DEVELOPMENTAL NEUROBIOLOGY, Issue 4 2006
Robert H. Ring
Abstract Brain derived neurotrophic factor (BDNF) exhibits a sequence of actions on neurons ranging from acute enhancement of transmission to long-term promotion of neurite outgrowth and synaptogenesis associated with learning and memory. The manifold effects of BDNF on neuronal modifications may be mediated by genomic alterations. We previously found that BDNF treatment acutely increases transcription of the synaptic vesicle protein Rab3A, required for trophin-induced synaptic plasticity, as well as the peptide VGF, which increases during learning. To elucidate comprehensive transcriptional programs associated with short- and long-term BDNF exposure, we now examine mRNA abundance and complexity using Affymetrix GeneChips in cultured hippocampal neurons. Consistent with the modulation of synaptic plasticity, BDNF treatment (3,6 h) induced mRNAs encoding the synapse-associated proteins synaptojanin 2, neuronal pentraxin 1, septin 9, and ryanodine receptor 2. BDNF also induced expression of mRNAs encoding neuropeptides (6,12 h), including prepronociceptin, neuropeptide Y, and secretogranin. To determine whether these neuropeptides induced by BDNF mediate neuronal development, we examined their effects on hippocampal neurons. The four mature peptides derived from post-translational processing of the ppNociceptin propeptide induced the expression of several immediate early genes in hippocampal cultures, indicating neuronal activation. To examine the significance of activation, the effects of nociceptin (orphanin FQ) and nocistatin on neurite outgrowth were examined. Quantitative morphometric analysis revealed that nociceptin significantly increased both average neurite length and average number of neurites per neuron, while nocistatin had no effect on these parameters. These results reveal a novel role for nociceptin and suggest that these neuropeptide systems may contribute to the regulation of neuronal function by BDNF. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

Weak hand preference in children with down syndrome is associated with language deficits

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2008
M. A. Groen
Abstract This study explores associations between language ability and hand preference in children with Down syndrome. Compared to typically developing children of the same age, children with Down syndrome showed weaker hand preference, were less consistent in the hand they used and also less willing to reach to extreme positions in contralateral space. Within the group of children with Down syndrome, those who showed a stronger or more consistent hand preference had better language and memory skills. This association could not be explained by differences in non-verbal cognitive ability or hearing loss. These findings are discussed within the theory of neurolinguistic development proposed by Locke [Locke (1997). Brain & Language, 58, 265,326]. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 242,250, 2008. [source]

Cerebral cortical laminar necrosis on diffusion-weighted MRI in hypoglycaemic encephalopathy

DIABETIC MEDICINE, Issue 8 2005
Y. Yoneda
Abstract Background Laminar necrosis of the cerebral cortex characterized neuropathologically by delayed selective neuronal necrosis occurs in hypoglycaemic encephalopathy and other brain diseases. Case report A 37-year-old male with insulin-treated Type 1 diabetes mellitus developed hypoglycaemic encephalopathy associated with respiratory failure. Brain diffusion-weighted MRI during the subacute period demonstrated high signals along the cerebral cortex. Brain single-photon emission computed tomography showed diffuse, severe cerebral hypoperfusion. The patient remained comatose and died 1 month later. Conclusions High signals along the cortical bands on diffusion-weighted MRI suggest cortical laminar necrosis, although a postmortem examination was unavailable. Sustained hypoglycaemic brain injury, possibly associated with respiratory hypoxia, may be the underlying mechanism. [source]

Visual deficits in developmental dyslexia: relationships between non-linguistic visual tasks and their contribution to components of reading

DYSLEXIA, Issue 2 2008
Manon W. Jones
Abstract Developmental dyslexia is often characterized by a visual deficit, but the nature of this impairment and how it relates to reading ability is disputed (Brain 2003; 126: 841,865). In order to investigate this issue, we compared groups of adults with and without dyslexia on the Ternus, visual-search and symbols tasks. Dyslexic readers yielded more errors on the visual-search and symbols tasks compared with non-dyslexic readers. A positive correlation between visual-search and symbols task performance suggests a common mechanism shared by these tasks. Performance on the visual-search and symbols tasks also correlated with non-word reading and rapid automatized naming measures, and visual search contributed independent variance to non-word reading. The Ternus task did not discriminate reading groups nor contributed significant variance to reading measures. We consider how visual-attention processes might underlie specific component reading measures. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Genomics of Brain and Blood: Progress and Pitfalls

