Psychology Around Us:

Chapter 3
Neuroscience
 Learning Objectives (1 of 3)

1. Understand the key methods that scientists use to learn about nervous
system anatomy and functioning.
2. Name and describe the functions and subdivisions of the two major parts
of the nervous system and become familiar with current research in spinal
cord injury.
3. List key structures of the brain and describe their relationships to our
behaviour.

Copyright ©2022 John Wiley and Sons Canada, Ltd. 2

 Learning Objectives (2 of 3)

4. Describe the two major types of cells in the nervous system and describe
the primary functions of each.
5. Describe what happens when a neuron “fires,” and how neurons
communicate with one another to produce behaviour, become familiar
with neural networks and neuroplasticity.

Copyright ©2022 John Wiley and Sons Canada, Ltd. 3

 Learning Objectives (3 of 3)
6. Explore the neuroscience findings regarding brain injury and the evidence
for brain lateralization.
7. Describe the basic theory of evolution and explain how it has influenced
our understanding of the human nervous system and the evolution of the
human brain.

Copyright ©2022 John Wiley and Sons Canada, Ltd. 4

 Neuroscience
• The study of the brain and the nervous system.

By Jensflorian - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=39237155

The Brain Has Huge Cultural Impact
 Other Brains?
• Animals?
• Computers?
• Artificial Intelligence?
HOW DO WE STUDY THE BRAIN?
 Techniques for Studying the Brain
• Examining autopsy tissue
• Testing patients with certain types of brain damage
• Recording electrical activity from the brain
– E.g. Electroencephalography (EEG)
• Animal studies
• TMS (Transcranial Magnetic Stimulation)
– Delivery of electromagnetic pulse
 Neuroimaging
• Techniques that allow for studying brain activity and structure by
obtaining visual images in awake humans
• Neuroimaging techniques include the following:
– MRI (Magnetic Resonance Imaging)
– fMRI (Functional Magnetic Resonance Imaging)
– CAT or CT (Computerized Axial Tomography)
– PET (Positron Emission Tomography)
– DTI (Diffusion Tensor Imaging)
 Brain Imaging Examples

CAT scan MRI DTI

 Organization of the Nervous System
• Central nervous system (CNS) – consists of the brain and spinal
cord
• Peripheral nervous system (PNS) – consists of all the nerves
that deliver information from the periphery to the CNS
• Neurons – the cells that carry information between the parts
of our body and the nervous system
 Types of Neurons
• Afferent neurons – carry signals from the PNS to the CNS
• Efferent neurons – carry signals from the CNS to the PNS,
muscles, and glands
• Interneurons – the relay cells between different neuron types;
for example, interneurons are found in the spinal cord
between the motor and sensory neurons
 Peripheral Nervous System
• Somatic nervous system – all the nerves that:
– gather sensory information from the body, neck, and
head and deliver it to the spinal cord and brain
– send information about movement from the CNS to the
muscles of the body, neck, and head
• Autonomic nervous system – comprises the sympathetic and
parasympathetic nervous systems
 Autonomic Nervous System
• Sympathetic nervous system – responsible for the fight-or-
flight reaction
• Parasympathetic nervous system – reverses the effect of the
sympathetic nervous system to return the body to its resting
state
CENTRAL NERVOUS SYSTEM
 The Spine
• Portion of the central nervous system that extends down
from the base of the brain and mediates sensory and
motor information.
Reflex
Circuit
of the
Spinal
Cord
 Spinal Cord Injuries
• A spinal cord injury occurs when the nerves that make up the
spinal cord itself are damaged
• Sometimes when injuries occur, the spinal cord still functions
early after the injury, but subsequent inflammation can
permanently damage the spinal cord, leading to permanent
deficits
 The Brain
• Lots of bits of anatomy to learn; do your best to memorize
the parts and their core functions
• Think about what makes the human brain unique
• Think about what it means that humans developed brains
like the ones we have
– What evolutionary advantage (if any) did it provide?
– What does the size and location of different structures tell us?
 3D Tour of the brain
• https://www.brainfacts.org/3d-brain
 Structures of the Brain (1 of 3)
• Hindbrain
• Medulla, pons,
cerebellum,
reticular formation
• Regulates basic life
functions; part of
the brain closest to
the spinal cord
 Structures of the Brain (2 of 3)
• Midbrain
• Substantia nigra
• Important in the
fluidity of
movement and
inhibiting
movements
 Structures of the Brain (3 of 3)
• Forebrain
• Thalamus,
hypothalamus,
pituitary gland,
limbic system,
basal ganglia,
cerebral cortex
 Parts of the Hindbrain
• Medulla
– regulates heartbeat, breathing, sneezing, and coughing
• Pons – bridge between the medulla and other brain areas
– important for sleep, dreaming, breathing, swallowing, eye movements,
and facial sensation and expression
• Cerebellum
– important for motor coordination and certain types of learning that
involve movement, such as learning to play the piano
• Reticular formation
– regulates sleep/wake cycle Involved in wakefulness, arousal, and mood
 Parts of the Forebrain
• Thalamus
– serves as a relay station for incoming sensory information
• Hypothalamus
– important for motivation, basic drives, and control of the endocrine
system
• Pituitary gland
– regulates hormones
• The limbic system
– involved in the regulation of motivation, emotion, and learning and
memory
 The Limbic System
• Amygdala
– involved in processing fear
• Hippocampus
– important for certain types of learning and memory
 More Parts of the Forebrain
• Basal ganglia
– plays a role in cognitive flexibility and voluntary movement control
– Includes the nucleus accumbens, important for motivation and
reward learning
• Cerebral cortex
– responsible for complex functions: consciousness, language, and
thought
– One of the things that makes humans most distinct from other
animals
 Functions of the Cerebral Cortex
• Sensory Cortex – registers sensory neurons (touch)
• Motor Cortex – registers the motor neurons (muscles)
• Association Cortex – registers complex functions, including
higher-order sensory processing, integrating information from
different senses, thinking, and planning
 Cerebral Cortex
• Occipital lobe (back of brain) – vision
• Temporal lobe (sides of brain) – processes information about auditory stimuli
and language, and recognizing complex visual stimuli (such as faces)
• Parietal lobe – sensory integration
• Frontal lobe (front of brain) – higher intellectual thinking
• Prefrontal lobe – memory, morality, mood, and planning
 Parallel Processing
• Parallel processing – Communication within and between the
lobes of the brain allows us to perform complex functions
simultaneously.
Speech
• Broca’s area (frontal lobe)
– speech production
• Wernicke’s area (temporal
lobe) – language
comprehension
Motor and Sensory Cortices
 Localization of Function
• Means that specific parts of the
cortex are important for specific
behaviors or abilities.

