Imaging neurochemical and neural signalling with fiber photometry

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The ability to use information flexibly and execute appropriate adaptive behaviours in response to changing environmental conditions is essential for survival in all species, and our previous work has shown the brain chemical dopamine, particularly within the frontal lobes plays a crucial role in these processes. Disruptions in dopamine signaling within different brain regions including the frontal lobes and its subcortical connections impedes different forms of cognitive flexibility and other forms of cognition, including shifting between different behavioural strategies and decision making about different choices associated with different risks and rewards. The contribution of dopamine to these processes is thought to be mediated in part by brief, “phasic” increases and decreases in the activity of midbrain dopamine neurons that signal rewarded and non-rewarded events, and may be associated with similar changes in activity in neurons that receive these dopamine signals. However, how different behavioural events are encoded by brief changes in neurochemical and neural activity within the frontal lobes and interconnected regions remains to be clarified, as does their causal contribution to behavior. To address this issue directly, the present proposal is requesting specialized fiber photometry imagining equipment that will enable us to monitor changes in dopamine transmission and neural activity. Additional equipment is also requested to enable us to concurrently manipulate these signals in a temporally-precise manner with laser light. In essence, we hope that by monitoring changes in this activity under normal conditions and when activating/inhibiting dopamine neurons during specific behavioral events (e.g., initiation of actions, evaluation of their outcomes) we will ascertain precisely how these signals control behaviour on a second-to-second basis. The requested equipment is essential for us to employ this approach, enabling us to provide direct experimental data regarding the function of phasic neurochemical and neural signaling. This information will provide crucial insight into how a fundamental form of dopamine communication contributes to different aspects of reward-related learning and modification of learned behaviours in response to changes in reward contingencies.