Brain oscillatory analysis of visual working memory errors

Download
index.pdf
2019
Mapelli, Igor
Show full item record
298
views
128
downloads
Brain dynamics of memory formation were explored throughout a working memory (WM) task. Electroencephalography data were acquired from participants while presented with grayscale photos of object categories (each category defined by images sharing a common gist). Following a short delay, two probes were shown to test memory accuracy. Time-frequency representations of successful and erroneous memories were contrasted. Additionally, brain connectivity was studied via coherency and phase-amplitude coupling (PAC). Where significant differences were identified, oscillatory properties of false memories (a novel item of the same category recognized as familiar) were compared with those of successful and erroneous memories. Spectral analysis revealed occipital theta power for encoding of successful and false memories to be smaller when compared to other memory errors. The reduced theta power indicates successful encoding and reflects efficient activation of the underlying neural assemblies. During the retention interval, prominent alpha-beta activity over right parieto-occipital channels was found to be larger for false memories and errors when compared to correct responses. High levels of alpha-beta oscillatory activity for errors indicate poor maintenance leading to inefficient allocation of WM resources. For false memories, they imply necessary cognitive effort to manage an extra semantic and perceptual load induced during encoding. Significant fronto-occipital coherency was measured: Possibly, theta and alpha band coherency reflect central executive functions of WM, whereas beta band coherency indicates coordination of local assemblies related to stimulus representations. Significant theta/gamma PAC, linked to WM retention of sequentially encoded stimuli, and alpha/gamma PAC, reflecting processing of visuo-spatial information, were also observed.
Neurology., Neurosciences., Short-term memory., Electroencephalography.
http://etd.lib.metu.edu.tr/upload/12623069/index.pdf
https://hdl.handle.net/11511/28036
Graduate School of Informatics, Thesis

Suggestions

Brain Oscillatory Correlates of Visual Short-Term Memory Errors
Mapelli, Igor; Özkurt, Tolga Esat (2019-02-13)
Brain dynamics of memory formation were explored during encoding and retention intervals of a visual working memory task. EEG data were acquired while subjects were exposed to grayscale images of widely known object categories (e.g., "luggage," "chair," and "car"). Following a short delay, two probes were shown to test memory accuracy. Oscillatory portraits of successful and erroneous memories were contrasted. Where significant differences were identified, oscillatory traits of false memories (i.e., when a ...
Aging Slows Access to Temporal Information From Working Memory
Kılıç Özhan, Aslı; Oztekin, Ilke (Oxford University Press (OUP), 2017-11-01)
To evaluate the impact of aging on controlled memory search operations, we investigated the retrieval of temporal order information from working memory (WM).
Brain Computer Interfaces for Silent Speech
TABAR, Yousef Rezaei; Halıcı, Uğur (2017-05-01)
Brain Computer Interface (BCI) systems provide control of external devices by using only brain activity. In recent years, there has been a great interest in developing BCI systems for different applications. These systems are capable of solving daily life problems for both healthy and disabled people. One of the most important applications of BCI is to provide communication for disabled people that are totally paralysed. In this paper, different parts of a BCI system and different methods used in each part ...
Age related changes in recognition memory for emotional stimuli
Kılıç, Aslı; Gökçay, Didem; Department of Cognitive Sciences (2007)
Recognition memory - a type of episodic memory in long term memory - is known in the literature to be affected by emotion, aging and the modality of the presented stimuli. The major aim of this study was to investigate whether emotional stimuli enhances recognition memory. Another goal was to observe whether modality and aging effects are present and differentiable in a non-Western subject sample. In literature, emotion studies were based on mainly two dimensions of emotions: valence and arousal. However, t...
Brain Computer Interfaces
Halıcı, Uğur (null; 2015-11-12)
Brain Computer Interface (BCI) systems provide control of external devices by using only brain activity. In recent years, there has been a great interest in developing BCI systems for different applications. These systems are capable of solving daily life problems for both healthy and disabled people. One of the most important applications of BCI is to provide communication for disabled people that are totally paralysed. In this paper, different parts of a BCI system and different methods used in each part ...
Citation Formats
I. Mapelli, “Brain oscillatory analysis of visual working memory errors,” Ph.D. - Doctoral Program, Middle East Technical University, 2019.
METU IIS - Integrated Information Service open@metu.edu.tr