The cognitive neuroscience of memory and consciousness

In this chapter, we delineate the neural activity associated with conscious memories characterized by different degrees of ‘retrieval content’ (i.e. sensory/contextual detail). Based primarily on neuroimaging evidence, we identify the neural regions that are associated most consistently with the following conscious memory processes: retrieval success versus retrieval attempt, remembering versus knowing, and true recognition versus false recognition. A number of patterns emerge from the comparison of memories with high retrieval content (i.e., retrieval success, remembering, and true recognition) and memories with low retrieval content (i.e., retrieval attempt, knowing, and false recognition). Memories with both high and low retrieval content are associated with activity in the prefrontal and parietal cortex, indicating that these regions are generally associated with retrieval. There is also evidence that memories with low retrieval content are associated with activity in the prefrontal cortex to a greater degree than memories with high retrieval content, suggesting that low retrieval content memories are associated with greater postretrieval monitoring (although this activity does not necessarily reflect differential retrieval content per se). Finally, memories with high retrieval content, to a greater degree than memories with low retrieval content, are associated with activity in the parietal cortex and sensory cortex (along with the medial temporal lobe for retrieval success > attempt and remembering > knowing). This increased activity in sensory cortex (and medial temporal lobe) for memories with high retrieval content indicates that conscious memories are constructed by reactivation of encoded item features at retrieval.