EPILEPSIA, Issue 10 2006
Frank R Sharp
Summary:, Gene expression profiles in brain and blood of animals and humans can be useful for diagnosis, prognosis, and treatment of epilepsy. This article reviews recent progress and prospects for the future. [source]

Altered Tryptophan Metabolism in the Brain of Cystatin B -Deficient Mice: A Model System for Progressive Myoclonus Epilepsy

EPILEPSIA, Issue 10 2006
Annika Vaarmann
Summary:,Purpose: Progressive myoclonus epilepsy of the Unverricht,Lundborg type (EPM1) is a rare neurologic disorder, associated with mutations in the Cystatin B (Cstb) gene. Mice lacking Cstb, a cysteine protease inhibitor of the cathepsine family of proteases, provide a mammalian model for EPM1 by displaying similarly progressive ataxia, myoclonic seizures, and neurodegeneration. However, the linkage of Cstb deficit on the molecular level to pathologic features like myoclonic jerks or tonic,clonic seizures has remained unclear. We examined the tryptophan (TRP) metabolism, along the serotonin (5HT) and kynurenine (KYN) pathway in the brain of Cstb -deficient mice, in relation to their possible involvement in the seizure phenotype. Methods: TRP and its metabolites, along the 5HT and KYN pathways, were assayed in brain tissue by high-pressure liquid chromatography (HPLC) with electrochemical detection. The inverted wire grid and mild handling tests were used for evaluation of ataxia and myoclonic activity. Results: The Cstb -deficient mice had constitutively increased TRP, 5HT, and 5-hydroxyindole acetic acid (5HIAA) levels in the cerebral cortex and cerebellum and increased levels of KYN in the cerebellum. These neurochemical changes were accompanied with ataxia and an apparent myoclonic phenotype among the Cstb -deficient mice. Conclusions: Our findings suggest that secondary processes (i.e., overstimulation of serotoninergic transmission) on the cellular level, initiated by Cstb deficiency in specific brain regions, may be responsible for the myoclonic/seizure phenotype in EPM1. [source]

Propagation Dynamics of Epileptiform Activity Acutely Induced by Bicuculline in the Hippocampal,Parahippocampal Region of the Isolated Guinea Pig Brain

EPILEPSIA, Issue 12 2005
Laura Uva
Summary:,Purpose: Aim of the study is to investigate the involvement of parahippocampal subregions in the generation and in the propagation of focal epileptiform discharges in an acute model of seizure generation in the temporal lobe induced by arterial application of bicuculline in the in vitro isolated guinea pig brain preparation. Methods: Electrophysiological recordings were simultaneously performed with single electrodes and multichannel silicon probes in the entorhinal, perirhinal, and piriform cortices and in the area CA1 of the hippocampus of the in vitro isolated guinea pig brain. Interictal and ictal epileptiform discharges restricted to the temporal region were induced by a brief (3,5 min) arterial perfusion of the GABAA receptor antagonist, bicuculline methiodide (50 ,M). Current source density analysis of laminar field profiles performed with the silicon probes was carried out at different sites to establish network interactions responsible for the generation of epileptiform potentials. Nonlinear regression analysis was conducted on extracellular recordings during ictal onset in order to quantify the degree of interaction between fast activities generated at different sites, as well as time delays. Results: Experiments were performed in 31 isolated guinea pig brains. Bicuculline-induced interictal and ictal epileptiform activities that showed variability of spatial propagation and time course in the olfactory,temporal region. The most commonly observed pattern (n = 23) was characterized by the initial appearance of interictal spikes (ISs) in the piriform cortex (PC), which propagated to the lateral entorhinal region. Independent and asynchronous preictal spikes originated in the entorhinal cortex (EC)/hippocampus and progressed into ictal fast discharges (around 25 Hz) restricted to the entorhinal/hippocampal region. The local generation of fast activity was verified and confirmed both by CSD and phase shift analysis performed on laminar profiles. Fast activity was followed by synchronous afterdischarges that propagated to the perirhinal cortex (PRC) (but not to the PC). Within 1,9 min, the ictal discharge ceased and a postictal period of depression occurred, after which periodic ISs in the PC resumed. Unlike preictal ISs, postictal ISs propagated to the PRC. Conclusions: Several studies proposed that reciprocal connections between the entorhinal and the PRC are under a very efficient inhibitory control (1). We report that ISs determined by acute bicuculline treatment in the isolated guinea pig brain progress from the PC to the hippocampus/EC just before ictal onset. Ictal discharges are characterized by a peculiar pattern of fast activity that originates from the entorhinal/hippocampal region and only secondarily propagates to the PRC. Postictal propagation of ISs to the PRC occured exclusively when an ictal discharge was generated in the hippocampal/entorhinal region. The results suggest that reiteration of ictal events may promote changes in propagation pattern of epileptiform discharges that could act as trigger elements in the development of temporal lobe epilepsy. [source]

