biofeedback is accompanied by increase of alpha activity in the central, front and anteriofrontal brain parts and so indicates the formation of thalamocortical relations of neural network in order to optimize the vegetal regulation of heart function. There was an increase in alpha- and beta1-activity in the parietal, central, frontal and temporal brain parts during the IV variant of EEG activity and so that it provides the relief of neural networks communication for information processing. As a result of V variance of EEG activity there was the increase of power spectrum of theta activity in the central and frontal parts of both cerebral hemispheres, so it was associated with the cortical-hippocampal interactions to achieve a successful biofeedback.

  13. Cortical response to social interaction is affected by gender.

    Science.gov (United States)

    Pavlova, Marina; Guerreschi, Michele; Lutzenberger, Werner; Sokolov, Alexander N; Krägeloh-Mann, Ingeborg

    2010-04-15

    The ability of humans to predict and explain other people's actions is of immense value for adaptive behavior and nonverbal communication. Gender differences are often evident in the comprehension of social signals, but the underlying neurobiological basis for these differences is unclear. Combining visual psychophysics with an analysis of neuromagnetic activity, we assessed gender effects on the induced oscillatory response to visual social interaction revealed by motion. A robust difference in the induced gamma response was found between females and males over the left prefrontal cortex, a region implicated in perceptual decision making. The induced gamma neuromagnetic response peaked earlier in females than in males. Moreover, it appears that females anticipate social interaction predicting others' actions ahead of their realization, whereas males require accumulation of more sensory evidence for proper social decisions. The findings reflect gender-dependent modes in cortical processing of visually acquired social information. Contrary to popular wisdom, the outcome of this study indicates that gender effects are not evident in the neural circuitry underpinning visual social perception, but in the regions engaged in perceptual decision making. Copyright 2009 Elsevier Inc. All rights reserved.

  14. GammaWorkshops Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramebaeck, H. (ed.) (Swedish Defence Research Agency (Sweden)); Straalberg, E. (Institute for Energy Technology, Kjeller (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority, STUK (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (Iceland))

    2012-01-15

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

  15. Cortical control of whisker movement.

    Science.gov (United States)

    Petersen, Carl C H

    2014-01-01

    Facial muscles drive whisker movements, which are important for active tactile sensory perception in mice and rats. These whisker muscles are innervated by cholinergic motor neurons located in the lateral facial nucleus. The whisker motor neurons receive synaptic inputs from premotor neurons, which are located within the brain stem, the midbrain, and the neocortex. Complex, distributed neural circuits therefore regulate whisker movement during behavior. This review focuses specifically on cortical whisker motor control. The whisker primary motor cortex (M1) strongly innervates brain stem reticular nuclei containing whisker premotor neurons, which might form a central pattern generator for rhythmic whisker protraction. In a parallel analogous pathway, the whisker primary somatosensory cortex (S1) strongly projects to the brain stem spinal trigeminal interpolaris nucleus, which contains whisker premotor neurons innervating muscles for whisker retraction. These anatomical pathways may play important functional roles, since stimulation of M1 drives exploratory rhythmic whisking, whereas stimulation of S1 drives whisker retraction.

  16. The origin of cortical neurons

    Directory of Open Access Journals (Sweden)

    J.G. Parnavelas

    2002-12-01

    Full Text Available Neurons of the mammalian cerebral cortex comprise two broad classes: pyramidal neurons, which project to distant targets, and the inhibitory nonpyramidal cells, the cortical interneurons. Pyramidal neurons are generated in the germinal ventricular zone, which lines the lateral ventricles, and migrate along the processes of radial glial cells to their positions in the developing cortex in an `inside-out' sequence. The GABA-containing nonpyramidal cells originate for the most part in the ganglionic eminence, the primordium of the basal ganglia in the ventral telencephalon. These cells follow tangential migratory routes to enter the cortex and are in close association with the corticofugal axonal system. Once they enter the cortex, they move towards the ventricular zone, possibly to obtain positional information, before they migrate radially in the direction of the pial surface to take up their positions in the developing cortex. The mechanisms that guide interneurons throughout these long and complex migratory routes are currently under investigation.

  17. Cortical cartography and Caret software.

    Science.gov (United States)

    Van Essen, David C

    2012-08-15

    Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret's development in a historical context that spans three decades of brain mapping--from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret's distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Unsupervised fetal cortical surface parcellation

    Science.gov (United States)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  19. Rhythm and timing in autism: learning to dance

    Science.gov (United States)

    Amos, Pat

    2013-01-01

    In recent years, a significant body of research has focused on challenges to neural connectivity as a key to understanding autism. In contrast to attempts to identify a single static, primarily brain-based deficit, children and adults diagnosed with autism are increasingly perceived as out of sync with their internal and external environments in dynamic ways that must also involve operations of the peripheral nervous systems. The noisiness that seems to occur in both directions of neural flow may help explain challenges to movement and sensing, and ultimately to entrainment with circadian rhythms and social interactions across the autism spectrum, profound differences in the rhythm and timing of movement have been tracked to infancy. Difficulties with self-synchrony inhibit praxis, and can disrupt the “dance of relationship” through which caregiver and child build meaning. Different sensory aspects of a situation may fail to match up; ultimately, intentions and actions themselves may be uncoupled. This uncoupling may help explain the expressions of alienation from the actions of one's body which recur in the autobiographical autism literature. Multi-modal/cross-modal coordination of different types of sensory information into coherent events may be difficult to achieve because amodal properties (e.g., rhythm and tempo) that help unite perceptions are unreliable. One question posed to the connectivity research concerns the role of rhythm and timing in this operation, and whether these can be mobilized to reduce overload and enhance performance. A case is made for developmental research addressing how people with autism actively explore and make sense of their environments. The parent/author recommends investigating approaches such as scaffolding interactions via rhythm, following the person's lead, slowing the pace, discriminating between intentional communication and “stray” motor patterns, and organizing information through one sensory mode at a time. PMID

  20. Rhythm and timing in autism: learning to dance.

    Science.gov (United States)

    Amos, Pat

    2013-01-01

    In recent years, a significant body of research has focused on challenges to neural connectivity as a key to understanding autism. In contrast to attempts to identify a single static, primarily brain-based deficit, children and adults diagnosed with autism are increasingly perceived as out of sync with their internal and external environments in dynamic ways that must also involve operations of the peripheral nervous systems. The noisiness that seems to occur in both directions of neural flow may help explain challenges to movement and sensing, and ultimately to entrainment with circadian rhythms and social interactions across the autism spectrum, profound differences in the rhythm and timing of movement have been tracked to infancy. Difficulties with self-synchrony inhibit praxis, and can disrupt the "dance of relationship" through which caregiver and child build meaning. Different sensory aspects of a situation may fail to match up; ultimately, intentions and actions themselves may be uncoupled. This uncoupling may help explain the expressions of alienation from the actions of one's body which recur in the autobiographical autism literature. Multi-modal/cross-modal coordination of different types of sensory information into coherent events may be difficult to achieve because amodal properties (e.g., rhythm and tempo) that help unite perceptions are unreliable. One question posed to the connectivity research concerns the role of rhythm and timing in this operation, and whether these can be mobilized to reduce overload and enhance performance. A case is made for developmental research addressing how people with autism actively explore and make sense of their environments. The parent/author recommends investigating approaches such as scaffolding interactions via rhythm, following the person's lead, slowing the pace, discriminating between intentional communication and "stray" motor patterns, and organizing information through one sensory mode at a time.