AAI Scientific Cultural Services Ltd.

Nicosia, Cyprus

AAI Scientific Cultural Services Ltd.

Nicosia, Cyprus
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Papadelis C.,RIKEN | Papadelis C.,University of Trento | Eickhoff S.B.,Jülich Research Center | Eickhoff S.B.,RWTH Aachen | And 4 more authors.
NeuroImage | Year: 2011

This study combines source analysis imaging data for early somatosensory processing and the probabilistic cytoarchitectonic maps (PCMs). Human somatosensory evoked fields (SEFs) were recorded by stimulating left and right median nerves. Filtering the recorded responses in different frequency ranges identified the most responsive frequency band. The short-latency averaged SEFs were analyzed using a single equivalent current dipole (ECD) model and magnetic field tomography (MFT). The identified foci of activity were superimposed with PCMs. Two major components of opposite polarity were prominent around 21 and 31. ms. A weak component around 25. ms was also identified. For the most responsive frequency band (50-150. Hz) ECD and MFT revealed one focal source at the contralateral Brodmann area 3b (BA3b) at the peak of N20. The component ~. 25. ms was localised in Brodmann area 1 (BA1) in 50-150. Hz. By using ECD, focal generators around 28-30. ms located initially in BA3b and 2. ms later to BA1. MFT also revealed two focal sources - one in BA3b and one in BA1 for these latencies. Our results provide direct evidence that the earliest cortical response after median nerve stimulation is generated within the contralateral BA3b. BA1 activation few milliseconds later indicates a serial mode of somatosensory processing within cytoarchitectonic SI subdivisions. Analysis of non-invasive magnetoencephalography (MEG) data and the use of PCMs allow unambiguous and quantitative (probabilistic) interpretation of cytoarchitectonic identity of activated areas following median nerve stimulation, even with the simple ECD model, but only when the model fits the data extremely well. © 2010 Elsevier Inc.


Maruyama M.,RIKEN | Ioannides A.A.,AAI Scientific Cultural Services Ltd.
Journal of Neuroscience Methods | Year: 2010

Reconstruction of neural current sources from magnetoencephalography (MEG) data provides two independent estimates of the instantaneous current modulus and its direction. Here, we explore how different information on the modulus and direction affects the inter-hemisphere connectivity of the human medial temporal complex (hMT+). Connectivity was quantified by mutual information values of paired time series of current moduli or directions, with the joint probability distribution estimated with an optimized Gaussian kernel. These time series were obtained from tomographic analysis of single-trial MEG responses to a visual motion stimulus. With a high-contrast stimulus, connectivity measures based on the modulus were relatively strong in the prestimulus period, continuing until 100. ms after stimulus onset. The strongest modulus connectivity was produced with a long lag (19. ms) of the right hMT+ after the left hMT+. On the other hand, connectivity measures based on direction were relatively strong after 100. ms, with a short delay of less than 6. ms. These results suggest that nonspecific and probably indirect communication between the homologous areas is turned, by the stimulus arrival, into more precise and direct communication through the corpus callosum. The orientation of the estimated current vector for the strong connectivity can be explained by the curvature of the active cortical sheet. The temporal patterns of modulus and directional connectivity were different at low contrast, but similar to those at high contrast. We conclude that the modulus and direction indicate distinct functional connectivity modes. © 2010 Elsevier B.V.


Ioannides A.A.,AAI Scientific Cultural Services Ltd. | Poghosyan V.,AAI Scientific Cultural Services Ltd.
NeuroImage | Year: 2012