Vigabatrin, but not Gabapentin or Topiramate, Produces Concentration-related Effects on Enzymes and Intermediates of the GABA Shunt in Rat Brain and Retina

EPILEPSIA, Issue 7 2003
Graeme J. Sills
Summary: Purpose: The antiepileptic drug (AED) vigabatrin (VGB), which exerts its pharmacologic effects on the ,-aminobutyric acid (GABA) system, causes concentric visual field constriction in >40% of exposed adults. This may be a class effect of all agents with GABA-related mechanisms of action. We compared the concentration-related effects of VGB in rat brain and eye with those of gabapentin (GBP) and topiramate (TPM), both of which have been reported to elevate brain GABA concentrations in humans. Methods: Adult male rats (n = 10) were administered 0.9% saline (control), VGB (250, 500, 1,000 mg/kg), GBP (50, 100, 200 mg/kg), or TPM (12.5, 25, 50, 100 mg/kg). At 2 h after dosing, animals were killed, a blood sample obtained, the brain dissected into eight distinct regions, and the retina and vitreous humor isolated from each eye. Samples were analyzed for several GABA-related neurochemical parameters, and serum and tissue drug concentrations determined. Results: VGB treatment produced a significant (p < 0.05) dose-related increase in GABA concentrations and decrease in GABA-transaminase activity in all tissues investigated. This effect was most pronounced in the retina, where VGB concentrations were 18.5-fold higher than those in brain. In contrast, GBP and TPM were without effect on any of the neurochemical parameters investigated and did not accumulate appreciably in the retina. Conclusions: These findings corroborate a previously reported accumulation of VGB in the retina, which may be responsible for the visual field constriction observed clinically. This phenomenon does not appear to extend to other GABAergic drugs, suggesting that these agents might not cause visual field defects. [source]

FDG-PET Images Quantified by Probabilistic Atlas of Brain and Surgical Prognosis of Temporal Lobe Epilepsy

EPILEPSIA, Issue 9 2002
Sang Kun Lee
Summary: ,Purpose: This study evaluated the relation between hypometabolism, diagnosed by fluorodeoxyglucose positron emission tomography (FDG-PET), and the surgical outcome of a large and homogeneous series of cases of mesial temporal lobe epilepsy (mTLE), by using a probabilistic atlas of the human brain (statistical probabilistic anatomical maps: SPAM). Methods: Ninety-five surgically proven intractable mTLE patients and 22 age-matched controls were spatially normalized to the average brain PET template of international consortium of brain mapping (ICBM). The diagnosis of mTLE was confirmed by the presence of hippocampal sclerosis on magnetic resonance imaging (MRI) and video-EEG monitoring. Counts from normalized PET images were multiplied by the probability from 98 volumes of interest (VOIs) of SPAM. Asymmetric indexes (AIs) reflecting the severity of hypometabolism were calculated by counts of selected 12 VOIs from SPAM images in both temporal lobes. Extent of hypometabolism was determined by the number of voxels showing decreased metabolism in each VOI segmented by SPAM. Results: Of the 95 patients studied, 76 (80%) were seizure free, and 19 (20%) had postoperative seizures for the ,2-year follow-up period. No significant association between the severity of hypometabolism in each VOI of the temporal lobe and surgical outcome was identified (p > 0.05). The number of voxels showing decreased hypometabolism was not significantly different between the good- and poor-outcome groups (p > 0.05). Conclusions: Our results demonstrated that focal severity and extent of hypometabolism quantified by a probabilistic atlas of brain were not related to the surgical outcome in mTLE patients who had hippocampal sclerosis on MRI. We should develop a more localized and specified anatomic map for mTLE for further results. [source]

