*Here we provide materials (in so far as copyright allows) and anonymised behavioural data as well as code and summary data files related to the following study:* **A naturalistic paradigm to investigate post-encoding neural activation patterns in relation to subsequent voluntary and intrusive recall of distressing events**. by Renée M. Visser, Richard N. Henson & Emily A. Holmes *For the raw imaging files, please see https://openneuro.org/datasets/ds003721* ---------- **STUDY INFORMATION** **Background** While neuroimaging has provided insights into the formation of episodic memories in relation to voluntary memory recall, less is known about neural mechanisms that cause memories to occur involuntarily, for example as intrusive memories of trauma. Here we investigated brain activity shortly after viewing distressing events as a function of whether memories for those events later intruded involuntarily. The post-encoding period is particularly important because it is a period when clinical interventions could be applied. **Methods** Thirty-two healthy volunteers underwent functional Magnetic Resonance Imaging (fMRI) while viewing distressing film clips, interspersed with five minutes of awake (post-encoding) rest. Voluntary memories of the films were assessed using free recall and verbal and visual recognition tests after a week, while intrusive (involuntary) memories were recorded in a diary throughout that week. **Results** When analysing fMRI responses related to watching the films, we replicated prior findings that those “hotspots” (salient moments within the films) that would later become intrusive elicited higher activation in parts of the brain’s salience network. Surprisingly, while the post-encoding persistence of multi-voxel correlation structures associated with entire film clips predicted subsequent voluntary recall, there was no evidence that they predicted subsequent intrusions. **Conclusions** These results replicate findings regarding the formation of intrusive memories during encoding, and extend findings regarding the consolidation of information in post-encoding rest in relation to voluntary memory. While we provided a first step using a naturalistic paradigm, further research is needed to elucidate the role of post-encoding neural processes in the development of intrusive memories. **Experimental design** The experiment, consisting of three sessions, combined the trauma film paradigm with fMRI scanning, and the completion of a diary to record the daily frequency of intrusive memories over a week. During session 1 six film clips previously shown to elicit a high number of intrusive memories were presented. Clips depicted scenes involving actual or threatened death or serious injury. Each clip was approximately one minute and followed by a 5-minute rest period. After the encoding phase, an additional 6-minute resting-state scan was acquired during which participants pressed a button if an image of the film popped into their minds. At the end of session 1 participants were given a pen-and-paper diary to record any intrusive memories of the films for the following week. Instructions were similar to previous studies (e.g., Lau-Zhu, Henson & Holmes, 2019), defining intrusive memories as mental images from the film clips (“pictures in your mind’s eye”) that occurred spontaneously, i.e., came to mind unbidden. Approximately 24 hrs after session 1 participants returned for session 2, and were shown brief written descriptions to help them retrieve 3 out of 6 film clips. Session 3 took place in a laboratory 7-8 days after session 1 and started with voluntary memory recall tests, i.e., (cued) free recall, and verbal and visual recognition, followed by an intrusion provocation task. In addition, several self-report measures were administered across the three days. **Please cite the following references if you use these data or materials:** Visser, R M, Henson, R N, & Holmes, E A, (in press). “A naturalistic paradigm to investigate post-encoding neural activation patterns in relation to subsequent voluntary and intrusive recall of distressing events. *Biological Psychiatry: Cognitive Neuroscience and Neuroimaging*” **Funding** RMV received support from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie agreement no. 705641 (SUAI/023/ RG92025) and the Netherlands Organisation for Scientific Research (NWO Veni 016.195.246). RNH is supported by UK Medical Research Council Programme (SUAG/046 G101400). EAH receives support from the Swedish Research Council (VR) 2017-00957, the Lupina Foundation, and the Oak Foundation (OCAY-18-442).