Primates form and use abstract rules
In a nutshell: A new theoretical framework describes how humans and other primates use the prefrontal cortex to make and update the rules that guide their behaviours.
To perceive our surroundings and help us respond appropriately, our brains use abstract rules and categories to classify objects and events based on past experience.
For example, imagine arriving in a new city for the first time. Maybe you want to find something to eat, take a bus somewhere else, or explore. Using abstract rules, your brain can efficiently classify and group novel objects into behaviourally relevant categories to help you satisfy your current or future needs.
Without these rules, the brain would need to analyse every piece of information and compare it to every other piece of information that it has stored. Apart from taking a huge amount of brain power, this would make it impossible to ever react quickly to anything.
Abstract rules and categories give structure to our perception and thinking. They underpin many of our behaviours, such as planning, social interaction, reasoning and flexibility in adapting to new situations. Difficulties in creating these rules and using them properly have been linked to neuropsychological disorders such as autism spectrum disorder and schizophrenia.
When and how abstract rules emerge in the brain are therefore a topic of extensive research and debate. There is growing evidence that the prefrontal cortex has an important role in humans and non-human primates. However, damage to this region of the brain does not necessarily impair rule-dependent behaviour.
In a recent article in Nature Reviews Neuroscience, Brain Function CoE and Monash Biomedicine Discovery Institute researcher Farshad Mansouri and colleagues propose a framework for how abstract rules are formed and used in the primate brain.
They describe different types of rules, such as object matching versus non-matching, colour matching versus shape matching, and matching the number of items. For each type, they review evidence from human and animal studies to determine similarities and differences between species.
Based on this knowledge, the authors propose that abstract rules emerge from a dynamic, multi-stage process involving different brain mechanisms and memory. In this process, the prefrontal cortex is involved in forming, storing, retrieving and updating rules. In stable environments, the rules are reinforced, and little prefrontal cortex involvement is required. In new or changing environments, however, the rules are continually formed and updated. This requires more cognitive resources and the contribution of the prefrontal cortex.
This framework helps to explain the role of the prefrontal cortex in the emergence and implementation of abstract rules for controlling primate behaviour.
The researchers hope to study in more detail what brain mechanisms contribute to the formation and use of abstract rules.
Mansouri, F. A., Freedman, D. J., Buckley, M. J. (2020). Emergence of abstract rules in the primate brain. Nature Reviews Neuroscience, doi: 10.1038/s41583-020-0364-5
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