Students: Please note that this is a lecture outline that I share with you to help you with your note taking. It is not an exact duplicate of any power points and/or discussions that may be conducted in class.
Topic Presentation: Neuroscience and Behavior
I. How the Body Communicates Internally
A. Two communication systems
- The Nervous System – fast acting and focused
- The Endocrine System – slow acting
B. The Basic Building Block of the Nervous System
- The Neuron
- Receive, integrate, and transmit electrochemical messages
- Approximately 100 billion nerve cells in adult brain
ii. Types of Neurons (Neurons pass information in one direction only so separate nerve pathways are required for delivering and responding to neural messages. These pathways are called the sensory and motor pathways.)
- Sensory Neurons
- Carry messages to the central nervous system (toward the brain)
- Afferent – specialized sensory neurons that are sensitive to external stimuli
- Motor Neurons
a. Carry messages to the muscles of the body (away from the brain)
- Efferent
c. Note: Every one of your actions arises from neural impulses from the brain delivered to your muscles.
- Interneurons
- Relay Information
- Form complex circuits in the brain
- What is the Essential Anatomy of a Neuron?
- The Cell Body/Soma
- The Dendrites
- Axon Hillock
- Axon
- Myelin Sheath
- Terminal buttons
- Vesicles
- Neurotransmitters
- How do Neurons Communicate?
- Communication within the neuron (in order)
- Dendrites – receives information
- From other neurons
- Cell Body/Soma – processes information
- Axon hillock
- Axon – transmits information to next neuron via Action Potential
- Action Potential
- All or none
- A stimulus will either ‘fire’ the neuron or it will fail to fire it.
- Positive Ions flow into the neuron (depolarizing the negative charge in the axon) and moves along the axon membrane
- Resting Potential
- Slight negative charge across the membrane
- Terminal Button
- Communication between neurons – Synaptic Transmission
- Synaptic Cleft (Gap)
- Synapse
- Electrical impulse in the axon is converted into a chemical message
- Neurotransmitters
- Biochemical substances released into the synaptic cleft to stimulate or suppress other neurons
- Different kinds of Neurotransmitters molecules have specific shapes
- Receptors
- Lock and Key
- Reuptake
- Types of Neurotransmitters
- Dopamine
Excess implicated in Schizophrenia
- Serotonin
Imbalances implicated in depression
- Norepinephrine
- Acetylcholine
Disturbances can produce memory problems
- GABA
- Glutamate
- Endorphins
- The influence of neurotransmitters
- Certain neurotransmitters are only found in specific places (designated pathways in the brain)
- Different neurotransmitters have different effects
- Changes in amounts of neurotransmitters can affect our mood, memories, mental abilities, hunger, and more
- Boosting or diminishing the effects of neurotransmitters
- Diet
- Drugs
- Psychoactive drugs cross the blood brain barrier interact with neural signaling pathways
- Can increase the release of neurotransmitters into the cleft
- Can block neurotransmitter reuptake
- Can directly activate or inactivate post synaptic receptors.
- Enhance (agonistic) or inhibit (antagonistic) the natural chemical processes.
- Example: Prozac (SSRI) blocks return of serotonin to sending neuron
- Glial Cells – The other cell in the nervous system!
- Specialized support cells for neurons
- Form the Myelin Sheath
- Multiple Sclerosis is a disease that involves degeneration of the myelin sheath.
- Plasticity – Ability of the nervous system to adapt or change
- Learning
- Effects of experience
- Repair
- Examples
- After Ashley permanently damaged her left frontal lobe and lost the ability to speak (though she can still understand speech) she was able to recover some of her speech due to other parts of the brain taking over lost functions.
C. The Divisions of the Nervous System
- Central Nervous System
- Peripheral Nervous System
- relays information directly from the outside world to the brain
D. The Endocrine System
- Secretes hormones into the bloodstream reaching many distant organs
- Pituitary gland can either stimulate or inhibit the release of hormones from a gland.
- Adrenal gland produces hormones that energize your body for “fight or flight” responses.
II. The Brain
A. How We Study the Brain
- Lesions and Probes
- EEG
- An amplified recoding of brain electrical waves
- Brain Scans
- CT
- Computerized image of X rays passed through the brain at various angles
- PET
- A composite picture of neuron activity produced by detecting atomic particles emitted by a radioactive dye
- MRI
- Best for distinguishing between closely related brain structures
- fMRI
- distinguishes more active tissue from less active ones
- Other
B. Layers and Functions of the Brain
- Brain Stem and Cerebellum
· Drives vital functions such as heart rate, breathing, digestion
- Limbic System
· Adds emotions, complex motives, increased memory abilities
- Cerebrum
· Enables reasoning, planning, creating, problem solving
· Accounts for 2/3 of brain’s total mass
· Corpus callosum interconnects the two hemispheres of the brain
C. The Brain Stem Area
- Medulla
- basic bodily functions like breathing!
- cross over location of some nerve fibers that interconnect the left and right side of the body
- Pons
- regulates sleep
- Reticular formation (reticular activating system)
- regulates awake and alertness
- Thalamus: directs most incoming and outgoing signals, focuses attention
- “sensory switchboard” for all sensory systems except smell.
- Example: Listening to your favorite music involves the transfer of the auditory information from the ear through the thalamus en route to the auditory cortex.
D. Cerebellum: controls complex movements; orders series
- Examples: tap dancing, walking a tightrope, balance beam
- Functions are mostly automatic
E. Limbic System
- Hippocampus-memory
- Example: damage would impact your ability to name events that occurred after the damage (newer information)
- IF damaged , you would not be able to attend college
- Amygdala – emotion
- A stroke damaging part of the amygdale could change your emotions such as calming an angry disposition.
- Hypothalamus- regulates
- appetite, thirst
- sexual behavior
- temperature
- motivation
- communicates directed to the pituitary “master gland” of the endocrine system -
- pleasure centers
- homeostasis (body’s internal balance or equilibrium)
- Concept Check
F. Cerebral Cortex – forms the outer layer of he brain (divided into lobes by central and lateral fissures).
- Frontal Lobes
- Personality and Temperament
- Motor Control
- Motor cortex – left and right sides govern opposite side of body
- Planning
- Damage to frontal lobes can have devastating effects on human action and personality
- Parietal Lobes
- Somatosensory cortex
- Tactile experiences such as temperature, texture, density
- Location of objects in space
- Coordination of various senses
- Occipital Lobes
- Vision
- Color
- Movement
- Shape
- Shading
- Visual Cortex
- Devoted mostly to the retina
- Temporal Lobes
- Auditory Cortex
- Memory
- Association Cortex across the Lobes
- interpretation, planning
- Example: deciding as to whether you want to ask an attractive person out for a date
- Cerebral Hemispheres/Cerebral Dominance – The tendency for each hemisphere of the brain to take control of different functions
- Left –
- language centers
- Broca’s area
- Wernike’s area
- analytical and verbal processing including vocabulary
- Memory for words and numbers
- Anxiety and emotion
- Movement sequences
- Right
- Spatial orientation processing
- Facial recognition
- Music and shape memory
- Emotional responsiveness