Brain evolution relating to family, play, and the separation call.

Area of Science:

• Evolutionary Biology
• Neuroscience
• Paleontology

Background:

• Mammals evolved from mammal-like reptiles (therapsids) during the Pangaean era, approximately 250 million years ago.
• The transition from reptiles to mammals was marked by significant behavioral and neurological developments.

Purpose of the Study:

• To investigate the evolutionary origins of key mammalian behaviors: nursing, audiovocal communication, and play.
• To explore the neuroanatomical basis, specifically the thalamocingulate division of the limbic system, underlying these behaviors.

Main Methods:

• Comparative neuroanatomy examining the triune forebrain structure in mammals.
• Analysis of evolutionary transitions from reptilian to mammalian brain structures.
• Inference of functional roles for the thalamocingulate division and prefrontal neocortex in mammalian behavior.

Main Results:

• Identified nursing, audiovocal communication (e.g., separation calls), and play as crucial developments in mammalian evolution.
• The thalamocingulate division, a derivative of early mammals, is proposed as a key structure for these behaviors.
• This division lacks a reptilian counterpart and connects to the prefrontal neocortex, vital for social behaviors.

Conclusions:

• The evolution of the thalamocingulate division was critical for the development of the mammalian behavioral triad.
• This neuroanatomical development facilitated maternal care, offspring communication, and social bonding in early mammals.
• The prefrontal neocortex, linked to this system, plays a role in human familial acculturation.