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Re: Pitch perception shift caused by carbamazepine / delay shift
Thanks for Martin’s comment on the question of Pitch perception shift caused by carbamazepine.
Martin pointed out that as to yawning, the pitch shift may be related to the overall sound attenuation, as people easily confuse loudness shift and pitch shift.
In the literature on carbamazepine-induced pitch perception shift, however, I have not found any description of loudness shift. As carbamazepine-induced pitch perception shift were reported by some musicians with absolute pitch, I think they can distinguish pitch shift from sound attenuation.
Carbamazepine-induced pitch perception shift appears real. But this effect is not easily explained by current pitch models. A model of pitch perception is presented involving an array of delay lines and inhibitory gating neurons. It is my feeling that carbamazepine may affect the behavior of "delay neurons".
For example, if a neuron delays the input for 1 ms and carbamazepine makes it delay the input for 1.01 ms. Then, a complex tone with f0=990 Hz would be perceived as f0=1000 Hz.
If a neuron delays the input for 1 ms and carbamazepine makes it delay the input for 0.99 ms. Then, a complex tone with f0=1010 Hz would be perceived as f0=1000 Hz.
This hypothesis is partially supported by the carbamazepine-activating effect on the peripheral auditory system. See
Wakamoto H, Kume A, & Nakano N. Elevated pitch perception owing to carbamazepine-activating effect on the peripheral auditory system: auditory brainstem response study. J Child Neurol. 2004 Jun;19(6):453-5.
My hypothesis predicts carbamazepine-activating effect on the binaural processing that relays on time difference. However, this hypothesis awaits physiological evidence.
Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
> ----- Original Message -----
> From: "chen-gia tsai" <tsai.cc@LYCOS.COM>
> To: <AUDITORY@LISTS.MCGILL.CA>
> Sent: Monday, November 01, 2004 7:49 AM
> Subject: Pitch perception shift caused by carbamazepine
> > Dear list,
> > It has been reported that pitch perception shift can be caused by
> carbamazepine. I wonder if this phenomenon favors "place" models or
> "temporal" models of pitch. Another question is: is this relevant to pitch
> perception shift during yawning?
> > Thank you very much.
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