Different attention types select and focus brain resources on relevant sensory information. However, key questions remain unresolved: when and where cortical visual processing is first modulated by different types of attention? How do such modulatory effects spread thereafter? Here, we address these issues for spatial and category-specific types of attention using magnetoencephalography (MEG). First we identified the dynamics of visual attention-independent sensory processing to serve as a baseline framework for the attentional modulations of interest. We found that visual information is processed through the entire hierarchy of visual areas in at least two phases, in the 40-130. ms and 130-230. ms periods respectively. Spatial attention modulations were identified from the beginning of the initial stimulus-evoked response in the primary visual cortex ~. 70. ms post-stimulus. Category-specific attention modulated face processing beginning from the first face-specific response in high-level object-related areas ~. 100. ms post-stimulus, substantially earlier than previously reported for face-directed attention. Thus both attention types modulated responses during the first processing phase, beginning at the earliest brain area capable of coding the attentional target. Thereafter attentional effects propagated through the visual cortex together with the stimulus-evoked activity. Category-specific attention did not affect the first-phase responses in low-level strongly retinotopic visual areas, while the second-phase responses were enhanced when the stimulus was the response target and reduced when it was a distractor. Responses during both phases in high-level object-related areas were enhanced by category-specific attention independent of their target/distractor status. Spatial attention effects were stronger in low-level areas, whereas category-specific attention effects were stronger in high-level object-related areas. © 2012 Elsevier Inc.


Grant
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: HCO-06-2015 | Award Amount: 2.98M | Year: 2015

Smoking is the largest avoidable cause of preventable morbidity worldwide. It causes most of the cases of lung cancer and chronic obstructive pulmonary disease (COPD) and contributes to the development of other lung diseases. The control of smoking is considered as a highly important intervention for the prevention of lung diseases. Tobacco consumption is highly influenced by socioeconomic factors. SmokeFreeBrain aims to address the effectiveness of a multi-level variety of interventions aiming at smoking cessation in high risk target groups within High Middle Income Countries (HMIC) such as unemployed young adults, COPD and asthma patients, as well as within the general population in Low Middle Income Countries (LMIC). The project addresses existing approaches aiming to prevent lung diseases caused by tobacco while at the same time it develops new treatments and analyzes their contextual adaptability to the local and global health care system. SmokeFreeBrain follows an interdisciplinary approach exploiting consortiums expertise in various relevant fields in order to generate new knowledge. State of the art techniques in toxicology, pulmonary medicine, neuroscience and behavior will be utilized to evaluate the effectiveness of: (i) Public Service Announcement (PSA) against smoking, (ii) the use of electronic cigarettes with and without nicotine as a harm reduction approach and/or cessation aid, (iii) a specifically developed neurofeedback intervention protocol against smoking addiction, (iv) a specifically developed intervention protocol based on behavioral therapy, social media/mobile apps and short text messages (sms) and (v) pharmacologic interventions. The main objective of the project is to evaluate the interventions in terms of health economics, by studying their cost-effectiveness, and proposing a scalable plan and a clear pathway to embedding the proposed interventions into policy and practice both in LMIC as well as in HMIC.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ICT-2011.5.1 | Award Amount: 4.30M | Year: 2011

Epilepsy, the propensity for recurrent, unprovoked epileptic seizures, is the most common serious neurological disorder, affecting over 50 million people worldwide. Epileptic seizures manifest with a wide variety of motor, cognitive, affective, and autonomic symptoms and signs and associated changes in the electrical activities of the brain (EEG), heart (ECG), muscles (EMG), skin (GSR), as well as changes in other important measurable biological parameters, such as respiration and blood pressure. Their recognition and full understanding is the basis for their optimal management and treatment, but presently is unsatisfactory in many respects. Epileptic seizures occur unpredictably and typically outside hospital and are often misdiagnosed as other episodic disturbances such as syncope, psychogenic and sleep disorders, with which they may co-exist, blurring the clinical presentation; on the other hand, costs of hospital evaluation are substantial, frequently without the desirable results, due to suboptimal monitoring capabilities. \nReliable diagnosis requires state of the art monitoring and communication technologies providing real-time, accurate and continuous brain and body multi-parametric data measurements, suited to the patients medical condition and normal environment and facing issues of patient and data security, integrity and privacy. \nIn this project we will manage and analyse a large number of already acquired and new multimodal and advanced technology data from brain and body activities of epileptic patients and controls (MEG, multichannel EEG, video, ECG, GSR, EMG, etc) aiming to design ARMOR, a more holistic, personalized, medically efficient and economical monitoring system.\nNew methods and tools will be developed for multimodal data pre-processing and fusion of information from various sources. Novel approaches for large scale analysis (both real-time and offline) of multi-parametric streaming and archived data will be introduced to discover patterns and associations between external indicators and mental states, detect correlations among parallel observations, and identify vital signs changing significantly. Moreover methods for automatically summarizing results and efficiently managing medical data will be developed. ARMOR will incorporate models derived from data analysis based on already existing communication platform solutions emphasising on security and ethical issues and performing required adaptations to meet specifications. Special effort will be devoted in areas such as data anonymization and provision of required service.\nARMOR will provide flexible monitoring optimized for each patient and will be tested in several case studies and evaluated as a wide use ambulatory monitoring tool for seizures efficient diagnosis and management including possibilities for detecting premonitory signs and feedback to the patient.


