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Re: The Auditory Continuity Illusion/Temporal Induction

Dear all,
There's some electrophysiological work in animals that has bearing on the issue of continuity. Mitch Sutter has strong evidence that the illusion is operative in macaques, and he has some accompanying electrophysiology (that has not been published yet to the best of my knowledge) showing correlates of induction in primary auditory cortex. We (Las et al. J. Neurosci. 2005) published data related to the coding of a pure tone in fluctuating masker. Although our main emphasis was on comodulation masking release, the results can be interpreted in terms of continuity. In short, the responses of neurons in A1 of cats to the interrupted noise were very strong and locked to the noise envelope. Adding a low-level tone close to the BF of the neurons suppressed the envelope locking, resulting in responses that were similar to those evoked by tones in silence. Thus, these neurons seem to reflect the perceived continuity of the tone, ignoring the noise. We have further demonstrated that neurons with these responses are present in the auditory thalamus but not in the inferior colliculus. All of this would suggest that activity that reflects the continuity of the tone is already present in thalamus/primary auditory cortex (although anesthetized cats are certainly not awake humans). We don't know however whether this activity is generated there or whether we see a reflection of processing at higher brain areas.

Israel Nelken
Dept. of Neurobiology The Alexander Silberman Institute of Life Sciences
Edmond Safra Campus, Givat Ram | Tel: Int-972-2-6584229
Hebrew University | Fax: Int-972-2-6586077 Jerusalem 91904, ISRAEL | Email: israel@xxxxxxxxxxxxx