Abstract
Aging is associated with cognitive decline and alterations in early perceptual processes. Studies in the auditory and visual sensory modalities have shown that the mismatch negativity [or the mismatch response (MMR)], an event-related potential (ERP) elicited by a deviant stimulus in a background of homogenous events, diminishes with aging and cognitive decline. However, the effects of aging on the somatosensory MMR (sMMR) are not known. In the current study, we recorded ERPs to electrical pulses to different fingers of the left hand in a passive oddball experiment in young (22–36 years) and elderly (66–95 years) adults engaged in a visual task. The MMR was found to deviants as compared to standards at two latency ranges: 180–220 ms and 250–290 ms post-stimulus onset. At 180–220 ms, within the young, the MMR was found at medial electrode sites, whereas aged did not show any amplitude difference between the stimulus types at the same latency range. At 250–290 ms, the MMR was evident with attenuated amplitude and narrowed scalp distribution among aged (Fz) compared to young (fronto-centrally and lateral parietal sites). Hence, the results reveal that the somatosensory change detection mechanism is altered in aging. The sMMR can be used as a reliable measure of age-related changes in sensory-cognitive functions.
Highlights
It is suggested that the brain can rapidly and effortlessly learn the regularities in the stimulus environment and predict what should happen in the future (Wacongne et al, 2012)
The somatosensory MMR (sMMR) was positive in polarity and elicited at two latency ranges in young: centro-parietally at 180–220 and fronto-centrally at 250–290 ms after the stimulus www.frontiersin.org
Shinozaki et al (1998) found a central positive deflection to middle or index finger deviants at 100–200 ms post-stimulus, compatible to the early sMMR found in the present study
Summary
It is suggested that the brain can rapidly and effortlessly learn the regularities in the stimulus environment and predict what should happen in the future (Wacongne et al, 2012). The brain is capable to detect sudden changes in the perceptual environment even without attentive resources. The change detection and predictive coding of the environmental events is gradually declined (Ruzzoli et al, 2012; see Winkler and Czigler, 2012). The mismatch negativity (MMN) is a component of ERPs that occurs when the brain detects a change in a background of homogenous events (Näätänen, 1992). Its elicitation reflects predictive coding of the stimulus environment (Garrido et al, 2009; Wacongne et al, 2012). The MMN has been originally discovered in the auditory modality (Näätänen et al, 1978), but there is extensive evidence of the existence of its visual analog (for reviews see Kimura, 2012; Winkler and Czigler, 2012)
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