Using Imagination to Understand the Neural Basis of Episodic Memory

“…2005), episodic future thinking (Atance and O’Neill, 2001; Addis et al., 2007; Schacter and Addis, 2007; Szpunar et al., 2007), the default mode (Raichle et al., 2001) and daydreaming (Mason et al., 2007), leading to suggestions that it performs a general function (Buckner and Carroll, 2007;…”

“…theory of mind (Kumaran and Maguire, 2005; Amodio and Frith, 2006) and episodic future thinking (Addis et al., 2007) suggesting that the amPFC and PCC might be supporting pro- cesses related to the self (Conway and Pleydell-Pearce, 2000) and mental time travel (Wheeler et al., 1997; Tulving, 2002).”

“…a purely created imagined experience does not have the same reliance or effect on the imaginer’s self-schema compared with a real episodic memory (Conway and Pleydell-Pearce, 2000; Gallagher, 2000) although both likely involve the adoption of an egocentric viewpoint (Burgess, 2006) on the part…”

“…bears a striking resemblance to networks found to support self-reflection (Johnson et al., 2002), theory of mind (Kumaran and Maguire, 2005; Amodio and Frith, 2006) and episodic future thinking (Addis et al., 2007) suggesting that the amPFC and PCC might be supporting pro- cesses related…”

“Moreover, by using rich imaginary memories as a well matched comparison task we were able to isolate processes specific to episodic memory, such as the use of self-schema (Conway and Pleydell-Pearce, 2000; Gallagher, 2000), a sense of familiarity and mental time travel (Tulving, 2002).”

“, 2001), and perhaps even daydreaming (Mason et al., 2007).”

“…network (also replicated in this study with the RM RO contrast) has also been activated in a variety of other circumstances including navigation (Burgess et al., 2002; Hartley et al., 2003; Spiers and Maguire, 2006), spatial tasks (Maguire et al., 2003; Kumaran and Maguire, 2005), episodic…”

“…a key component of episodic memory recall lends additional support to constructive theories of episodic memory (Bartlett, 1932; Schacter et al., 1998) and the recently proposed constructive episodic simulation function of the episodic memory system (Schacter and Addis, 2007; Schacter et al., 2007).”

“…visual scene images (Montaldi et al., 2006; Takashima et al., 2006; Elman et al., 2013; van Assche et al., 2016), learning navigational routes (Burgess et al., 2001; Bray et al., 2015), and even imagining past events or future events in familiar places (Hassabis et al., 2007; Szpunar et al., 2009).”

“In line with previous results [30], we found that the DMN regions generally showed more activity during IntEnc than Ext-Enc conditions.”

“…imagining fictitious and future events, and navigating in large-scale space share a set of brain regions in common that has come to be known as a 'core' network (Addis, Wong, & Schacter, 2007; Hassabis, Kumaran, & Maguire, 2007; Spiers & Maguire, 2006; Szpunar, Watson, & McDermott, 2007).”

“…Christoff et al., 2004; Stark and Squire, 2001) and has been associated with memory retrieval (Squire et al., 2004), future thinking (Addis et al., 2009), andmental simulation (Hassabis et al., 2007), which form a large portion of spontaneous thought content (Klinger, 2009; Klinger and Cox, 1987).”

“Keywords: default mode network, evolution, gesture, hippocampus, language, mental time travel, mind wandering, Pleistocene”

“…underlies an internal mode of cognition (Buckner et al., 2008) mediating various internally-oriented processes , including remembering the past (Hassabis et al., 2007a), envisioning the future (Szpunar et al., 2007), and thinking about another person's perspective (Saxe and Kanwisher, 2003).”

“It may be that varying consistent with studies examining visualization, construction, and identification of complex visual scenes and spatial information (Burgess et al., 2001; Addis et al., 2007; Epstein and Higgins, 2007; Hassabis et al., 2007).”

“For example, Hassabis et al. (2007) contrasted recollection of autobiographical experiences and of previously imagined, fictional experiences.”

“The hypothesis of a ‘scene’ as the basic cognitive mechanism underlying the human ability to remember the past and to envision the future was supported by their subsequent fMRI study ( Hassabis, Kumaran, & Maguire, 2007b ).”

“A distributed network of regions are also involved in scene construction, including the hippocampus, parahippocampal gyrus, retrosplenial and posterior parietal cortices, middle temporal cortices, and medial prefrontal cortex (Hassabis et al., 2007).”

“Neuroimaging and neuropsychological research has revealed a core network involved in imagining events, whether past or future, real or fictitious (Okuda et al., 2003; Addis et al., 2007; Hassabis et al., 2007a,b).”

“While one could not use strictly autobiographical information to help complete this task, one could do so by constructing imaginary scenes or scenarios, an activity that recent research has shown also depends on the hippocampus and related structures (Hassabis et al., 2007; Schacter et al., 2007).”

“, 2012), and recruitment of this region also contributes to the ability to construct a complex and realistic scene of the personal past (Hassabis et al., 2007; Summerfield et al., 2009).”

“…in the current article does not account for detailed aspects of experiential simulation (such as mental imagery) that may be invoked in conceptual tasks (e.g. Louwerse and Hutchinson 2012), episodic memory (e.g. Hassabis et al. 2007), inferences and theory-of-mind (Hagoort and Indefrey 2014).”

“Posterior cingulate cortices were also preferentially activated by non-living sound-sources, which are regions previously reported to be associated with various aspects of visual imagery, visual spatial context, and memory (Vogt et al., 1992; Hassabis et al., 2007).”

“…integration of relevant semantic, contextual and sensory components, stored in their modality specific cortical areas (Wheeler, Petersen, & Buckner, 2000), the product of which has a coherent spatial context (Hassabis, Kumaran, Vann, et al., 2007), and can then later be manipulated and visualised.”

