Control of Attention by the Motor System: A Motor Bias Theory of Attention

Lead Research Organisation: Durham University
Department Name: Psychology

Abstract

Humans must process an overwhelming amount of visual information with limited cognitive resources. Spatial attention allows us to select the relevant information. A metaphor for attention is that of a spotlight; only things within the 'beam' of attention are processed. A widely held view is that control of the spotlight is implemented by the motor system. If we wish to attend to something, we plan (but don't necessarily execute) an action that would orient the eyes or hands to that thing. This 'Premotor' theory of attention has been very influential, but does not explain the full range of empirical data. This project will test a new Motor Bias theory of attention which offers a new explanation of the relationship between motor control and attention. Specifically, it is argued that movement preparation influences attention in a stochastic fashion, such that attention is more likely to be allocated to movement goals when (a) the same goal is being selected by more than one effector system, (b) the movement is close to being initiated and (c) the organism is confident that the movement will reliably acquire the desired target. The project aims to precisely characterise the interaction between attention and the motor system by testing these principles. Understanding the psychology of attention will also inform the development of novel rehabilitation techniques for patients with neuropsychological deficits of attention.

Planned Impact

There are a number of ways in which we plan to disseminate our findings to different groups. To engage with the broad range of scientists and practitioners interested in attention and the motor system we plan to host a research workshop at the end of the project during which we will set out our MBTA. This workshop will include a specific session dedicated to engaging school pupils and undergraduates with our research. We will also develop a webpage to report on our progress, and provide regular updates on our research via social media (e.g. twitter.com/AttentionLab). These updates will be written to be accessible to the general public, and will not require any specialist knowledge. To engage with the broader public the results of our project will be described as part of the PIs and the post-doc's normal public engagement activities (i.e. talks and open days aimed at schoolchildren and events such as café scientifique). The research will also be publicised through mainstream media outlets by the Durham University media relations team. We will engage with the academic community by publishing the results of our project in leading scientific journals and by presenting our results at scientific meetings (e.g. meetings of learned societies such as the Experimental Psychology Society) and international scientific conferences (European Conference on Visual Perception, Society for Neuroscience, Vision Science Society).

Publications

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Smith DT (2021) Cognitive and motor processes in visuospatial attention: An interactionist perspective. in Cortex; a journal devoted to the study of the nervous system and behavior

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Casteau S (2020) Covert attention beyond the range of eye-movements: Evidence for a dissociation between exogenous and endogenous orienting. in Cortex; a journal devoted to the study of the nervous system and behavior

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Smith DT (2019) The effect of offset cues on saccade programming and covert attention. in Quarterly journal of experimental psychology (2006)

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Casteau S (2021) The presence of placeholders modulates the naso-temporal asymmetry in the remote distractor effect. in Cortex; a journal devoted to the study of the nervous system and behavior

