Effect of cognitive state on the consolidation of basic and complex memories
MetadataShow full item record
Recent research demonstrates that new verbal memories are retained better if learning is followed by a brief period of wakeful rest. This effect is hypothesised to be the result of wakeful rest providing a state that is conducive for early-stage cellular consolidation (i.e. strengthening of specific memory traces) by protecting this process from interfering sensory input and associated encoding. The aims of this PhD project were to (i) examine whether the benefit of wakeful rest extends to the retention of complex spatial memories, and (ii) explore the effects of different cognitive states on memory consolidation. In order to address the first aim, three virtual reality spatial memory experiments were conducted. In young and older adults, wakeful rest not only enhanced the retention of complex spatial memories, but it also promoted the systems-level integration of spatial memories into accurate cognitive maps, a function, hitherto, assumed to be specific to sleep (Chapters 2-4). Pilot work also tentatively suggested that wakeful rest enhances the retention of complex spatial memories (i.e. a recently travelled route) in patients with amnestic Mild Cognitive Impairment (Chapter 4). In order to address the second aim, five experiments were run in young adults. The first experiment directly compared the effects of wakeful rest and sleep, two states that are positively associated with consolidation. Wakeful rest enhanced the retention of a list of known words, whereas a similar-length period of sleep enhanced the acquisition of novel linguistic constraints (Chapter 5). The final four experiments revealed that, similar to continuous external sensory input, internally generated autobiographical thinking activities (recalling the past and imagining the future) interfere with consolidation (Chapter 6). Together, the findings reported in this thesis reveal that wakeful rest promotes the strengthening (cellular consolidation) and wider integration (systems consolidation) of basic and complex declarative memories, and that this effect is contingent on a reduction in external sensory input as well as rich autobiographical thought.