Comparative studies of goal-directed actions
Meaningful translation of non-human primate work towards the understanding of human cognition and disease depends on elucidating similarities and differences between species. Using event-related BOLD fMRI, we have shown that humans and monkeys exhibit different levels of spatial selectivity during saccade preparation in otherwise homologous fronto-parietal regions12. Our recent work extended these findings by showing substantial differences in fronto-parietal activation patterns during spatial free-choice in humans as compared to monkeys, with seemingly uniquely human activation of pre-supplemental motor area and insula by the internally-generated free-choice; importantly, those effects were not related to differences in training history (in preparation). Moreover, we recently found that in humans, the preparation of free-choice saccade or reach actions, as compared to the instructed actions, activates largely overlapping prefrontal circuitry, suggesting mainly effector-unspecific, general encoding of choice-related processing (in preparation). In a collaboration with clinicians who implant depth electrodes in epileptic patients to localize seizures, our group is analyzing intracranial LFP activity recorded during similar tasks to directly compare spatial encoding and decision signals between methods (fMRI vs electrophysiology) and the two species.
The fascination about decision-making under uncertainty elicited our interest in metacognitive abilities across species. We have shown that during perceptual decisions under time pressure, humans can use post-decision wagering to read out not only their level of certainty of being correct, but also certainty of being incorrect (also known as “error detection”, e.g. due to post-decisional evidence accumulation)13, and that many brain regions encode such bi-directional certainty in fMRI activation patterns (in preparation). It remains to be seen if macaques might utilize the post-decision wagering to signal not only their perceptual confidence in being correct, but also their errors.
1. Kagan, I., Iyer, A., Lindner, A., and Andersen, R.A. (2010). Space representation for eye movements is more contralateral in monkeys than in humans. Proc Natl Acad Sci U S A 107, 7933–7938. doi.org/10.1073/pnas.1002825107.
Metacognition
The fascination about decision-making under uncertainty elicited our interest in metacognitive abilities across species. We have shown that during perceptual decisions under time pressure, humans can use post-decision wagering to read out not only their level of certainty of being correct, but also certainty of being incorrect (also known as “error detection”, e.g. due to post-decisional evidence accumulation)2, and that many brain regions encode such bi-directional certainty in fMRI activation patterns (in preparation). It remains to be seen if macaques might utilize the post-decision wagering to signal not only their perceptual confidence in being correct, but also their errors.
2. Moreira, C.M., Rollwage, M., Kaduk, K., Wilke, M., and Kagan, I. (2018). Post-decision wagering after perceptual judgments reveals bi-directional certainty readouts. Cognition 176, 40–52. doi.org/10.1016/j.cognition.2018.02.026.