Comments on: To discover the point of sleep, scientists breed flies that nod off on demand

By: skeptic

skeptic — Sat, 09 Jul 2011 16:09:02 +0000

The Donlea-Shaw paper’s explanation is not convincing. How do we know the authors are really looking at increased sleep? Do the flies recover quickly after the foreign channels are turned off? Do the flies stop moving for other reasons – e.g. are they in pain? How do we know that the neurons they say are responsible normally regulate sleep? Exactly what are the foreign channels doing to the neurons? They are not sodium channels as you say but calcium channels, and calcium does many things to cells. Do the effects of sustained excess calcium replicate the normal roles of these cells? Can the authors get the opposite effect – increased waking – by turning off the neurons in which they express the foreign channels?

By: Kandeda Trefil

Kandeda Trefil — Wed, 29 Jun 2011 19:14:47 +0000

My father, who suffered from severe bipolar disorder (He died of it at age 41, before the FDA approved lithium as a medicine.) was an ambitious, extremely hard-working farmer (On his own he amassed ownership of over 800 acres in 10 years). The bottom land he farmed had steep hills on the side and a creek that ran down the middle of most fields. In a manic phase he got about 2 hours of sleep per night…BED sleep, that is.

Riding behind him on the tractor I’ve observed his doing this:

Cultivating a straight row, he’d fall asleep almost immediately, but he’d wake up very shortly before he reached the creek, turn, and immediately fall asleep again. When he was within seconds of reaching the steep hill that signaled the row’s opposite end…BAM!…He was awake and he’d turn once more…again and again.

By: Tony

Tony — Tue, 28 Jun 2011 20:24:45 +0000

Hmm! Intersting!

Has anyone ever thought to further this study to possibly help those who suffer from Alzheimer’s? If you can tell one to sleep by manipulation in this manner, and sleep increases memory capabilities; is it possible to munipulate the brain to produce the effects of sleep without actually sleeping? Perhaps this would, if not defeat it, at least help fight the degratory effects of Alzheimer’s.

By: Leah Drake

Leah Drake — Mon, 27 Jun 2011 18:27:19 +0000

@Torbjörn Larsson, OM: “Nothing in the article supports a connection between timing of learning and sleeping and the amount of consolidated memories. That is you reading something into this that simply isn’t there.”

I agree I took more out of the article than the direct implications. Not the least of which I am using the flies’ results to make an inference about my own human life. I simply thought the possible connection was interesting.

Here is my reasoning:

This article suggests that a function of sleep is to trim away extra synapses. It seems logical to me that if you fire synapses to create short term memories right before this process, this would make them more enforced, more likely to survive the paring down and more likely to become long term memories.

The following quote from the blog post also shows a connection between timing of learning and sleeping and the amount of consolidated memories.

“Donlea also tested his flies with light bursts of courtship training. Normally, these only produce short-term memories, which fade after a few hours. *But if the flies had a nap after their training, they developed long-term memories* for the weird-smelling males that lasted for days. This supports the idea that sleep helps to consolidate memories.” (emphasis mine)

I can see a parallel between this test and my original non-scientifically-rigorous anecdote about studying in the evening before a good night’s rest.

By: vinoy

vinoy — Mon, 27 Jun 2011 01:25:25 +0000

This is a fascinating paper! Thanks for the great writeup and bringing attention to this paper.
One small point – I do believe that the TRPA1 channel that they used are part of the TRP family of ion channels that are thought to be calcium channels and not sodium channels (to the best of my knowledge).

By: Torbjörn Larsson, OM

Torbjörn Larsson, OM — Sun, 26 Jun 2011 23:15:02 +0000

Ah, finally a theory that seems to go somewhere! Those social vs solitary flies sleeping times are suggestive.

@ Leah Drake:

Nothing in the article supports a connection between timing of learning and sleeping and the amount of consolidated memories. That is you reading something into this that simply isn’t there.

[Or you read it out of the paper, in which case I would be interested of where exactly; it would indeed be neat.]

If anything, the article suggests naively that unless you adjust your sleeping time rereading can be a waste of time. =D

By: Ed Yong

Ed Yong — Sun, 26 Jun 2011 21:22:40 +0000

Thanks PP – I’ve amended the sentence accordingly.

By: Comrade PhysioProf

Comrade PhysioProf — Sun, 26 Jun 2011 19:11:48 +0000

Just a clarification: Donlea didn’t “tweak” the ion channels he used in his experiments. Both the temperature-insensitive and temperature-sensitive ion channel reagents were developed by other scientists in other labs, and have been used extensively in a wide variety of published work.

Donlea’s innovations in Paul Shaw’s lab are twofold:

(1) He used these well-established reagents to identify and control a population of neurons that–when activated–induce sleep.

(2) He exploited this new ability to acutely induce sleep to demonstrate that sleep allows a short-term memory that would otherwise have not have been to be consolidated into a long-term memory.

By: Leah Drake

Leah Drake — Sun, 26 Jun 2011 17:20:20 +0000

Hi Ed,

I love your blog! Thanks for writing!

This piece was very interesting, and reminded me of a childhood memory. My mother was a middle school math teacher (and now I’m a high school science teacher), and she gave me the following study advice: reread all of your study notes as the last thing you do before you go to bed at night, and it will help you remember in the morning. I found it extremely helpful for memorizing as well as making creative connections. This research you posted supports this advice.

I will continue to read your blog with interest!
Leah