Efsun Annac, Ph.D.

Our collaborative work with Dr. Katarzyna Kurcyus and Nina M. Hanning is published in the Journal of Neuroscience with the title: Opposite dynamics of GABA and glutamate levels in the occipital cortex during visual processing Katarzyna Kurcyus ,  Efsun Annac ,  Nina M. Hanning ,  Ashley D. Harris ,  Georg Oeltzschner ,  Richard Edden  and  Valentin Riedl Abstract: Magnetic resonance spectroscopy (MRS) measures the two most common inhibitory and excitatory neurotransmitters, GABA and glutamate, in the human brain. However, the role of MRS-derived GABA and glutamate signals in relation to system-level neural signaling and behavior is not fully understood. In this study, we investigated levels of GABA and glutamate in the visual cortex of healthy human participants (both genders) in three functional states with increasing visual input. Compared to a baseline state of eyes closed, GABA levels decreased after opening the eyes in darkness and Glx leve...

A secondary task is not always costly: Context‐based guidance of visual search survives interference from a demanding working memory task Efsun Annac, Xuelian Zang, Hermann J. M üller, & Thomas Geyer Abstract:  Repeatedly encountering a visual search display with the target located at a fixed position relative to the distractors facilitates target detection, relative to novel displays – which is attributed to search guidance by (acquired) long‐term memory (LTM) of the distractor ‘context’ of the target. Previous research has shown that this ‘contextual cueing’ effect is severely impeded during learning when participants have to perform a demanding spatial working memory (WM) task concurrently with the search task, though it does become manifest when the WM task is removed. This has led to the proposal that search guidance by LT context memories critically depends on spatial WM to become ‘expressed’ in behaviour . On this background, this study, of two experiments, aske...