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Singing Mice and Brain Chemistry
Shirlockc writes "The Public Library of Science has a research article on how male mice actually sing in the presence of females. They actually posted some of the audios adjusted for human ears as these songs are ultrasonic. The authors are comparing these warbles to bird songs. The songs are quite complex so do the mice learn them and/or improve on them? This can be a potential model for investigating how brain chemistry works during learning."
This won't work on most systems, since most speakers for "general" use don't include ultrasonic frequencies.
Speakers available for use with computers tend to have a range between ~15Hz and ~24kHz. The article says the mice sing at a frequency between 30kHz and 110kHz. Thus, the original tracks wouldn't play on most people's speakers.
Use a pieso speaker. They can be found in digital wristwaches (ones make sound, the flat copper colored disk) or on newer motherboards as a plugin speaker (little short tube with two wires - black and red one end - and an opening with copperish disk on the other) They can be obtained from RadioShack usually housed in black plasic and are round and flat, ranging in size from small coin to palm size. Piezzo speakers are used in ultra sonic equipment, with some skill you can build an ultrasonic gun, and train the annoying neightboor dog to restrain it's barking habit (barking=piercing ringing in ear). Most humans cant hear ultrasonic, but will get annoyed when in same space with ultrasonic emission.
Partly true, although speakers' frequency response tends to be attenuated gradually, so that at one frequency, it's N decibels quieter than at a frequency an octave lower on the high end, etc. So, the speakers may be capable of producing 110 kHz, just at a reduced level like maybe tens of decibels quieter than the normal level the speakers can produce. Of course, it depends on the type of speaker. Many cheap computer speakers are full-range (not two-way or three-way) cone speakers with horrible high-end frequency response. They may not even reach to the edge of human hearing without significant attenuation.
However, of much more concern is something that's going to limit the frequency response in a very drastic way: the D/A converter in the sound card. The highest frequency a D/A converter produces (or at least that it produces in a way that's modulated by the audio data, but I digress...) is the nyquist frequency, which is half the sampling rate. So, if you have a sound card with a 48 kHz sampling rate on its D/A, which is very, very common, then the highest possible frequency you will get out of it is 24 kHz.
In order to produce a non-zero volume at 110 kHz, you will need a sound card with a sampling rate of 220 kHz, which is really quite uncommon. You can get cards with 192 kHz sampling rates now, so you should be able to hit up to 96 kHz, which is only 0.2 octaves away from 110 kHz, which is fairly close considering the entire range from 30 kHz to 110 kHz is almost 2 octaves, so you are only cutting out 1/10th of the range (the way the ears hear it). So, it should be possible to do it without super-expensive equipment, but it won't be possible on your average desktop PC.
Look at the URL. It was an April Fool's joke.
My roommate's yorkshire terriers are going nuts when I play it, and my St Bernard hasn't moved a muscle... It can't be something that they truly recognize, but they're running around my computer trying to find the source.
What the hell's a "gewie?"
My neighbour had one of those ultrasonic dog barking things, it would generate a piercing ringing in my ear whenever any dog in the vicinity barked (and it didn't change the dog's behaviour one iota),
I found that much more annoying than the barking.
Except that even the cards with the 192kSample/sec DACs won't reproduce much above 20 kHz. Remember, in a proper design you have to follow the DAC with a reconstruction filter as your signal will have spectral aliases every Fs. The idea of running a 192 kSample/second rate is to allow the reconstruction filter to gradually roll off from 20kHz to the Nyquist frequency of 96kHz, rather than the rather sharp roll-off from 20kHz to 22.05 kHz you see in 44.1kSample/sec gear. You also avoid the sin(x)/x roll-off in the reconstructed audio, as the roll-off in a 96kHz Nyquist frequency system is still pretty flat at 20kHz.
However, if you wanted to experiment with this, you could try to find an old (and I do mean old) Zenith remote control from the 1970's - they used ultrasound rather than IR as modern gear does, at about a 30kHz frequency. You could then drive that speaker from a DAC on the printer port, possibly with a simple timer chip to create the sample clock so that the computer "thinks" it is seeing a normal printer on the interface (that way you can avoid a great deal of the latency issues, especially if you use a printer port with a hardware FIFO.) You could eliminate the reconstruction filter as the transducer will do most of your filtering for you. Failing that, here are some transducers that will Git 'R Done.
www.eFax.com are spammers
I think you're misunderstanding how natural selection works if you assume that everything that developers (whether it's a physical feature or a character trait or something) has to have a direct advantage. It doesn't - it's also possible that it just developed as the secondary effect of some underlying cause.
