Evolution of the Human Brain

Introduction

• Human brain evolution began hundreds of millions of years ago.
• Initially, the brain coordinated and governed body functions.
• Evolutionary history reflected in species from fish to primates.
• Distinct functions found in the cerebral cortex and other brain areas.
• Behavioral differences between men and women linked to brain evolution.
• Mental illnesses may have evolutionary roots.

Overview of Brain Evolution

• The brain evolved through natural selection over eons.
• Initial function of the nervous system: support bodily functions for survival.
• The concept that the body served the brain instead of the other way around.
• Enteric nervous system (gut brain) may be the first type of brain to evolve.

Evidence from Cnidarians

• Cnidarians, like jellyfish, possess a nerve net but no head brain.
• This simple nervous system facilitates basic movement and digestion.

The Nervous System as a Biological Government

• Taylor Guthrie's Argument: The nervous system acts as a biological government.
• Evolution of the nervous system to meet physiological needs and safety.
• Older brain regions manage physiological functions, while newer regions handle orientation to danger.

Human Ancestry and Brain Structure

• Humans descended from an ancestor similar to chimpanzees.
• Evolutionary lineage: mammals -> reptiles -> fish.
• Comparative brain structures across fish, reptiles, mammals, and humans.
  • Key Structures: Cerebral cortex, cerebellum, brainstem, rhinecephalon.
• Fish brain is mostly brainstem; human brain is mainly cerebral cortex.

Functional Units of the Brain

• Cortex: Neocortex for complex thought and perception.
• Subcortical Regions: Manage bodily functions and emotions.
• Neocortex has a unique architecture with cortical columns modeling reality.

Cognitive Control and the Prefrontal Cortex (PFC)

• PFC enables inhibition of impulses and cognitive control.
• David Badre's Definition: Cognitive control bridges goals and actions.
• Functions include generative behavior and episodic future thought.
• Other mammals have PFCs, but they are less complex than in humans.

Evolutionary Changes in Brain Function

• Evolutionary adaptations affect psychology and mental processes.
• Differences in sexual behavior between men and women explained by evolutionary strategies.
  • Men tend to seek multiple partners; women focus on nurturing few offspring for survival.

Mental Illness and Evolution

• Mental illnesses may be exaggerated traits from evolutionary advantages.
• Anxiety can lead to heightened alertness and avoidance of threats.
• Symptoms of depression may have evolved for energy resource allocation in response to threats.

Conclusion

• The evolution of the human brain and its psychological implications are complex and not fully understood.
• This video serves as a coarse overview of human brain evolution.
• Encouragement to subscribe and participate in discussions.