Measuring brain activity during visual object recognition

Investigations of the human visual system are carried out at the Laboratory of
Experimental Ophthalmology in Groningen. Visual information processing and the
underlying neural mechanisms are studied by employing psychophysics and *brain
imaging* (functional MRI (fMRI)) techniques. This field of research is relevant
because it contributes to the understanding of how humans are able to perceive
the environment, how the brain works, and how human behavior arises.

The specific goal of this research is to achieve a better understanding of
visual object recognition. Object recognition is an important part of visual
perception. There is a still controversy around the manner in which object
information is processed in the brain and there are currently several
contradicting theories. Our research will lead to new insights about how
sensory input from the eye is processed in the brain, grouped, and recognised
as objects. This can be used to test the existing theories, and develop new
ones if necessary.

The techniques developed and the results of this research will contribute to
the understanding of disturbed perception, for instance caused by eye disease,
cerebral haemorrhage, neurological disorders or neurodegenerative diseases.
Another example is apperceptive agnosia; people with this condition are not
able to link individual parts of a visual stimulus together as a whole, which
cause problems with recognition in a lot of situations. Our results and methods
may also be applied in order to develop more efficient training- and
revalidation methods.

Participants are presented with visual stimuli during fMRI experiments, focused
on the measurement of brain activity, and they are requested to make a decision
about what they have perceived. Eye-movements are recorded during the
recognition task. Additionally, recordings of brain activity in the absence of
a task (resting state measurements) are carried out.

There are no risks involved in this research. Participants will be exposed to a
magnetic field of 3 Tesla and rapidly switching magnetic gradients and radio
frequency fields. This strength of field is standard for fMRI and MRI research.
At this moment, there have not been any reported side effects. In rare cases,
stimulation of a peripheral nerve (abdomen) can take place due to the switching
magnetic gradients. This can cause a tickling sensation, which is harmless.