“…retrieve context-relevant information during scene construction tasks (Bertossi et al., 2016a) – which involve cues that are relatively unconstrained (Hassabis et al., 2007a) – while being also unable to suppress context-irrelevant information while confabulating (Turner et al., 2008), suggests…”

“…including self-reference (Kelley et al., 2002; Northoff et al., 2006), episodic memory retrieval (Buckner et al., 2008b), envisioning the future (Szpunar et al., 2007), mental imaginary (Hassabis et al., 2007; Daselaar et al., 2010), and mentalizing (Gusnard et al., 2001; Amodio and Frith, 2006).”

“…regions within the medial temporal lobe and medial prefrontal cortex exhibit greater activity during autobiographical memory retrieval than during recognition memory (Conway et al., 1999; Nyberg et al., 2002; Cabeza et al., 2004; Hassabis et al., 2007; Summerfield et al., 2009; Elman et al., 2013).”

“, 2009) and imagining future and fictitious events (Addis et al., 2007; Hassabis et al., 2007; Szpunar et al., 2007; Botzung et al., 2008; Summerfield et al., 2009).”

“Hippocampal activation has been linked to the imagination of future, past, and fictitious events (Addis et al., 2007; Hassabis et al., 2007a; Botzung et al., 2008), although it is as yet unclear whether the degree of hippocampal engagement differs between conditions (Addis et al., 2007; Botzung et…”

“In an fMRI study, Hassabis et al. (2007) demonstrated that imagination and episodic memory share some neural substrates .”

“…of autobiographical memory and future/hypothetical thinking, participants have been explicitly prompted by task instructions to reconstruct the sights, sounds, and subjective experiences that accompanied or might accompany an event (Addis et al., 2007; Hassabis et al., 2007; Szpunar et al., 2007).”

“Imaging studies in humans have shown that these same neural networks are activated while imagining the future (Addis et al. 2007; Hassabis et al. 2007; Schacter et al. 2007).”

“U N C O R R E C with visualization and imagination ability (Hassabis et al., 2007), likely important to visuo-spatial processing demands of the RPM task.”

“This shows that our classification analysis was not biased towards invariably producing above chance accuracies for permanence.”

“Accordingly, it has been shown that neural activation patterns during future planning largely overlap with activation patterns during memory retrieval tasks (Buckner & Carroll 2007, Hassabis et al. 2007, Schacter et al. 2012).”

“Retrosplenial involvement in the current task is consistent with an involvement in visualization, construction, and identification of complex visual scenes and spatial information (Addis et al., 2007; Burgess et al., 2001; Epstein and Higgins, 2007; Hassabis et al., 2007).”

“*Data from Hassabis et al. (2007b).”

“Indeed, deficits in episodic simulation Hippocampus have been observed in amnesia when probed at both the specific (Hassabis et al., 2007b; Race et al., 2011) and the general (Klein et al., 2002; Andelman et al., 2010) levels, and the hippocampus is engaged during episodic prospection both when…”

“, Johnson and Johnson, 2014), imagined scenes (Hassabis et al., 2007) and vivid, contextually detailed, specific AMs (Addis et al.”

“It appears that a similar brain network supports episodic memory processing (Hassabis and Maguire, 2009; Hassabis et al., 2007; Summerfield et al., 2009), simulation of future events (Schacter et al.”

“…supporting multiple cognitive functions including episodic memory (Scoville and Milner, 1957), the imagination of fictitious and future experiences (Hassabis et al., 2007; Addis et al., 2007), spatial navigation (Chersi and Burgess, 2015; Maguire et al., 2006), visual perception (Lee et al., 2012;…”

“Scenes, the canonical type of spatial context, engage brain areas associated with autobiographical memory and imagination (Hassabis et al., 2007; Spreng et al., 2009; Zeidman et al., 2015; Hodgetts et al., 2016).”

“Similarly, these regions have been implicated in the generation and maintenance of complex and spatially coherent fictitious scenes (Hassabis et al., 2007a), a process whichmay be critical for the recollection of past events, and lends itself to the idea that memory is by nature a constructive…”

“The same area, however, is engaged during autobiographic and episodic memory [Hassabis et al., 2007; Svoboda et al., 2006] as well as in supporting associations related to scene context [Bar, 2009].”

“Mental simulation is a cornerstone of human cognition [3] and is involved in physical reasoning [4,5], spatial reasoning [6], motor control [7], memory [8], scene construction [9], language [10], counterfactual reasoning [11,12], and more.”

“The hippocampus has more recently been linked with other roles including imagination of fictitious and future experiences (Hassabis et al., 2007; Addis et al., 2007), visuospatial mental imagery (Dalton et al.”

“The memories used in this study are recent compared with other patient and neuroimaging studies in which the most recent memories may be years old (but see Rekkas and Constable, 2005; Hassabis et al., 2007).”

“…regions are sensitive to processing the scenarios or what participants imagined was happening in an event (e.g. medial prefrontal, posterior cingulate, temporal–parietal and middle temporal cortices are sensitive to the scenarios associated with future social events), people…”

“We speculate that people with increased R precuneate volume may also place an emphasis on worldly experiences over the inner life of imagination [58], which, in turn, may predispose them to adopt a non-religious life stance.”

“2001), and imagining past events or future events in familiar places (Hassabis et al. 2007; Szpunar et al. 2009).”

“Traditionally associated with episodic memory [1], neuroimaging and neuropsychological studies have consistently implicated the human hippocampus in a range of other functions including the imagination of fictive and future experiences [2,3], navigation [4 ,5], complex spatial perception [6–8] and decision-making [9,1…”

“, 1994), mental imagery (Burgess, 2008; Hassabis et al., 2007), and metaphor comprehension (Mashal et al.”