Maturational Aspects of Epilepsy Mechanisms and Consequences for the Immature Brain

EPILEPSIA, Issue 5 2001
Russell M. Sanchez
First page of article [source]

Distribution and Initiation of Seizure Activity in a Rat Brain with Subcortical Band Heterotopia

EPILEPSIA, Issue 5 2000
Zong-Fu Chen
Summary: Purpose: Misplaced (heterotopic) cortical neurons are a common feature of developmental epilepsies. To better understand seizure disorders associated with cortical heterotopia, the sites of aberrant discharge activity were investigated in vivo and in vitro in a seizure-prone mutant rat (tish) exhibiting subcortical band heterotopia. Methods: Depth electrode recordings and postmortem assessment of regional c- fos mRNA levels were used to characterize the distribution of aberrant discharge activity during spontaneous seizures in vivo. Electrophysiologic recordings of spontaneous and evoked activity also were performed by using in vitro brain slices from the tish rat treated with proconvulsant drugs (penicillin and 4-aminopyridine). Results: Depth electrode recordings demonstrate that seizure activity begins almost simultaneously in the normotopic and heterotopic areas of the tish neocortex. Spontaneous seizures induce c- fos mRNA in normotopic and heterotopic neocortical areas, and limbic regions. The threshold concentrations of proconvulsant drugs for inducing epileptiform spiking were similar in the normotopic and heterotopic areas of tish brain slices. Manipulations that blocked communication between the normotopic and heterotopic areas of the cortex inhibited spiking in the heterotopic, but not the normotopic, area of the cortex. Conclusions: These findings indicate that aberrant discharge activity occurs in normotopic and heterotopic areas of the neocortex, and in certain limbic regions during spontaneous seizures in the tish rat. Normotopic neurons are more prone to exhibit epileptiform activity than are heterotopic neurons in the tish cortex, and heterotopic neurons are recruited into spiking by activity initiated in normotopic neurons. The findings indicate that seizures in the tish brain primarily involve telencephalic structures, and suggest that normotopic neurons are responsible for initiating seizures in the dysplastic neocortex. [source]

Interactive Atlas of the Human Brain

EUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2009
K. A. Jellinger
No abstract is available for this article. [source]

Kynurenines in the Brain, from Experiments to Clinics

EUROPEAN JOURNAL OF NEUROLOGY, Issue 11 2007
K.A. Jellinger
No abstract is available for this article. [source]

Kynurenines in the Brain , From Experiments to Clinics

EUROPEAN JOURNAL OF NEUROLOGY, Issue 12 2006
K. A. Jellinger
No abstract is available for this article. [source]

The Lost Self: Pasthologies of the Brain and Identity

EUROPEAN JOURNAL OF NEUROLOGY, Issue 10 2006
K. A. Jellinger
No abstract is available for this article. [source]

Minds Behind the Brain.

EUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2006
A History of the Pioneers, their Discoveries
No abstract is available for this article. [source]

Three successful years and a promising future for Genes, Brain and Behavior

GENES, BRAIN AND BEHAVIOR, Issue 1 2005
Wim E. Crusio
No abstract is available for this article. [source]

Memory enhancement: the progress and our fears

GENES, BRAIN AND BEHAVIOR, Issue 4 2003
R. Gerlai
In a recent article Rose (2002) raises numerous crucial issues with regard to the research into and the use of cognition or memory enhancing agents. Although development of ,smart' drugs is in its infancy, his paper delineates some issues society may have to face when these drugs arrive. Questions about the development of such drugs may be interesting to several readers of Genes Brain and Behavior given the wealth of information expected to be gained on brain function from studies using genetic approaches including mutagenesis, transgenic techniques and genomics in general. Besides the scientific questions, several ethical issues may need to be addressed that are of interest to us all. Rose (2002) discusses some of these questions, but perhaps presents a too negative view on the problems, especially with regard to the present and future of memory research. This paper is intended to focus mainly on the scientific questions and argues that our fear of complex ethical problems should not make us throw the baby (i.e., our research and discoveries) out with the bath water. [source]

