In this longitudinal study, all components of the CNV significantly decreased and the habituation of the iCNV increased during the observed 8 years. These results correspond with our previous cross-sectional study which demonstrated a pronounced reduction in the iCNV amplitude and an increase in iCNV habituation with age in healthy subjects in late adolescence and early adulthood [
17]. Indeed, healthy pre-school and primary school children are characterized by significantly larger iCNV amplitudes and more pronounced loss of the iCNV habituation than healthy adults [
13,
17]. These developmental CNV features of children were interpreted in terms of the influence of cerebral maturation on processes of cortical excitability and information processing in healthy individuals [
8,
13,
17,
22,
23]. Note that the longitudinal study demonstrated all CNV components undergoing changes and reduction over 8 years. It seems likely that the overall voltage of cortical negativity over the vertex decreases with time. Since all components are influenced by maturation, the results are difficult to interpret in terms of the functional significance of each particular component. It may be misleading to say that the reduction of iCNV and the increase in its habituation with time may reflect the maturation of orienting reactions and early motor preparation as part of response anticipation [
5,
6,
13,
36], reduction of the lCNV may be attributed to the maturation of advanced motor preparation and sensory attention [
7,
8], and the reduction of PINV may represent the maturation of movement and contingency evaluation [
37,
38]. It is more likely that developmental changes influenced unspecific mechanisms which underly all components, such as mechanisms which regulate cortical excitability [
4]. Taking into account the recent work of Bender et al. [
23], it may be suggested that the reduction of the CNV voltage over Cz with increasing age may be due to developmental changes in modulatory circuits of the brainstem, i.e. due to reduced influences of the unspecific ascending reticular formation on the excitability in the cortico-striato-thalamo-cortical loop [
3,
39]. Alternatively, our results may be explained by increasing influence of prefrontal cortex on thalamo-cortical circuitry, since the control function of the prefrontal cortex matures into late adolescence/early adulthood [
40]. Finally, the described neurophysiological changes may be related to an unspecific decrease of overall cortical excitability with age. Different studies have shown that the amplitudes of negative evoked potentials decrease and positive potentials increase with increasing age [
41,
42]. Event-related potential negativity is interpreted as a representation of cortical excitability, facilitating the processing of sensory input, while positivity is a manifestation of neuronal inhibition [
3,
4]. Therefore, sensory maturation results in the predominance of inhibitory over facilitatory processing seen in reduction of all negative components of evoked potentials, including the CNV. Our data cannot pinpoint which particular mechanism underlies CNV changes with increasing age. One possible way to answer this question is the analysis of age-related changes in CNV topography [
8,
23,
43]. However, the data from 1998 were obtained only from Cz, so investigation of topography is not possible in this study.