- Fixation>Unpredictable target>Memorize location>Delay>Saccade
- Used in previous investigations to separately analyze visual, mnemonic, and motor related activity  

Oculomotor Delayed Response Task

- More prominent in PPC
- More active in nonmatch delays

Retrospective Representation

More prominent in FEF
- More active in match delays (maintaining motor intention) 

Prospective Representation 

- Oculomotor Delayed Response Task
- Controlling Response Selection 
- During a working memory delay one can either 1. look back at a past event, or 2. look forward to a future event
- Masking pattern to disrupt iconic visual memory

New York University

There is converging functional neuroimaging evidence for the involvement of the sustained activity in the prefrontal cortex underlying the process of working memory during the delay period in a working memory task. And due to the fact that the PFC has a lot of cortico-cortico connections and coritco-subcortico connections, it might be the case that these different connections probably mediate different component processes of working memory. It has been believed for example the the cortical network might mediate the maintenance of goals, while the subcortical networks mediates response selection and motor control

The Neural Basis of Working Memory

Curtis, C. E., Rao, V. Y. & D’Esposito, M. (2004). Maintenance of spatial and motor codes during oculomotor delayed response tasks. J Neurosci 24, 930–940. https://doi.org/10.1523/JNEUROSCI.5640-03.2004

Maintenance of spatial and motor codes during oculomotor delayed response tasks

It has been proposed that the different subdivisions of the PFC may be responsible for maintaining different types of information. Emergence of "what" and "where" pathways. 
Ventrolateral PCF >> nonspatial information, eg. object's shape
Dorsolateral PFC >> spatial information, eg. object's location

Subdivisions within the PFC - Information type

Ventral PFC >> were information is initially received + comparisons between maintained information
Dorsal PFC >>Information monitoring and manipulation

Subdivisions within the PFC - Operation Type

Coding Schemes for Working Memory Mechanisms 

Oscillatory activity is modulated in these brain regions

•	Prefrontal region

•	Parietal region

•	Medial temporal region


Brain regions associated with working memory (WM) processing

-	FN400 activity
-	Alpha activity
-	Theta activity

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