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1.
We studied the relationship between perceptual switching in the Necker cube and long-distance transient phase synchronization in EEG. Transient periods of response related synchrony between parietal and frontal areas were observed. They start 800–600, ms prior to the switch response and occur in pairs. Four types of pairs could be distinguished, two of which are accompanied by transient alpha band activity in the occipital area. The results indicate that perceptual switching processes involve parietal and frontal areas; these are the ones that are normally associated with various cognitive processes. Sensory information in the visual areas is involved in some, but not in all, of switching processes. The intrinsic variability, as well as the participating areas, points to the role of strategic cognitive processes in perceptual switching. 相似文献
2.
Blinks and saccades cause transient interruptions of visual input. To investigate how such effects influence our perceptual
state, we analyzed the time courses of blink and saccade rates in relation to perceptual switching in the Necker cube. Both
time courses of blink and saccade rates showed peaks at different moments along the switching process. A peak in blinking
rate appeared 1,000 ms prior to the switching responses. Blinks occurring around this peak were associated with subsequent
switching to the preferred interpretation of the Necker cube. Saccade rates showed a peak 150 ms prior to the switching response.
The direction of saccades around this peak was predictive of the perceived orientation of the Necker cube afterwards. Peak
blinks were followed and peak saccades were preceded by transient parietal theta band activity indicating the changing of
the perceptual interpretation. Precisely-timed blinks, therefore, can initiate perceptual switching, and precisely-timed saccades
can facilitate an ongoing change of interpretation. 相似文献
3.
Ozaki TJ 《PloS one》2011,6(5):e20079
Previous effective connectivity analyses of functional magnetic resonance imaging (fMRI) have revealed dynamic causal streams along the dorsal attention network (DAN) during voluntary attentional control in the human brain. During resting state, however, fMRI has shown that the DAN is also intrinsically configured by functional connectivity, even in the absence of explicit task demands, and that may conflict with effective connectivity studies. To resolve this contradiction, we performed an effective connectivity analysis based on partial Granger causality (pGC) on event-related fMRI data during Posner's cueing paradigm while optimizing experimental and imaging parameters for pGC analysis. Analysis by pGC can factor out exogenous or latent influences due to unmeasured variables. Typical regions along the DAN with greater activation during orienting than withholding of attention were selected as regions of interest (ROIs). pGC analysis on fMRI data from the ROIs showed that frontal-to-parietal top-down causal streams along the DAN appeared during (voluntary) orienting, but not during other, less-attentive and/or resting-like conditions. These results demonstrate that these causal streams along the DAN exclusively mediate voluntary covert orienting. These findings suggest that neural representations of attention in frontal regions are at the top of the hierarchy of the DAN for embodying voluntary attentional control. 相似文献
4.
A. A. Cherninskii I. G. Zima N. Ye. Makarchouk N. G. Piskorskaya S. A. Kryzhanovskii 《Neurophysiology》2009,41(1):63-70
We recorded EEG in adult volunteers in the course of perception of smells of plant essential oils under conditions of directed
attention. It was found that perception of olfactory information, even in the case of mild intensity of the smells inducing
no aversive effects, correlates with noticeable changes in the EEG characteristics mostly typical of the reaction of nonspecific
EEG activation induced by sensory stimulation and manifested in a decrease in the spectral power, SP, of low-frequency EEG
components (6–10 Hz)). In addition, the SP of relatively high-frequency EEG components (11–25 Hz) increased; this effect was
most pronounced in the occipital regions of the neocortex. Perception of the smells of essential oils was also accompanied
by increases in the coherence of EEG oscillations, most intense in the β2 range (20–25 Hz). Such modifications were maximum
in the left temporal/parietal region; this is interpreted as an indication of the special role of these cortical areas in
the processes of interaction between the neocortical part of the olfactory analyzer and the respective structures of other
analyzer systems. It is hypothesized that such interaction is necessary for the formation of a semantic image of the analyzed
stimuli.
Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 70–78, January–February, 2009. 相似文献
5.
Norbert Fürstenau 《Biological cybernetics》2010,103(3):175-198
Simulation results of bistable perception due to ambiguous visual stimuli are presented which are obtained with a behavioral
nonlinear dynamics model using perception–attention–memory coupling. This model provides an explanation of recent experimental
results of Gao et al. (Cogn Process 7:105–112, 2006a) and it supports their speculation that the fractal character of perceptual
dominance time series may be understood in terms of nonlinear and reentrant dynamics of brain processing. Percept reversals
are induced by attention fatigue and noise, with an attention bias which balances the relative percept duration. Dynamical
coupling of the attention bias to the perception state introduces memory effects leading to significant long range correlations
of perceptual duration times as quantified by the Hurst parameter H > 0.5 (Mandelbrot, The fractal geometry of nature, 1991), in agreement with Gao et al. (Cogn Process 7:105–112, 2006a). 相似文献
6.
Isoglu-Alkaç U Basar-Eroglu C Ademoglu A Demiralp T Miener M Stadler M 《Biological cybernetics》2000,82(4):313-320
Since the first observation of perceptual reversal by Necker, many theoretical approaches have been proposed. In a previous
study, we showed that a positive wave appeared approximately 250 ms prior to the button press of the subjects, indicating
perceptual reversal during the observation of the Necker cube figure. A basic difficulty in this type of study is the possible
jitter in the latency of the button press due to the variability of the subjects' reaction time during a recording session.
To overcome this difficulty, a pattern selection method based on the wavelet transform was proposed in the previous study.
A dominant positive wavelet coefficient in the delta band was found to represent the perceptual-reversal-related positivity.
In the present study, we aim to analyze the changes in the alpha frequency band during perceptual reversal by using the Necker
cube. The RMS values of the alpha frequency band were measured for two time periods: ±3 SD around the mean peak latency of
the perceptual-reversal-related positivity and a time window of the same length before the positive wave. We found significantly
increased delta power and decreased alpha power during the perceptual-reversal-related positivity.
Received: 29 March 1999 / Accepted in revised form: 15 October 1999 相似文献
7.
Ümmühan İşoğlu-Alkaç Canan Başar-Eroğlu Ahmet Ademoğlu Tamer Demiralp Michael Miener Michael Stadler 《Biological cybernetics》1998,79(5):437-442
In previous studies, a perceptual switching related potential was obtained during the observation of a multistable dynamic
reversal pattern, where the averaging of the single responses was triggered by subjects pressing a button. The present methodological
study aims to increase the signal quality of perceptual switching related potentials considering the dependence of the measurement
method on the reaction time of the subject, which may vary significantly during a session, leading to low-amplitude waveform
in the averaged event-related-potential (ERP). To overcome this problem in measuring the electrophysiological correlate of
an internal event, a pattern selection method based on the wavelet transform (WT) is proposed to choose a subset of single
ERPs with more homogenous latencies. Nine subjects observed a Necker cube and were instructed to press the button immediately
after perceptual switching. A slow, low-amplitude positive wave with frontocentral amplitude maxima was observed around 250 ms
prior to the button press. After the application of a 5 octave WT on single sweeps, the time-frequency coefficients obtained
in each octave were averaged across trials. The most dominant feature representing the averaged ERP was the delta (0.5–4 Hz)
coefficient occurring between 250 and 125 ms before the button press. By averaging the subset of the single sweeps containing
this property, a sharpening and significant amplitude increase of the response peak was observed.
Received: 12 September 1997 / Accepted in revised form: 9 July 1998 相似文献
8.
