Parietal cortical structure and function in attentional disorders

Lead Research Organisation: University of Oxford
Department Name: Experimental Psychology

Abstract

When people suffer from stroke, which happens to about 150000 people each year in the UK, they often are left with a very specific type of impairment. They can see and move normally, but they act as if they ignore parts of their surroundings. Usually, following a stroke on the right side of the brain these patients ignore the left part of their surroundings. Researchers have traditionally focused on trying to determine the function of the damaged brain area in the hope of finding clues to restoring normal functioning in these patients. However, it is increasingly clear that it is important to understand the brain and disorders of brain function in terms of the interactions of networks of brain areas rather than simply focusing on a single brain area. Thus, the problems experienced by patients who have suffered a stroke might not be explained purely by the damage to a single brain region, but by the effects that damage to one area has on activity elsewhere in the brain. If this is true, to develop a treatment one should not just focus on the damaged area, but on the consequences of the damage to other brain regions. In this project, we try to investigate this possibility. In healthy volunteers, we will map the brain structures that are often damaged in stroke and investigate their contribution to the problems stroke patients experience. This will be done using a combination of neuroscientific research techniques that allow us to probe the living brain non-invasively. Also, we will investigate the possibility of alleviating the problems experienced by stroke patients by treating changes in distributed patterns of brain activity.

Technical Summary

Damage to the parietal cortex, for example after stroke, results in severe disorders of attention. Although these patients? visual and motor capabilities seem unimpaired, they fail to react normally to their environment. The severity of such impairments is a strong negative predictor of successful recovery. Traditionally, research has focused on the specific location of the brain lesion and treatment has focused on regaining the function of the damaged area. Recent advances in the understanding of neural processes underlying attention, however, suggest such disorders are better understood in terms of the distributed function of a network of regions. According to this ?network view?, the impairments following a parietal lesion are not simply due parietal damage, but to resulting changes in neural activity throughout the cortical network. The goal of the current project is to evaluate this claim. The results will be applicable to basic research on the nature of attention, clinical understanding of the basis of attentional disorders following stroke, and treatment development. Experiment 1 will use diffusion-weighted imaging to establish the core component regions of parietal cortex on the basis of anatomical connectivity in both human and non-human primates. Experiments 2-4 will investigate the functional interactions of parietal cortex pertinent to the understanding of neglect. Although there has been interest in the possibility that parietal cortex modulates activity in early visual areas we will also investigate parietal involvement in memory updating and response selection mechanisms. We will capitalize on, first, our laboratory?s development of methods for combined transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) and event-related potential (ERP) recording during cognitive tasks. This makes it possible to manipulate or disrupt parietal activity and measure the impact on other brain regions. Second, we will exploit computational and probabilistic approaches to understanding of behaviour that we have used in other research and here adapt to the case of visuospatial function. Experiment 5 exploits our recently developed methods for combining TMS with DWI to directly relate physiological indices of functional interaction with structural indices of anatomical connectivity. Finally, we will exploit the results of the previous experiments to investigate changes in parietal network function in neglect patients. The proposed research will provide an important step in our understanding of the neural control of attention, the causes of attentional disorders, and avenues for their possible treatment.

Publications

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Akaishi R (2016) Neural Mechanisms of Credit Assignment in a Multicue Environment. in The Journal of neuroscience : the official journal of the Society for Neuroscience

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Boorman ED (2013) Ventromedial prefrontal and anterior cingulate cortex adopt choice and default reference frames during sequential multi-alternative choice. in The Journal of neuroscience : the official journal of the Society for Neuroscience

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Buch ER (2010) A network centered on ventral premotor cortex exerts both facilitatory and inhibitory control over primary motor cortex during action reprogramming. in The Journal of neuroscience : the official journal of the Society for Neuroscience

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Buch ER (2011) Noninvasive associative plasticity induction in a corticocortical pathway of the human brain. in The Journal of neuroscience : the official journal of the Society for Neuroscience

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Gould IC (2012) Effects of decision variables and intraparietal stimulation on sensorimotor oscillatory activity in the human brain. in The Journal of neuroscience : the official journal of the Society for Neuroscience

 
Description MRC Programme Grant
Amount £2,500,000 (GBP)
Organisation Medical Research Council (MRC) 
Sector Academic/University
Country United Kingdom
Start 04/2011 
End 03/2016
 
Description Wellcome Trust Studentship
Amount £100,000 (GBP)
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2012 
End 09/2015
 
Description Wellcome Trust Stundentship
Amount £100,000 (GBP)
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2008 
End 09/2011
 
Title Delineations of cortical areas for use in MRI scanning experiments 
Description Delineations of cortical areas for use in MRI scanning experiments 
Type Of Material Data analysis technique 
Year Produced 2009 
Provided To Others? Yes  
Impact Tomassini V, Jbabdi S, Klein JC, Behrens TE, Pozzilli C, Matthews PM, Rushworth MF, Johansen-Berg H. Diffusion-weighted imaging tractography-based parcellation of the human lateral premotor cortex identifies dorsal and ventral subregions with anatomical and functional specializations. J Neurosci. 2007 Sep 9;27(38):10259-69. 
 
Description Biophysical mechanisms of goal-based decision-making 
Organisation University of Oxford
Department Oxford Centre for Functional MRI of the Brain (FMRIB)
Country United Kingdom 
Sector Academic/University 
PI Contribution Supervisor of Wellcome Research Career Development Fellow
Collaborator Contribution experimental collaborations and data analysis collaborations
Impact multi-disciplinary collaboration between neuroscientience and engineering approaches to decision making
Start Year 2009
 
Description Cortical and mesolimbic dopamine interactions during cost-benefit value calculation 
Organisation University of Oxford
Department Department of Experimental Psychology
Country United Kingdom 
Sector Academic/University 
PI Contribution Joint collaborative projects investigating brain mechanisms of decision making
Collaborator Contribution Research Collaborations
Impact Joint collaborative investigations of neural mechanisms of decision making
Start Year 2010
 
Description School visit (Oxford) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Type Of Presentation Workshop Facilitator
Geographic Reach Local
Primary Audience Schools
Results and Impact 30 children attended talks and participated in brain related workshops

children learned about brains
Year(s) Of Engagement Activity 2012
 
Description presentation at Science Oxford 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact presented research in neuroscience, on neural plasticity, in animal models to general audience

increased knowledge of neuroscience
Year(s) Of Engagement Activity 2011