Our research programme can
be divided into two principal areas: basic visual neuroscience
and clinical vision research. On this page we have summarized
some of the main topics within each of these two strands. In addition,
we have also included a brief description of some previous research
on colour vision in honeybees. This page
in currently under construction.
A. Basic visual
Colour is a fundamental aspect of our visual experience
and enables us to recognize objects fast and reliably.
Traditionally, colour research has focused on colour as
an isolated visual feature. However, it is now apparent
that chromatic information also facilitates a multitude
of other visual tasks and is available in many visual areas
in the cortex.
Our aim is to try and understand the functional organization
of cortical colour processes and their interactions with
other submodalities (e.g. form, depth and motion) and tasks.
The results of our research are directly applicable in
robotics e.g. for the development of artificial visual systems,
as well as for medical advances in visual prostheses.
We always perceive the colour of a ripe banana as being
yellow – in spite of the fact that the spectral distribution
of the light reflected from the banana into our eyes changes
under different illuminations (compare the two images, one
of which has more red illumination).
This phenomenon is called colour constancy. It results
from a series of neural processes which comprise all stages
of the visual pathways, and even includes cognitive influences.
Colour constancy is therefore an important phenomenon which
may help to unravel the cortical computations underlying
Colour in Motion
Colour and motion perception are generally believed to
be processed independently from one another, and for this
reason classical colour research has primarily used static
However, in real life many of the objects we see e.g.
people, animals and cars also move. The aim of our investigations
is to examine how colour and motion interact.
Click on the checkerboard to see how a moving grey square
appears to change to a pink colour when the background pattern
Colour in Action
The visual properties of objects, and the visual control
of a hand grasping them, are processed in separate pathways.
In this project we investigate how colour signals from
the perceptual pathway interact with signals from the motor
pathway when guiding hand movements. See also Dyslexia.
The relative number of long- (red) and middle- wavelength
(green) cones in the retina varies considerably from person
to person. We investigate how this influences visual performances
such as colour discrimination, colour constancy, and contrast
Vision at low light levels (below 0.01 cd/m2, i.e. moonlight)
is mediated by the highly sensitive rod photoreceptors and
their subsequent neuronal network. In contrast to the retinal
functions of rod vision, little is known about the cortical
processes underlying night vision.
B. Clinical vision research
Congenital stationary night blindness
CSNB is a relatively frequent form of inherited night
blindness. We are interested in the perceptual consequences
of this retinal disorder for night and day vision.
As the population in Europe gets older it becomes increasingly
important to understand the effects of ageing on vision.
As we age, the optical media in our eyes become less transparent
especially for shorter wavelengths (“yellowing”).
There is also a considerable loss of photoreceptors and
subsequent neurons, which potentially reduces the efficiency
and sensitivity of the visual system.
We are interested in how this affects visual perception
in the elderly and how the visual system may compensate
for age related changes by “hardware” adjustments.
Our investigations are primarily concerned with the effect
of ageing on contrast sensitivity, colour constancy and
Dylsexia is a term used to describe reduced ability in
reading and writing, in spite of normal intelligence and
sufficient teaching. It is one of the most frequent learning
disorders and affects 5-10% of the population. We investigate
possible deficits in the visual pathways and particular
their interaction with the motor system (sensorimotor integration).
C. Animal models
Colour Vision in Bees
The honeybee (Apis mellifera) has excellent colour
vision, ranging from UV through blue to green (but no red!).
As in humans, the bee's colour vision is trichromatic and
similar phenomena have been described as those observed
for human colour vision (simultaneous and successive colour
contrast, colour constancy, etc). The bee is, therefore,
an excellent animal model for understanding colour vision
on an evolutionary basis.