Neurons and the Nervous System

Biological Bases of Behavior

• Biology is relevant in a psychology course for understanding the connection between biological systems and mental processes, which can help us live healthier lives.
• The composition of the brain significantly determines who an individual is.

Labs

• Candy Neurons: Construct a neuron using circular and long flexible candies (excluding those with peanuts), ensuring enough for your group.
• Build a Brain Project: A brain model can be created beginning on Friday
• Models can be created in groups of three and use materials like styrofoam, playdoh, legos, or cake.
• Bring table protection in anticipation of a messy construction.

Interaction of Heredity and Environment

• Human traits can develop through experience or be present at birth.
• Traits include: personality, beliefs, intelligence, mental health, and language.
• Psychologists debated for years whether nature or nurture determined who individuals become.
• Prevailing view today: nature and nurture BOTH contribute to our individual formation.
• Epigenetics helps understand the interaction between nature and the environment
• Epigenetics examines how the environment can trigger or block genetic expression, which determines which genes activate.
• Children born during a famine are more prone to coronary disease/obesity due to famine conditions affecting their pregnant mothers.

Understanding Nature and Nurture

• Evolutionary Psychology: Humans are alike due to shared biology and evolutionary history.
• Natural Selection: Organisms compete to survive, and biological/behavioral variations increase chances of reproduction/survival. Characteristics change overtime
• Eugenics was a discriminatory 19th-20th century movement.
• Eugenics measured human traits, encouraged only the "fit" to reproduce, and applied evolutionary perspective to support the idea.
• Behavior Genetics: Examines how individuals differ due to differing genes and environments
• Today, most psychologists study and support learning from differences.
• Nurture works on what nature provides.
• Family Studies can be done to assess whether similar genetic structures and environments lead to similar responses in health interventions (diet, exercise, medication).
• Twin Studies explores nature vs nurture: Identical twins' similarities suggest nature, while fraternal twins' suggest nurture.
• Adoptive studies find that personality resemblance among those raised together (adopted or not) is slight, except in identical twins.

Overview of the Nervous System

• Nervous System: the body's speedy electrochemical communication network consisting of nerve cells
• Contains the Central nervous system (brain and spinal chord) and peripheral nervous system (all other nerves)

Central Nervous System (CNS)

• Includes the brain and spinal cord and acts as the body's decision-maker
• Neural networks: interconnected neural cells that create more connections as experience is gained
• The CNS important in the body and encased in bone

Peripheral Nervous System (PNS)

• Consists of all nerves not encased in bone
• Sensory and motor neurons connect the CNS to the rest of the body.
• The PNS gathers information from the body and transmits CNS decisions and is divided into two categories: somatic and autonomic.

Somatic Nervous System

• Controls voluntary muscle movement
• Uses motor neurons
• Is a skeletal nervous system Receives sensory information, interprets it, and transports orders to the CNS, which controls the muscles

Autonomic Nervous System

• Controls the automatic functions of the body and is divided into sympathetic and parasympathetic categories.

Sympathetic Nervous System

• Activates bodily systems
• It induces a fight or flight response and activates the freeze response
• Heart rate spikes automatically, breathing accelerates, pupils dilate, glucose is stimulated, and urination is inhibited.

Parasympathetic Nervous System

• Calms the body and slows the body down after a stressful event
• Breathing and heart rate slow down, pupils constrict.

Heart Rate Demonstration

• During experiments, experimenters take radial pulses and position heart rate record sheets to record wrist data.
• During the demonstration, experimenters should not move their hand off the subject’s wrist between counts.
• Typically, the data will fall under the base rate (normal), arousal (subject remembers the event), recovery (return to normal).
• Medical and mental health professionals warn of mental stress causing physical or biological ailments.

Biological Psychology and Neurotransmission

• Module covers neuron structure and types
• A neuron, or nerve cell, is the basic unit of the nervous systems

Neuron Function and Glial Cells

• Neurons possess several unique types and specific jobs
• Main functions of every: receive messages, carry messages, send messages
• Thoughts occur when firing these messages
• Glial Cells were once thought to be "helper cells" and only neurons communicated in the nervous system
• Glial cells communicate: together and with neurons via chemical neurotransmitters
• They support, nourish, protect/insulate, and manage waste of neurons while also playing a role in learning and thinking.

Types of Neurons

• Sensory afferent neurons send messages from body tissues and sensory receptors to CNS
• Interneurons are internal communication neurons are more complex and numerous
• Motor efferent neurons carry instructions from the CNS to muscles and glands

Sensory Neurons

• These neurons are afferent because they carry Messages from body tissues & sensory receptors inward.
• Sensory neurons measure things like the volume of the air, the volume/loudness of a noise

Motor Neurons

• Motor Neurons are efferent and carry instructions from the CNS to muscle and glands.
• They carry mesages out from your nervous system

Sensory vs Motor Neurons

• Sensory Neurons: have different types for each different sense that respond to non-chemical stimulation that send that stimulus as an afferent signal to the brain
• Motor Neurons: Connect to all of our muscles and are the only way our thoughts can exist in the real world. Can react to involuntary signals and send efferent signals from the brain

