a two-week period, in a diary. During this two-week period, participants also had to come into a laboratory at intervals, and were instructed to recall memories from certain life periods (e.g., high school, first five years of marriage). Following this, comparing their involuntary memories to a control condition found that a significant number of their involuntary memories related to the time period they were instructed to recall. Such findings suggest that involuntary memories may be primed by even the simplest of cognitive tasks—namely, reminiscing and recalling the past. Neurological basis Research studies regarding the neurological functions of involuntary memory have been few in number. Thus far, only two neuroimaging studies have been conducted comparing involuntary memories to voluntary memories using Positron Emission Tomography (PET). The first study found that while involuntary memory retrieval is mediated by the hippocampus, a structure of the brain known to be associated with successful episodic memory retrieval, involvement of the hippocampus was independent of whether or not remembering was intentional. The researchers believe this suggests that involuntary memories may reflect the “relative automaticity” of hippocampally-mediated retrieval. However, their research mainly focuses on identifying areas and functions involved in intentional retrieval. Activity in the medial/lateral parietal and right prefrontal cortex was insensitive to depth of encoding, but rather, varied depending on the intentionality of retrieval. These areas were increasingly engaged during intentional retrieval, suggesting that one function of this region may be to align remembering to aid with current behavioral goals. This is distinct from involuntary memory, where individuals do not consciously retrieve memories that will be most helpful to their current situation; however, it remains unclear if this process is unconsciously undertaken by the brain. When dealing with involuntary word recognition tasks, activity in areas such as the left inferior frontal gyrus, left superior temporal gyrus, left hippocampus, and right superior occipital cortex have all been implicated. Yet, areas and structures that are uniquely associated with involuntary memory remain unclear and more research is needed to understand the cognitive and neurological basis of this memory phenomenon. The second study found that the medial temporal lobe, the posterior cingulate gyrus, and the precuneus, are activated during retrieval success with or without executive control seen within the right dorsolateral prefrontal cortex. This implies that involuntary memories are successfully retrieved using the same system as voluntary memory when retrieving perceptual information. This is significant because it suggests that