Psychology ETDs

Publication Date

Summer 7-11-2019

Abstract

Previous work has demonstrated that anodal transcranial direct current stimulation (tDCS) applied to the right ventrolateral prefrontal cortex (rVLPFC) is capable of accelerating learning of a threat identification and classification task. However, questions remain as to the cognitive mechanisms underlying this effect, and whether the observed tDCS mediated learning is specific to threatening stimuli or, rather, a more generalizable learning processes. The goal of the current project was to isolate specific aspects of the threat detection task in order to exemplify previous findings. A number of pre-test measures were included to attempt to decipher the characteristics of subjects who are most likely to benefit from stimulation. A novel classification task was devised, during which subjects learned to classify pictures of European streets into two categories using two rules. Fifty-four subjects were randomly assigned to receive 30 minutes of anodal (n = 18), cathodal (n = 18), or sham (n = 18) tDCS. A linear mixed model revealed a significant interaction between condition and training block in performance increases after training (p = 0.002). Compared to a 4.2% increase in sham subjects, anodal tDCS increased categorization accuracy by 20.6% (d = 1.71) and cathodal tDCS by 14.4% (d = 1.16). A logistic regression was run to predict rule learning in the experimental task using pre-test measures as predictors, with the final model predicting rule learning group by 75.9 %. Overall, these results provide further evidence for the capacity of tDCS applied to rVLPFC to enhance learning, showing greater than quadrupling of performance in a difficult novel classification task. These data suggest a generalized learning enhancement, such that other learning tasks may also benefit from this tDCS protocol. Additionally, the results point to ways in which individual characteristics might influence subsequent tDCS-mediated learning.

Degree Name

Psychology

Level of Degree

Masters

Department Name

Psychology

First Committee Member (Chair)

Vincent P. Clark, Ph.D.

Second Committee Member

Katie Witkiewitz Ph.D.

Third Committee Member

Eric Ruthruff, Ph.D.

Language

English

Keywords

NIBS, tDCS, Neuroplasticity, Learning, VLPFC, IFG

Document Type

Thesis

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