Interneurons

• Interneurons manage internal communications and complex signaling in the human body
• There are billions of interneurons in the human nervous system and are only found inside the CNS

Reflex Arc

• Sensory neurons in the PNS and CNS: send messages to interneurons who then send messages to motor neurons.
• Touching a very hot cup of coffee invokes the reflex arc
• Receptor sites in the nervous system pick up the pain and alert sensory PNS neurons which report that message between your interneurons inside the spinal cord to alert motor neurons so you retract

Neuron Details

• Instructions are given to create a candy model of a neuron. To highlight:
  • Nucleus: a part that contains DNA and coded production of proteins
  • Soma: this part protects the nucleus
  • Other key areas: Dendrites, Axon, Myelin Sheath/terminal branches

Neuron Communication and Reaction Potentials

• The process of neural transmission occurs in an orderly, systematic way.
• Transmission Requires: Resting Potential, Polarized
• Other Terms to Know:Action Potential, Depolarize, Stimulus, Threshold, All-or-nothing Principle, Axon, Refractory Period
• Action Potential speed increases with the myelin sheath.

Candy Neuron Construction

• Create a candy neuron model using an provided diagram's parts and functions. Slides should cover:
• Dendrites, Ions, Positively charged Sodium, Postive Potassium, Stimulus Neurotransmitters, Receptors, Threshold, All-or-Nothing, Action Potential, Gated Channels
• Depolarization, Positively Charged Sodium, Negative Charge, Action Potential, Sodium Gates, Potassium Gates, Myelin Sheath
• Resting Potential, Polarized, Negative Charge, Positive Charge

Neural Transmission Disruptions

• Multiple Sclerosis is characterized by breakdown of the myelin sheath, which affects brain-muscle coordination and cognition.
• Myasthenia Gravis is a neuromuscular ailment where ACh neurotransmitter is blocked, causing muscle weakness, impaired control, or paralysis.

Neurons Communication and Transmitters

• Synaptic Gap: the tiny space (one millionth of an inch) between the axon terminal of one neuron and the receiving neuron.
• Neurotransmitters: are chemical messengers that cross the gap to bind receptor sites on the receiving neuron.
• Reuptake: which the sending neuron reabsorbs the excess neurotransmitters

Neurotransmitter Examples

• Acetylcholine (ACh): involved with muscle action, memories; Alzheimer's linked to deteriorating ACh.
• Dopamine: controls movement, thought, emotion; Parkinson's linked to low dopamine, schizophrenia with too much dopamine. -Serotonin: linked to moods; depression linked to low serotonin.
• Endorphins: involved in pain control. Highly addictive drugs impact endorphins
• "Runner's High" is an example of an action controlled by endorphins

Neurotransmitter Activity

• Neurotransmitters may cause malfunctions which can in turn cause disease
• Diseases like Alzehimers, parkinsons, as well as over stimluation are all linked to problems with neurotransmitters

Biological Psychology and Neuron Details

• The Build a Brain Project consists of creating a model of the brains, the details of which will be covered in future sections

The Cerebral Cortex

• The cerebral cortex intricate layers are cerebral hemispheres and ultimate control.
• Watch Crash Course Psychology #4 "Brain Hemispheres”

Structure of the Cerebral Cortex

• Contains Frontal Lobe, Parietal Lobe, Temporal Lobe, and Occipital Lobe

Cerebral Cortex Lobes

• Frontal Lobe: Behind the forehead, it is involved in muscle movement and speaking.
• Parietal Lobe: At the top of the head towards the rear that receives sensory input for touch and body position.
• Occipital Lobe: at the back of the head and receives information from the visual fields.
• Temporal Lobe: Roughly above ears and includes auditory area and has linguistic processing and receives information from the opposite ear

Cerebral Cortex Functions

• Sensory Cortex: Area at the front of parietal lobes that registers and processes body, touch, and movement sensations. The sensitivity of the region dictates the area dedicated to it
• The greater a sensitivity for a region the larger dedicated sensory cortex.
• Motor Cortex: an area, at the read of frontal lobes, that controls voluntary movements.
• Association Areas are responsible for: learning, remembering, and thinking

Cerebral Processes and Association

• Prefrontal Cortex controls: planning, judgement, processing
• Parietal Lobes: Responsible for logic
• Temporal Lobe: Recognizes faces Broca’s Area: Responsible for speaking Wernicke’s Area: Responsible for understanding language

Brain Adaption and Change

• Plasticity: A brain's ability to change and reorganize new pathways after injury.
• Neural components and Tools of Discovery consist of older lower level functions that influence greater more complex processes.

Brain Exploration

• CT Scan: X-ray photographs taken from different angles and combined by a computer into a composite slice.
• PET Scan: Detects visual display
• MRI: Used to produce images of brain anatomy.
• EEG: is an amplified recording

This quiz explores the primary functions of neurons, the role of glial cells, and neuronal communication. It also covers the sympathetic nervous system's effects and the connection between mental stress and physical health. Furthermore, it touches on neurons involved in visual processing.