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Biophysiology. Was there a difference between the exercised personalities and the meditated personalities? What factors determine your scores? The nervous system underlies everything we do. Understanding biology is fundamental to understanding behaviour.

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  • Was there a difference between the exercised personalities and the meditated personalities?
  • What factors determine your scores?
  • The nervous system underlies everything we do. Understanding biology is fundamental to understanding behaviour.
  • We need to know the mechanics of sensation before we can understand perception.
count the f s
the biological level of analysis
The Biological Level of Analysis
  • Explanations for thoughts, behaviours, perceptions, and emotions are more complicated than this…
three key principles that define the biological level of analysis
Three key principles that define the biological level of analysis:
  • Emotions and behaviour are the products of the anatomy and physiology of the nervous and endocrine systems
  • Patterns of behaviour can be inherited
  • Animal research may inform our understanding of behaviour
I. Emotions and behaviour are the products of the anatomy and physiology of the nervous and endocrine systems
  • All observable behaviour, including mental activity (emotions and cognition) can be traced back to physiological events.
  • Links have been found between physiological events and physiological activity in three areas:
    • Neurotransmitters
    • Hormones
    • Brain localization
where does behaviour thought come from
Where does behaviour/thought come from?
  • Reflects the idea that causes of emotions, behaviour, and thought lay within the human body.
  • Requires study of the nervous system and how the brain interacts with the rest of the body and the endocrine system.
ii patterns of behaviour can be inherited
II. Patterns of behaviour can be inherited
  • Focused on two branches of research:
  • Evolutionary psychology – Humans have changed physically and behaviourally according to the demands of the environment.
  • Genetics – transmitted from parents to children and over time, physical characteristics and behaviours that are helpful to an individual or group will be passed on
examples of topics
Examples of topics:
    • Homosexuality
    • Intelligence
    • Criminal behaviour
    • Schizophrenia
  • Are these characteristics a product of inherited physiology? Genetics?
  • What are the implications of the discovery that one or more of these characteristics have a genetic component? How will that change our understanding of these things?
diathesis stress model
Diathesis-stress Model
  • Diathesis-stress Model – a genetic predisposition to disorders like depression can be inherited however, an environmental trigger like childhood trauma is required to make the depression manifest itself.
iii animal research may inform our understanding of behaviour
III. Animal research may inform our understanding of behaviour
  • Based on the idea that the human being is a type of animal
  • Therefore it is valid to make inferences about human behaviour based on animal research because the mechanisms that underlie behaviour are the core similarity we share with animals.
  • The closer the animal is related to humans, the stronger the inference from research we can make.

Evolutionary effects can be studied on organisms with shorter lifespans – fruit flies, foxes, mice, etc.

  • How does Pavlov’s Dog demonstrate this principle?
  • What are the advantages and disadvantages of using animals in psychological research?
the biological level of analysis tends to use three main types of inquiry
The biological level of analysis tends to use three main types of inquiry:
  • Laboratory experiments
  • Case studies
  • Correlational studies
get out a fresh sheet of paper
Get out a fresh sheet of paper
  • Write your name on the top right corner.
  • Put today’s date on the top left.
  • Take good, neat, colorful notes.
  • Write the following on the first four lines along the left margin.
  • Neatness /4
  • Comprehensiveness /2
  • Organized /2
  • Total /8
the biological basis of behaviour
The Biological Basis of Behaviour
  • In order to understand the mind, psychologists must first understand how the body works and is constructed.
  • Before becoming a software engineer, you must first know how a computer is put together and how it works.
the basic hardware
The basic hardware
  • The nervous system is composed of billions of cells called neurons.
  • Neuron – individual cells that receive, integrate, and transmit information.
  • We lose an average of 10,000 per day, but over a lifetime, that amounts to less than 2% of the total.

Receptors – specialized structures capable of turning stimuli in the environment into electrical impulses in the body.

  • Afferent nerves – nerves that transmit signals into the brain.
  • Efferent nerves – nerves that carry signals from the brain to the muscles.
  • If the cell body were the size of a basketball the axon would be a garden hose the length of Manhattan Island.




