The Biological Basis of
Psychological
Functioning & Behavior
Intro to Psychology
Instructor: Cheri Sayavong
Overview


Link between physiological and
psychological processes
What we will cover today
• Structure/Function of Neuron and
Neurotransmitters
• The Human Nervous System
• The Spinal Cord
• Major Structures of the Human Brain
• Male vs. Female Brain
MODULE 7
NEURONS: THE BASIC ELEMENTS OF
BEHAVIOR
Psychobiology

Examines the biological foundations
of behavior and mental processes
Basic Building Blocks

Neurons and nerve cells
are the basic building blocks
of the brain and nervous
system.
Neurons

Neurons are the basic components of
the nervous system
• Neurons receive and transmit
information

Our bodies have as many as 1 trillion
neurons!
 Neurons are the messengers
Typical Neuron Structure
Neuron - a microscopic cell that transmits information – in
the form of neural impulses – from one part of the body to
another (Gerow, 2012)

Neurons: The
Messengers
•
•
•
•
•
•
Receive and transmit
information
Neuron cell body makeup:
nucleus
cytoplasm
cell membrane
Nucleus – chromosomes
and genes
Cytoplasm – keeps the cell
alive
Cell membrane – protects
the cell
Neurons are comprised of
dendrites (receive
messages) and axons (send
messages)
Neuron Cell Body (Soma)
The Role of Myelin


Myelin Sheath– a white substance composed of
fat and protein
• Protects the axon
• Acts as an insulator
• Separates the activity of one neuron from
another
• Speeds up impulses
Axon Terminals/Terminal Buttons – where axons
end and neurons communicate with other
neurons
Loss of Myelin  Disorders


Loss of myelin produces many disorders
Most common is Multiple Sclerosis
• Occurs when myelin has been destroyed
and replaced by scars of hardened tissue
(medical terms is “sclera”)
• Symptoms depend on where myelin is lost
• No known cure – meds to slow progression
and improve function exist
YouTube Clip: Illustration of a
Neuron Structure

If you are more of a visual learner, watch
this 3-minute YouTube clip to get a better
understanding of the structure of a neuron
and how messages are sent and received.
• If you feel comfortable with the material thus
far, you are not required to watch this video
• https://youtu.be/lpNDLBQOoW8
Use it or Lose it

Born with all the neurons we will
have
• Unused neurons die off and are not
replaced by new ones


makes neuron unique from other cells the
reproduce like skin & blood cells
Function of lost neuron can be taken over
by surviving neurons
Neurogenesis


The production of
functioning neurons
after birth
Research Studies
• 1990s neurogenesis
occurred with rodents
• Current research shown
neurogenesis in the
lower brain center and
cerebral cortex
• EVIDENCE SUGGESTS
BRAIN CAN
REGENERATE LOST
NEURONS!!!!
Neurogenesis – Podcast
https://www.youtube.com/wa
tch?v=B_tjKYvEziI
Sandrine Thuret – neuroscientist
(11 minute podcast)
Function of Neurons

The function of a neuron is to transmit
neural impulses throughout the nervous
system
• Neural impulse – “a rapid, reversible change in
the electrical charges within and outside a
neuron” (Gerow, 2012)
 Chemical ions – carry electrical charge (+/-)
that attract
• Resting Potential (more – on the inside of neuron)
• Action Potential (more + on inside of neuron)
• Refractory Period – when neuron cannot fire
Neuron Threshold

The minimum level of stimulation
needed to fire
• Neurons either fire or don’t fire 
known as the All-Or-None law

What determines if we see bright/dim lights
is the # of neurons that are firing (brighter
lights = higher # neurons firing)
How Neurons
Communicate
Synaptic
Transmission
-
Once an impulse
reaches the axon
terminal of a
neuron
neurotransmitters
are released to
communicate with
other neurons
-
Either stimulate the
neuron (excitation) or
prevent neuron from
firing (inhibition)
Neurotransmitters


Neurotransmitter – chemicals that
communicate messages from one
neuron to another across the
synapse
Neurotransmitters must fit like a
puzzle
• Excitatory Message = FIRE
• Inhibitory Message = DON’T FIRE
Common Neurotransmitters


Acetylcholine(ACh) – stimulates muscle
contractions; associated with memory
formation and arousal
• Alzheimer’s Disease – too little ACh
Norepinephrine – maintains vigilance
and activation; high level emotional
arousal such as heart rate/blood pressure
• Depression – too little/Anxiety – too
much
Common Neurotransmitters

Dopamine – mood regulation;
reward & pleasure stimuli; thought
disturbances; impairment of
movement
• Parkinson’s – too little = movement/too
much = involuntary movements

Serotonin – sleep/wake cycles;
depression and aggression
Common Neurotransmitters

