I have tried to explain my research project in a fun, simple and non-technical way in the form of a poem.
In my PhD project, I am investigating the lexical interface or the "lemma" in the brain with regards to spoken language production and comprehension and investigating what is shared between word production and comprehension. A popular theory claims that that the lemma intermediates between semantics, syntax and spoken word form associated with the word and that it lies at the intersection of production and comprehension[1]. My project is an attempt to find this shared interface between production and comprehension.
I use a variety of methods - behavioral, neuroimaging and brain stimulation - to study what is shared between word production and comprehension (see below for details).
My PhD supervisors are Ardi Roelofs, James McQueen and Vitória Piai.
Behavioral : Cumulative Semantic Effects
The first study in my project was a behavioral study where I studied the cumulative semantic effect across two word production and two word comprehension tasks. This study was meant to highlight that cumulative semantic effects also occur during comprehension, and thus, likely involve the lemma or lexical-concept levels. This study also served as a behavioral pilot for my fMRI study.
As a follow-up to this study, I conducted a second behavioral experiment aimed at providing evidence for one of two opposing viewpoints with regards for existence of lemmas in word production (and comprehension). I supervised two by two honours (bachelors) students, who assisted me during this project.
Following up on this work, I had planned and prepared for a third study on cumulative semantic effects, this time investigating the effects both across modality (word production and word comprehension) and across unrelated languages (Italian & Indonesian). I supervised a master student in their thesis for this project. However, we could not complete this study as the pandemic made testing in Italy impossible in 2020.
Neuroimaging : Investigating the lexical interface
I also conducted an fMRI (functional Magnetic Resonance Imaging) study, in which I investigated the localisation of the lexical interface or the lemma. There are different theories about the localisation of the lemma in the brain and I tested two such theories. Participants lay in an MRI scanner and performed four tasks - two word production and two comprehension tasks, while their brains were scanned. I have exciting results (see latest poster) upon having analysed this data and the manuscript is currently under preparation.
TMS : Investigating the lexical interface
We use the spatial brain co-ordinates obtained from the fMRI study to apply Transcranial Magnetic Stimulation (TMS) to the brains of our participants and see if such a stimulation has an effect on their word production and comprehension (see poster for design and methods). As of June 2021, the data collection for this study is in-progress.