Genes, Brain and Behavior entering its second year

GENES, BRAIN AND BEHAVIOR, Issue 1 2003
Wim E. Crusio
No abstract is available for this article. [source]

Genes, Brain and Behavior: Aiming for a new synthesis

GENES, BRAIN AND BEHAVIOR, Issue 1 2002
Wim E. Crusio
[source]

The role of medial temporal lobe in retrieving spatial and nonspatial relations from episodic and semantic memory

HIPPOCAMPUS, Issue 1 2010
Lee Ryan
Abstract This study examined the involvement of medial temporal lobe, especially the hippocampus, in processing spatial and nonspatial relations using episodic and semantic versions of a relational judgment task. Participants studied object arrays and were tested on different types of relations between pairs of objects. Three prevalent views of hippocampal function were considered. Cognitive map theory (O'Keefe and Nadel (1978) The Hippocampus as a Cognitive Map. USA: Oxford University Press) emphasizes hippocampal involvement in spatial relational tasks. Multiple trace theory (Nadel and Moscovitch (1997) Memory consolidation, retrograde amnesia and the hippocampal complex Curr Opin Neurobiol 7:217,227) emphasizes hippocampal involvement in episodic tasks. Eichenbaum and Cohen's ((2001) From Conditioning to Conscious Recollection: Memory Systems of the Brain. USA: Oxford University Press) relational theory predicts equivalent hippocampal involvement in all relational tasks within both semantic and episodic memory. The fMRI results provided partial support for all three theories, though none of them fit the data perfectly. We observed hippocampal activation during all relational tasks, with increased activation for spatial compared to nonspatial relations, and for episodic compared to semantic relations. The placement of activation along the anterior-posterior axis of the hippocampus also differentiated the conditions. We suggest a view of hippocampal function in memory that incorporates aspects of all three theories. © 2009 Wiley-Liss, Inc. [source]

Brain,behavior correlation in children depends on the neurocognitive network

HUMAN BRAIN MAPPING, Issue 2 2004
James R. Booth
We examined brain,behavior correlations in 12 children (age range 9.3 to 11.7 years) during a selective attention task that required the visual search of a conjunction of features and during a response inhibition task that required the inhibition of a pre-potent response during "no-go" blocks. We found that the association between performance in these tasks and brain activation as measured by functional magnetic resonance imaging (fMRI) depended on the neurocognitive network. Specifically, better performance during the no-go task was associated with greater activation in the response inhibition network including the prefrontal cortex and basal ganglia. In contrast, better performance during the visual search task was associated with less activation in the selective attention network including superior parietal lobule and lateral premotor cortex. These results show that the relation of performance to the magnitude of neural activation is complex and may display differential relationships based on the cognitive domain, anatomical region, and perhaps also developmental stage. Hum Brain Mapping 23:99,108, 2004. © 2004 Wiley-Liss, Inc. [source]

Electrophysiological Signals of Familiarity and Recency in the Infant Brain

INFANCY, Issue 5 2010
Kelly A. Snyder
Electrophysiological work in nonhuman primates has established the existence of multiple types of signals in the temporal lobe that contribute to recognition memory, including information regarding a stimulus's relative novelty, familiarity, and recency of occurrence. We used high-density event-related potentials (ERPs) to examine whether young infants represent these distinct types of information about previously experienced items. Twenty-four different highly familiar and initially novel items were each repeated exactly once either immediately (Experiment 1), or following one intervening item (Experiment 2). A late slow wave (LSW) component of the ERP exhibited neural responses consistent with recency signals over right-central leads, but only when there were no intervening stimuli between repetitions. The LSW also exhibited responses consistent with familiarity signals over anterior-temporal leads, but only when there were intervening stimuli between repetitions. A mid-latency negative component (i.e., the Nc) also distinguished familiar from novel items, but did not exhibit a pattern of responding consistent with familiarity signals. These findings suggest that infants encode information about a variety of objects from their natural environments into long-term memory, and can discriminate between familiar and unfamiliar items, and between recently seen and new items, very quickly (within 1 sec). They also suggest that infants represent information about not only whether a stimulus is familiar or unfamiliar but also whether it has been seen recently. [source]

In reply to Commentary: "What Are the Unintended Consequences of Changing the Diagnostic Paradigm for Subarachnoid Hemorrhage After Brain Computed Tomography to Computed Topographic Angiography in Place of Lumbar Puncture?"