Styliadis C.,Aristotle University of Thessaloniki | Kartsidis P.,Aristotle University of Thessaloniki | Paraskevopoulos E.,Aristotle University of Thessaloniki | Ioannides A.A.,AAI Scientific Cultural Services Ltd. | Bamidis P.D.,Aristotle University of Thessaloniki
Neural Plasticity | Year: 2015

The present study investigates whether a combined cognitive and physical training may induce changes in the cortical activity as measured via electroencephalogram (EEG) and whether this change may index a deceleration of pathological processes of brain aging. Seventy seniors meeting the clinical criteria of mild cognitive impairment (MCI) were equally divided into 5 groups: 3 experimental groups engaged in eight-week cognitive and/or physical training and 2 control groups: active and passive. A 5-minute long resting state EEG was measured before and after the intervention. Cortical EEG sources were modelled by exact low resolution brain electromagnetic tomography (eLORETA). Cognitive function was assessed before and after intervention using a battery of neuropsychological tests including the minimental state examination (MMSE). A significant training effect was identified only after the combined training scheme: a decrease in the post- compared to pre-training activity of precuneus/posterior cingulate cortex in delta, theta, and beta bands. This effect was correlated to improvements in cognitive capacity as evaluated by MMSE scores. Our results indicate that combined physical and cognitive training shows indices of a positive neuroplastic effect in MCI patients and that EEG may serve as a potential index of gains versus cognitive declines and neurodegeneration. This trial is registered with ClinicalTrials.gov Identifier NCT02313935. © 2015 Charis Styliadis et al.


Styliadis C.,Aristotle University of Thessaloniki | Ioannides A.A.,AAI Scientific Cultural Services Ltd. | Bamidis P.D.,Aristotle University of Thessaloniki | Papadelis C.,Harvard University
NeuroImage | Year: 2015

The cerebellum participates in emotion-related neural circuits formed by different cortical and subcortical areas, which sub-serve arousal and valence. Recent neuroimaging studies have shown a functional specificity of cerebellar lobules in the processing of emotional stimuli. However, little is known about the temporal component of this process. The goal of the current study is to assess the spatiotemporal profile of neural responses within the cerebellum during the processing of arousal and valence. We hypothesized that the excitation and timing of distinct cerebellar lobules is influenced by the emotional content of the stimuli. By using magnetoencephalography, we recorded magnetic fields from twelve healthy human individuals while passively viewing affective pictures rated along arousal and valence. By using a beamformer, we localized gamma-band activity in the cerebellum across time and we related the foci of activity to the anatomical organization of the cerebellum. Successive cerebellar activations were observed within distinct lobules starting ~. 160. ms after the stimuli onset. Arousal was processed within both vermal (VI and VIIIa) and hemispheric (left Crus II) lobules. Valence (left VI) and its interaction (left V and left Crus I) with arousal were processed only within hemispheric lobules. Arousal processing was identified first at early latencies (160. ms) and was long-lived (until 980. ms). In contrast, the processing of valence and its interaction to arousal was short lived at later stages (420-530. ms and 570-640. ms respectively). Our findings provide for the first time evidence that distinct cerebellar lobules process arousal, valence, and their interaction in a parallel yet temporally hierarchical manner determined by the emotional content of the stimuli. © 2015 Elsevier Inc.


