muhammetikbalsahan.github.io

Muhammet Ikbal ŞAHAN

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I am a doctor in Psychology (PhD) and currently holding a postdoctoral researcher position in Cognitive Neuroscience at the department of Experimental Psychology, Ghent University funded. My research is funded by the Flemish Research Council (FWO).

Research Interest

Working memory (WM) and attention are two major conceptual pillars of human cognition, and how they relate to each other is a topic of intense interest at cognitive, neural, and theoretical levels of investigation. My research interests are in the mechanisms underlying perceptual processing and working memory storage of visual, spatial, and verbal information at the behavioral, computational, and neural levels. Moreover, I am interested in how abstract semantic knowledge and temporal information are processed and stored in working memory. I investigate these topics using behavioral paradigms, eye-tracking, and fMRI.

Short Bio

I completed my Ph.D. under the supervision of Prof. Wim Fias and Prof. Tom Verguts at the department of Experimental Pscyhology, Ghent Universtiy. During my PhD, I addressed the question how attention and working memory interact at the behavioral, neural and computational level. For the computational part, I got interested in modeling (e.g., mixture models) the distribution of attentional resources in WM for which I collaborated with the group of Prof. Masud Husain (University of Oxford). As for the neural part, I wanted to lay down the neural bases of attentional prioritisation in working memory using advanced machine learning techniques on fMRI data (e.g., MVPA, RSA, and IEM) for which I conducted a series of experiments as a visiting researcher in prof. Bradley Postle’s lab (University of Wisconsin-Madison).

Following up on my PhD, I continued working with Prof. Wim Fias to investigate the role of spatial attention in more abstract domains of cognition like semantic knowledge and temporal information. My current research focuses on the involvement of the sensorimotor system, and in particular the oculomotor system for holding and processing temporal information. I have successfully obtained a post-doc research grant to address these questions. Within this framework, I am collaborating with Prof. Sebastiaan Mathôt (University of Groningen) specifically to address the oculomotor involvement in working memory.

Projects

Tracking the mind’s eye: The role of visuospatial processes in verbal working memory rehearsal.

Ongoing | Flemish Research Council (FWO) | Junior Post-doctoral Fellowshsip

Selection mechanisms in working memory: A neurocognitive approach

Concluded | Ghent University Special Research Fund (BOF) | PhD Read more…

Research

In preparation

  1. Sahan, M. I., Mathôt, S., & Fias, W. (in prep). Attention-based rehearsal: Patterns of eye movements reveal how visuospatial information is maintained in short-term memory.
  2. Sahan, M. I., Fias, W., & Mathôt, S. (in prep). Pupillometric measures reveal the semantic contents of attended words in verbal working memory.

Peer-reviewed articles

  1. Cristoforetti, G., Majerus, S., Sahan, M. I., van Dijck, J. P., & Fias, W. (2022). Neural Patterns in Parietal Cortex and Hippocampus Distinguish Retrieval of Start versus End Positions in Working Memory. Journal of Cognitive Neuroscience, 34(7), 1230-1245. https://doi.org/10.1162/jocn_a_01860
  2. Declercq, M., Bellon, E., Sahan, M. I., Fias, W., & De Smedt, B. (2022). Arithmetic learning in children: An fMRI training study. Neuropsychologia, 169, 108183. https://doi.org/10.1016/j.neuropsychologia.2022.108183
  3. Sahan, M. I., van Dijck, J. P., & Fias, W. (2022). Eye-movements reveal the serial position of the attended item in verbal working memory. Psychonomic Bulletin & Review, 29(2), 530-540. https://doi.org/10.3758/s13423-021-02005-9
  4. Sahan, M. I., Fias, W., Ansari, D., & Lyons, I. M. (2021). From counting to retrieving: Neural networks underlying alphabet arithmetic learning. Journal of Cognitive Neuroscience, 34(1), 16-33. https://doi.org/10.1162/jocn_a_01789
  5. Rasoulzadeh, V., Sahan, M. I., van Dijck, J. P., Abrahamse, E., Marzecova, A., Verguts, T., & Fias, W. (2021). Spatial attention in serial order working memory: an EEG study. Cerebral Cortex, 31(5), 2482-2493. https://doi.org/10.1093/cercor/bhaa368
  6. Sheldon, A. D., Saad, E., Sahan, M. I., Meyering, E. E., Starrett, M. J., LaRocque, J. J., N.,S., Rose & Postle, B. R. (2021). Attention Biases Competition for Visual Representation via Dissociable Influences from Frontal and Parietal Cortex. Journal of Cognitive Neuroscience, 33(4), 739-755. https://doi.org/10.1162/jocn_a_01672
  7. Sahan, M. I., Sheldon, A. D., & Postle, B. R. (2020). The neural consequences of attentional prioritization of internal representations in visual working memory. Journal of Cognitive Neuroscience, 32(5), 917-944. https://doi.org/10.1162/jocn_a_01517
  8. Sahan, M. I., Majerus, S., Andres, M., & Fias, W. (2019). Functionally distinct contributions of parietal cortex to a numerical landmark task: an fMRI study. Cortex, 114, 28-40. https://doi.org/10.1016/j.cortex.2018.11.005
  9. tiberghien, K., Sahan, M. I., De Smedt, B., Fias, W., & Lyons, I. M. (2019). Disentangling neural sources of problem size and interference effects in multiplication. Journal of Cognitive Neuroscience, 31(3), 453-467. https://doi.org/10.1162/jocn_a_01359
  10. Sahan, M. I., Dalmaijer, E. S., Verguts, T., Husain, M., & Fias, W. (2019). The graded fate of unattended stimulus representations in visuospatial working memory. Frontiers in psychology, 10, 374. https://doi.org/10.3389/fpsyg.2019.00374
  11. Elsherif, M. M., Sahan, M. I., & Rotshtein, P. (2017). The perceptual saliency of fearful eyes and smiles: A signal detection study. PloS one, 12(3), e0173199. https://doi.org/10.1371/journal.pone.0173199
  12. Sahan, M. I., Verguts, T., Boehler, C. N., Pourtois, G., & Fias, W. (2015). Paying attention to working memory: Similarities in the spatial distribution of attention in mental and physical space. Psychonomic bulletin & review, 1-8. https://doi.org/10.3758/s13423-015-0990-5

