The consolidation and long-term memory persistence of newly formed memory traces have been demonstrated to benefit from several processes, particularly those that occur during sleep (Diekelmann and Born 2010). Furthermore, the modulation of neural oscillations during sleep has been shown to modulate subsequent memory performance (Cellini and Mednick, 2019, Barham et al., 2016), suggesting that it may be a mediating factor of sleep consolidation (Booth et al. 2022). Its impact on memory performance varies, depending on the stimulating frequency and individual characteristics (Booth et al. 2022). However, consolidation processes are not limited to sleep. Waking replay of previously encoded representations may improve subsequent memory for procedural learning (Buch et al. 2021), as well as episodic memory (Deuker et al., 2013, Staresina et al., 2013, Tambini and Davachi, 2019). Consequently, memory consolidation may similarly be impacted by changes in oscillatory brain activity during wakefulness.

Our previous research showed that engaging in EEG neurofeedback (NFB) to upregulate Theta/Beta power ratio immediately after learning enhances subsequent retention of motor sequence learning (Rozengurt et al. 2016), recall of studied pictures (Rozengurt et al. 2017), object-location memory (Shtoots et al. 2021), and episodic memory for details presented in a movie (Rozengurt et al. 2023). This was in contrast to memory performance in individuals who were trained to upregulate EEG Beta/Theta ratio power, and to those who did not undergo neurofeedback. Importantly, the observed positive effects of Theta/Beta power upregulation on memory performance persisted up to a week after intervention.

While this line of research showcases the beneficial effects of post-encoding Theta/Beta power augmentation by NFB on various types of memory, it remains to be determined whether this intervention can improve the consolidation of information required for the representation of real-life episodic memories. A prominent feature of episodic memory involves the spatial context in which the encoded event took place (Tulving, 1993, Burgess et al., 2002). Orienting and remembering the spatial layout of an environment relies on spatial navigation, a fundamental cognitive ability that allows organisms to acquire and retain a spatial representation of various settings (Epstein et al. 2017). The hippocampus has emerged as a crucial structure underlying spatial navigation, particularly in the formation and retrieval of “cognitive maps” that represent the geometric relationships between landmarks and goals (Epstein et al., 2017).

Spatial memory can be categorized into several distinct types, each supported by unique neural mechanisms. Egocentric spatial processing involves encoding locations relative to one’s own position, primarily engaging the parietal cortex (Burgess, 2006, Rolls, 2020). Allocentric spatial representations enable to store and retrieve spatial associations independent of the individual's position, and heavily relies on the hippocampus for creating ‘cognitive maps’ of the environment (Ekstrom et al., 2014, Ekstrom and Yonelinas, 2020). Route memory pertains to the ability to recall specific paths or sequences of movements, involving the hippocampus and prefrontal cortex (Epstein et al. 2017).

Static spatial memory, such as object-location memory, involves recalling the specific positions of objects within a stationary environment. This type of memory is mediated by medial temporal lobe structures, enabling individuals to remember where items are placed relative to one another (Ekstrom et al., 2014, Ekstrom and Yonelinas, 2020). In contrast, navigation memory encompasses the ability to travel through and explore routes within an environment, integrating information from various sensory inputs to form cognitive maps. This dynamic process involves not only the hippocampus but also the prefrontal cortex, which supports planning and decision-making during the process of navigation (Epstein et al. 2017), as well as parietal regions that contribute to spatial awareness (Burgess 2008).

Theta rhythms (4–8 Hz), which are particularly prominent in the hippocampus during navigation, have been linked to spatial learning and memory consolidation (Buzsáki 2002). Frontal midline theta oscillations were suggested to reflect the integration of cognitive control processes mediated by the frontal cortex, with memory processes facilitated by the hippocampus (Mitchell et al. 2008). A recent study showed that frontal-midline theta oscillations are critical in the early stages of navigation, particularly at intersections where navigational decisions are made (Du et al. 2023). We have recently demonstrated that upregulating Theta/Beta ratio power through neurofeedback (NFB) enhanced visuo-spatial memory for object location one week after initial acquisition, as reflected in reduced errors in location marking and faster reaction time for correct answers in individuals who were trained to increase theta/beta power (Shtoots et al. 2021). In that study, the task consisted of forming static spatial memory representations, which was gauged by instructing participants to recall the specific positions of objects within a stationary environment.

In the current study, we expanded the task into active navigation within a dynamic virtual spatial environment situated in a virtual Minecraft platform. We hypothesized that post-acquisition increases in Theta/Beta ratio oscillations recorded from the frontal lobe would benefit the persistence of spatial memory performance of specific object locations within the environment. We aimed at examining the effects of post-acquisition changes in Theta/Beta power ratio on both immediate and long-term spatial memory performance, providing insights into potential impacts on consolidation processes.

Participants were required to navigate within a Minecraft-based virtual environment. Minecraft is a sandbox video game that allows players to build, explore, and interact with virtual worlds. Its open-ended nature and immersive environment make it a valuable tool in scientific research, particularly in psychology, education, and cognitive science (Simon et al. 2022) The game's customizable environment enables controlled experiments to examine how players learn and remember spatial layouts, similar to real-world navigation studies (Clemenson et al., 2015, Clemenson and Stark, 2015). As in our previous studies (Shtoots et al., 2021, Rozengurt et al., 2016, 2017, 2023), participants completed a learning phase, followed immediately by an EEG-based NFB session targeting specific frequency bands or a passive control condition. Spatial memory navigation probes were administered immediately after, one day, and one week later to ascertain the long-term effects of Theta/Beta ratio changes in the early consolidation window that follows the creation of spatial memory. Our prediction was that participants who up-regulate their theta/beta power ratio will show superior spatial memory performance (e.g., shorter time needed to find target objects) than active and passive control groups both in immediate and long-term retention assessments.