WII-3

Cognition and higher vestibular disorders

Principal Investigator:

Paul Taylor

 

Objectives:

This group has three inter-related aims: firstly, to characterise neurological disorders, particularly those involving cognitive-vestibular interactions; secondly, to investigate the neural basis of perception, action and awareness; and thirdly, to develop methods used in cognitive and clinical neuroscience e.g. TMS.

 

Current project descriptions:

I.) Attention and Action

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“Attentional” processes are responsible for selecting out what we perceive, become aware of, and act towards. To study the neural basis of attention, in most of our studies to date we stimulated different brain areas using Transcranial Magnetic Stimulation (TMS) while normal human participants performed various psychophysical tasks, which require paying attention to some visual stimuli and ignoring others. TMS has the key methodological strengths of being able to dissociate causal roles of different brain areas, and explore the timing at which these areas are critical. Evidence on causation and timing can then inform cognitive neuroscientific theories. For example, a couple of our recent papers have explored the function of a part of the posterior parietal lobe (the right angular gyrus). This brain area is important for performing tasks that intuitively seem purely perceptual, such as looking for a conspicuous red visual target amongst grey distractors, and yet from using TMS over this region it could be shown that its critical function – what it is really necessary for – is not only perceptual in nature, but also related to remembering what has just happened and then acting on it (e.g. Bocca et al. 2015, Taylor et al. 2011), supporting a sensorimotor view of this area’s function.

 

II.) Perception and awareness

Our brain seems not only able to select out stimuli and control our actions but also – perhaps relatedly – to generate the elusive subjective feeling of conscious awareness. One way that researchers have investigated this is by showing participants visual stimuli, under careful situations where the visual stimulus stays the same, but what participants perceive changes – for example presenting a visual flash so faint that people only report seeing it about half the time. By comparing what goes on in the brain when people do versus do not report seeing this stimulus, it is hoped to further our understanding about how it is that a percept reaches reported conscious awareness. We have explored the neural basis of this effect by using a special phenomenon called a “phosphene” as the stimulus. Phosphenes in this context refer to the visual flashes people report seeing when TMS is applied to parts of the brain. This research has characterised how it is that when a stimulus is seen, compared to unseen, it captures our attention more strongly (Rangelov et al. 2015), and is processed differently in the brain (Taylor et al. 2010).

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III.) Combined brain stimulation and recording methods

 The burgeoning method of combined TMS-EEG allows us to record neural activity in the brain immediately after it is stimulated. We can see a very different spread of activation across the brain according to what brain area was stimulated and what task people are performing. These differences can then inform cognitive neuroscientific and psychological ideas of the functional connectivity underlying interactions between perception, attention, action and awareness (Taylor and Thut, 2012).

 

IV.) Neural mechanisms underlying cognitive and higher vestibular disorders.

In April 2015 this group moved to the German Center for Vertigo and Balance Disorders at the Klinikum Grosshadern, the university hospital of LMU Munich. Our current work extends the above projects, studying the neural mechanisms underlying cognitive and higher vestibular disorders.

 

Methods:  

  • Multimodal Imaging (MCM-I)
  • Computational modeling (MCM-M)
  • Eye tracking (MCM-T)

 

Relevant publications:

Bocca, F., Töllner, T., Müller, H.J., Taylor, P.C. (in press). The right angular gyrus combines perceptual and response-related expectancies in visual search: TMS-EEG evidence. Brain Stimulation.

Rangelov, D., Müller, H.J., Taylor, P.C. (2015). Occipital TMS at phosphene detection threshold captures attention automatically. Neuroimage, 109, 199-205.

Soutschek, A.,  Taylor, P.C., Müller, H.J., Schubert, T. (2013). Dissociable Mechanisms Control Conflict during Perception and Response Selection: a Transcranial Magnetic Stimulation study. Journal of Neuroscience, 33(13):5647-5654

Taylor, P.C., Thut, G. (2012). Brain activity underlying visual perception and attention as inferred from TMS-EEG: a review. Brain Stimulation, 5(2), 124-9.

Taylor, P.C., Muggleton, N.G., Kalla, R., Walsh,V., Eimer,M. (2011). TMS of the right angular gyrus modulates priming of pop-out in visual search: combined TMS-ERP evidence. Journal of Neurophysiology, 106(6), 3001-9.

Taylor, P.C., Walsh,V., Eimer,M. (2010). The neural signature of phosphene perception. Human Brain Mapping, 31(9), 1408-1417.

 

 

Team:

 

Contact:

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Paul C.J. Taylor

Professor of cognitive and higher vestibular disorders
German Center for Vertigo and Balance Disorders, Klinikum Grosshadern, LMU Munich

Marchionistr. 15

81377 München

Germany

Email: paul.taylor@med.uni-muenchen.de

Tel: + 49 (0) 89 4400 76984