Testing network properties of episodic memory using non-invasive brain stimulation

Episodic memory depends on the hippocampus and its coordination with a distributed network of interconnected brain areas. Recent findings indicate that the function of this network can be altered using network-targeted transcranial magnetic stimulation (TMS). These stimulation experiments have identified increases in episodic memory and the network-wide coordination it requires. Network-target stimulation differs from the dominant framework for TMS experiments, in which stimulation is considered a focal virtual lesion. We offer a conceptual framework for important distinctions between network-wide and focal effects of stimulation on episodic memory and discuss factors that may influence the quality and quantity of stimulation effects. Findings from these experiments indicate that many properties of episodic memory can be effectively studied at the network level via noninvasive stimulation.