Updating p300 an integrative theory of p3a and p3b
The presence, magnitude, topography and timing of this signal are often used as metrics of cognitive function in decision making processes.While the neural substrates of this ERP component still remain hazy, the reproducibility and ubiquity of this signal makes it a common choice for psychological tests in both the clinic and laboratory.More specifically, the P300 is thought to reflect processes involved in stimulus evaluation or categorization.It is usually elicited using the oddball paradigm, in which low-probability target items are mixed with high-probability non-target (or "standard") items.Event-Related Potentials (ERP) are changes in brain activity detected using electroencephalographic (EEG) methods.One well-studied ERP is the P3b, which is generally elicited by asking participants to press a key when presented a target stimulus (e.g., “T”) that is intermixed with a much more commonly presented non-target stimulus (e.g., “S”).Some notable deviations in individual participants are discussed.
The signal is typically measured most strongly by the electrodes covering the parietal lobe.
Subgroup analysis showed that oddball paradigm elicited attenuated P3b amplitude in Pz electrode among ASD subjects.
This meta-analysis suggests ASD patients have abnormalities in P300 component, which may represent for deficits in cognition, attention orientation and working memory processing, particularly in the decision-making processing condition.
A total of 407 ASD patients and 457 TD controls from 32 studies were included in this analysis.
Reduced amplitude of P3b was found in ASD group (SMD = −0.505, 95 % CI −0.873, −0.138) compared with TD group, but no difference of P3b latency, P3a amplitude, or P3a latency was found between groups.
Search for updating p300 an integrative theory of p3a and p3b:
Chapman and Bragdon speculated that this differential response to the numbers, which came to be known as the P300 response, resulted from the fact that the numbers were meaningful to the participants, based on the task that they were asked to perform.