abstract Gerald Coorey

Gerald Coorey (Karolinska Institute, Sweden, and University College London, UK)

A mechanistic model of mismatch negativity in the ageing human brain

The mismatch negativity (MMN) is an electric or magnetic signal generated by the brain in response to novel events embedded in a stream of repeated stimuli. The MMN reflects the brain’s ability to perform automatic comparisons between consecutive stimuli and provides an electrophysiological index of sensory learning and perceptual accuracy. Using Dynamic Causal Modelling a mechanistic model of the MMN can be inferred from EEG/MEG data including the effective connectivity within the cortical network generating the signal. Several studies have shown changes in the MMN with age, though the neurobiological causes have not been fully described. We will present a mechanistic model of these changes using Dynamic Causal Modelling which suggest a decline in a frontal control mechanism together with changes in effective connectivity between temporal and frontal regions. We will further discuss the effect this might have on cognitive function and its assessment in the ageing brain.