Research Grants

  1. Post-doctoral Research Fellowship funded by the Flemish Research Council (€181.200,00) | 2020-2022 | The funding is for three years supporting the research project titled: “Tracking the mind’s eye: The role of visuospatial processes in verbal working memory rehearsal” (FWO grant 1215621N)
  2. Grant for long research stay in Groningen, the Netherlands by the Flemish Research Foundation (€10.098,00). | 2022 | Visited the lab of prof. dr. Sebastiaan Mathôt for six months to investigate the role of visuospatial processes in verbal working memory using pupillometry (FWO grant V403022N).
  3. FWO Grant for participation at a conference abroad (€1.000,00). | 2020 | Presented a talk title “Looking through the mind’s eye: eye-movements reveal the spatiotemporal evolution of attentional shifts in serial order WM” at the European Workshop on Cognitive Neuropsychology in Bressanone, Italy. The talk was nominated for the Best Presentation. (FWO grant K104320N)
  4. Grant for long research stay in Wisconsin-Madison, USA by the Flemish Research Foundation (€9.000,00)| 2017 | Visited the lab of prof. dr. Bradley Postle for six months to investigate the interplay between spatial attention and working memory using machine learning tools on fMRI data (FWO grant V431616N).
  5. FWO Grant for participation at a workshop abroad (€1.000,00) | 2017 | Presented a talk titled “What are the neural consequences of attentional prioritization on internal memory representations? at the The crossroads of attention in working memory: Consolidation, Refreshing and Removal-conference in Valais, Switzerland.

Scientific Awards

  1. Best Poster Award at the “Searching for the WM engram” conference held in Groningen. | May 2022 | Award in recognition to the poster titled: “Attention-based rehearsal: Patterns of eye movements reveal how visuospatial information is maintained in short-term memory.” Read more…
  2. Stad Gent artistic grant to create an artistic translation of our scientific work (€4.000,00). | September 2021 | Together with a group of artists: Laura Zuallaert, Alican Unal and Joline Vermeulen, I am preparing an art performance based on our recent eye-tracking work titled “The anatomy of the gaze”. Our partners are GUM (Ghent University Museum), dr. Guislain Museum and Stad Gent.

Ongoing collaborations

  1. Collaborator: prof. dr. Sebastiaan Mathôt, Department of Experimental Psychology, University of Groningen, the Netherlands. Tracking the mind’s eye using pupillometry in order to reveal the role of visuospatial processes in verbal working memory.
  2. Collaborator: prof. dr. Mehdi Senoussi, CLLE lab, Université de Toulouse, France. Attentional selection in visuospatial working memory: Does alpha suppression reflect distractor suppression or target enhancement?
  3. Collaborator: dr. Aytaç Karabay, New York University Abu Dhabi, Abu Dhabi. Serial dependence in visual working memory: attraction vs repulsion?

Invited Talks

  1. Invited by prof dr. Wim Gevers (Université Libre de Bruxelles, BE) and prof. dr. Mehdi Senoussi (Université de Toulouse, FR) to the symposium: Representing spatial and ordinal information in working memory at the Belgian Association of Psychological Sciences. “The interplay between spatial processes and verbal working memory” (February 2021)
  2. Invited by prof. dr. Kia Nobre (Oxford Centre for Human Brain Activity, UK) at the University of Oxford, Oxford. |February 2019| “The Odyssey from the External Physical World to the Internal Mental World.” https://sites.google.com/site/neuroxillations/about. (February 2019)

Conference contributions

Teaching

Teaching fellow

Academic mentoring (N>20)

Recent Selection:

Societal and Administrative Responsibilities

Competences

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