The Biology of The Mind

• The Biology of the Mind

Mind and Body

• Mind-body dualism has been the concept for most of history with a person's mind considered separate from the body.
• Psychological experience is tied to a person's physical being, and is a relatively new idea (materialism).
• Biological and biochemical processes underlie all human behavior and thought.
• Biology does not simply control what people do, however environmental forces, actions, and choices can modify the brain such that physical and chemical changes occur every time someone learns, remembers, feels, or acts.
• Rats in enriched environments develop more neuron connections versus those in boring environments.
• Infant rats deprived of touch grow less, have fewer neuron connections, and have higher stress hormones.
• Premature infants who receive massage grow faster and show better cognitive development than those not massaged.

The Nervous System

• The nervous system is the body's speedy electrochemical communication system.
• It directs and is influenced by behavior and thought.
• It is the physical basis for pyschological experience
• The nervous system is divided into 2 major subsystems:

Central Nervous System (CNS)

• Includes the brain and spinal cord.

Peripheral Nervous System (PNS)

• Consists of all other nerve cells.
• Somatic Nervous System is a division of the perpherial nervous system, and controls skeletal muscles in the body.
• Autonomic Nervous System is a division of the PNS, and controls glands and other muscles.
• The Sympathetic Nervous System, a division of the ANS, arouses the body and mobilizes the energy during stressful situations.
• The Parasympathetic Nervous System, a division of the ANS, calms the body and conserves energy.
• The Parasympathetic Nervous System maintains homeostasis.

Neurons

• Neurons are the functional units of the nervous system.
• They are cells that communicate with one another and organize every aspect of experience.
• The human brain has approximately 100,000,000,000 neurons.
• There may be 10,000 times more connections between neurons than neurons themselves, and they form complex networks.
• Neurons relay and store information.
• They move muscles and bones.
• They also regulate all internal processes and sense information from the outside world.
• Neurons make and release neurotransmitters such as dopamine and serotonin.
• They work with the Endocrine System (hormones) to accomplish tasks.
• Sensory neurons carry incoming information from sense receptors to the CNS.
• Motor neurons carry outgoing information from the CNS to muscles and glands.
• Interneurons connect the two neurons.

Glial Cells

• Glial cells are considered important helper cells.
• They help to nourish the neurons, move them around, cleaning up debris.
• They form myelin and repair neurons.
• They also attack foreign substances like viruses and bacteria.
• There are 10x more glial cells than neurons, the brain is mostly glia.
• Neurons grow new networks, reaching out to connect with one another, "firing" or "staying" together.
• Like other cells, neurons have a cell membrane, a nucleus with organelles, and the same genetic material as other cells.
• Specialized structures allow for neuron communication using axons, dendrites, terminal buttons, synaptic vesicles, and receptors.
• An action potential is an electrical impulse and when it occurs, all of it transmits (the "all or nothing" principle).
• Axons are single fibers extending from the neuron that can be microscopic or more than 2 feet long.
• They serve as transmitters for cells, carrying the nerve impulses to other neurons.
• Many axons have a myelin sheath, a fatty substance, that insulates it from other neurons and makes nerve signals move faster.
• At the end of an axon fiber is a terminal button containing synaptic vesicles which contain neurotransmitters.
• Neurons are single nerve cells.
• Nerves consist of neural "cables" containing many axons.
• Nerves are part of the peripheral nervous system and connecting muscles, glands, and sense organs to the central nervous system.
• Dendrites are usually multiple, shorter fibers than axons.
• They receive signals from the axons of other neurons and are cells "receivers".
• Axons and dendrites of adjacent cells do not touch.
• There is a gap between them, chemicals called neurotransmitters are released.
• All communication between neurons is accomplished via neurotransmitters migrating across the synaptic gap, binding with receptor sites on the dendrites of adjacent neurons.

Connectome

• The structure and function of the brain makes people who they are.
• Understand the complexity of the minds and brains is how the neurons talk to each other.
• It is an example of science working from a theory to a testable hypothesis to experiment.