Detection of Cognitive States from fMRI data using Machine Learning Techniques

Over the past decade functional Magnetic Resonance Imaging (fMRI) has emerged as a powerful technique to locate activity of human brain while engaged in a particular task or cognitive state. We consider the inverse problem of detecting the cognitive state of a human subject based on the fMRI data. We have explored classification techniques such as Gaussian Naive Bayes, k-Nearest Neighbour and Support Vector Machines. In order to reduce the very high dimensional fMRI data, we have used three feature selection strategies. Discriminating features and activity based features were used to select features for the problem of identifying the instantaneous cognitive state given a single fMRI scan and correlation based features were used when fMRI data from a single time interval was given. A case study of visuo-motor sequence learning is presented. The set of cognitive states we are interested in detecting are whether the subject has learnt a sequence, and if the subject is paying attention only towards the position or towards both the color and position of the visual stimuli. We have successfully used correlation based features to detect position-color related cognitive states with 80% accuracy and the cognitive states related to learning with 62.5% accuracy

Methods and Approaches for Characterizing Learning Related Changes Observed in functional MRI Data — A Review

Brain imaging data have so far revealed a wealth of information about neuronal circuits involved in higher mental functions like memory, attention, emotion, language etc. Our efforts are toward understanding the learning related effects in brain activity during the acquisition of visuo-motor sequential skills. The aim of this paper is to survey various methods and approaches of analysis that allow the characterization of learning related changes in fMRI data. Traditional imaging analysis using the Statistical Parametric Map (SPM) approach averages out temporal changes and presents overall differences between different stages of learning. We outline other potential approaches for revealing learning effects such as statistical time series analysis, modelling of haemodynamic response function and independent component analysis. We present example case studies from our visuo-motor sequence learning experiments to describe application of SPM and statistical time series analyses. Our review highlights that the problem of characterizing learning induced changes in fMRI data remains an interesting and challenging open research problem

A Multi-disciplinary Approach to the Investigation of Aspects of Serial Order in Cognition

Serial order processing or Sequence processing underlies many human activities such as speech, language, skill learning, planning, problem solving, etc. Investigating the\ud neural bases of sequence processing enables us to understand serial order in cognition and helps us building intelligent devices. In the current paper, various\ud cognitive issues related to sequence processing will be discussed with examples. Some of the issues are: distributed versus local representation, pre-wired versus\ud adaptive origins of representation, implicit versus explicit learning, fixed/flat versus hierarchical organization, timing aspects, order information embedded in sequences, primacy versus recency in list learning and aspects of sequence perception such as recognition, recall and generation. Experimental results that give evidence for the involvement of various brain areas will be described. Finally, theoretical frameworks based on Markov models and Reinforcement Learning paradigm will be presented. These theoretical ideas are useful for studying sequential phenomena in a principled way

An unusual bilateral variation of musculocutaneous nerve.

Musculocutaneous nerve arises from the lateral cord (C5,6,7) of brachial plexus. Communications between the branches of brachial plexus are not so common. During routine dissection, we observed bilateral variation in 60-year-old female cadaver. In the present case, median nerve represented as a musculocutaneous nerve which supplied biceps brachii and brachialis, further continued into forearm as lateral cutaneous nerve of forearm on the right arm. This branch did not pass through coracobrachialis muscle but the coracobrachialis was innervated by a branch from lateral cord of brachial plexus. We also observed an abnormal communicating branch between the musculocutaneous and median nerve on left side of the arm. These kinds of variations are important for surgeons while performing surgeries of axilla and upperlimb

Signal Integrity Analysis of Modified Coplanar Waveguide Structure Using ADI-FDTD Method

Very Large Scale Integration (VLSI) technology shrinks to Deep Sub Micron (DSM) geometries, interconnect is becoming a limiting factor in determining circuit performance. High speed interconnect suffers from signal integrity effects like crosstalk, and propagation delay thereby degrading the entire system operation. In order to reduce the adverse signal integrity effects, if is necessary for the interconnect to have accurate physical dimensions. The interconnection and packaging related issues are main factors that determine the number of circuits that can be integrated in a chip as well as the chip performance. In this paper, it is proposed to simulate high speed interconnect structures using Alternate Direction Implicit Finite-Difference Time-Domain Method (ADI-FDTD) method. The electrical parameters such as mutual inductance and mutual capacitance were calculated from E and H fields for Coplanar waveguide (CPW) and Stacked Grounded Coplanar waveguide (SGCPW). Keywords: Interconnects, ADI-FDTD Method, Coplanar Waveguide, Crosstalk and Signal Integrit

