Some of the causes in children for Dark circles under eyes in children may include: 1  Lack of sleep. 2  Nasal congestion. 3  Black eye due to trauma.  Frequent eye 1  rubbing. Hayfever.  Inherited 1  trait. Dehydration. 2  Allergies. 3  Eczema. Phenol sulfotransferase deficiency.
From From P300 Development across the Lifespan: A Systematic Review and Meta-Analysis. The latency and amplitude of the P300 response may vary as a function of age. The P300 (P3) wave is an event related potential (ERP) component elicited in the process of decision making.pplications in brain-computer interfacing (BCI) have also been proposed. The P300 has a number of desirable qualities that aid in implementation of such systems. First, the waveform is consistently detectable and is elicited in response to precise stimuli.
Similarly our heart and our brain have wave patterns. The wave pattern of the heart is measured by ECG (electro cardiograph). The brain waves are measured by EEG (electro encephalograph). Using the brain wave studies, scientists have discovered that our brain waves are of four types. The brain waves also have peaks that are similar to the peaks we see in water waves.