**5. Conclusions**

In this study, we explored how varying degrees of both stimulus familiarity and mental imagery vividness ratings influenced verbal learning scores, as measured with an incidental recall task. Importantly, using relevant imaging research, we inferred dominant RSN activation patterns based on the reported strength of our neuropsychological variables at the time of stimulus presentation. We contrasted our results amongs<sup>t</sup> three theoretical frameworks, namely: Paivio's associative theories, Normans' non-monotonic plasticity theory, and the newly postulated RSN memory interference hypothesis. The findings supported the latter hypothesis given that noun cues with the highest probability of being recalled were associated with noun cues which had the least amount of predicted RSN competition during stimulus presentation. The outcomes of this study, although preliminary, support the idea that a critical component of successful and e fficient memory consolidation does not rely on the particular RSN present at the time of memory encoding (DMN or TPN), but rather it relies upon having minimal RSN activation variability between DMN and TPN at the time of memory encoding. This distinction could highlight relevant RSN biomarkers in the diagnosis of the mental health disorders a ffected by memory deficits. The RSN memory interference hypothesis could also help to illuminate our understanding of the broader neurophysiology of memory processes, complementing and expanding single-neuron neuroplasticity theories.

**Author Contributions:** Conceptualization, E.L. and A.D.; Data curation, E.L. and A.D.; Formal analysis, E.L.; Funding acquisition, A.D.; Investigation, E.L. and A.D.; Methodology, A.D.; Project administration, A.D.; Resources, E.L. and A.D.; Supervision, A.D.; Visualization, E.L.; Writing—original draft, E.L. and A.D.; Writing—review and editing, E.L. and A.D.

**Funding:** This research was partly funded by a gran<sup>t</sup> from the Social Sciences and Humanities Research Council of Canada to A.D.

**Acknowledgments:** We thank Andrew Faulkner for handling preliminary set up of the corpus of data and database. We thank the two anonymous reviewers for their comments and statistical suggestions which have improved the paper.

**Conflicts of Interest:** The authors report no conflict of interest regarding the publication of this paper.

**Appendix A**

**Figure A1.** Schematic depicting the three contrasting models of memory consolidation. Each model depicts its predicted memory consolidation scores in relation to the three possible combinations of variable strength at the time of encoding. The width of the arrows signifies the strength of the variables at encoding.