Endorphins – pain suppression;
pleasure derived from risky behavior
• Disorders that impact one’s ability feel
pain
• http://www.youtube.com/watch?v=JMV
QknfLA2s&feature=related


Glutamate – learning, memory and
pain perception
Gamma-Amino Butyric Acid (GABA) –
eating, aggression and sleeping
Interesting Studies Concerning
Neurons

Neurotheology (Andrew Newberg)

Author of “How God Changes Your Brain”
• Are the brains of atheists and religious people different?
• What is going on in a person’s brain when they are
praying or communicating with God?

https://www.youtube.com/watch?v=6lAzPW
S1Yhc
• (17 minute long interview)

Mark Waldman – “My Brain on God”

https://www.youtube.com/watch?v=ZjnCGY
fFDKw

(19 minutes long)
MODULE 8:
The Nervous System & The
Endocrine System
“He who joyfully marches to music in rank and
file has already earned my contempt. He has
been given a large brain by mistake, since for
him a spinal cord would suffice.”
-Albert Einstein (1879-1955)
What is the Nervous System?

Communication network
• Coordinates & directs body’s actions

3 basic tasks of Nervous System
• Receive sensory messages
• Organize that input & integrate
w/existing info
• Use integrated info to send messages to
muscles & glands
Nervous System Organization
Central Nervous
System
Brain
Spinal Cord
Peripheral
Nervous System
The Spinal Cord & Reflexes
Transmits Messages
between brain & body
 Contains a bundle of
neurons the run from
the brain down the
back
Controls
Reflexes

Reflexes – automatic,
involuntary responses
to incoming stimulus
• Sensory (afferent)
neurons

Perimeter of body 
nervous system &
brain
• Motor (efferent)
neurons

The spinal cord is the primary
means of transmitting
messages between the brain
and the rest of the body

Brain  to
muscles/glands
Types of Neurons



Sensory Neurons- carry impulses
toward the brain or spinal cord
Motor Neurons – carry impulses
away from the spinal cord and brain
to muscles and glands
Interneurons – neurons within the
central nervous system
The Spinal Cord

Connects the brain
to the rest of the
body
• Spinal cord housed
inside vertebral
column for
protection

Made up of 31 segments
• Spinal cord injuries =
loss of communication
Major Functions of Spinal Cord

#1 Communication - carry messages
between nerves & brain
• Interneurons carry messages to/from

Two major neural pathways
• Ascending – from extremities/organs to brain
• Descending – from brain to organs/muscles

If spinal cord is damaged no
communication occurs (loss of function)
Major Functions of Spinal Cord


#2: Integrative Function
Involves mediating spinal reflexes
(automatic behaviors that occur
without conscious awareness)
• “Knee-jerk reactions”
Spinal Cord Injuries


Kevin Everett –
NFL Buffalo Bills
Suffered spinal
cord injury (2007)
Advancement in
Treatment
• Hypothermia
treatment –
prevent swelling
and hemorrhage
• Walking now!!
THE PERIPHERAL NERVOUS
SYSTEM
The Peripheral Nervous System
(PNS)


PNS is comprised of all the parts of
the nervous system except the brain
and spinal cord
Major divisions of the PNS:
• Somatic Division – controls voluntary
movements
• Autonomic Division – controls
involuntary movement
Autonomic Nervous System


Prepares body for action during a
crisis, threat or stressful situation
Sympathetic Division
• Prepares body to act (increase heartrate)

Parasympathetic Division
• Acts to calm the body after emergency (decrease
breathing)
THE ENDOCRINE SYSTEM



ENS sends messages via the
bloodstream by secreting hormones
Hormones – chemicals that regulate
the functioning or growth of the body
Pituitary Gland “the master gland”
MODULE 9
THE BRAIN
How Scientists Study The Brain





Accident & Injury
Surgical Intervention
Electrical Stimulation
Electrical Recording
Brain Imaging
Accident & Injury

Scientist work
backward to see
what part of the
brain is damaged
in an accident
Brain Imaging
CT Scan & PET Scans
fMRI
 Functional Magnetic
Resonance Imaging
(fMRI) – noninvasive
devise that provides
images of the brain
• Measure movement of
molecules
• See neural activity in
the brain
Electrical Stimulation &
Recording

Electrical
Stimulation
• Electrodes (wire)
placed in the brain
that delivers an
electrical current
and looking for
reaction/effect
Surgical Intervention

Conduct
procedures such as
surgically cutting
or removing
(ablation) part of
the brain to see
what effects can be
seen
Three evolutionary layers of the
brain
The Central Core
The Limbic System
The Cerebral Hemispheres
The Central Core
Medulla – heart
rate/BP
Pons – sleep/wake
cycles
Cerebellum –
balance &
coordination
Midbrain – hearing,
sight and pain
Hypothalamusmotivation/emotion
Reticular Formation
– attention and
alertness
Hippocampus – new
memories
Amygdalaemotions selfpreservation
Thalamus – sensory
relay
The Limbic System
“The Animal Brain”



