EyeProprio

Daniela presented work from the lab at ECVP in Trieste. An abstract of her presentation is below.

Gaze and attention:
mechanisms underlying the therapeutic effect of

smooth pursuit eye
movement training in spatial neglect

Daniela Balslev and Alexandra
Mitchell

Left smooth pursuit eye movement training
(LSPT) in response to optokinetic stimulation has become a promising
rehabilitation method in spatial neglect. The mechanisms underlying the
therapeutic effect however, remain unknown. During LSPT, errors in visual
localization in the direction of the eye movement indicate changes in the gaze
direction estimate. Here we show that in healthy participants LSPT causes not
only a shift in the perceived direction of gaze, but also a corresponding
displacement in the allocation of attention. Both changes outlast the period of
optokinetic stimulation. This result refines theoretical models for spatial
attention by highlighting a tight coupling between attention and gaze.
Furthermore, it forms a first step for establishing a causal link between the
adaptation in the sensorimotor gaze signals and the recovery in spatial
neglect.

A PhD scholarship in Cognitive Neuroscience starting in September 2018 is available at the University of St Andrews. The student will use Transcranial Magnetic Stimulation (TMS) to investigate the role of oculosensory and oculomotor signals in spatial attention.

The project is at the interface between Psychology and Neuroscience and should be of interest to students not only in these disciplines, but also in computer science, physics, biology, engineering, maths, medicine and related areas. She or he will be supervised by me and Amelia Hunt and will join multidisciplinary teams interested in Vision Science at St Andrews and the nearby Aberdeen. Experience with TMS, eye tracking, psychophysics and Matlab programming would be an advantage, but not a requirement. The student will have the opportunity to learn these methods.

This PhD scholarship is funded via the BBSRC/EASTBIO scheme, so one of the eligibility criteria for the student is UK residency. Other funding for EU students is available from The School of Psychology and Neuroscience at St Andrews.

Application deadline for BBSRC/EASTBIO studentship: December 4th, 2017

You can read more detailed information about the project, the application procedure and the eligibility criteria here.

If interested, please get in touch, you can email me at daniela.balslev@st-andrews.ac.uk

Dr Dan Smith from the University of Durham will give a Seminar on Friday, November 11th at 3:30 pm in the Old Library of the School of Psychology and Neuroscience at St Andrews.

Associations
and dissociations between attention and oculomotor control

The systems used to control covert, mental
process such as spatial attention are closely linked with the systems used to
control eye-movements. However, the extent to which these cognitive
processes depend upon the oculomotor system remains
controversial. In this talk I will present data from behavioural and
neuropsychological experiments examining the interactions between motor
programming and covert attention. The results of these studies will be
interpreted in terms of a ‘Motor Bias’ theory of attention, which proposes that
activation in the oculomotor motor system feeds into the process of biased
competition in the visual system, but is not the sole arbiter of the locus of
spatial attention

It is very difficult to manipulate the rotation signals from the eye
muscles.
Two researchers from Japan, Higashiyama and Adachi, had a cool idea, they asked people to put their
heads upside down, so muscles have to work against gravity in an
unusual way. They show changes in depth perception in this condition, which underscores the importance of the sensorimotor signals to spatial cognition.

You can read their paper here and you can have a chuckle about the 2016 IgNobels here

In our lab we have been applying Transcranial Magnetic Stimulation (TMS) over the somatosensory cortex to manipulate oculoproprioception in a slightly more controlled way. No IgNobels so far…

On a serious note, it is great to see eye proprioception, a relatively “nerdy” topic, featuring in the main-stream media. Also nice to have a Plan B for the lab, just in case the TMS machine stops working 🙂

Well done to Dr Odoj for defending his thesis on July 1st!

The supervisor is very proud, and feels slightly guilty for the long-distance communication, between Copenhagen, Tuebingen and St Andrews.
Well deserved congratulations!

Thanks to the Committee members – Heiner Deubel, Kenneth Holmqvist and Mathias Gondan for their positive reviews and to the University of Copenhagen for hosting the defense.

Barthel’s PhD thesis can be downloaded here

Graduate students interested to join the lab, please get in touch with a CV and a brief paragraph that describes a possible research project. Funding information can be found here

Alex and Daniela are attending the EPS Workshop on Oculomotor Readiness and Covert Attention organized by Dan Smith at University of Durham.

It was Alex first poster session – WELL DONE ALEX!

Summary of Daniela’s talk

Oculoproprioception
–
an eye position signal selective for coding the locus of attention?

The most commonly observed neural
representations for visual attention encode location relative to the direction
of gaze. Without information about the rotation of one’s own eyes in the orbits
cars around us in traffic or food on our plate would appear to change location
with every eye movement. Furthermore, gaze information is necessary to align visual
locations with sound or touch to enable cross-modal interactions. Despite
the importance of the gaze information in the brain’s representations for
spatial attention, the sources of this gaze input to the attention maps have
remained unknown.

There are two main signals of eye rotation. The
copy of the command sent to the extraocular muscles (corollary discharge, CD)
is predictive, therefore faster. The reafference from these muscles
(oculoproprioception, OP) is slower, but more accurate. In my talk I will
argue that these signals are used flexibly, depending on behavioral
goals. Locating objects relative to the body, for instance to guide a
pointing movement, relies mainly on the fast signal, CD. In contrast, OP seems
to be more important for perception, i.e, allocating attention in the
body-centered space.

Role of oculoproprioception in coding the locus of attention.

Barthel Odoj and Daniela Balslev’s paper has just been accepted for publication in Journal of Cognitive Neuroscience. This means two things:
1. Barthel’s PhD thesis is now ready to be submitted (fingers crossed!).
2. We are closer to understanding how eye and attention are related. The paper shows that the feedback signals from the eye movements (oculoproprioception) is incorporated into attention maps to align retinotopic snapshots to the world. Repetitive transcranial magnetic stimulation over the somatosensory cortex perturbs this signal and cause a 1 degree error in the perceived angle of gaze. The same intervention diverts attention away by 1 degree away from a target, without affecting the ability to locate the target for reaching. Feedback signals from eye movement appear more important for perception, whereas action relies more on the predictive signals, presumably because of the neural processing speed constraints.