Visual Working Memory
Attentional Orienting Within the Spatial Layout of Visual Working Memory
The human visual working memory (WM) system enables us to store a limited amount of task-relevant visual information temporally in mind. However, it is still an open issue how this WM information is maintained in the brain. The currently dominant views advocated by prominent WM models hold that the units of memory are configured either as independent feature representations, integrated bound objects, or a combination of both.
In a recent study (Töllner et al., 2015, NYAS), we approached this issue by measuring lateralized brain electrical activity during a retro-cue paradigm, in order to track people’s ability to access WM representations as a function of the dimensional relation between WM items and task settings. We found that both factors selectively influence WM access: whereas cross relative to intradimensional WM targets gave rise to enhanced contralateral delay activity (CDA) amplitudes, localization relative to identification task demands yielded speeded CDA and manual response times. As these dimension-based findings are not reconcilable with contemporary feature- and/or object-based accounts, we proposed an alternative view that is based on the hierarchical feature-bundle model. In detail, we argue that WM units may consist of three hierarchically structured levels of representations, with an intermediate dimensionally organized level that mediates between top-level object and lower-level feature representations.
Wiegand, I., Hennig-Fast, K., Kilian, B., Müller, H. J., Töllner, T., Möller, H.J., Engel, R. R., & Finke, K. (2016). EEG correlates of visual short-term memory as neuro-cognitive endophenotypes of ADHD. Neuropsychologia, 85, 91-99.
Töllner, T., Mink, M., & Müller, H. J. (2015). Searching for targets in visual working memory: Investigating a "dimensional feature bundle" (DFB) model. Annals of the New York Academy of Sciences, 1339 (1), 32-44.
Töllner, T., Eschmann, K., Rusch, T., & Müller, H. J. (2014). Contralateral delay activity reveals dimension-based attentional orienting to locations in visual working memory. Attention, Perception, & Psychophysics, 76 (3), 655-662.
Wiegand, I., Töllner, T., Habekost, T., Dyrholm, M., Müller, H. J., & Finke, K. (2014). Distinct neural markers of TVA-based visual processing speed and short-term storage capacity parameters. Cerebral Cortex, 24 (8), 1967-1978.