Styliadis C.,Aristotle University of Thessaloniki | Ioannides A.A.,AAI Scientific Cultural Services Ltd. | Bamidis P.D.,Aristotle University of Thessaloniki | Papadelis C.,Harvard University
International Journal of Psychophysiology | Year: 2014

It is widely accepted that the amygdala plays a crucial role in the processing of emotions. The precise nature of its involvement is however unclear. We hypothesized that ambivalent findings from neuroimaging studies that report amygdala's activity in emotions, are due to distinct functional specificity of amygdala's sub-divisions and specifically to differential reactivity to arousal and valence. The goal of the present study is to characterize the amygdala response to affective stimuli by disentangling the contributions of arousal and valence. Our hypothesis was prompted by recent reports claiming anatomical sub-divisions of amygdala based on cytoarchitecture and the functional maps obtained from diverse behavioral, emotional, and physiological stimulation. We measured magnetoencephalography (MEG) recordings from 12 healthy individuals passively exposed to affective stimuli from the International Affective Picture System (IAPS) collection using a 2 (Valence levels). ×. 2 (Arousal levels) design. Source power was estimated using a beamformer technique with the activations referring to the amygdala sub-divisions defined through probabilistic cytoarchitectonic maps. Right laterobasal amygdala activity was found to mediate negative valence (elicited by unpleasant stimuli) while left centromedial activity was characterized by an interaction of valence by arousal (arousing pleasant stimuli). We did not find a main effect for amygdala activations in any of its sub-divisions for arousal modulation. To the best of our knowledge, our findings from non-invasive MEG data indicate for the first time, a distinct functional specificity of amygdala anatomical sub-divisions in the emotional processing. © 2013 Elsevier B.V.


Liu L.,RIKEN | Liu L.,AAI Scientific Cultural Services Ltd. | Ioannides A.A.,RIKEN | Ioannides A.A.,AAI Scientific Cultural Services Ltd.
PLoS ONE | Year: 2010

It is now apparent that the visual system reacts to stimuli very fast, with many brain areas activated within 100 ms. It is, however, unclear how much detail is extracted about stimulus properties in the early stages of visual processing. Here, using magnetoencephalography we show that the visual system separates different facial expressions of emotion well within 100 ms after image onset, and that this separation is processed differently depending on where in the visual field the stimulus is presented. Seven right-handed males participated in a face affect recognition experiment in which they viewed happy, fearful and neutral faces. Blocks of images were shown either at the center or in one of the four quadrants of the visual field. For centrally presented faces, the emotions were separated fast, first in the right superior temporal sulcus (STS; 35-48 ms), followed by the right amygdala (57-64 ms) and medial pre-frontal cortex (83-96 ms). For faces presented in the periphery, the emotions were separated first in the ipsilateral amygdala and contralateral STS. We conclude that amygdala and STS likely play a different role in early visual processing, recruiting distinct neural networks for action: the amygdala alerts sub-cortical centers for appropriate autonomic system response for fight or flight decisions, while the STS facilitates more cognitive appraisal of situations and links appropriate cortical sites together. It is then likely that different problems may arise when either network fails to initiate or function properly. © 2010 Liu, Ioannides.


Plomp G.,RIKEN | Plomp G.,Ecole Polytechnique Federale de Lausanne | Van Leeuwen C.,RIKEN | Ioannides A.A.,RIKEN | Ioannides A.A.,AAI Scientific Cultural Services Ltd
Human Brain Mapping | Year: 2010

We studied the spatiotemporal characteristics of cortical activity in early visual areas and the fusiform gyri (FG) by means of magnetoencephalography (MEG). Subjects performed a visual classification task, in which letters and visually similar pseudoletters were presented in different surrounds and under different task demands. The stimuli appeared in a cued half of the visual field (VF). We observed prestimulus effects on amplitudes in V1 and Cuneus relating to VF and task demands, suggesting a combination of active anticipation and specialized routing of activity in visual processing. Amplitudes in the right FG between 150 and 350 ms after stimulus onset reflected task demands, while those in the left FG between 300 and 400 ms showed selectivity for graphemes. The contrasting stimulus-evoked effects in the right and left FG show that the former area is sensitive to task demands irrespective of stimulus content, whereas the left FG is sensitive to stimulus content irrespectively of task demand. © 2009 Wiley-Liss, Inc.

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