The neural basis of serial biases in spatial working memory

Abstract

Transcranial magnetic stimulation (TMS) is a technique that stimulates the brain using electromagnetic pulses. This technology has a wide range of uses, from the treatment of certain pathologies, such as drug-resistant depression, to its use in research related to neuronal functionality. Serial dependence refers to a cognitive phenomenon where an individual's perception, or memory of a current stimulus, is influenced by the previous stimulus. This thesis consisted of an experiment involving 12 participants in which TMS was used to study the nature of serial dependence in spatial working memory (WM) as part of the line of research on serial dependence carried out by the Compte Lab. Participants performed a WM task while we applied TMS stimulation and we collected behavioral and EEG data. With the support of previous work, this thesis seeks to provide additional data and establish a direction for future analyses and studies in the field. Therefore, the objectives of this thesis are: firstly, to replicate the results previously obtained by the Compte Lab in order to strengthen the hypotheses put forward with regard to serial dependency and the effect that the TMS pulse has on it [5]. Secondly, to conduct new analyses with respect to the side the brain is being stimulated and the visual hemifield of stimulus appearance. Finally, to obtain the electroencephalogram (EEG) to investigate neural responses to TMS pulses in this task. The objectives of replication of the results with respect to temporality were met, but future analysis of the EEG data obtained is required to corroborate them. The objectives regarding the validation of previous results on the hemifields in which the stimuli appear were also met. No robust conclusions could be drawn regarding the effect of TMS when it was applied in one hemisphere or the other. This was due to the fact that the dataset was divided into too many different subgroups. With so few data per subplot, it was not possible to draw conclusions. The goal of conducting the experiment and obtaining EEG data in each session was successfully achieved.