The aim of this study was to apply frequency bands to explore how mental rotation strategies affect the identification of 2D figures. Eighteen adults were recruited for this study. In the ERP experiments, the participants were required to identify 2D figures with mental rotation. The results showed the differences between the high-achieving (HA) and low-achieving (LA) spatial ability participants in their use of mental rotation for identifying 2D figures. At 300-380 ms, the HA participants showed higher brain activity in the right hemisphere than in other brain areas, whereas the LA participants showed activity in the whole brain. At 520 to 620 ms, the areas of brain activity were in the opposite hemisphere for the HA and LA participants. The highest brain activity was shown in the left hemisphere of the HA participants and in the right hemisphere for the LA participants at 520 to 620 ms. The implication of this study is that right hemisphere specialization for mental rotation might appear in early cognitive processing, but in late cognitive processing, the left hemisphere specialization form of mental rotation might show an advantage.

Auditory phase-synchronization near 40Hz is reportedly related to sensory stimulation. This study applied the phase synchrony analysis and Bi-coherence analyses to analyze the electroencephalographic measurements. Four experimental stages were conducted with 34 healthy high school students to collect the data: (A) resting with eyes closed, (B) listening to the classical music, (C) resting with eyes closed, and (D) listening to popular music. The result shows that the whole brain phase-synchronization occurs at 40Hz and lasts about 400 ms, which is quite different from the estimated 40Hz phase-coupling lasting about 20–25 ms in previous studies and seems to play an important role in inducing auditory attention loss. Additionally, the result also shows that hypersynchronous states may affect perceptual processing. This study develops an original nonlinear time serial analytical approach and suggests that 40Hz phase-synchronization might be an important indicator in perceptual process.

Mental rotation is an important psychological process for identifying rotated or misoriented objects. In this study, ERPs were recorded while 18 participants responded to two types of two-dimensional (2D) pictures. The participants matched the pictures of a blank Task without using mental rotation, but used mental rotation to match the pictures of Task A. The ERPs data were analyzed using spatial complexity analysis. The results showed: a) the rotation-related negativity of the ERPs data was shown when mental rotation was performed; b) the EEG data showed a significantly greater synchronization in the fast frequency bands (> 20 Hz) when the participants used their mental rotation ability.

Recent changes in ongoing background activity are one of the most popular approaches to investigate brain activity for understanding child development. However, research using event-related responses of cortico-cortical connections to explore changes during childhood is rare. This study investigates mature changes in brain connectivity in associative reorganization patterns and hypothesizes that age-related changes affect oscillatory connections. The sample included children aged 7 years, 11 years, and adults. The 3 groups were studied in the time-frequency domain to analyze event-related cross phase coherence (ERPCOH) between different parts of the brain as they performed an auditory oddball task. Compared to the adult participants, the 11-year-old participants were found to have increased connectivity in theta (4-7 Hz), beta-2 (20-30 Hz), and gamma bands (30-50 Hz) in the early component (N1, 80-140 ms), although ERPCOH value decreased in the alpha-1 (7-10 Hz) and alpha-2 bands (10-13 Hz). Compared to the 11-year-old participants, 7-year-old participants had greater connectivity decreases in all frequency bands, most significantly in theta, beta-2, and gamma bands.

Brain dynamics is an important issue in understanding child development. However, very little research of the event-related responses has been used to explore changes during childhood. The aim of this study was to investigate mature changes in spatiotemporal organization of brain dynamics. We hypothesized that oscillatory event-related brain activity were affected by age-related changes. The sample include three age groups, namely 7 years (N = 18), 11 years (N = 18), and adults (N = 18). The event-related spectral power (ERPSP), and inter-trial phase locking (ITPL) of the event-related potentials (ERPs) were obtained from the time-frequency analysis of the auditory oddball task. Results revealed that: (a) decreased theta power, but alpha power increased with age; (b) the values of ITPL in the theta and alpha bands increased with age. These suggest that ERPSP, and ITPL provide useful indicators of cognitive maturation processes in children aged 7 and 11 years.