David Dupret – MRC Brain Network Dynamics Unit at the University of Oxford
Temporal dynamics of neuronal activity engaged in the expression of hippocampal representation of space
How does the brain support the emergence of internal representations of the external world and what are the mechanisms underlying the persistence of a limited subset of these representations? In this talk I will present a series of experiments that address these central questions of neuroscience by monitoring and manipulating neuronal representation of space in the mouse hippocampus. First, I will present recently published work that establishes how a spatial representation can be artificially modified to influence the behaviour associated with a drug-place memory. I will then describe ongoing experiments that demonstrate a central role of reverberating activity during sleep/rest behaviour in the consolidation of newly-acquired place representations. Finally, I will present preliminary data revealing a possible network mechanism underlying the translation of the neural representation of space in the hippocampal-accumbens axis into behavioural performance. Our findings highlight how short-timescale neuronal dynamics support the expression of internal representation of space and their translation into actions.
Christian Luescher – Department of Basic Neurosciences and Neuroscience Centre, Unversity of Geneva
The emergence of a circuit model for addiction
Addiction is a disease of altered behaviour. Addicts use drugs compulsively and will continue to do so despite negative consequences. Even after prolonged periods of abstinence, addicts are at risk of relapse, particularly when cues evoke memories that are associated with drug use. Rodent models mimic many of the core components of addiction, from the initial drug reinforcement to cue-associated relapse and continued drug intake despite negative consequences. Rodent models have also enabled unprecedented mechanistic insight into addiction, revealing plasticity of glutamatergic synaptic transmission evoked by the strong activation of mesolimbic dopamine—a defining feature of all addictive drugs—as a neural substrate for these drug-adaptive behaviours. Cell type–specific optogenetic manipulations have allowed both identification of the relevant circuits and design of protocols to reverse drug-evoked plasticity and to establish links of causality with drug-adaptive behaviours. The emergence of a circuit model for addiction will open the door for novel therapies, such as deep brain stimulation.