 
Description The human field of vision is very broad. We can see things that are up to 120 degree into the periphery. Our first experiments have shown that covert attention (the ability to pay attention to things without looking at them) can only be allocated to locations up ~40 degrees into the periphery. This is as far as the eye can move without needing a combined eye-head movement. This result shows that covert attention is limited by the range of eye-movements, not the range of the visual system. However, there are two types of 'covert attention'. Exogenous attention is engaged when something salient captures attention (e.g. a flashing blue light when driving), whereas endogenous attention is engaged when we choose to pay attention to something (e.g. a student covertly monitoring thier phone while sitting in a lecture). This difference is important, because our next experiments showed that only exogenous attention was limited by the range of eye-movements. In our next series of experiments we explored how quickly participants could shift attention to the periphery in response to a peripheral cue. Here we found an unexpected result. The widely held view is that attention gradually builds up at the cued location over the course of ~100 milliseconds. However, we found that participants moved attention to the peripheral cue almost instantly, with no gradual build up of attention. Our subsequent experiments showed that the widely held 'gradual accumulation' view was an artefact of the experimental design of earlier studies (they did not measure performance at uncued location), and reflected the effect of arousal, rather than attention per se. This finding challenges the canonical view of the mechanisms of attentional orienting and offers new insight into the cognitive mechanisms of attention. A third set of experiments explored how interfering with the planning of movements affected attention. In these studies we used a neural stimulation technique called Transcranial Magnetic Stimulation (TMS) to disrupt brain regions known to be involved in the programming of movements. We found that TMS over FEF interfered with shift of attention caused by the planning of eye-movements, but not the shifts of attention caused by planning arm movements. We concluded that different effector systems have their own pool of attention resource, which is consistent with our Motor Bias Theory of Attention. A final package of experiments explored the relationship between working memory and attention. In these studies we ask what happens when a person must look at one location while remembering a different location. The Premotor Theory predicts that attention should be allocated only to the goal of the eye-movement, whereas Motor Bias Theory predicts that attention will be split between the saccade goal and the remembered location. We observed the latter, consistent with our Motor Bias Theory. Thanks to the grant we were also able to examine attention and short-term memory in a group of patients with a disease called Progressive Supranuclear Palsy who have problems making eye-movements. We applied the theoretical knowledge developed from the lab-based experiments to devise two new tests designed to help help differentiate PSP from other motor disorders such as Parkinson's disease. The results of our pilot study were very promising, as consistent with Motor Bias Theory, the patients with PSP had significant impairments of attention and STM compared to Parkinson's disease. This discovery has led to a larger project, funded by the Dunhill Medical Trust, designed to develop these tests in a larger sample of patients.
Exploitation Route These results are helping us and our collaborators develop a new theoretical model of attention we call "Motor Bias Theory". We have applied these findings to understanding and developing new therapies for neuropsychological disorders such as Neglect, Hemianopia and Progressive Supranuclear Palsy. Specifically, the findings also led to a grant from the Dunhill Medical Trust to apply the principles of Motor Bias Theory to understanding attention and memory problems in patients with neurodegenerative disorders affecting the motor system, such as PSP and Parkinson's disease. The relationship between working memory and motor control is being further investigated by a PhD student at Durham University under the supervision of Prof Dan Smith, who is funded via the ESRC NINEDTP.
Sectors Healthcare

URL http://motorbiasproject.com/
 
Description We have applied the theoretical insights gained from our lab-based experiments to better understand attention and memory is neurodegenerative diseases that affect the motor system. We first showed that Progressive Supranuclear Palsy was associated with much more severe impairments of attention and memory than Parkinson's disease at the group level (see Smith, Casteau & Archibald 2021), then won a grant from the DMT extend this research to explore whether our tests could be used to effectively categorize patients as having PSP or PD. This work was used by the PSP Association as part of their communications with people with PSP, and Prof Smith has written several articles for the PSP Association magazine to help communicate this research to patients. Prof Smith has also discussed these findings with clinicians with expertise in motor disorders at NHS events
First Year Of Impact 2019
Sector Healthcare
 
Description Research Project Grant
Amount £148,494 (GBP)
Funding ID RPGF1906\153 
Organisation The Dunhill Medical Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 05/2020 
End 05/2023
 
Description Small Grant Scheme
Amount £3,500 (GBP)
Organisation Experimental Psychology Society (EPS) 
Sector Charity/Non Profit
Country United Kingdom
Start 12/2020 
End 12/2022
 
Description Progressive Supranuclear Palsy Project 
Organisation South Tees Hospitals NHS Foundation Trust
Department Department of Cellular Pathology
Country United Kingdom 
Sector Hospitals 
PI Contribution I applied some of the ideas developed during this award to begin developing a new test for a disease called Progressive Supranuclear Palsy. This collaboration was also strongly influenced by my previous ESRC grant
Collaborator Contribution Dr Neil Archibald has helped recruit patients with PSP and acts as the local NHS investigator
Impact We have published a paper and a book chapter outlining some preliminary results
Start Year 2017
 
Description Article for PSP Association news letter 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Patients, carers and/or patient groups
Results and Impact I wrote an article about how the motor system interacts with cognitive processes such as attention and memory, and how we plan to use this knowledge to better understand a disease called Progressive Supranuclear Palsy (PSP). After the article was published i had emails from several people with PSP who were interested in knowing more about the research and how we planned to develop new projects with applied goals of helping people with PSP
Year(s) Of Engagement Activity 2019
URL https://pspassociation.org.uk/information-and-support/just-been-diagnosed/psp-matters/