Efferent nerves

Afferent nerve






Sensory neurons carry signals from the outer parts of your body (periphery) into the central nervous system.

  • Motor neurons (motoneurons) carry signals from the central nervous system to the outer parts (muscles, skin, glands) of your body.
  • Interneurons connect various neurons within the brain and spinal cord.
The simplest type of neural pathway is a monosynaptic (single connection) reflex pathway, like the knee-jerk reflex.
  • When the doctor taps the right spot on your knee with a rubber hammer, receptors send a signal into the spinal cord through a sensory neuron. The sensory neuron passes the message to a motor neuron that controls your leg muscles. Nerve impulses travel down the motor neuron and stimulate the appropriate leg muscle to contract.
  • The response is a muscular jerk that happens quickly and does not involve your brain.
  • As tasks become more complex, the pathway "circuitry" gets more complicated and the brain gets involved.
triggering the threshold
Triggering the threshold
  • When a sensation reaches the threshold a signal is triggered in the dendrites of the neuron.
  • Threshold – the minimum intensity required to trigger a chain reaction in a neuron. (55 millivolts in mammals)
  • Some threshold stimuli…
  • A candle flame 50kms away on a clear dark night.
  • A ticking watch at 6 meters in a quiet room
  • One teaspoon of sugar in 7 liters of water.
  • The wing of a bee falling on your cheek from 1 cm away.
the electrochemical signal
The electrochemical signal
  • The signal that travels the length of the neuron is actually a change in the polarity of the outside of the axon.
  • The resting charge on the cell is -70 millivolts.
  • This charge is created by a membrane around the cell that keeps positively charged sodium ions (Na+) on the outside of the cell and positively charged potassium ions (K+) in the inside.
  • Once the threshold is achieved in the cell body, the protein “gates” of the axon open and Na+ ions rush in.
  • For 1 millisecond, the outside of the axon body becomes – and the interior becomes +.
  • The polarity of the axon body is reversed as the threshold is achieved.
  • Gates in the cell membrane open briefly to let Na+ ions rush in.
  • These gates quickly close and K+ ions slowly leak out and the cell begins to actively pump Na+ ions back out.
  • This returns the cell to it’s resting state.
  • The depolarization of the cell produces electric currents that stimulate the threshold value in neighboring regions as the impulse travels down the axon.
all or none law
All or None Law
  • Once the impulse is triggered, the intensity of the signal is constant.
  • All or None Law – the stimulus does not provide the energy of the nervous impulse.
  • This means that a stronger sensation is caused by a greater number of neurons being stimulated, not a stronger impulse.
  • The All or None Law is important for the study of sensations like pain.
  • Intense sensation can be caused by two factors:
  • A strong stimulus will trigger a higher NUMBER of neurons to fire
  • A strong stimulus will trigger a greater FREQUENCY in the neuron impulse.
  • The highest frequency in the human body is 1,000 impulses/second
synaptic transmission
Synaptic Transmission
  • Scientists had always believed that there was some mechanism connecting two neurons together.
  • This was finally proven in 1920 by Otto Loewi.
  • Lowei’s experiment proved that the transmission from one neuron to the next involved a chemical substance.
  • Synapse – the gap between the axon terminals of the transmitting neuron and the dendrites of the receiving neuron.
synaptic transmission1
Synaptic Transmission
  • As the impulse reaches the axon terminals, tiny sacs of specialized proteins called synaptic vesicles rupture at the surface of the terminal.
  • These vesicles pop and release a chemical into the synapse called a neurotransmitter.
  • Neurotransmitter – chemical substance that is released at the terminal end of the neuron that travel across the synapse and have an excitory or inhibitory effect on the adjacent neuron.
  • As each neurotransmitter crosses the synapse, it lands on specialized receptor cells on the dendrites of the next neuron.
  • The receptors then lower the action potential of the neuron.
  • As each neurotransmitter reaches a receptor, the action potential is lowered more and more until the threshold is reached and an impulse is triggered.
lock and key model
Lock and Key Model
  • Each neurotransmitter is paired with the special receptor at the end of the post-synaptic neuron. Each receptor can only be activated by it’s paired neurotransmitter.
  • Excess neurotransmitter in the synapse is removed to prevent prolonged stimulus and interference in two ways:
