247 research outputs found
Temporal Multivariate Pattern Analysis (tMVPA): a single trial approach exploring the temporal dynamics of the BOLD signal
fMRI provides spatial resolution that is unmatched by non-invasive neuroimaging techniques. Its temporal dynamics however are typically neglected due to the sluggishness of the hemodynamic signal. We present temporal multivariate pattern analysis (tMVPA), a method for investigating the temporal evolution of neural representations in fMRI data, computed on single-trial BOLD time-courses, leveraging both spatial and temporal components of the fMRI signal. We implemented an expanding sliding window approach that allows identifying the time-window of an effect. We demonstrate that tMVPA can successfully detect condition-specific multivariate modulations over time, in the absence of mean BOLD amplitude differences. Using Monte-Carlo simulations and synthetic data, we quantified family-wise error rate (FWER) and statistical power. Both at the group and single-subject levels, FWER was either at or significantly below 5%. We reached the desired power with 18 subjects and 12 trials for the group level, and with 14 trials in the single-subject scenario. We compare the tMVPA statistical evaluation to that of a linear support vector machine (SVM). SVM outperformed tMVPA with large N and trial numbers. Conversely, tMVPA, leveraging on single trials analyses, outperformed SVM in low N and trials and in a single-subject scenario. Recent evidence suggesting that the BOLD signal carries finer-grained temporal information than previously thought, advocates the need for analytical tools, such as tMVPA, tailored to investigate BOLD temporal dynamics. The comparable performance between tMVPA and SVM, a powerful and reliable tool for fMRI, supports the validity of our technique
A hypothesis-driven method based on machine learning for neuroimaging data analysis
There remains an open question about the usefulness and the interpretation of machine learning (ML)
approaches for discrimination of spatial patterns of brain images between samples or activation states.
In the last few decades, these approaches have limited their operation to feature extraction and linear
classification tasks for between-group inference. In this context, statistical inference is assessed by randomly
permuting image labels or by the use of random effect models that consider between-subject variability.
These multivariate ML-based statistical pipelines, whilst potentially more effective for detecting
activations than hypotheses-driven methods, have lost their mathematical elegance, ease of interpretation,
and spatial localization of the ubiquitous General linear Model (GLM). Recently, the estimation of
the conventional GLM parameters has been demonstrated to be connected to an univariate classification
task when the design matrix in the GLM is expressed as a binary indicator matrix. In this paper we
explore the complete connection between the univariate GLM and ML-based regressions. To this purpose
we derive a refined statistical test with the GLM based on the parameters obtained by a linear Support
Vector Regression (SVR) in the inverse problem (SVR-iGLM). Subsequently, random field theory (RFT) is
employed for assessing statistical significance following a conventional GLM benchmark. Experimental
results demonstrate how parameter estimations derived from each model (mainly GLM and SVR) result
in different experimental design estimates that are significantly related to the predefined functional task.
Moreover, using real data from a multisite initiative the proposed ML-based inference demonstrates statistical
power and the control of false positives, outperforming the regular GLM.MCIN/AEIFEDER ``Una manera de hacer Europa" RTI2018-098913-B100Junta de AndaluciaEuropean Commission CV20-45250
A-TIC-080-UGR18
B-TIC586-UGR20
P20-00525research project ACACIA US-1264994European CommissionJunta de Andalucia (Consejeria de Economia, Conocimiento, Empresas y Universidad
An Overview on Artificial Intelligence Techniques for Diagnosis of Schizophrenia Based on Magnetic Resonance Imaging Modalities: Methods, Challenges, and Future Works
Schizophrenia (SZ) is a mental disorder that typically emerges in late
adolescence or early adulthood. It reduces the life expectancy of patients by
15 years. Abnormal behavior, perception of emotions, social relationships, and
reality perception are among its most significant symptoms. Past studies have
revealed the temporal and anterior lobes of hippocampus regions of brain get
affected by SZ. Also, increased volume of cerebrospinal fluid (CSF) and
decreased volume of white and gray matter can be observed due to this disease.
