How midbrain circuits integrate sensory information during target selection

Dr Florencia Iacaruso
Research Fellow 2016

Dr Florencia Iacaruso
University of Oxford

By recording neuronal activity in the superior colliculus while mice choose between visual and auditory cues previously associated with a reward, the project will identify fundamental principles of neural circuit organization underlying cognition and decision making and advance the knowledge about the neural basis for guiding attention in a multisensory world.

The brain has the ability to switch attention between the different senses. For example, even if traffic lights are seen turning green the decision to cross the road would not be made if an ambulance siren was heard. To take this decision, the brain has to integrate visual and auditory information with the perceived relevance of each stimulus based on previous associations, such as the potential warning signal represented by the sound of the siren. The aim of the project is to unravel the circuits within the brain that underlie this process, by focusing on the superior colliculus, a brain area important for combining information from different senses and for focusing attention toward the ones that matter.

First, by recording neuronal activity in the superior colliculus both during and after the animal has learned to localize a light or a sound to receive a reward, the project will be able to study how superior colliculus neurons represent information about the stimulus as it becomes behaviourally relevant. 

"to identify fundamental principles of neural circuit organization underlying cognition and decision-making"

Secondly, using a cutting edge approach for visualising the anatomy of the nerve cells, the research will be able to follow their connections to other brain areas, such as the substantia nigra pars compacta, lateral posterior nucleus and pontine reticular nucleus, known to be involved in planning movements, detecting salient events in the outside world and attending to the whereabouts of those events.  The research will study the signals that are carried by superior colliculus neurons that connect with each of these targets while the animal localizes the light or the sound and switches attention between the two sensory modalities to receive a reward.

By functionally dissecting the neural circuits involved in this sensory-guided behaviour, this project will help us understand how different sources of information are combined and redistributed within the brain to perform orienting behaviours. The work is expected to identify fundamental principles of neural circuit organization underlying cognition and decision-making and advance knowledge about the neural basis for guiding attention in a multisensory world, which is essential to understanding how this process becomes disrupted in attention deficit disorders.