  • Enzymes located in the synapse break down the chemicals into smaller component parts.
  • The axon terminal will reabsorb excess back into the neuron cell.
  • The list:
  • Ach
  • 5HT
  • GABA
  • NE
  • DA
  • Amphetamines
  • Curare
  • Endorphins
  • You will be numbered by me
  • Your assignment: Research and record the function of the neurotransmitter that corresponds to your number.
  • You will trade, compare and copy notes from your classmates.
  • A short quiz will follow
the nervous system
The Nervous System
  • The nervous system constantly monitors, controls and maintains an optimal state in the body called homeostasis.
the nervous system has two parts
The nervous system has two parts:
  • The Central Nervous System – the brain and spinal cord. The spinal cord consists of a large bundle of nerve fibres that run down the back and transmit signals between the body and the brain.
  • The Peripheral Nervous System – includes the smaller nerves that branch out from the spinal cord. These nerves take information from the body’s organs to the central nervous system and return information to the organs.
the peripheral nervous system is divided into two functions
The peripheral nervous system is divided into two functions:
  • Somatic division – concerned with the control of the skeletal musculature and the transmissions from the sense organs.
  • Autonomic division – serves the structures that are concerned with basic life processes such as heart beat, contraction of the stomach and intestines, and genital organs.
brain structures
Brain structures
  • Where the spinal cord meets the brain is the brain stem, attached to the brain stem are two structures;
  • the cerebral hemispheres, which totally envelope the brain stem
  • the cerebellum which is attached further down and is much smaller.
the brain itself can be divided into three portions
The brain itself can be divided into three portions:
  • The forebrain
  • The mid-brain
  • The hindbrain
the hindbrain
The Hindbrain
  • What two structures are located in the hindbrain?
  • The medulla and the cerebellum.
what are the functions of the two parts of the hindbrain
What are the functions of the two parts of the hindbrain?
  • The medulla controls heartbeat, circulation, respiration, and other vital functions.
  • The cerebellum controls balance and muscular coordination.
the midbrain
The Midbrain
  • What is the dominant structure in the midbrain?
  • The reticular formation.
how is the midbrain related to sleep
How is the midbrain related to sleep?
  • It is related to activation of other parts of the brain and when it is deactivated regulates sleep.
the forebrain
The Forebrain
  • What is the function of the thalamus?
  • It coordinates and regulates information from sensory organs and motor centers to the cerebral cortex.
what is your guess as to the effect of overstimulation of the hypothalamus why
What is your guess as to the effect of overstimulation of the hypothalamus? Why?
  • Because the hypothalamus controls behaviours related to basic biological urges, overstimulation would probably lead to someone who eats, drinks, and sleeps too much and is probably inappropriate frequently.
what is meant by functional summit
What is meant by “functional summit”?
  • Functional summit refers to the most complex, most capable, and most sophisticated part of the human body. It is the part of the body that is capable of the most significant and powerful actions.
what are the four lobes of the cerebral hemisphere
What are the four lobes of the cerebral hemisphere?
  • Frontal, parietal, occipital, temporal lobes.
What is the function of the cerebral cortex? Why do scientists believe that is a recent development in evolution?
  • The cerebral cortex is the location for higher brain functions like thinking, memory, and planned and voluntary action. Scientists believe it is a recent evolutionary adaptation because many organisms lack one like fish, and many have only the beginnings of one like reptiles, and birds.
what do you think happened to leonard s brain based on these notes
What do you think happened to Leonard’s brain based on these notes?
  • Leonard must have suffered damage to his basal ganglia when he was young because it is the location of dopamine circuits and Leonard’s condition improved after taking synthetic dopamine.
why do you think the limbic system called the old cortex what does this mean about human behaviour
Why do you think the limbic system called the “old cortex”? What does this mean about “human” behaviour?
  • Because the limbic system is involved in motivation and emotion, it is linked to more primitive and basic functions whereas the cerebral cortex is involved in rationality, thinking, memory, and planning.