V. A. Ponomarev O. V. Kropotova Yu. D. Kropotov Yu. I. Polyakov 《Human physiology》2000,26(3):251-257
Evoked desynchronization and synchronization of EEG in θ (4–7.5 Hz), α (7.5–14 Hz) and β (14–20 Hz) ranges were recorded by
19 electrodes in healthy volunteer adolescents and those with attention deficit hyperactivity syndrome in the modified GO/NO-GO
test. Two stimuli (high and low tone) were presented in pairs with 1 s intervals inside the pair and 1.5 s intervals between
the pairs. Test subjects had to push the button in response to presentation of a pair of high tones and to ignore other stimulus
combinations. The components of evoked EEG synchronization in α-θ range that were revealed in the frontocentral and temporoparietal
brain regions in connection with inhibition of action (inhibition of movements and making a decision to cancel sensory-motor
task performance) were statistically significantly lower in subjects with attention deficit hyperactivity disorder compared
with that in healthy subjects. 相似文献
9.
Electroencephalograms (EEGs) were recorded in 19 standard derivations in 88 healthy subjects (students) in the state of rest
with eyes open and during memorization (learning) of verbal bilingual semantic pairs (the Latin and Russian languages) and
retrieval of information from memory (control). The estimates of EEG coherence in these states were compared for the following
frequency bands: θ (4–7 Hz), α1 (7–10 Hz), α2 (10–13 Hz), β1 (13–18 Hz), β2 (18–30 Hz), and γ (30–40 Hz). Compared to the state of rest, the decrease in coherence in the pairs of derivations from the
frontal and central cortical areas in all EEG frequency bands was the most pronounced for memorization, and the increase in
coherence in the interhemispheric derivation pairs of the parietal-occipital region in most of the frequency bands was the
most pronounced for retrieval. In addition, in the pairs formed by derivations from the parietal-occipital region with derivations
from the frontal and central regions, retrieval is also characterized by an increase in coherence in the β2 and γ bands along with its decrease in the low-frequency ranges. The dynamics of EEG coherence, when comparing the states
of memorization and retrieval, is more statistically significant in the interhemispheric and cross-hemispheric pairs of derivations
than in the intrahemispheric pairs. The revealed topographic specificity of the dynamics of EEG coherence owing to the change
of state is considered in terms of the notion on cognitive-specific forms of sustained goal-directed mental attention. 相似文献
10.
Alexander N. Pisarchik Rider Jaimes-Reátegui C. D. Alejandro Magallón-García C. Obed Castillo-Morales 《Biological cybernetics》2014,108(4):397-404
Stochastic dynamics and critical slowing down were studied experimentally and numerically near the onset of dynamical bistability in visual perception under the influence of noise. Exploring the Necker cube as the essential example of an ambiguous figure, and using its wire contrast as a control parameter, we measured dynamical hysteresis in two coexisting percepts as a function of both the velocity of the parameter change and the background luminance. The bifurcation analysis allowed us to estimate the level of cognitive noise inherent to brain neural cells activity, which induced intermittent switches between different perception states. The results of numerical simulations with a simple energy model are in good qualitative agreement with psychological experiments. 相似文献
11.
South polar skuas, SPS, (Catharacta maccormicki) and brown skuas, BS, (C. antarctica lonnbergi) are regarded as opportunistic predators. When breeding in sympatry, BS feed mainly on penguin eggs and chicks, while SPS
forage almost exclusively at sea. The objective of this study was to determine the diet composition of adult SPS and BS breeding
in sympatry, in order to assess food resource partitioning between these species. The total number of food items consumed
was 375 for BS and 682 for SPS in 1992–93, and 427 for BS and 579 for SPS in 1995–96. The pellets composition was significantly
correlated between skua species for the same breeding season (r
s = 0.67, p = 0.0062 and r
s = 0.81, p < 0.001, for 1992–93 and 1995–96, respectively), and between breeding seasons for the same skua species (r
s = 0.71, p = 0.001 and r
s = 0.81, p < 0.001, for SPS and BS, respectively). Trophic niche breadth of BS was wider than that of SPS (B
A(BS) = 0.28 and B
A(SPS) = 0.24; Z = 7.67; p < 0.001). The trophic niche overlap between BS and SPS was over 65% in both breeding seasons. In agreement with other studies
on the diet of these skua species in situations of sympatry, SPS consumed more fish and BS consumed more birds. 相似文献
12.