Residual thermal and moisture influences on the strain energy release rate analysis of edge delamination

A laminated plate theory analysis is developed to calculate the strain energy release rate associated with edge delamination growth in a composite laminate. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. The strain energy release rate, G, increased when residual thermal effects were combined with applied mechanical strains, but then decreased when increasing moisture content was included. A quasi-three-dimensional finite element analysis indicated identical trends and demonstrated these same trends for the individual strain energy release rate components, G sub I and G sub II, associated with interlaminar tension and shear. An experimental study indicated that for T300/5208 graphite-epoxy composites, the inclusion of residual thermal and moisture stresses did not significantly alter the calculation of interlaminar fracture toughness from strain energy release rate analysis of edge delamination data taken at room temperature, ambient conditions

Mathematical Modelling the Drying Kinetics of Beetroot Strips during Convective Drying at Different Temperatures

The thin layer drying of beetroot strips was evaluated at drying temperatures from 60 °C to 90 °C using convective dryer at inlet air velocity of 1.0 m/s. The different drying models were tested to evaluate the drying characteristics of beetroot strips. The investigations showed that Page’s and modified Page’s equations were satisfactorily describing the drying behaviour of beetroot strips during convective drying with appreciable high correlation coefficient (0.9971<r<0.9990) with low error values. The effective moisture diffusivity was increased from 3.563 x 10-10 m2/s to 8.038 x 10-10 m2/s with increase in drying temperature. The temperature dependency of effective moisture diffusivity was described by Arrhenius equation and activation energy for moisture diffusivity was 30.08 KJ/mol. The drying kinetic coefficients were significantly (p<0.05) affected by drying air temperature. The exponents of models were decreased linearly with drying air temperature during drying of beetroot strips. The equilibrium moisture content was markedly affected by drying air temperature and it decreased linearly with drying air temperature. The results were very useful in standardisation and optimisation of drying process of beetroot strips in large scale commercial production

Spontaneous Onset of Bacterial Cellulitis in Lower Limbs with Chronic Obstructive Venous Disease

AbstractBackgroundCellulitis, often recurrent is a common complication of severe chronic venous disease (CVD) when dermatitis or ulcer is present. The skin breakdown obviously provides easy entry for bacteria but other factors such as oedema and lymphatic dysfunction likely play a role in pathogenesis as well. An iliac obstructive lesion is commonly present and correction with stent(s) often heals dermatitis/ulcer and relieves cellulitis. The current manuscript focuses on a relatively infrequent “spontaneous” variety of cellulitis which also occurs in obstructive venous disease in the absence of overt skin breakdown. Stenting results are of particular interest in this subset because its therapeutic efficacy can be related to factors other than healing of dermatitis/ulceration (portal of entry).Material and methodsOne thousand and nine limbs underwent iliac vein stenting for symptomatic CVD over a 7 year period; 29 limbs that were stented to treat spontaneous recurrent cellulitis of two or more prior attacks and 16 additional limbs with only one prior episode (stented for other indications) are analysed. Eighty two percent of the limbs had obvious swelling and the remainder had none at the time of stenting when cellulitis was inactive. Iliac vein outflow obstruction was found by intravascular ultrasound (IVUS) and all limbs were stented.ResultsMedian age was 54 and male to female ratio 1:2. Aetiology of iliac obstruction was post-thrombotic in 33% and non-thrombotic in 67%. Preoperatively, lymphatic abnormalities were present in 17 (38%) of the limbs: no activity in 7, delayed flow in 8 and pooling of isotope in the lower leg in 2 limbs. Swelling and pain improved significantly after stent placement. Cumulative freedom from recurrent attacks of cellulitis was 76% at 3 years.ConclusionIliac vein outflow obstruction may underlie CVD limbs afflicted with cellulitis. IVUS examination is recommended if cellulitis is recurrent and conventional therapy had failed. Correction of outflow obstruction by venous stent placement appears to yield moderate freedom from repeat infections in the near term