ACADEMIC EMERGENCY MEDICINE, Issue 9 2010
Robert F. McCormack MD
No abstract is available for this article. [source]

Brain and behavior interface: Stress and the developing brain

INFANT MENTAL HEALTH JOURNAL, Issue 3 2003
Megan R. Gunnar
Animal studies have shown that mother,infant interactions can have long-term impacts on areas of the brain that regulate fearful behavior and the physiology of stress. Here, the research on human infants and children is reviewed with an eye to whether early experiences have similar effects in our species. Research shows that during the first year, sensitive and responsive caregiving becomes a powerful regulator of emotional behavior and neuroendocrine stress hormone activity in young children. Indeed, quality-of-care effects can be detected for children throughout the preschool years. Reviewed research suggests that temperament affects the likelihood that children will show increases in stress hormones as the quality of their care decreases. Finally, we review the literature on stress hormone activity in children who have been maltreated early in life, and explore the critical question of whether enhancing care later in development can reverse the effects on behavior and neurobiology of early adverse experiences. ©2003 Michigan Association for Infant Mental Health. [source]

Recovery of Enterococcus faecalis after single- or multiple-visit root canal treatments carried out in infected teeth ex vivo

INTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2005
N. Vivacqua-Gomes
Abstract Aim, To assess the presence of Enterococcus faecalis after root canal treatment in single or multiple visits in an ex vivo model. Methodology, Forty-five premolar teeth were infected ex vivo with E. faecalis for 60 days. The canals were then prepared using a crowndown technique with System GT and Gates,Glidden burs and irrigated with 2% chlorhexidine gel. The specimens were divided into five groups (G1, G2, G3, G4 and G5) according to the time elapsed between chemical,mechanical preparation and root canal filling, the irrigant solution used and the use or nonuse of a calcium hydroxide intra-canal medicament. The teeth were then root-filled and incubated for 60 days at 37 °C. Dentine chips were removed from the canal walls with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing Brain,Heart Infusion broth. These samples were placed onto agar plates and colony forming units were counted after 24 h at 37 °C. Data were ranked and analysed using the Kruskal,Wallis statistical test. Results,Enterococcus faecalis was recovered from 20% (three of 15 specimens) of G1 (chlorhexidine irrigation and immediate root filling in a single visit), 25% (four of 15 specimens) of G2 (chlorhexidine irrigation and filling after 14 days use of a calcium hydroxide dressing in multiple visits), 40% (two of five specimens) of G3 (chlorhexidine irrigation and filling after 7 days), 60% (three of five specimens) of G4 (saline irrigation and filling after 7 days) and from 100% (five of five specimens) of G5 (saline irrigation and immediate filling without sealer). Conclusions, Neither single- nor multiple-visit root canal treatment ex vivo, eliminated E. faecalis completely from dentinal tubules. Up to 60 days after root filling, E. faecalis remained viable inside dentinal tubules. When no sealer was used, E. faecalis presented a higher growth rate. [source]

Improved GMM with parameter initialization for unsupervised adaptation of Brain,Computer interface

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 6 2010
Guangquan Liu
Abstract An important property of brain signals is their nonstationarity. How to adapt a brain,computer interface (BCI) to the changing brain states is one of the challenges faced by BCI researchers, especially in real application where the subject's real intent is unknown to the system. Gaussian mixture model (GMM) has been used for the unsupervised adaptation of the classifier in BCI. In this paper, a method of initializing the model parameters is proposed for expectation maximization-based GMM parameter estimation. This improved GMM method and other two existing unsupervised adaptation methods are applied to groups of constructed artificial data with different data properties. Performances of these methods in different situations are analyzed. Compared with the other two unsupervised adaptation methods, this method shows a better ability of adapting to changes and discovering class information from unlabelled data. The methods are also applied to real EEG data recorded in 19 experiments. For real data, the proposed method achieves an error rate significantly lower than the other two unsupervised methods. Results of the real data agree with the analysis based on the artificial data, which confirms not only the effectiveness of our method but also the validity of the constructed data. Copyright © 2009 John Wiley & Sons, Ltd. [source]