Relationships between personality and lateralization of sensory inputs

In humans and other vertebrates, sensory information is sometimes lateralized towards one brain hemisphere that dominates the control of a task. Although sensory lateralization may depend on the stimuli being processed, the degree or direction of lateralization can differ according to behavioural phenotype. Accordingly, personality may play an important role in lateralization, yet there is a lack of evidence regarding how lateralizations are utilized to process information and promote a personality-based response to a particular situation. Here we show that simultaneous stimulus processing and organization of personality-based responses can be accomplished via differences in laterality between senses. We demonstrate this by examining novel object inspection in the weakly electric fish Gnathonemus petersii. We found that electrosensing is lateralized in this species, but differently between personality phenotypes: bold fish were lateralized towards the right hemisphere and timid fish the left. By contrast, visual laterality did not vary with personality; rather the left hemisphere was dominant across the population, as is common for fish when visually analysing unfamiliar objects. This evidence reveals differences in functional laterality between sensory systems and the role of personality in eliciting these differences. The species has a stronger input of electrical signals than visual signals in its brain; therefore, sensory representation in the brain might drive the laterality differences.