Duke University | Howard Hughes Undergraduate Program

I guess I’m a little overdue for a blog update. A little overdue on certain assigned blog topics, too. But we’ll ignore that second part for now…

Anyways, on Friday, experiment finally worked. For the past few weeks, we’d been struggling to get dye loading to work well in our slices (problems with dye solubility and slice health). Friday everything came together and the results (though only proof of experimental design concept; not yet useful in addressing the question of the nature of cortical circuits) were beautiful. Watching neurons light up after stimulation was like watching an incredible fireworks show. Better really, considering that all the flashing was coming from the complex activity of networks of living cells. Incredible. I’ll try to post a few images from the experiment later. Can’t wait to get back to work tomorrow!

HF
 

Another blog. Blogging was definitely not part of my expectations for research this summer, but oh well.

I can’t say that I have any concrete expectations for my summer research. Concrete expectations after all are almost always confounded by unexpected circumstances, especially in research, in which unexpected results and challenges seem to be the norm. In general, I hope that I can reasonably expect this summer to make some small but substantiated contribution to my lab and to the field (with considerable emphasis on small); this, I think, is the general purpose of any research, even research conducted during the course of a (painfully short) summer internship. Any contribution I could make to my lab is of course much smaller than the great benefits I not only expect, but already know, I’ll get from the internship in education and introduction to new techniques. Already the program has introduced me to a whole new world of systems neuroscience (before the internship I was almost exclusively interested in the molecular and genetic areas of the field) and a number of really cool techniques (two-photon microscopy is awesome).

HF
 

This blog will probably be somewhat less impressive than those of my colleagues, both because I don’t have a camera and won’t be able to post any photos, and because I hope that I’ll be too busy with research to put very much into it. And because I have a bit of a personal aversion to blogs and blogging. But that’s a topic for discussion for another time… In person, in the real, physical world. Maybe over lunch or something.

But at any rate:  Apart from this blogging, I’m really excited to be a part of the Howard Hughes program, and even more excited about my project for the summer. I’ll be working under David Fitzpatrick in the neurobiology department, doing research on the functional microarchitecture of visual cortex.

Visual cortex in most mammals is known to have very specific organization (columns of neurons that respond selectively to orientation, position, direction of movement, etc. arranged orderly across cortex… for more information check out work by Hubel and Weisel, or maybe take Psy 91). Still, the patterns of organization of individual neurons, the fundamental circuitry underlying visual processing, remains largely unknown.

In order to help address this, I’ll be working on bulk loading of calcium sensitive dyes and two-photon microscopy in living cortical tissue slices. In (very, very) brief: Bulk loading of calcium sensitive dyes is a technique for staining large populations of neurons and can be used to observe neural response properties (calcium ion flow is a central property of activity in neurons). Two-photon microscopy is a somewhat new technique that can be used to image live tissue at high resolution and to a depth of about 300 micrometers (standard one-photon fluorescence confocal microcopy can’t do any of this). Together, bulk loading and two-photon microscopy should allow us to trace the activity of neurons in visual cortex in response to stimulation of input neurons, and so allow us to map in the neural circuits underlying vision in extremely fine (single cell) detail.

So far, I’ve been reading as much background literature as I can on the topic to get myself up to speed, and looking for successful published methods of live in vitro bulk loading. Wednesday I shadowed someone who was doing bulk loading for a different lab. Friday, with much help from Sharon and Julie (infinitely helpful fellow lab members—thanks guys!), I worked on building and setting up a system for tissue slice incubation and staining (a lot of cutting, gluing, and digging through drawers full of random hardware—actually a lot of fun). I’ll start the actual wet work in the next few days. Can’t wait!

I guess I’ll be keeping you (whoever you are) updated as the project progresses.

HF