Re: The Auditory Continuity Illusion/Temporal Induction

[Israel Nelken <israel@xxxxxxxxxxxxx>]

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.
   Eli

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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
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