Papers by Andreas Ioannides
Proceedings of the 2018 International Conference on Education Technology Management
This paper investigates the potential for developing a neuroscience-based system for enhancing th... more This paper investigates the potential for developing a neuroscience-based system for enhancing the human resource (HR) development process. The proposed system is firstly considered for application in the tourism industry because of its HR intensive characteristics. The aim is to relate different categories of adults in various ways based on their performance at work and previous educational experience, to their Individual Learning Capability (ILC). This is carried out in a set of experimental tests using specialized neuroscience equipment. In this way cognitive attributes can be mapped for targeted occupational categories. This will enable HR managers in the industry to easily identify the learning capabilities of their workforce and therefore create an effective plan for human capital development. The proposed system makes use of a specialized device developed by the authors, which has the capability of making field measurements. This is a novelty that makes the experiment possible with less costs without sacrificing the data quality. Previously such data could only be obtained at very specialized laboratory conditions. With the proposed ILC evaluation system we can bring the real talents of people in the forefront and support them in building the necessary capabilities to be effective.
Frontiers in Human Neuroscience, 2016
Current Research in Physiology, 2022
High amplitude electroencephalogram (EEG) events, like unitary K-complex (KC), are used to partit... more High amplitude electroencephalogram (EEG) events, like unitary K-complex (KC), are used to partition sleep into stages and hence define the hypnogram, a key instrument of sleep medicine. Throughout sleep the heart rate (HR) changes, often as a steady HR increase leading to a peak, what is known as a heart rate surge (HRS). The hypnogram is often unavailable when most needed, when sleep is disturbed and the graphoelements lose their identity. The hypnogram is also difficult to define during normal sleep, particularly at the start of sleep and the periods that precede and follow rapid eye movement (REM) sleep. Here, we use objective quantitative criteria that group together periods that cannot be assigned to a conventional sleep stage into what we call REM0 periods, with the presence of a HRS one of their defining properties. Extended REM0 periods are characterized by highly regular sequences of HRS that generate an infra-low oscillation around 0.05 Hz. During these regular sequence of HRS, and just before each HRS event, we find avalanches of high amplitude events for each one of the mass electrophysiological signals, i.e. related to eye movement, the motor system and the general neural activity. The most prominent features of long REM0 periods are sequences of three to five KCs which we label multiple K-complexes (KCm). Regarding HRS, a clear dissociation is demonstrated between the presence or absence of high gamma band spectral power (55–95 Hz) of the two types of KCm events: KCm events with strong high frequencies (KCmWSHF) cluster just before the peak of HRS, while KCm between HRS show no increase in high gamma band (KCmNOHF). Tomographic estimates of activity from magnetoencephalography (MEG) in pre-KC periods (single and multiple) showed common increases in the cholinergic Nucleus Basalis of Meynert in the alpha band. The direct contrast of KCmWSHF with KCmNOHF showed increases in all subjects in the high sigma band in the base of the pons and in three subjects in both the delta and high gamma bands in the medial Pontine Reticular Formation (mPRF), the putative Long Lead Initial pulse (LLIP) for Ponto-Geniculo-Occipital (PGO) waves.
European Journal of Neuroscience, 1998
Biomag 96, 2000
A general method for obtaining continuous solutions to the biomagnetic inverse problem was first ... more A general method for obtaining continuous solutions to the biomagnetic inverse problem was first presented during the 1989 Biomagnetism conference. From the outset, the method was developed for three-dimensional source spaces [1, 2] but, partly to reduce computational demands and partly for ease of presentation, the first major publication of the method [3] used two-dimensional reconstructions. Soon afterwards the algorithms were ported to a transputer, making possible the analysis of large sets of MEG data. The output (estimates of the primary current density in a three-dimensional source space) was displayed by taking slices (tomes) through the source space leading to a series of MFT (Magnetic Field Tomographie) images. Later forms of representation included time integrals and activation curves, describing the evolution of activity within specified Regions of Interest (ROI). Animations run on the transputer array and recorded on video, were by far the most effective presentation tool, showing in colour-coded form the changes in the activity against a background of coregistered MRI slices[4]. Early reconstructions used averaged data but the emphasis has recently shifted to analysis of single trial or continuous data [5, 6]. Each three-dimensional study was underpinned by thorough tests with Computer generated data which, however, have been only superficially reported because of space limitations. We have previously described our philosophy and method [3], the transputer based implementation [7] and the logic in the various algorithmic steps [8]. However, the lack of published material on the background tests must be the cause of misrepresentations of MFT in some recent publications dealing with distributed source analysis, e.g. [9]. The present paper makes good this omission and uses computer-generated data to illustrate the power and limitations of MFT as a 3D imaging method, using realistic sensor configurations and signals that are neurophysiologically realistic in terms of location and temporal characteristics.
