Steady state topography

In applying the SST methodology audio visual material is presented simultaneously with a peripheral, spatially diffuse visual flicker and Fourier techniques are used to extract the amplitude and the phase of the SSVEP at the stimulus frequency. When the stimulus frequency is in the alpha frequency range (8 Hz – 13 Hz), the SSVEP can be recorded from the occipital region and also from other 'non-visual' regions such as the frontal and prefrontal cortex and the temporal and parietal cortex. Most SST studies use a visual stimulus in the upper alpha frequency range (10 Hz – 13 Hz) or gamma frequency range (30 Hz – 100 Hz) to elicit the SSVEP. Changes in the SSVEP amplitude and phase coinciding with a cognitive task or other material such as a television advertisement are then interpreted as changes in regional brain activity associated with the cognitive task. SSVEP amplitude changes are interpreted in a similar fashion to changes in upper alpha EEG amplitude while changes in SSVEP phase are expressed as changes in SSVEP latency. An SSVEP latency reduction is interpreted physiologically as increased synaptic excitation in the neural networks generating the SSVEP implying increased regional brain activity and vice versa. == Scientific and biomedical applications ==

The SST methodology has been used to examine normal brain function associated with visual vigilance, long-term memory, emotional processes, as well as disturbed brain functions such as schizophrenia and attention deficit hyperactivity disorder == Commercial applications ==

The SST methodology has been applied commercially in areas such as consumer neuroscience, neuromarketing, media and entertainment research. In this application area SST is used to measure second by second changes in brain activity associated with a wide range of communication media. By measuring brain activity at a number of scalp locations it is possible to estimate second by second changes in a number of relevant psychological parameters including, Long-term Memory Encoding, Engagement (sense of personal relevance), Motivational Valence (whether the material attracts or repels the viewer) as well as Emotional Intensity (arousal) and Visual Attention. Research indicates that a major SST indicator of advertising effectiveness is the level of long-term memory encoding of the key message or the brand in the advertisement. Twitter inc famously used SST technology to explore and test the power of the platform. ==References==