neurodudes

In the September Nature Neuroscience, we have a promising new technique: Millisecond-timescale, genetically targeted optical control of neural activity.

I think several people have suggested doing something like this before but no one has actually done it. What they’ve done is genetically modified (by lentivirus, for those curious) ordinary hippocampal neurons in culture, adding the same photo-electric transducing protein — rhodopsin – found in photoreceptors. Yup. You heard me right. They’ve expressed a cation-channel-gating rhodopsin in ordinary hippocampal neurons. With an standard fluorescence microscope (Xenon lamp + Chroma GFP cube), they can photostimulate single action potentials (and sub-threshold depolarizations) in single neurons.

Now here’s my idea for bioengineers to take this to the next level: Add a second photosensitive protein tied to an inhibitory channel. Ideally, we would want total separation between the stimulating wavelengths for the two different (excitatory, inhibitory) channels. Now, you have a system where all neurons can be directly excited or inhibited with different laser lines. In other words, a network of neurons where all voltages can be fully controlled. Sweet!

This seems like a great tool to add to the existing arsenal of photostimulation techniques (like photoelectric effect-based light-on-silicon stimulation that was pioneered by Goda lab.) Here’s a question: Is this the end of multi-electrode arrays? In slice, we already have single spike detection with Ca-sensitive dyes from Yuste’s lab. Now, we have optical single spike stimulation. Perhaps MEAs will be relegated to the domain implantable devices. Regardless, I’m proud to see several of the authors are from Stanford! Read on for the full abstract. (more…)

I [Eric Thomson] have started a new blog for discussion of Hille’s classic Ion Channels of Excitable Membranes:

http://neurochannels.blogspot.com

Participate, tell your friends, get the book.

[From Neville: Just a note for the guest posters. It's fine to promote neuroscience-related materials (well, nothing overtly commercial... unless it's *really* cool). Still, if you're making a guest post -- something which we encourage and have directions on how to do on the right sidebar of the screen -- please put your name in the post. If you feel so inclined, it also wouldn't hurt to put in a few sentences about where you're from and your relation to the field -- ie. grad student, postdoc, industry, prof, regular guy or girl interested in brain stuff, etc. Thanks!]