The neural basis of imagination: An evolutionary perspective

Area of Science:

• Neuroscience
• Evolutionary Biology
• Cognitive Science

Background:

• Behavioral tasks operationalize imagination but are insufficient for inferring animal cognition.
• The default mode network (DMN) is central to human imagination.
• Understanding the evolutionary basis of the DMN may illuminate animal imagination.

Purpose of the Study:

• To trace the evolutionary origin of the default mode network (DMN).
• To understand the neural innovations underlying the DMN's evolution in mammals.
• To explore the potential for imagination in non-human animals.

Main Methods:

• Comparative neuroanatomy of the default mode network (DMN).
• Analysis of neural structures like the neocortex and hippocampus across mammalian evolution.
• Review of existing literature on animal cognition and imagination.

Main Results:

• The evolution of the DMN involved key innovations at the base of the mammalian lineage, including neocortex emergence and hippocampal reorganization.
• Parallel evolution of the neocortex and hippocampus included 3D organization, canonical microcircuits, and pyramidal neuron development.
• Previous studies may have underestimated hippocampal modifications' role in brain evolution and imagination.

Conclusions:

• Significant neural innovations in early mammals, particularly in the hippocampus, are crucial for understanding the evolution of imagination.
• A functionally similar network to the mammalian DMN is expected in birds, indicating convergent evolution.
• Further research into animal cognition may reveal indicators of imagination, potentially linked to language in humans.