Examining the neural basis of unitization: A review

Associative memory refers to the ability to form and remember associations between individual pieces of information rather than memory for a single object or word. Encoding associations in memory tends to be a more difficult task than item encoding as associative memory requires encoding multiple items as well as the specific links amongst the items. Associative memory has been shown to require cortical medial temporal lobe (MTL) engagement, to process context and item information, respectively, in addition to hippocampal engagement that is needed for the binding of distinct information. The need to engage greater and more disparate neural resources in order to execute associative encoding tasks often comes at a cost with respect to memory success, notably, there is poorer associative memory compared to item memory performance. Accordingly, researchers have worked to identify interventions and strategies aimed at reducing the effort and neural resources required for successful associative memory processing. One such means of support is the concept of unitization. Unitization has traditionally been defined as the process by which two or more discrete items are processed, or encoded, such that they are perceived as a single ensemble. The current review will explore the neural research on unitization while taking into account the behavioral benefits that accompany the process.