Development of behavioral parameters and ERPs in a novel-target visual detection paradigm in children, adolescents and young adults

Abstract

Background: The present study analyzes the development of ERPs related to the process of selecting targets based on their novelty.

Methods: One hundred and sixty-seven subjects from 6 to 26 years old were recorded with 30 electrodes during a visual target novelty paradigm.

Results: Behavioral results showed good performance in children that improved with age: a decrease in RTs and errors and an increase in the d' sensitivity parameter with age were obtained. In addition, the C response bias parameter evolved from a conservative to a neutral bias with age. Fronto-polar Selection Positivity (FSP) was statistically significant in all the age groups when standards and targets were compared. There was a statistically significant difference in the posterior Selection Negativity (SN) between the target and standard conditions in all age groups. The P3a component obtained was statistically significant in the emergent adult (18-21 years) and young adult (22-26 years) groups. The modulation of the P3b component by novel targets was statistically significant in all the age groups, but it decreased in amplitude with age. Peak latencies of the FSP and P3b components decreased with age.

Conclusions: The results reveal differences in the ERP indexes for the cognitive evaluation of the stimuli presented, depending on the age of the subjects. The ability of the target condition to induce the modulation of the studied components would depend on the posterior-anterior gradient of cortex maturation and on the gradient of maturation of the low to higher order association areas.

Fig. 1

An example of a trial of the Oddball task. Presentation of a sequence of cartoons where the bee was the frequent standard stimulus and other cartoons were the infrequent novel target stimuli. The subject had to respond to the novel stimuli. See the details in the text

Fig. 2

Inverse model regressions between the age expressed in days and the behavioral parameters: RTs (a), the standard deviations of RTs (b), the Coefficient of Variation (c), false alarms to standard stimuli (d); omissions to targets (e) anticipations to targets (f); total errors (g), d′ sensitivity parameter (h), and the response bias parameter (C) (i). Errors were expressed in percentage of errors for each error category

Fig. 3

ERPs for midline electrodes in the two studied conditions: target and standard. The amplitudes elicited by the target stimuli were higher than the amplitudes elicited by the standard stimuli in most components and age groups. In addition, the different morphologies of ERPs in the two conditions can be observed. The components P2f (P2 frontal), P2p (P2 posterior), P3a and P3b are indicated by arrows

Fig. 4

Difference waves obtained by subtracting the ERPs in the standard condition from the ERPs in the target condition. The differences between age groups seem to be due to different latencies rather than to different morphologies. The horizontal bars indicate the time windows used for statistical analysis. Two different time windows marked for a component indicate that for the statistics, the early window is used for the older subjects and late latencies for younger subjects (see details in the Methods and Results sections). eFSP early Frontal Selection Positivity, lFSP late Frontal Selection Positivity, SN Selection Negativity, t1_P3a early latency P3a, t2_P3a Late latency P3a, eP3b early P3b, lP3b late P3b, SW Slow Wave

Fig. 5

Topographies of the different components of the difference wave in different latencies for the different age groups. eFSP early Frontal Selection Positivity, lFSP late Frontal Selection Positivity, SN Selection Negativity, t1_P3a early latency P3a, t2_P3a Late latency P3a, eP3b early P3b, lP3b late P3b, SW Slow Wave

Fig. 6

Mean amplitude values of the ERPs in target and standard conditions at the latencies of the P2f, P2p, P3a, P3b and SW components (a, b, c, d and e, respectively). FSP and SN must be interpreted as the difference waves of the target minus standard conditions in (a) and (b). The represented amplitudes correspond to the average voltage amplitude in the selected electrodes for each component (see the Methods section). T Target, S Standard

Fig. 7

Inverse regression between the peak latency of the ERP components FSP (a) and P3b (b), with the age expressed in days

Fig. 8

Mean voltage of the peak-to-peak amplitude of the increase in the P3b modulation induced by the target condition. Note the higher P3b in the children’s group (group of 6–9 years) compared to the other age groups