#SfN13: Day 1

Today I had the treat of meeting Garrett Smith, a fellow North Carolinian, here from Davidson College in Davidson, NC (less than an hour from where I grew up! and where my sister-in-law currently works as an adjunct assistant biology professor). I planned on visiting his poster when I saw it dealt with medial septum (MS), a brain structure that I'm very interested in, and I was not disappointed.

Garrett was kind enough to guide me through his research: the MS provides excitatory cholinergic and inhibitory GABAergic inputs to the dentate gyrus (DG). In addition, a major input to the DG comes from the ipsilateral entorhinal cortex (EC) through the perforant path. There are also a small number of DG connections from the contralateral EC, but apparently not enough to cause depolarization to threshold in the DG (as measured by population spikes in the DG when the contralateral EC is stimulated).

All this changes when the ipsilateral EC is lesioned. Without the perforant path input, something signals the MS and the contralateral EC to form more synapses with the DG. The added input allows the contralateral EC, when stimulated, to provide inputs resulting in population spikes in the DG.

What Garrett's group found was that stimulating the MS shortly before stimulating the contralateral EC significantly increased the size of the population spike evoked from EC stimulation. This indicates that the MS could be involved in the recovery of learning and memory following an ipsilateral EC lesion in rodents by strengthening the contralateral EC input to the DG. What role exactly this plays in vivo is unknown, though it is compelling, as all these structures are involved in learning and memory.

The mechanism by which the MS achieves this potentiating effect is also unknown, but they plan on investigating it in future studies by studying how the DG responds to cholinergic and GABAergic inputs individually.

It was a good day, and I'm excited for tomorrow!

2013-11-09 23.12.46-1

Posted November 10th, 2013 in Career, Neuroscience, Science.