Monday, June 25, 2012

ISOT 2012, day 3

(For previous entries, see days one, and two.)

Lots of insect olfaction today, which is not my wheelhouse. Apparently some mosquitos are racist, and prefer to bite humans over guinea pigs, or vice versa. There were some interesting posters (e.g. ENaC knockout mice still retain some salt taste sensitivity), but it's I'm not sure how interesting brief poster summaries would be. Instead, two general points.

Zuker is well known for pushing the labelled line story from the periphery to insular cortex. In contrast every other taste researcher has found that the situation is more complicated: single cells can respond to multiple tastes on the tongue and in cortex; and some receptor knockouts can still respond to the tastes that should have been elided. So I've used this conference as an opportunity to see what other taste researchers think about Zuker's story. Their responses usually start with the phrase, "his data is beautiful but..." then give examples of results that can't fit the labeled line story. I haven't found another researcher who endorses Zuker's view, which is strange considering how high profile Zuker is. It is difficult to tell where clear-headed scientific thinking ends, and personal politics begins.

Second, while looking at posters,  I saw a number of people using channelrhodopsin by stimulating with long (>5 ms) pulses. This strikes me as incredibly imprecise, as you cannot know how the stimulated cell is firing, only that it is depolarized. Instead I'm a strong advocate of using pulsed stimulation at specific frequencies (up to 50 Hz!), so you can know exactly how the stimulated cells are firing. And to argue from authority, most high profile papers I can think of also used pulsed stimulation. People are certainly getting results with the long pulses, but I feel strange trying to interpret the results. I would be interested to know what other people who use ChR2 think.

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