Case in point: the genitals of female spotted hyenas. (Look it up if you want details - suffice to say that it's not possible to visually distinguish the two genders without quite literally grabbing the animal by the balls and checking whether they are present or not). IANAB (I Am Not A Biologist), but people have wondered what purpose they might serve for a long time, and some clumsy theories based on the greeting rituals of spotted hyenas were constructed, but it took everyone a while to realise that they're not actually serving any purpose.
Quite the opposite, actually; they complicate birth quite a lot, for example, but still, they developed. The real reason is that female spotted hyenas have an extremely high level of testosterone, and the peculiar genitals are just a side effect of that, one the disadvantages of which do not outweigh the advantages of the high testosterone level itself (so natural selection still favoured the high testosterone levels even though they had rather visible side effects).
I'm not saying that this is something that can be applied to in the case of mice singing for prospective sexual partners, of course, but I wanted to point out that the idea that every feature and behaviour must be directly explainable in terms of why natural selection and evolution would favour it can be misleading.
quidquid latine dictum sit altum videtur.
As someone who works in the lab that just released this paper (but who was not an author), it's interesting to read the discussion about whether this counts as "dumb research" that shouldn't be funded.
A little background: whether or not these mouse vocalizations count as "song" is in no way the primary focus of our lab. Our work actually focuses on using the pheromone-detection system of mice (aka the accessory olfactory system) as a (relatively) simple model system in which questions about pattern recognition and memory formation can be asked. The idea isn't that how mice recognize other mice and what they do next is intrinsically interesting, but rather that questions of how mammalian brains put together circuitry that can recognize and remember patterns in incoming sensory information is both intrinsically interesting and in the long run highly pertinent to many areas of medical research (ranging from exploring the causes of autism to developing treatments for Alzheimer's) - and that this system happens to be one of the most accessible systems in which these phenomenon can be studied.
This paper was actually a complete tangent to this primary focus, which came about when my boss and a coworker were trying to use these vocalizations as a behavioral indicator of whether a male mouse thinks it is or is not detecting the presence of a female (something that can help us understand the rest of our lab's data). As long as they were recording the vocalizations, however, they figured they might as well look at them a bit - and were startled to discover how complex they were. Thinking that this it was possible that knowing about this complexity could prove useful to other researchers who study stuff more related to this kind of thing (for example, the study of how birdsong develops is proving to be really fruitful right now - but if you could do this kind of work in an animal where genetic modification is becoming routine, the pace could be improved even more), they submitted a paper that contained primarily an analysis of the original point of the research but with an additional section analyzing the vocalizations. It was the journal itself that suggested that it made more sense to publish the analysis of the vocalizations as a separate paper.
We in the lab have all been rather taken aback by the press coverage of this story. Seeing as it was in many ways a tangent to the main purpose of the lab (and not actually a part of ANY grant, just to answer the implied question in a comment a bit further down), it's a bit startling to see it become a popular story. It's really somewhat frustrating to realize just how much a science story's media coverage is determined by the "cuteness" of the story - in this case, the popularity of the story seems to be due primarily to the fact that 1) all of the words involved are easy to understand (everyone knows what mice are, and knows what singing is...), 2) people like to hear about things that have to do with mating and/or relationships and/or pheromones, and 3) the mental picture of mice singing songs is cute.
Partly because of this, we've been wondering a bit what the impact of this coverage will be on the public's perception of the utility of science funding. I absolutely believe that funding of basic science is in the long run the best way to promote major advances with real utility - the discovery of DNA through an offshoot of what seemed to be obscure molecular work and its current centrality to the majority of medical research is one of the best examples - and I certainly wouldn't be working the hours I work for the pay I receive if I didn't believe in what I was doing. But even in the 4-5 years I've been at this institution the decrease in the availability of funds for basic research has been obvious, and I worry a lot about the extent to which this concept is communicated to the public & what failures in this realm will mean for future funding of basic research.
If anything, this recent experience of how the media covers science has made me