ABSTRACT
Age-related effects on novelty processing have been reported and are linked with changes in frontal lobe functioning. Auditory novelty processing and habituation of the novelty P3 event-related potential were investigated in younger and older adults. Novelty processing, as indexed by novelty P3 amplitude, was similar between the groups. We found the expected decrease in novelty P3 amplitude at frontal regions in younger adults with repetition of novel stimuli. In contrast, older adults displayed no evidence of habituation, rather an increase in novelty P3 amplitude at frontal sites was found when novel stimuli were repeated. We extend current understanding of novelty processing in normal aging by comparing this habituation related-hyperfrontality with intellectual functioning.
Subject(s)
Aging , Evoked Potentials, Auditory/physiology , Frontal Lobe/physiology , Habituation, Psychophysiologic/physiology , Acoustic Stimulation/methods , Adolescent , Adult , Aged , Brain Mapping , Electroencephalography/methods , Female , Humans , Male , Middle Aged , Psychoacoustics , Reaction Time/physiology , Young AdultABSTRACT
OBJECTIVE: The aim of this study was to describe the normative development of the electrophysiological response to auditory and visual novelty in children living in rural Kenya. METHODS: We examined event-related potentials (ERPs) elicited by novel auditory and visual stimuli in 178 normally-developing children aged 4-12 years (86 boys, mean 6.7 years, SD 1.8 years and 92 girls, mean 6.6 years, SD 1.5 years) who were living in rural Kenya. RESULTS: The latency of early components (auditory P1 and visual N170) decreased with age and their amplitudes also tended to decrease with age. The changes in longer-latency components (Auditory N2, P3a and visual Nc, P3a) were more modality-specific; the N2 amplitude to novel stimuli decreased with age and the auditory P3a increased in both latency and amplitude with age. The Nc amplitude decreased with age while visual P3a amplitude tended to increase, though not linearly. CONCLUSIONS: The changes in the timing and magnitude of early-latency ERPs likely reflect brain maturational processes. The age-related changes to auditory stimuli generally occurred later than those to visual stimuli suggesting that visual processing matures faster than auditory processing. SIGNIFICANCE: ERPs may be used to assess children's cognitive development in rural areas of Africa.
Subject(s)
Child Development/physiology , Evoked Potentials, Auditory/physiology , Evoked Potentials, Visual/physiology , Acoustic Stimulation/methods , Age Factors , Brain Mapping , Child , Child, Preschool , Electroencephalography/methods , Female , Humans , Kenya/ethnology , Male , Photic Stimulation/methods , Reaction Time/physiologyABSTRACT
The behavioral inhibition system [Gray, J. A. The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system. Oxford: Oxford University Press, 1982] proposes that anxiety is associated with the processing of novel stimuli. We aimed to explore this relationship by recording auditory event-related potentials associated with unexpected novel noises in typically developing children. Children aged 10-14 years with low (n = 12) and high (n = 11) self-report trait anxiety were assessed using a novelty oddball task. The N1 associated with novel stimuli, specifically the "N1c" component maximal at temporal lobe sites, was of significantly longer latency (p = .014) and greater amplitude (p = .004) in the high compared with the low anxious group. This group difference was supported by linear correlations between N1c amplitude and trait anxiety scores. There was no effect of anxiety on the later novelty P3. These data suggest a subtle moderating role of trait anxiety on brain response to novelty, and further research with clinically anxious children is indicated.