A mechanistic model of mismatch negativity in the ageing brain

作者：Cooray Gerald^*; Garrido Marta I; Hyllienmark L; Brismar Tom

来源：Clinical Neurophysiology, 2014, 125(9): 1774-1782.

DOI：10.1016/j.clinph.2014.01.015

Objective: We investigated the neurophysiological mechanisms underpinning the generation of the mismatch negativity (MMN) in the ageing brain.
Methods: We used dynamic causal modelling (DCM) to study connectivity models for healthy young and old subjects. MMN was elicited with an auditory odd-ball paradigm in two groups of healthy subjects with mean age 74 (n = 30) and 26 (n = 26). DCM was implemented using up to five cortical nodes. We tested models with different hierarchical complexities.
Results: We showed that the network generating MMN consisted of 5 nodes that could modulate all intra- and inter-nodal connections. The inversion of this model showed that old subjects had increased input from rSTG to the rIFG (p < 0.01) together with increased inhibition of pyramidal cells (p < 0.05). Furthermore, there was reduced modulation of activity within rIFG (p < 0.02) on stimulus change.
Conclusion: The age related change in MMN is due to a decline in frontal-based control mechanisms, with alterations in connectivity between temporal and frontal regions together with a dysregulation of the excitatory-inhibitory balance in the rIFG.
Significance: This study provides for the first time a neurobiological explanation for the age related changes of the MMN in the ageing brain.

• 出版日期2014-9