• E.g. Phineas Gage

• After his injury, he recovered
physically, but experienced a
change in personality
 How Does the Nervous System Work? (1 of 2)

• Neuron – a nerve cell

o Sensory – gathers sensory information
o Motor – communicates information to the muscles
o Interneuron – communicates with sensory and motor
neurons and other interneurons
The Structure of Neurons
 How Does the Nervous System
Work? (2 of 2)
• Glia – cells that make up the nervous system in addition to
neurons
– Astroglia – creates blood-brain barrier, influences
communication between neurons, and helps heal brain
damage
– Oligodendroglia – provides myelin to speed up
transmission of neurons
– Microglia – cleans up dead cells and prevents infection in
the brain
 How Neurons Work
• The really simple version:
– Neurons hold electrical charges
– Neurons contain chemical
messengers
– When “triggered” a neuron will
“fire” and send an electrical cue
to release chemicals that will
then “trigger” an adjacent
neuron. And so on.
 How Do Neurons Work? (1 of 3)
• Resting potential – when a neuron is at rest, it is negatively charged inside
(intracellular) relative to the outside (extracellular)
 How Do Neurons Work? (2 of 3)
Action potential
• When a neuron fires, pores in the neuron (ion channels) open
to let charged ions flow into and out of the neuron
• The neuron becomes more positive in the inside relative to the
outside
 How Do Neurons Work? (3 of 3)
• Action potential
– This shift in electrical charge triggers the axon terminals to release
neurotransmitters
The Action Potential
How Neurons Work
 All-or-None Principle
• Either a neuron is sufficiently stimulated to start an
action potential (all) or it is not (none). Immediately
after a neuron has fired, it cannot fire again (refractory
period).
 Nodes of Ranvier
• The nodes of Ranvier are the regions of bare axon that are between
areas wrapped in myelin. Action potentials travel down myelinated
axons by jumping from node to node.
 Communication Across the Synapse
• An action potential triggers the release of neurotransmitters
(specialized chemicals) into the synapse (the space between
neurons)
• Neurotransmitter molecules are contained in synaptic vesicles
• These chemical neurotransmitters are taken up by the
neurotransmitter receptors (proteins in cell membrane that
recognize specific molecules) in a neighbouring neuron
 Neurotransmitter Receptors (1 of 2)