Fibromyalgia (FMS) is a chronic, painful disorder often associated with measurable deficiencies in attention. Since EEG biofeedback
(EEG-BF) has been used successfully to treat attention problems, we reasoned that this modality might be helpful in the treatment
of attention problems in FMS. We also speculated that improvement in central nervous system (CNS) function might be accompanied
by improvement in FMS somatic symptoms. We studied fifteen FMS patients with attention problems, demonstrated by visual and
auditory continuous performance testing (CPT), while completing 40 or more EEG-BF sessions. Training consisted of a “SMR protocol”
that augmented 12–15 Hz brainwaves (sensory motor rhythm; SMR), while simultaneously inhibiting 4–7 Hz brainwaves (theta)
and 22–30 Hz brainwaves (high beta). Serial measurements of pain, fatigue, psychological distress, morning stiffness, and
tenderness were also obtained. Sixty-three FMS patients who received standard medical care, but who did not receive EEG-BF,
served as controls. Visual, but not auditory, attention improved significantly (P < 0.008). EEG-BF treated subjects also showed improvement in tenderness, pain and fatigue. Somatic symptoms did not change
significantly in controls. Visual attention parameters and certain somatic features of FMS appear to improve with an EEG-BF
SMR protocol. EEG-BF training in FMS deserves further study. 相似文献
13.
Daisuke Shimaoka Keiichi Kitajo Kunihiko Kaneko Yoko Yamaguchi 《Nonlinear biomedical physics》2010,4(Z1):S7
Background
It has been discussed that neural phase-synchrony across distant cortical areas (or global phase-synchrony) was correlated with various aspects of consciousness. The generating process of the synchrony, however, remains largely unknown. As a first step, we investigate transient process of global phase-synchrony, focusing on phase-synchronized clusters. We hypothesize that the phase-synchronized clusters are dynamically organized before global synchrony and clustering patterns depend on perceptual conditions.Methods
In an EEG study, Kitajo reported that phase-synchrony across distant cortical areas was selectively enhanced by top-down attention around 4 Hz in Necker cube perception. Here, we further analyzed the phase-synchronized clusters using hierarchical clustering which sequentially binds up the nearest electrodes based on similarity of phase locking between the cortical signals. First, we classified dominant components of the phase-synchronized clusters over time. We then investigated how the phase-synchronized clusters change with time, focusing on their size and spatial structure.Results
Phase-locked clusters organized a stable spatial pattern common to the perceptual conditions. In addition, the phase-locked clusters were modulated transiently depending on the perceptual conditions and the time from the perceptual switch. When top-down attention succeeded in switching perception as subjects intended, independent clusters at frontal and occipital areas grew to connect with each other around the time of the perceptual switch. However, the clusters in the occipital and left parietal areas remained divided when top-down attention failed in switching perception. When no primary biases exist, the cluster in the occipital area grew to its maximum at the time of the perceptual switch within the occipital area.Conclusions
Our study confirmed the existence of stable phase-synchronized clusters. Furthermore, these clusters were transiently connected with each other. The connecting pattern depended on subjects’ internal states. These results suggest that subjects’ attentional states are associated with distinct spatio-temporal patterns of the phase-locked clusters.14.
