RT Journal Article
SR Electronic
T1 Model-Based Fixation-Pattern Similarity Analysis Reveals Adaptive Changes in Face-Viewing Strategies Following Aversive Learning
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 125682
DO 10.1101/125682
A1 Lea Kampermann
A1 Niklas Wilming
A1 Arjen Alink
A1 Christian Büchel
A1 Selim Onat
YR 2017
UL http://biorxiv.org/content/early/2017/06/07/125682.abstract
AB Learning to associate an event with an aversive outcome typically leads to generalization when similar situations are encountered. In real-world situations, generalization must be based on the sensory evidence collected through active exploration, which in turn can also be influenced by aversive learning. However, we currently do not know how far exploration strategies can be shaped by learning and whether or not learning results in adaptive changes during the course of ensuing generalization. Here, we investigated learning-induced changes in eye-movement patterns using a similarity-based multivariate fixation-pattern analysis together with a set of parametrically controlled stimuli. Humans learnt to associate an aversive outcome (a mild electric shock) with one face along a circular perceptual continuum, whereas the most dissimilar face on this continuum was kept neutral. Before learning, eye-movement patterns mirrored the similarity characteristics of the stimulus continuum, indicating that exploration was mainly guided by subtle physical differences between the faces. Aversive learning resulted in a global increase in dissimilarity of eye movement patterns during generalization. Model-based analysis of the similarity geometry indicated that this was specifically driven by a separation of patterns along the adversity gradient, defined between the reinforced and neutral face. These findings show that aversive learning can introduce substantial remodeling of exploration patterns in an adaptive manner during viewing of faces. We suggest that separation of patterns for harmful and safe prototypes results from an internal categorization process operating along the perceptual continuum following learning.Authors Summary Eye movements can shed light on the global objectives of the nervous system, as they represent the final behavioral outcome of complex neuronal processes. They can therefore provide important insights into systems level alterations induced by aversive learning, which is important to elucidate as many anxiety disorders are believed to result from an inability to form optimal aversive representations. Participants associated an aversive outcome with a given face positioned along a similarity continuum, thereby learning facial prototypes for adversity and safety. We examined eye-movement patterns during viewing of these faces by characterizing their similarity relationships. Before learning, the known similarity relationships between the stimuli could be estimated based on eye-movement patterns recorded during viewing of these faces. This indicates that exploration of neutral faces was mainly driven by their physical characteristics. Aversive learning gave rise to a decrease in similarity of viewing patterns specifically along the adversity gradient, indicating the presence of a new exploration strategy for the newly learnt adversity and safety prototypes. Our results provide evidence for adaptive changes in viewing strategies of faces with learning, and are compatible with the view that the nervous system achieves categorization to distinguish safety and adversity following aversive experiences.