Mind, Body, and the Nervous System

• The biology of the mind includes serotonin and dopamine pathways.

Mind and Body

• A person's mind was thought to be separate from the body for most of history, called mind-body dualism.
• The relatively new idea of materialism considers psychological experience completely tied to our physical beings.

Biological Understanding of Behavior

• Biological and biochemical processes underlie all human behavior and thought.
• Biology alone does not control actions, rather environmental forces, actions, and choices also modify the brain.
• Physical and chemical changes occur in the brain whenever we learn, remember, feel, or act.

Biological Understanding of Behavior and Mental Processes

• Rats in enriched environments develop more neuron connections than those in boring environments (Rosenzweig & Bennet, 1972).
• Rats deprived of touch in infancy grow less, have fewer neuron connections, and higher stress hormones (Schanburg, 2003).
• Premature infants who receive massage grow faster and show better cognitive development than those who aren't touched (Field, 2010).

Nervous System

• The nervous system supplies the physical basis for psychological experience.
• It is the speedy, electrochemical communication system that both directs and is influenced by behavior and thought.
• The two major subsystems are the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
• The CNS contains the brain and spinal cord.
• The PNS contains all other nerve cells.
• The PNS is divided into the Somatic Nervous System and the Autonomic Nervous System.
• The Somatic Nervous System controls skeletal muscles.
• The Autonomic Nervous System controls glands and other muscles.
• The Autonomic Nervous System is divided into the Sympathetic Nervous System and the Parasympathetic Nervous System.
• The Sympathetic Nervous System arouses the body, mobilizing energy in stressful situations.
• The Parasympathetic Nervous System calms the body, conserving energy and maintaining homeostasis.

Neurons

• Neurons are the functional unit of the nervous system.
• Neurons communicate with each other and organize every aspect of our experience.
• There are approximately 100,000,000,000 neurons in the human brain and they form complex networks.
• Neurons may have 10,000 times more connections between them than there are neurons themselves.

Main Jobs of Neurons

• Relaying information
• Storing information, covering all memories and data.
• Regulating all internal processes.
• Sensing information from the outside world (eyes, ears, nose, etc.)
• Making and Releasing neurotransmitters (dopamine, serotonin, etc.)
• Working with the Endocrine System (hormones)

Kinds of Neurons

• Sensory neurons carry incoming information from the 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 important helper cells with many functions.
• Glial cells help nourish neurons, move neurons around, and clean up debris.
• Glial cells form myelin, repair neurons, and attack intruders, such as viruses and bacteria.
• There are 10 times more glia than neurons, so the brain is mostly glia.

Neuron Structure

• Neurons are similar to other cells in the body, including a cell membrane, a nucleus with organelles, and genetic material.
• Neurons have specialized structures that allow for communications, including axons, dendrites, terminal buttons, synaptic vesicles, and receptors.

Axons

• Single fibers that extend from the neuron.
• Axons can be either microscopic or more than 2 feet in length.
• Axons serve as transmitter for the cell, and carry nerve impulses toward other neurons
• Many axons are covered with a myelin sheath, that is a fatty substance that insulates it from other neurons, making nerve signals move faster.
• The area called the terminal button is at the end of the axon fiber.
• The small sacks inside a terminal button is called synaptic vesicles.
• Chemicals in those vesicles are called neurotransmitters.

Nerves vs. Neurons

• Neurons are single nerve cells.
• Nerves consist of neural “cables" containing many axons.
• Nerves are part of the peripheral nervous system, and connect muscles, glands, and sense organs to the central nervous system.

Dendrites

• Dendrites are multiple, usually shorter fibers, which receive signals from the axons of other neurons.
• Dendrites are cells “receivers”.

Synapses

• Synapses occur where axons and dendrites of adjacent cells never touch.
• Chemicals called Neurotransmitters are released in the gap between them .
• All communication between neurons is accomplished via neurotransmitters migrating across the synaptic gap and binding with receptor sites on the dendrites of adjacent neurons.

Connectome

• The structure and function of our brains, may make us who we are.
• Neurons communicate.

Explore the relationship between the mind and body, enriched environments, and the nervous system. Understand the function of neurons, synaptic connections, and the impact of touch on development. Review effects of the parasympathetic nervous system.