The neural representation of the self

Humans as a social species are dependent on social interactions for survival (Sedikides, Skowronski and Dunbar, 2006). To regulate appropriate behaviours in the social world, we need knowledge about ourselves and how others respond to us (Heatherton et al., 2007). Research on the self has been central in the field of psychology for more than a century (e.g., James, 1890). Although behavioural studies provide a fundamental understanding of the self, how the self is represented in the brain remains unclear.
The proposed study will rigorously examine how the self is represented in the brain, by using fMRI and MVPA. The self is a complex concept, which consists of various aspects and is related to many different psychological processes. Therefore, sensitively measuring the patterns of activation rather than solely knowing which regions are active, is important to increase the understanding of the self.

Participants will firstly take part in a behavioural session where they will judge whether various words describe them or not. Next, each participant will perform two tasks whilst in the fMRI scanner: a word judgement task and an attention task. They will be presented with two different types of stimuli: trait adjectives (e.g., trustworthy, lazy, etc.) and social categories (e.g., students, British, etc.). The aim of the study is to examine whether the self is special and uniquely represented in the brain. If it is special, the self condition should evoke similar activation patterns regardless of task and stimuli, which can be identified by MVPA.

We will recruit thirty neurologically healthy, right-handed adult participants with normal or corrected-to-normal vision. The sample size is based on previous studies (Kelley et al., 2002; Krishnan et al., 2016)

Behavioural task
Before the fMRI scan, participants will complete a behavioural task where they will judge whether social category words and trait adjectives describe themselves or not. This is to distinguish between self-relevant, and not relevant stimuli for the word judgement task (which they will perform during the fMRI session).

fMRI tasks
Participants will perform the following tasks whilst in the fMRI scanner:
1. Word judgement task: Participants will be presented with words that are either a trait adjective or a social category word. Their task will be to judge whether the words presented describes themselves or not.
2. Attention task: Participants will again be presented with the same trait adjectives or social category words. Their task will be to judge whether the word is written in italic or not.

For both tasks, the participants will indicate their answers by pressing one of two buttons on a response box in the scanner.

Analyses and Hypotheses:
We will firstly compare regions of neural activation for when participants are presented with self-relevant stimuli to when they are not, in both tasks. Secondly, we will examine whether self-relevant stimuli and other stimuli evoke similar activation patterns or not using MVPA. We hypothesise that self-relevant stimuli in both tasks will activate the CMS (univariate analysis) and that self-relevant stimuli in both tasks will evoke similar activation patterns in the CMS, while the patterns will be distinct from those evoked by other non-self-relevant stimuli (MVPA).

Understanding ourselves is crucial for many aspects of our lives, for example; social interactions, evaluating ourselves or regulating thoughts and behaviours to reach goals. Thus, it is important to understand the underlying neural and psychological processes of the self. Although the self has been thoroughly investigated for a long time, how the self is processed in the brain remains unknown. The aim is to close this gap in the literature by examining the representation of the self in the brain with MVPA. In this way, the proposed project crosses disciplinary boundaries by using tools from neuroscience and computer science.