The P300 refers to a positive EEG voltage deflection seen around 300 ms after the presentation of a novel stimulus. It can be recorded using stimuli of any sensory modality but most commonly in the auditory domain. The simplest paradigm used to elicit the P300 involves presenting repeated simple auditory tones of a given frequency every second or so. The P300 is generated when a tone of a different frequency is presented randomly at a rate of around 1 in 10 of the more common tones. It is observed by comparing the event-related potentials, time locked to the presentation of the tones, generated by the "frequent" versus the "rare" frequencies. It is seen most prominently over the parietal lobe. Unlike ► mismatch negativity, subjects need to be consciously attending to the stimuli. The presence, magnitude, topography, and time of this signal are often used as metrics of cognitive function in decision-making processes.

Anxiety and Depression 101

Anxiety and Depression 101

Everything you ever wanted to know about. We have been discussing depression and anxiety and how different information that is out on the market only seems to target one particular cure for these two common conditions that seem to walk hand in hand.

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