Of ear infections and tryptamines

[TheDEA.org]

A few months ago I apparently caught some sort of inner ear infection. Nothing serious, but it had the annoying effect of producing a low buzzing sound in one ear for about a week, probably due to irritation of the audio nerves.

Where it gets interesting is that whenever there was any sort of significant noise in the room (people talking, music, the TV) the noise completely disappeared. Any little noise at all in a higher frequency would completely cut it off like a switch; it wasn't simply a matter of not being able to hear it over the ambient noise. When the distracting noise stopped, the buzz returned instantly. Click on. Click off. Finally it occurred to me that the only realistic explanation of this was that my brain was filtering sound by frequency, suppressing some frequencies of sound on demand in order to better hear others. (That would also explain the seemingly curious ability to pick one voice out of a room.)

From an evolutionary standpoint, it makes sense; the ability to isolate a particular frequency range (such as that of the rustling of grass or the mating call of your own species) would have substantial survival value.

Now, I've also experienced the 'sound distortion' effect of 5-meo-DIPT, but was never able to come up with a satisfactory explanation for it. Viewed from the perspective of a parallel system with individual frequency ranges being inhibitable, the sound distortion makes a lot more sense: Drop out a bit of the upper range, make transmission marginal on the other frequencies, and you've got a bassy, warbling sound.

As far as why higher frequencies would be selectively affected, I'd guess it's a firing frequency problem; the nerves carrying lower frequencies would have to create and propagate fewer firing potentials, which could make them less vulnerable to interference.

Why hearing would be affected by this specific narrow group of drugs (DIPTs) but not most other tryptamines is another question entirely.

 

[Detrevni]

Maybe you have Tinnitus and tryptamines 'tuned you in' to the static noise that is heard in the midst of silence.

 

[TheDEA.org]

No. I haven't touched drugs in a long time, and the buzzing only lasted about a week. (Tinnitus is usually a higher-pitched sound too.)

 

[BilZ0r]

As far as why higher frequencies would be selectively affected, I'd guess it's a firing frequency problem; the nerves carrying lower frequencies would have to create and propagate fewer firing potentials, which could make them less vulnerable to interference.

Neurons carrying low and high pitched noises fire at the same frequency, that is to say, the frequency at which they fire represents volume, not frequency.

The classical neurophysiological explanation of the symptomes you describe is center-surround inhibition. Strong activation of sensory stimili inhibits things "around" it. In the case of vision, this is physical space (and gives rise to illusions like this). In peripheral sensation (of which hearing is most akin to) it is why rubbing a pain makes it go away, the activation of non-painful areas inhibits the physically close pain. In hearing, the effect is so that activation of a particular frequency makes it sound like there is less noise in the surrounding frequencies.

Why 5-methoxy is a particular auditory hallucinogen is an unusual mistery, but I suspect it's due to a non-5-HT2A mediated effect.