Putting Humpty together again: Decoding brain networks during real-world processing

Lead Research Organisation: University College London
Department Name: Cell and Developmental Biology

Abstract

An important task for cognitive neuroscience is to understand how the brain supports broad functions that are engaged in everyday life, like interpersonal communication. Great progress has been made by decomposing these functions into discrete processes that can be associated with activity in particular brain regions and networks. What we do not know, however, is if and how these processes operate together. Thus, our overarching goal will be to understand how brain networks supports real-world behaviours under more ecological conditions.


PhD project: aims and description (limit 300 words)

Participants will watch films while undergoing functional magnetic resonance imaging (fMRI). The general aim is decompose the resulting data into networks and to label functions of those networks using annotation and machine learning approaches. We then characterize if, when, and how different networks interact and change with experience and test novel hypotheses about how the brain supports real-world processing.
YR2. Neuroimage collection (supervised by Skipper). We will use fMRI to acquire anatomical and functional brain images from people watching three uncut fils in their native language. Each movie will be viewed by five adults who have not previously seen the film. We will use standard preprocessing routines on the data.
YRS2-3. Film annotation and decoding (supervised by Skipper and Griffin). Features in films should be labelled in detail to decode the brain processes associated with those features. Hand annotation of features for even one film requires an enormous amount of time. To reduce this time, we will, first, use existing text-based descriptions and automated labelling to provide detailed time locked features. Second, we will use the brain data itself to identify film times for acquiring more detailed annotations through crowd-sourced approaches. The result of both is very rich text based descriptions of the films that are ready for machine learning decoding. This will be done by dividing data into training, validation, and test datasets and using the annotations to test how effectively networks can be labelled with different algorithms. Machine-learning approaches that might be most successful (support vector machines, convolutional neural networks, random forests) produce systems whose operations are non-trivial to understand. Thus, a component of the work will involve development of methods to probe solutions, to discover the spatial/temporal activity patterns used for predictions. These serve as the foundation for understanding how the brain processes natural stimuli.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M009513/1 01/10/2015 31/03/2024
1902468 Studentship BB/M009513/1 01/10/2017 30/12/2021 Sarah Aliko
 
Description The human brain can be thought of as a complex network, similar to social networks. Investigating the structure and organisation of this network is fundamental for understanding how the human brain support complex functions, such as language processing/comprehension.
Most studies in the field, have made use of resting-state functional magnetic resonance imaging (fMRI) methods and low-resolution mathematical models (graph theory) to study the network organisation of the brain. The model resulting from this paradigm, is called modular network: the network is partitioned into sub-components, or modules, that have a specific function and are linked to a specific anatomical area of the brain. In this context, language appears to be a static function, with very little interaction with other regions of the brain.
In order to investigate complex human behaviour, naturalistic stimuli in the form of full-length movies during fMRI were used in the present study, coupled with high-resolution graph theoretical measures and individual subject variability. The pilot study on 30 participants, indicated that the brain has a core-periphery organisation: one component of the network is highly centralised, meaning that it is tightly connected to all other brain areas (the core); the rest of the brain (the periphery) is highly dynamic and varies based on task and context. Here, language processing appears to be a much more dynamic and complex function, with known language regions being high-connectivity hubs, and ~30% of the rest of the brain being part of peripheral language areas. The peripheral language region were never detected before, because of the use of central tendency measures (eg. group averages) and reductive stimuli. Therefore, these results put into question current views on the neurobiology of language.
Exploitation Route The present findings may change the way we think of language, from a rather localised function to a highly dynamic one. The results could be used to better understand and help treat patients who suffer from speech impediments, such as aphasia. Investigating exactly how context drives changes in language network dynamics will be the next step towards understanding how humans process and produce speech.
Sectors Education,Healthcare

 
Description Core periphery algorithm 
Organisation Ningbo University of Technology
Country China 
Sector Academic/University 
PI Contribution We provided the theoretical basis for the algorithm, as we identified a lack of specific core-periphery algorithms for brain data. We also provide the neuroimaging data to test the algorithm.
Collaborator Contribution Our partner has developed the algorithm specifically tailored to neuroimaging data.
Impact The collaboration has resulted in a new algorithm for core-periphery detection in complex neuroimaging (fMRI) data. The collaboration is also yielding two publications: one methods (algorithm) paper, and one theoretical (neuroscience) paper. The collaboration is multi-disciplinary: mathematics, computer science and neuroscience.
Start Year 2019