FRACTIONATING ATTENTIONAL AND MEMORY COMPONENTS IN A HUMAN OBJECT-LOCATION MEMORY TASK
Object-location visual short-term memory (VSTM) tasks have special diagnostic value for age-related neurocognitive disorders. One potential reason could be that VSTM requires the coordinated engagement of multiple cognitive components, similarly to everyday functions which may be impaired in the elderly. The CANTAB Paired Associates Learning (PAL) task is an object-location VSTM paradigm, wherein the locations of 4-6 sequentially presented putatively nonfigurative visual objects must be held in VSTM during a delay period, after which all objects are probed sequentially. In an attempt to dissociate the involvement of multiple memory systems and attentional components in a single session, we measured the PAL task along with a battery of memory tasks, including the Mnemonic Similarity Task as well as verbal and visual working memory tests. Also, at the beginning and at the end of the session, sustained and temporal attention was assessed using the Psychomotor Vigilance Test (PVT), supplemented by assessing subjective attentiveness and motivational states using visual analogue scales. According to these, both the sustained and temporal attentional components of the PVT declined through the course of the experimental session. Furthermore, the change in the temporal attentional component correlated with PAL task performance; this correlation was stronger in a more challenging version of the task. In order to expand upon these results, we use partial correlation analyses to fractionate the potential contribution of verbal STM, visual STM and pattern separation components to PAL task performance. Integrating and understanding these factors carries the possibility of improving the testing of both the status and the progression of neurocognitive disorders.