Two functional magnetic resonance imaging (fMRI) experiments were undertaken to measure the effect of neurofeedback training (NFT), in AD/HD children, on the neural substrates of selective attention and response inhibition. Twenty unmedicated AD/HD children participated to these experiments. Fifteen children were randomly assigned to the Experimental (EXP) group whereas the other five children were randomly assigned to the Control (CON) group. Only subjects in the EXP group underwent NFT. EXP subjects were trained to enhance the amplitude of the SMR (12–15 Hz) and beta 1 activity (15–18 Hz), and decrease the amplitude of theta activity (4–7 Hz). Subjects from both groups were scanned one week before the beginning of NFT (Time 1) and 1 week after the end of NFT (Time 2), while they performed a “Counting Stroop” task (Experiment 1) and a Go/No-Go task (Experiment 2). At Time 1, in both groups, the Counting Stroop task was associated with significant activation in the left superior parietal lobule. For the Go/No-Go task, no significant activity was detected in the EXP and CON groups. At Time 2, in both groups, the Counting Stroop task was associated with significant activation of the left superior parietal lobule. This time, however, there were significant loci of activation, in the EXP group, in the right ACC, left caudate nucleus, and left substantia nigra. No such activation loci were seen in CON subjects. For the Go/No-Go task, significant loci of activation were noted, in the EXP group, in the right ventrolateral prefrontal cortex, right ACcd, left thalamus, left caudate nucleus, and left substantia nigra. No significant activation of these brain regions was measured in CON subjects. These results suggest that NFT has the capacity to functionally normalize the brain systems mediating selective attention and response inhibition in AD/HD children. 相似文献
15.
Inferring the intentions of other people from their actions recruits an inferior fronto-parietal action observation network as well as a putative social network that includes the posterior superior temporal sulcus (STS). However, the functional dynamics within and among these networks remains unclear. Here we used functional magnetic resonance imaging (fMRI) and high-density electroencephalogram (EEG), with a repetition suppression design, to assess the spatio-temporal dynamics of decoding intentions. Suppression of fMRI activity to the repetition of the same intention was observed in inferior frontal lobe, anterior intraparietal sulcus (aIPS), and right STS. EEG global field power was reduced with repeated intentions at an early (starting at 60 ms) and a later (∼330 ms) period after the onset of a hand-on-object encounter. Source localization during these two intervals involved right STS and aIPS regions highly consistent with RS effects observed with fMRI. These results reveal the dynamic involvement of temporal and parietal networks at multiple stages during the intention decoding and without a strict segregation of intention decoding between these networks. 相似文献
16.
Independent component analysis (ICA) of 19-channel background EEG was performed in 111 patients with the early signs of depressive
disorders and in 526 healthy subjects. The power spectra of the independent components were compared in the depressive patients
and in healthy subjects at the eyes closed and eyes opened states. Statistically significant differences between the groups were detected in three frequency bands: θ (4–7.5 Hz), α
(7.5–14 Hz), and β (14–20 Hz). Increased θ and α activities in parietal and occipital derivations of depressive patients may
have been caused by a reduced cortical activity in the projection of these derivation. Diffuse enhancement of the β activity
may be correlated with anxiety symptoms that are pronounced in the clinical picture of depressive disorders at early stages
of the disease. ICA used to compare quantitative EEG parameters in different groups of patients and in healthy persons makes
it possible to localize the differences more accurately than the traditional analysis of EEG spectra. 相似文献
17.
Topographic analysis of dimension estimates of EEG and filtered rhythms in epileptic patients with complex partial seizures 总被引:2,自引:0,他引:2
Nonlinear dynamic properties were analyzed on the EEG and filtered rhythms recorded from healthy subjects and epileptic patients
with complex partial seizures. Estimates of correlation dimensions of control EEG, interictal EEG and ictal EEG were calculated.
The values were demonstrated on topograms. The delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (13–30 Hz) and gamma
(30–40 Hz) components were obtained and considered as signals from the cortex. Corresponding surrogate data was produced.
