Neural repetition suppression seems to be describing behavioral habituation on a neuronal level. What's the difference between these two terms?
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1$\begingroup$ Stating where you found these definitions would be helpful. $\endgroup$– Seanny123Feb 27, 2015 at 12:44
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$\begingroup$ Habituation: all through my undergrad. Repetition suppression: some guy who works in a neurosci. lab. $\endgroup$– RECURSIVE FARTSMar 1, 2015 at 5:36
1 Answer
The two concepts are analogous and mutually illustrative, but empirically refer to different levels of analysis: behavioral and neural.
Habituation
Habituation is a form of non-associative learning, specifically, learning that a stimulus is behaviorally unimportant. If I loudly and repeatedly bang on a metal pot immediately behind your head, you will probably be shocked, then uncomfortable, then annoyed, until you eventually learn to mostly ignore the unimportant sound. It is an effect detected in behavioral measures, rather than neural measures, and which, as any Google search will confirm, is well-established across many species. An example of the term's general usage from Wikipedia (which I hope is sufficient for illustration), noting the emphasis on the behavioral rather than neural scale:
The habituation process is a form of adaptive behavior (or neuroplasticity) that is classified as nonassociative learning. Nonassociative learning is a change in a response to a stimulus that does not involve associating the presented stimulus with another stimulus or event such as reward or punishment.
Repetition Suppression
Repetition suppression is a neural mechanism which attenuates (i.e., gradually decreases the intensity of) signals in the brain when a stimulus is detected repeatedly. Presenting the same visual stimulus repeatedly will therefore cause decreased response in some of the involved groups of visual neurons, which is also a useful effect in a number of behavioral research fields like memory and attention research. Two illustrative examples of the term's usage follow:
Memory
Furthermore, single-cell recordings show experience-based changes in perirhinal neuronal firing patterns broadly consistent with item recognition, wherein firing rates decrease in response to previously encountered relative to novel stimuli (Xiang and Brown, 1998). Such firing rate decreases, termed “repetition suppression” ...
Gonsalves, B. D., Kahn, I., Curran, T., Norman, K. A., & Wagner, A. D. (2005). Memory strength and repetition suppression: multimodal imaging of medial temporal cortical contributions to recognition. Neuron, 47(5), 751-761.
Face recognition
Repetition suppression, as manifested by the difference in response amplitude between the first and third repetitions of a target, was stronger for fearful than neutral faces.
Ishai, A., Pessoa, L., Bikle, P. C., & Ungerleider, L. G. (2004). Repetition suppression of faces is modulated by emotion. Proceedings of the National Academy of Sciences of the United States of America, 101(26), 9827-9832.
Clearly, habituation and repetition suppression share a lot of conceptual similarities, but it's important to remember that they are ultimately models of entirely different, if closely related physical phenomena which occur at completely different scales. Behavioral habituation relies to some extent on neural repetition suppression, but it does so through memory, attention and other cognitive systems. Repetition suppression alone is therefore not sufficient to explain behavioral habituation, or vice versa.
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1$\begingroup$ Interesting answer. Just out of interest to grasp your answer - is repetition suppression the same as neural adaptation? Neural adaptation is e.g. apparent when a sensory neuron is repeatedly stimulated - it will often decrease its spike rate or responsiveness to the stimulus. $\endgroup$– AliceD ♦Mar 22, 2015 at 12:10
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1$\begingroup$ @AliceD It is not. Neural adaptation is much, much more general, and can refer to almost any change over time. Repetition suppression is a more specific attenuating mechanism (attenuation refers to a loss in intensity over time, rather than any change over time). $\endgroup$ Mar 22, 2015 at 12:17
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1$\begingroup$ Definitely, it's very productive. I've clarified what I mean by attenuation in the answer. $\endgroup$ Mar 22, 2015 at 12:20
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1$\begingroup$ I voted up, but would in any case recommend adding references, especially to studies demonstrating the correlation between suppression and habituation. $\endgroup$– Arnon Weinberg ♦Mar 22, 2015 at 16:28
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1$\begingroup$ Perhaps I should have said "correlation, or lack thereof" - I would expect correlation where they overlap, and lack thereof where they don't. Anyways, great answer. :-) $\endgroup$– Arnon Weinberg ♦Mar 22, 2015 at 17:26