Describe and explain experimental paradigms and methods used to investigate visual memory and its neural underpinnings
A Coggle Diagram about summary (performance: stimulus/task/time dependent, capacity: 1-4 items, location: early visual areas prefrontal, parietal, inferotemporal and lateral occipital, processing/content: discrete, fixed resource, sparse and visual long-term memory: high fidelity for object color), basic issues (performance, capacity, localisation in the brain and processing, content), WORKING MEMORY: Grill-spector & Kanwisher (2005): different performance in memory/identification depending on object. accuracy was lower and reaction time longer on a within-category task (e.g. distinguish pigeon from other birds) than perceptual categorization task (e.g. birds vs. cars). However, performed just as quickly and accurately on categorization task as they did on a task requiring only object detection, VISUAL SHORT TERM MEMORY Todd & Marois 2004: visual scenes held in short-term memory - it's capacity is severely limited. with behvavioural performance and fMRI found that this small limit is neurally reflexted in one node of this network (posterior parietal cortex), LONG TERM MEMORY AND WORKING MEMORY: Olsson & Poom (2005): "visual memory needs categories" used non-verbal stimuli and looked at memory not only over time but also how many objects successfully stored in memory > traditional studies have used objects from same categories (shape, color) but this is long term memory: they looked at distinguishable intracategorical items and found max capacity to be not 4 objects but only 1 (lower capacity), VISUAL WORKING MEMORY: Harrison & Tong 2009: tried to understand how specific visual features can be remembered. found that orientation information persists in visual areas for unattended and attended stimuli (fMRI and pattern classification methods) . thus, early visual areas can retain specific information about visual features without physical stimulus but conclusion limited to orientation, visual memory provides an essential link between perception and higher cognitive functions; allowing for the active maintenance of information about stimuli no longer in view, VISUAL WORKING MEMORY: Zang & Luck 2008: provide independent measures of capacity and resolution with 3 working memory processing models. when presented with more than a few simple objects, humans store a high-resolution representation of a subset and no information about others. supports discrete-fixed-resolutions representations of memory. , LONG TERM MEMORY Brady et al 2013: wanted to know detail about representations and used color as a case study. shown real-world objects in different colors and asked to recall colors after delay. quantified variability of internal representations (variability of exactness of copy) and probability of forgetting. suggest constrain of common limit, such as a bound on the fidelity (exactness of copy) required to retrieve a memory representation and SHORT TERM MEMORY: Magnussen 2000:there's a low level perceptual memory mechanism identified by important attributes of a stimulus important in early visual processing. this mechanism is located early in the visual processing stream. composed of series os special-purpose mechanisms with indepdendent but limited procesing resources. operates on a pre-semantic level .