Fully developed only in mammals
Located between the central core
and the cerebral hemispheres
Learning and emotional behavior
• Hippocampus and amygdala are parts of
the limbic system (memories &
emotions associated with selfpreservation)
The Cerebral Cortex
“The New Brain”



Newest part of the
brain
• Distinguishes
humans from all
other mammals
Outer layer of brain
regulates complex
behaviors (thought,
vision, language, etc…)
Made up of 2
hemispheres & 4 lobes
Four Lobes of the Brain
The 4 Lobes of the Brain

Occipital Lobe
• Receives and processes visual info

Temporal Lobe
• Primary auditory cortex

Parietal Lobe
• Primary somatosensory area (sensations
such as heat, pressure, pain, spatial ability

Frontal Lobe
•
•
•
•
Primary motor cortex
Intelligence & personality
Center of Executive Function
Coordinates messages between lobes
Two Hemispheres of Brain

Left & right sides separate
• Take care of different aspects of the
same function

Connected by corpus callosum
• Communication between L/R brain

Lateralization
• Definition: some functions are carried
out exclusively by one side of the
brain
Contralateral Motor Control
Motor area controls
movement
• Right hemisphere
controls left side of
body
• Left hemisphere
controls right side
Contralateral Sensory Control




Sensory data crosses
over in pathways
leading to cortex
Visual crossover
left visual field to
right hemisphere
right field to left
hemisphere
Lateralized Brain Functions
Left Hemisphere
1.
Speech
2.
Movement of the
right side of the body
3.
Sensation on the
right side of the body
4.
Vision in the right
half of the visual field
Right Hemisphere
1.
Music and art
appreciation (drawing
ability)
2.
Movement of the left
side of the body
3.
Sensation on the left
side of the body
4. Vision in the left half
of the visual field
Right v. Left Brain
Left Brain
 See the details before
the whole picture
 Prone to reason and
hard facts
 Sequential and orderly
info processing
 Verbal
 Reality-oriented
(based on facts and
real-life
consequences)
Right Brain
 look at the whole
picture first and
details later
 Prone to “gut feelings”
and speculation
 Random info
processing
 Non-verbal
 Fantasy-oriented
(creative)
Neuroplasticity


The brain’s ability to change throughout
the life span through the addition of new
neurons, new interconnections between
neurons, and the reorganization of
information-processing areas
Neurogenesis – new neurons are created
in the brain during adulthood
• Preliminary results of experiments for
Parkinson’s disease
• Stem cells – could revolutionize medicine for
conditions that result from cell damage
(stroke/cancer)
“Girl Living With Half
Her Brain”
http://www.youtube.com/wat
ch?v=2MKNsI5CWoU&feature
=related
Corpus Callosum



Connects and
communicates
between
hemispheres
Dual side processing
If Corpus collosum is
cut?
• Sensory inputs
crossed
• Motor outputs
crossed
• Hemispheres can’t
exchange data
The ‘Split Brain’ Studies



Surgery for epilepsy
Roger Sperry, 1960s
Special apparatus
• picture input to one side
of brain
• screen blocks objects on
table from view
The ‘Split Brain’ Studies
 Picture to right brain
• Can’t name it
• Left hand can identify by
touch
The ‘Split Brain’ Studies
 Picture to right brain
• Can’t name it
• Left hand can identify by
touch
 Picture to left brain
• Can name it
• Left hand cannot identify by
touch
Split Brain Studies
• Split Brain Studies You Tube “Joe”

http://www.youtube.com/watch?v=lf
GwsAdS9Dc&feature=related
Gender Differences in the Brain

Men v. Women’s brain
• Position, connections and size
differences

On some tasks women use both
hemispheres and men only one for the same
task
• Differences evolved over time


Men better spatial-navigational skills
(hunters)
Women better memory for words, objects
and fine motor skills (food gathering,
cooking, etc..)
Brain Gender Studies – Video
Games

Males and their video games
• Experiment looked at the preference of
males for playing video games as it
relates to brain functioning/activity
(using MRI)

Found greater activity in limbic system
(associated with reward and addiction) in
males than females
Brain Gender Studies - Emotion

Women more emotional?
• Experiment (2002) involving recall or
recognize emotional information
• Women recalled emotional stimulating
photos 10-15% more accurate then
their male counterparts
• On brain imaging during the task,
women’s neural responses to emotional
scenes were more active than the men
in the experiment
Psychology of Gender


Are brains male or female?
Professor Daphna Joel – Ted Talk (14
mins long)
• https://www.youtube.com/watch?v=rYp
DU040yzc