Firstly, the influence of sampling parameters on the calculation was tested. The dimension estimates of the signals from the
frontal, temporal, parietal and occipital regions were computed and compared with the results of surrogate data. In the control
subjects, the estimates between the EEG and surrogate data did not differ (P > 0.05). The interictal EEG from the frontal region and occipital region, as well as its theta component from the frontal
region, and temporal region, showed obviously low dimensions (P < 0.01). The ictal EEG exhibited significantly low-dimension estimates across the scalp. All filtered rhythms from the temporal
region yielded lower results than those of the surrogate data (P < 0.01). The dimension estimates of the EEG and filtered components markedly changed when the neurological state varied.
For each neurological state, the dimension estimates were not uniform among the EEG and frequency components. The signal with
a different frequency range and in a different neurological state showed a different dimension estimate. Furthermore, the
theta and alpha components demonstrated the same estimates not only within each neurological state, but also among the different
states. These results indicate that the theta and alpha components may be caused by similar dynamic processes. We conclude
that the brain function underlying the ictal EEG has a simple mechanism. Several heterogeneous dynamic systems play important
roles in the generation of EEG.
Received: 10 December 1999 / Accepted in revised form: 8 May 2000 相似文献
18.
A presently unresolved question within the face perception literature is whether attending to the location of a face modulates face processing (i.e. spatial attention). Opinions on this matter diverge along methodological lines – where neuroimaging studies have observed that the allocation of spatial attention serves to enhance the neural response to a face, findings from behavioural paradigms suggest face processing is carried out independently of spatial attention. In the present study, we reconcile this divide by using a continuous behavioural response measure that indexes face processing at a temporal resolution not available in discrete behavioural measures (e.g. button press). Using reaching trajectories as our response measure, we observed that although participants were able to process faces both when attended and unattended (as others have found), face processing was not impervious to attentional modulation. Attending to the face conferred clear benefits on sex-classification processes at less than 350ms of stimulus processing time. These findings constitute the first reliable demonstration of the modulatory effects of both spatial and temporal attention on face processing within a behavioural paradigm. 相似文献
19.
Freeman WJ 《Biological cybernetics》2005,92(6):350-359
A mesoscopic field-theoretic approach is compared with neural network and brain imaging approaches to understanding brain dynamics. Analysis of high spatiotemporal resolution rabbit electroencephalogram (EEG) reveals neural fields in the form of spatial patterns in amplitude (AM) and phase (PM) modulation of gamma and beta carrier waves that serve to classify EEGs from trials with differing conditioned stimuli (CS+/−). Paleocortex exemplified by olfactory EEG has one AM–PM pattern at a time that forms by an input-dependent phase transition. Neocortex shows multiple overlapping AM–PM patterns before and during presentation of CSs. Modeling suggests that neocortex is stabilized in a scale-free state of self-organized criticality, enabling cooperative domains to form virtually instantaneously by phase transitions ranging in size from a few hypercolumns to an entire hemisphere. Self-organized local domains precede formation of global domains that supervene and contribute global modulations to local domains. This mechanism is proposed to explain Gestalt formation in perception. 相似文献
20.
Cognitive control requires the suppression of distracting information in order to focus on task-relevant information. We applied EEG source reconstruction via time-frequency linear constrained minimum variance beamforming to help elucidate the neural mechanisms involved in spatial conflict processing. Human subjects performed a Simon task, in which conflict was induced by incongruence between spatial location and response hand. We found an early (∼200 ms post-stimulus) conflict modulation in stimulus-contralateral parietal gamma (30–50 Hz), followed by a later alpha-band (8–12 Hz) conflict modulation, suggesting an early detection of spatial conflict and inhibition of spatial location processing. Inter-regional connectivity analyses assessed via cross-frequency coupling of theta (4–8 Hz), alpha, and gamma power revealed conflict-induced shifts in cortical network interactions: Congruent trials (relative to incongruent trials) had stronger coupling between frontal theta and stimulus-contrahemifield parietal alpha/gamma power, whereas incongruent trials had increased theta coupling between medial frontal and lateral frontal regions. These findings shed new light into the large-scale network dynamics of spatial conflict processing, and how those networks are shaped by oscillatory interactions. 相似文献