The magnetic resonance imaging (MRI) is the popular neuroimaging technique used
to explore structural/functional brain abnormalities in SZ disorder owing to
its high spatial resolution. Various artificial intelligence (AI) techniques
have been employed with advanced image/signal processing methods to obtain
accurate diagnosis of SZ. This paper presents a comprehensive overview of
studies conducted on automated diagnosis of SZ using MRI modalities. Main
findings, various challenges, and future works in developing the automated SZ
detection are described in this paper
Characterization of groups using composite kernels and multi-source fMRI analysis data: application to schizophrenia
Pattern classification of brain imaging data can enable the automatic detection of differences in cognitive processes of specific groups of interest. Furthermore, it can also give neuroanatomical information related to the regions of the brain that are most relevant to detect these differences by means of feature selection procedures, which are also well-suited to deal with the high dimensionality of brain imaging data. This work proposes the application of recursive feature elimination using a machine learning algorithm based on composite kernels to the classification of healthy controls and patients with schizophrenia. This framework, which evaluates nonlinear relationships between voxels, analyzes whole-brain fMRI data from an auditory task experiment that is segmented into anatomical regions and recursively eliminates the uninformative ones based on their relevance estimates, thus yielding the set of most discriminative brain areas for group classification. The collected data was processed using two analysis methods: the general linear model (GLM) and independent component analysis (ICA). GLM spatial maps as well as ICA temporal lobe and default mode component maps were then input to the classifier. A mean classification accuracy of up to 95% estimated with a leave-two-out cross-validation procedure was achieved by doing multi-source data classification. In addition, it is shown that the classification accuracy rate obtained by using multi-source data surpasses that reached by using single-source data, hence showing that this algorithm takes advantage of the complimentary nature of GLM and ICAPublicad
Automatic Autism Spectrum Disorder Detection Using Artificial Intelligence Methods with MRI Neuroimaging: A Review
Autism spectrum disorder (ASD) is a brain condition characterized by diverse
signs and symptoms that appear in early childhood. ASD is also associated with
communication deficits and repetitive behavior in affected individuals. Various
ASD detection methods have been developed, including neuroimaging modalities
and psychological tests. Among these methods, magnetic resonance imaging (MRI)
imaging modalities are of paramount importance to physicians. Clinicians rely
on MRI modalities to diagnose ASD accurately. The MRI modalities are
non-invasive methods that include functional (fMRI) and structural (sMRI)
neuroimaging methods. However, the process of diagnosing ASD with fMRI and sMRI
for specialists is often laborious and time-consuming; therefore, several
computer-aided design systems (CADS) based on artificial intelligence (AI) have
been developed to assist the specialist physicians. Conventional machine
learning (ML) and deep learning (DL) are the most popular schemes of AI used
for diagnosing ASD. This study aims to review the automated detection of ASD
using AI. We review several CADS that have been developed using ML techniques
for the automated diagnosis of ASD using MRI modalities. There has been very
limited work on the use of DL techniques to develop automated diagnostic models
for ASD. A summary of the studies developed using DL is provided in the
appendix. Then, the challenges encountered during the automated diagnosis of
ASD using MRI and AI techniques are described in detail. Additionally, a
graphical comparison of studies using ML and DL to diagnose ASD automatically
is discussed. We conclude by suggesting future approaches to detecting ASDs
using AI techniques and MRI neuroimaging
Automatic autism spectrum disorder detection using artificial intelligence methods with MRI neuroimaging: A review
Autism spectrum disorder (ASD) is a brain condition characterized by
diverse signs and symptoms that appear in early childhood. ASD is also
associated with communication deficits and repetitive behavior in affected
individuals. Various ASD detection methods have been developed, including
neuroimaging modalities and psychological tests. Among these methods,
magnetic resonance imaging (MRI) imaging modalities are of paramount
importance to physicians. Clinicians rely on MRI modalities to diagnose
ASD accurately. The MRI modalities are non-invasive methods that include
functional (fMRI) and structural (sMRI) neuroimaging methods. However,
diagnosing ASD with fMRI and sMRI for specialists is often laborious and
time-consuming; therefore, several computer-aided design systems (CADS)
based on artificial intelligence (AI) have been developed to assist specialist
physicians. Conventional machine learning (ML) and deep learning (DL) are
the most popular schemes of AI used for diagnosing ASD. This study aims to
review the automated detection of ASD using AI. We review several CADS that
have been developed using ML techniques for the automated diagnosis of
ASD using MRI modalities. There has been very limited work on the use of DL techniques to develop automated diagnostic models for ASD. A summary of
the studies developed using DL is provided in the Supplementary Appendix.
Then, the challenges encountered during the automated diagnosis of ASD
using MRI and AI techniques are described in detail. Additionally, a graphical
comparison of studies using ML and DL to diagnose ASD automatically
is discussed. We suggest future approaches to detecting ASDs using AI
techniques and MRI neuroimaging.Qatar National
Librar
Investigating visual and auditory scene feedback to early visual foveal and peripheral cortex using fMRI
No abstract available
- …