Encyclopedia of Neuroscience
Frontiers in Applied Mathematics and Statistics
In this article, we present a unified framework for the analysis and characterization of a comple... more In this article, we present a unified framework for the analysis and characterization of a complex system and demonstrate its application in two diverse fields: neuroscience and astrophysics. The framework brings together techniques from graph theory, applied mathematics, and dimensionality reduction through principal component analysis (PCA), separating linear PCA and its extensions. The implementation of the framework maps an abstract multidimensional set of data into reduced representations, which enable the extraction of its most important properties (features) characterizing its complexity. These reduced representations can be sign-posted by known examples to provide meaningful descriptions of the results that can spur explanations of phenomena and support or negate proposed mechanisms in each application. In this work, we focus on the clustering aspects, highlighting relatively fixed stable properties of the system under study. We include examples where clustering leads to sem...
Proceedings of the International Joint Conference on Neural Networks, 2003.
... [IO]Tzclcpi A., loannidcs A. A. and Poghosyan V. Early (N70m) [IIlMoradi F., Liu LC, ... Clin... more ... [IO]Tzclcpi A., loannidcs A. A. and Poghosyan V. Early (N70m) [IIlMoradi F., Liu LC, ... Clin. Neurophysiol. 52: 298 - 305 (1981) [24]Ress D., Benjamin T., Backus T. and Heeger D. J. Activity in primary visual cortex predicts performance in a visual detecting task. Norure Neurosci. ...
Background: Saccadic eye movements align the two eyes precisely to foveate a target. Trial-by-tri... more Background: Saccadic eye movements align the two eyes precisely to foveate a target. Trial-by-trial variance of eye movement is always observed within an identical experimental condition. This has often been treated as experimental error without addressing its significance. The present study examined statistical linkages between the two eyes' movements, namely interocular yoking, for the variance of eye position and velocity. Methods: Horizontal saccadic movements were recorded from twelve right-eye-dominant subjects while they decided on saccade direction in Go-Only sessions and on both saccade execution and direction in Go/NoGo sessions. We used infrared corneal reflection to record simultaneously and independently the movement of each eye. Quantitative measures of yoking were provided by mutual information analysis of eye position or velocity, which is sensitive to both linear and non-linear relationships between the eyes' movements. Our mutual information analysis relied on the variance of the eyes movements in each experimental condition. The range of movements for each eye varies for different conditions so yoking was further studied by comparing GO-Only vs. Go/NoGo sessions, leftward vs. rightward saccades. Results: Mutual information analysis showed that velocity yoking preceded positional yoking. Cognitive load increased trial variances of velocity with no increase in velocity yoking, suggesting that cognitive load may alter neural processes in areas to which oculomotor control is not tightly linked. The comparison between experimental conditions showed that interocular linkage in velocity variance of the right eye lagged that of the left eye during saccades. Conclusions: We conclude quantitative measure of interocular yoking based on trial-to-trial variance within a condition, as well as variance between conditions, provides a powerful tool for studying the binocular movement mechanism.
A study is made of the propagation of a deuteron through a nuclear medium. We consider the effect... more A study is made of the propagation of a deuteron through a nuclear medium. We consider the effect of the Pauli exclusion principle on the internal motion of the deuteron, for the idealized case of a deuteron propagating through infinite nuclear matter, assumed to be adequately described by the Fermi-gas model. This greatly simplifies the calculations and enables us to include explicitly the D-state component of the deuteron wavefunction in our model. It is shown that the action of the Pauli exclusion principle, on the D-state part of the deuteron, endowes various properties of the deuteron with strong dependence on the relative orientation of the deuteron spin and its linear momentum. The dependence of the binding energy of the deuteron on this relative orientation is particularly important, because, it can be associated with a new tensor term, of the T[p] type, in the deuteron optical potential. The strength of this tensor potential is found to be non-negligible at high incident de...
We investigate where the brain responds to affective and cognitive advertising stimuli. Subjects ... more We investigate where the brain responds to affective and cognitive advertising stimuli. Subjects were exposed to brand advertising whilst patterns of neural activity were being recorded by magnetoencephalography (MEG), a non-invasive technique which provides brain images for later analysis. The hypotheses were, first that more affective ads would be distinguished from more cognitive ads by observable, distinct brain activations and second that the affective sections of the ads would stimulate those parts of the brain shown to be associated with affect in previous neuroscience research unconnected with advertising. The hypotheses were broadly supported.
Advanced Methods in the Evaluation of Nuclear Scattering Data
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Frontiers in Human Neuroscience, 2016
Frontiers in Human Neuroscience, 2016
Frontiers in Human Neuroscience, 2016
Frontiers in Human Neuroscience, 2016
Advances in Clinical Neurophysiology, 2012
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Papers by Andreas Ioannides