NICOTINIC MECHANISMS IN BRAIN MOTIVATIONAL SYSTEMS

There are numerous learning and memory processes that are key to life. One such process is motivational learning. This can be modelled in laboratory animals using the Conditioned Place Preference technique. This exploits a form of Pavlovian conditioning whereby an animal learns to associate a particular environment with a rewarding or aversive stimulus. Mammalian learning and memory processes are complex systems involving interplay between different neuronal populations, neurotransmitters and receptors. The mesocorticolimbic pathway (consisting of dopaminergic neurones projecting from the ventral tegmental area to the nucleus accumbens and prefrontal cortex) is heavily implicated in motivational behaviour. In turn, neurons in the ventral tegmental area receive input from the prefrontal cortex (releasing glutamate as the neurotransmitter), as well as input from the pedunculpontine nucleus (releasing acetylcholine as the neurotransmitter). Nicotinic acetylcholine receptors are a family of receptors that mediate some of the actions of acetylcholine, and it has been proposed that these receptors modulate receptor crosstalk in the ventral tegmental area, and thus play a key role in motivational behaviour, learning and memory. This project will take a trans-disciplinary approach, integrating in vivo behavioural learning paradigms and in vitro neurochemical techniques to elucidate the specific roles of nicotinic acetylcholine receptors in mediating or modulating motivational learning processes.