• Postsynaptic potentials are electrical events in postsynaptic

neurons that occur when a neurotransmitter binds to one of its
receptors. When a receptor is activated, positive or negative
ions can flow through the receptor into the neuron.
 Neurotransmitter Receptors (2 of 2)

• Excitatory postsynaptic potentials (EPSPs) depolarize the

neuron and increase the likelihood of an action potential
• Inhibitory postsynaptic potentials (IPSPs) hyperpolarize the
neuron and decrease the likelihood of an action potential
 Neurotransmitters and Their
Functions
• Common neurotransmitters and drugs associated with each
Neurotransmitter Function Associated Drugs
Glutamate Learning and memory, Ketamine
movement, emotions, cognition

GABA Learning, anxiety regulation Valium (diazepam, used to relieve anxiety, muscle spasms);
Ambien (Zolpidem, used to treat insomnia)

Acetylcholine (Ach) Learning, attention, movement Nicotine

of muscles

Dopamine Movement, reward learning, Cocaine; heroin; methamphetamine

addiction

Serotonin Mood regulation, sleep, memory Ecstasy (MDMA); LSD (hallucinogens); monoamine oxidase
inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs;
antidepressants)

Norepinephrine Attention, arousal Adderall (a stimulant made up of dextroamphetamine and

amphetamine)
 Neural Networks
• Neural network: neurons form circuits or networks that expand the
communication among different brain regions. This image shows axons
and dendrites (red) extending from the neuronal cell bodies (blue).
WHAT HAPPENS WHEN OUR BRAIN
GETS HURT?
 Types of Brain Injury
• Traumatic brain injury – concussions, spinal cord
injuries
• Acquired brain injury
–Infections (e.g. meningitis)
–Exposure to toxins (e.g. carbon monoxide, alcohol)
–Tumours
–Degenerative diseases (Parkinson’s, Alzheimer’s)
–Strokes
 Treatment of Brain Injury
• Depends on type of injury
• Usually focused on restoring blood flow, reducing
swelling, treating infections, etc.
• When brain injury results in cognitive or behavioral
deficits, part of healing involves re-learning stuff (e.g.
physical therapy to help regain mobility)
 Neuroplasticity
• Neuroplasticity – the brain’s ability to make new
neural connections or to reorganize in response to
injury or experience
 Split-Brain Patients
• To treat severe epilepsy, sometimes a corpus callosotomy
is performed, meaning the corpus callosum is severed.
Corpus Callosum
• Connects the two brain
hemispheres
• Dense bundle of neural
fibres (axons) allow for
communication of
information from one side
of the brain to the other
Split-Brain Patients
 NO brain area works alone!
• And forget myths like “We
only use 10% of our brain”
HOW AND WHY DID OUR NERVOUS
SYSTEM DEVELOP THE WAY IT DID?
 Evolutionary Psychology
• Evolution – the process of the development and divergence of
life (species) on this planet
• Evolutionary psychology – studies how the process of
evolution has shaped the body and brain via the interaction of
our genes and the environment to produce our thoughts and
behaviours
• Common ancestor – an organism that is common to the
evolutionary history of two or more living species.
Evolution
of Life on
Earth
 Natural Selection
• Evolution by natural selection – animals with physical
and behavioural attributes well suited to their
environment are more likely to survive, reproduce, and
pass on their traits to their offspring
• Fitness – an individual’s ability to successfully grow to
maturity and have offspring
 Darwin’s Observations (1 of 2)
Darwin made four important
observations:
1) Animals were changing over
time
2) Aspects of species that seem
different on the surface, such
as a human hand, a bat’s
wing, and a cat’s paw, had
structural similarities
underneath
 Darwin’s Observations (2 of 2)
3) Selective breeding of captive animals leads to changes
in the appearance of the animal
4) Not all animals that are born will survive to maturity
and be able to reproduce
 Evolution of the Brain
• The Australopithecus skull on
the left is about one-third the
size of the present-day human
skull on the right.
• It has a much smaller frontal
area, which leads to the
assumption that the frontal
cortex in the Australopithecus
was also smaller.
 Modern Humans
• Not the pinnacle of life on Earth, just well-adapted to
certain set of circumstances.
• Key adaptation that sets humans apart is the nervous
system, and particularly the brain
• Human cerebral cortex is much larger, relatively speaking,
than in any other animal
• Cultural evolution thought to play an important role
HOW ARE HUMAN BRAINS UNIQUE?
WHAT ADVANTAGE DO THEY GIVE US?
 Copyright
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BREAK TIME!