Decision making under stressful conditions, is present throughout our daily life with somewhat higher incidence for
certain professionals. Good decisions, taken under stressful situations, are crucial for emergency-service personnel, air
traffic controllers, stock-market brokers, etc. These professional groups are required to process large amounts of
information, sometimes incomplete, in a relatively short time interval. Decisions have to be taken and the value of
information and future actions have to be updated, by comparing previous and current situations, under acute or
prolonged stress with significant impact on the prevention of injury and death, material damage or control of financial
costs.
The Orbitofrontal cortex has been repeatedly implicated decision-making both in primates and rats, particularly in
updating and utilizing the information value of environmental stimuli. Numerous studies suggest that OFC is involved,
amongst others, in estimating the reward value following multimodal integration of stimulus parameters (such as taste
and smell), mediating effects of secondary reinforces and in processes associated with devaluation and reversal learning.
Orbitofrontal cortex integrates information from multiple brain areas (sensory cortex, amygdala, hypothalamus,
perihippocampal regions) and interacts in working memory space with neighbouring Prefrontal cortex regions to produce
an appropriate behavioural response. Orbitofrontal cortex relies heavily on long term and working memory and
extensively connects with the hippocampal memory system.
The aim of this project it to assess how the main stress hormone in rodents, corticosterone (analogous to cortisol in
humans), affects behavioural and correlative electrophysiological responses in rats performing a spatial decision making
task.
Steering wheel maze room with geometric cues for
spatial
orientation during task performance
Port preference indicates risky,
safe or indifferent behavior
Rats are trained and tested on a hexagonal maze, with six symmetric reward ports, situated in a test room with highcontrast, extra-maze visual cues. Each port can be associated with a different type of outcome (e.g. safe or risky reward), and during training rats are expected to develop a preference for a particular reward condition
Rats develop a clear preference for low-risk reward ports during training on a probabilistic task
Electrophysiological recordings will be done with a Neuralynx Data Acquisition System. Neuronal ensemble activity will be used to study the effect of corticosterone on the electrophysiological correlates of decision making and memory encoding.
This page was last updated on 27 october 2011