Manipulating memory efficacy affects the behavioral and neural profiles of deterministic learning and decision-making

• Published in: Neuropsychologia 2018-06, Vol.114, p.214-230
• Main Authors: Tremel, Joshua J., Ortiz, Daniella M., Fiez, Julie A.
• Format: Article
• Language: English
• Subjects: Adolescent; Analysis of Variance; Association Learning - physiology; Basal ganglia; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Corpus Striatum - diagnostic imaging; Corpus Striatum - physiology; Decision Making - physiology; Discrimination Learning - physiology; Drift-diffusion model; Feedback; Female; Hippocampus; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Memory; Oxygen - blood; Reaction Time - physiology; Retention, Psychology - physiology; Striatum; Vocabulary; Young Adult
• ISSN: 0028-3932; 1873-3514; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2018.04.023

When making a decision, we have to identify, collect, and evaluate relevant bits of information to ensure an optimal outcome. How we approach a given choice can be influenced by prior experience. Contextual factors and structural elements of these past decisions can cause a shift in how information is encoded and can in turn influence later decision-making. In this two-experiment study, we sought to manipulate declarative memory efficacy and decision-making in a concurrent discrimination learning task by altering the amount of information to be learned. Subjects learned correct responses to pairs of items across several repetitions of a 50- or 100-pair set and were tested for memory retention. In one experiment, this memory test interrupted learning after an initial encoding experience in order to test for early encoding differences and associate those differences with changes in decision-making. In a second experiment, we used fMRI to probe neural differences between the two list-length groups related to decision-making across learning and assessed subsequent memory retention. We found that a striatum-based system was associated with decision-making patterns when learning a longer list of items, while a medial cortical network was associated with patterns when learning a shorter list. Additionally, the hippocampus was exclusively active for the shorter list group. Altogether, these behavioral, computational, and imaging results provide evidence that multiple types of mnemonic representations contribute to experienced-based decision-making. Moreover, contextual and structural factors of the task and of prior decisions can influence what types of evidence are drawn upon during decision-making. •Hippocampal activity is sensitive to a list-length manipulation.•Declarative memory profile is associated with higher decision thresholds.•Medial cortical regions are associated with higher decisions thresholds.•Procedural memory profile is associated with lower decision thresholds.•Striatal network is associated with lower decision thresholds.