Aging neuromodulation impairs associative binding: a neurocomputational account

ABSTRACT—Relative to young adults, older adults are particularly impaired in episodic memory tasks requiring associative binding of separate components into compound episodes, such as tasks requiring item-context and item-item binding. This associative-binding deficit has been attributed to senescent changes in frontal-hippocampal circuitry but has not been formally linked to impaired neuromodulation involving this circuitry. Previous neuro-computational work showed that impaired neuromodula-tion could result in less distinct neurocognitive represen-tations. Here we extend this computational principle to simulate aging-related deficits in associative binding. As expected, networks with simulated deficiency in neuro-modulation resulted in less distinct internal representa-tions than did networks simulating the processing an