Emily Mackevicius (Aronov Lab)
Probing how the hippocampus forms one-shot memories using memory savant birds

The hippocampus is critical for forming instantaneous (one-shot) memories.  What happens in the hippocampus at moments of memory storage and recall?  We have developed a radically new strategy to address this question – recording the hippocampus of memory savant birds, the food-caching tufted titmouse. Titmice prolifically hide excess food items in scattered locations, then return later to retrieve food using memory.  We have recorded, using calcium imaging, large populations of neurons from the titmouse hippocampus during bouts of food caching and retrieving.  I will present preliminary analysis of these data, including evidence for transient memory-related activity in the hippocampus, and reactivation of cache-related activity patterns preceding moments of food retrieval.



Justin O'Hare (Losonczy & Polleux Lab) 
Role of the ER calcium store in hippocampal synaptic plasticity and learning

Dendritic calcium is critical in determining how neurons respond and adapt to patterns of incoming excitation. The endoplasmic reticulum (ER), which pervades the dendritic arbor, sequesters high concentrations of calcium which it can release into the cytosol in response to strong synaptic activation. This feedforward release mechanism has been suggested to shape and drive calcium-dependent plasticity mechanisms underlying learning. Using place fields in hippocampal CA1 pyramidal neurons as a model system, combined with an acute genetic approach to ablate an endogenous mitochondrial buffering mechanism that normally mitigates the spread of intracellular calcium release, we directly test how this process shapes synaptic plasticity as evidenced by spatial tuning in apical and basal dendrites of single isolated pyramidal neurons during spatial navigation.