December 17, 2003

Habituation, continued

I started looking into EEG-measured habituation because of a comment that Pat had made on my thesis. I had quite casually written something about "waning interest and mental fatigue" limiting how long brain recordings can go for. Pat wanted a more scientific description, hopefully something about the brain's decay in terms of repeated stimuli. The correct term for this phenomenon is 'habituation'. As expected, there was a substantial body of literature on this topic.

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December 15, 2003

Infant Habituation

I want to know about habituation and EEG. Who did the first studies, what does it show? Basically habituation concerns the decay in EEG amplitude with repeated stimuli. What are the timescales involved? I'm just starting to make some headway. With adults there are many factors involved, for instance, we could start thinking about something else, or "try" to ignore the stimuli... for infants, it is a bit less obvious. Given this, here's an interesting quote from Regan [1] (the ABR is the Auditory Brainstem Response).

Compared with other EPs, the ABR is notably resistant to fatigue or habituation. The delivery of over 100,000 stimuli in 28 consecutive averages to a newborn infant produced no evident change in the response and in another study the ABR was not altered by 20 min of continuous stimulation.
Unfortunately, Regan gives only references for the two experiments, but nothing on habituation from the other EPs. Natus is a company that went big time doing ABRs on infants. Go Bill New!

References
[1] D. Regan, Human brain electrophysiology : evoked potentials and evoked magnetic fields in science and medicine, New York: Elsevier, 1989, p.266.

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