Neural substrates of memory control are engaged when participants encounter unexpected mnemonic stimuli (e.g., a new word when told to expect an old word). The present fMRI study ( n = 18) employed the likelihood cueing recognition task to elucidate the role of functional connectivity (fcMRI) networks in supporting memory control processes engaged by these unexpected events. Conventional task-evoked BOLD analyses recovered a memory control network similar to that previously reported, comprising medial prefrontal, lateral prefrontal, and inferior parietal regions. These were split by their differential affiliation to distinct fcMRI networks (“conflict detection” and “confirmatory retrieval” networks). Subsequent ROI analyses clarified the functional significance of this connectivity differentiation, with “conflict” network-affiliated regions specifically sensitive to cue strength, but not to response confidence, and “retrieval” network-affiliated regions showing the opposite pattern. BOLD time course analyses corroborated the segregation of memory control regions into “early” conflict detection and “late” retrieval analysis, with both processes underlying the allocation of memory control. Response specificity and time course findings were generalized beyond task-recruited ROIs to clusters within the large-scale fcMRI networks, suggesting that this connectivity architecture could underlie efficient processing of distinct processes within cognitive tasks. The findings raise important parallels between prevailing theories of memory and cognitive control.

Context memory retrieval tasks often implicate the left ventrolateral pFC (LVPFC) during functional imaging. Although this region has been linked to controlled semantic processing of materials, it may also play a more general role in selecting among competing episodic representations during demanding retrieval tasks. Thus, the LVPFC response during context memory retrieval may reflect either semantic processing of memoranda or adjudication of interfering episodic memories evoked by memoranda. To distinguish between these hypotheses, we contrasted context and item memory retrieval tasks for meaningful and nonmeaningful memoranda using fMRI. Increased LVPFC activation during context compared with item memory only occurred for meaningful memory probes. In contrast, even demanding context retrieval for nonmeaningful materials failed to engage LVPFC. These data demonstrate that the activation previously seen during episodic tasks likely reflects semantic processing of the probes during episodic retrieval attempt, not the selection among competing elicited episodic representations. Posterior middle temporal gyrus and the body/head of the caudate demonstrated the same selective response as LVPFC, although resting state functional connectivity analyses suggested that these two regions likely shared separate functional relationships with the LVPFC.