Open-ended and constrained modes of retrieval: Evaluating the PMAT framework across four recollection paradigms in a large-scale fMRI meta-analysis

Description: The Posterior Medial–Anterior Temporal (PMAT) framework proposes that episodic memory retrieval depends on interactions between systems specialized for contextual and item-related representations. However, its ability to account for differences among major forms of recollection remains unclear. The present fMRI meta-analysis examined four recollection paradigms: subjective, autobiographical, item–context, and item–item recollection. Particular emphasis was placed on the distinction between open-ended and constrained retrieval, conceptualized as a higher-level manifestation of PMAT-related functional principles. Activation Likelihood Estimation meta-analyses were conducted on 117 studies. PMAT-related involvement was quantified using a Distribution Index that measured the relative distribution of convergence across cortical networks and medial temporal lobe structures. Open-ended recollection (subjective and autobiographical) showed greater relative involvement of the posterior medial (PM) network and posterior hippocampus, whereas constrained recollection (item–context and item–item) showed greater involvement of the anterior temporal (AT) network and amygdala. Paradigm-level comparisons revealed a graded continuum of PM-to-AT engagement, spanning from subjective recollection through autobiographical and item–item recollection to item–context recollection. These findings extend the PMAT framework and suggest that open-ended versus constrained retrieval constitutes a meaningful organizational dimension of episodic memory.