Mr Ned Buckley BSc

By employing EEG we can pinpoint an event related potential known as the 'sustained posterior negativity' (SPN). The SPN is a 300-1000ms period of negative microvolt amplitude produced in the posterior region of the brain. An SPN at the scalp indicates the completion of perceptual organisation by the visual cortex (Bertamini et al., 2018). The SPN is a robust effect that is seemingly generated unconsciously and automatically. The effect is generated even when symmetry is not task relevant but is enhanced by active regularity discrimination (Makin et al., 2020).

Makin et al. (2024) found the SPN was robust to task manipulations, and work completed for publication found the Extrastriate symmetry network can cope with tight stimulus presentation deadlines.

See the complete Liverpool SPN catalogue on open science framework for more info

Pilot behavioural research suggests the brain can discriminate regularity above chance in durations of 16.67ms in a backward masking paradigm (which attempts to isolate feedforward processing from recurrent processing). Work completed for publication suggests the predictability of the symmetry axis has no impact on feedforward processing.