This would lead us to believe that, based on biology and brain functioning, what makes us human is our higher brain functions. What makes us more “advanced” is our rationality, our thinking, and our premeditation; not our emotions or our basic motivations.

the cerebral cortex
The Cerebral Cortex
  • The cerebral cortex is the key to human intelligence.
  • Without it, there can be no planning, no complex speech, no complex sequence of movement, no organizational perception.
function zones
Function zones
  • The cortex is divided into two zones based on their function:
  • I - Projection areas – serve as receiving areas for sensory information and as dispatching centers for motor commands.
  • II - Association areas – the remaining 2/3rds of the cortex is devoted to higher mental functions like planning, perceiving, remembering, thinking, and speech.
i projection areas
I- Projection areas
  • Motor projection areas of the cortex are linked with control parts of the body.
  • These can be mapped with a high degree of accuracy to create a motor homonculus, or a schema of the body as it is represented on the cortex.
sensory areas
Sensory areas
  • Each part of our body also has a designated area of the cortex devoted to sensation – called the somatosensory area.
  • This map can be used to create a sensory homunculus of the region of the brain devoted to sensation.
sensory areas1
Sensory areas
  • Other parts of the cortex are devoted to the different senses.
  • These are the visual cortex, and the auditory cortex.
ii association areas
II- Association Areas

Association areas are related to complex mental functions like speech, thinking, and remembering.

The precise locations of these activities can be discovered through lesions (damaged tissue) in the brain.

studying localization
Studying Localization


Explain one study related to localization of function in the brain

Examine one interaction between cognition and physiology in terms of behaviour. Evaluate two relevant studies.

Discuss the use of brain imaging technologies in investigating the relationship between biological factors and behaviour.

Discuss two effects of the environment on physiological processes.

case studies of people with naturally occurring brain damage
Case Studies of People with Naturally Occurring Brain Damage
  • Prior to the 20th century – main source of research into brain function – case studies
  • Lacked cause effect analysis
  • Eg.
    • Phineas Gage
    • Broca’s Area
    • Wernicke’s aphasia
broca s aphasia
Broca’s aphasia
  • A form of expressive aphasia generally caused by lesions in a region of the left frontal lobe
  • An association area that borders on the part of the motor projection zone that controls speech muscles
wernicke s aphasia
Wernicke’s aphasia
  • A form of receptive aphasia caused by lesions near the auditory projection zones of the parietal and temporal lobes impairing comprehension and production of language
  • Patients can make out words and sound patterns but cannot fully grasp their meaning.
technology and localization of brain function
Technology and localization of brain function:
  • Electroencephalogram
  • Computer tomography
  • Magnetic resonance imaging
  • Functional magnetic resonance imaging
  • Positron emission tomography
electroencephalogram eeg
Electroencephalogram – (EEG)
  • Electrodes placed in specific locations around the skull detect changes in electrical activity and display them visually.
  • Strengths – useful for broad based behaviours like sleeping (REM patterns)
  • Weaknesses – inaccurate, cannot narrow down brain activity to a specific region of the brain.
computed tomography ct
Computed tomography – (CT)
  • A combined computer and X ray image showing slices of the skull from multiple angles including the soft tissues of the brain.
  • Strengths – useful for showing structural changes within the brain such as tumors
  • Weaknesses – does not show brain activity
magnetic resonance imagery
Magnetic resonance imagery
  • strong magnetic fields can cause the protons in the water molecules in the body to align magnetically. When combined with radio frequency fields at the same time, systematic changes can be affected in the nuclei of the atoms in the body that scanners are able to detect when combined along 2 or 3 dimensions.
  • Strengths – can produce a detailed three dimensional image
  • Weaknesses – dangerous for certain individuals – pacemakers, metal implants
functional mri
Functional MRI
  • a variation of the MRI technique that relies on the fact that when neurons are active in a region of the brain, more blood is sent to that region. The fMRI can track these changes in the brain metabolism as they occur in patients as thoughts, emotions, or actions occur.
  • Strengths - This enables psychologists to map the functioning regions of the brain with a high degree of accuracy.
  • Weaknesses - ?
positron emission tomography pet scans
Positron Emission Tomography – PET scans
  • an imaging system that relies on the principle that the brain’s consumption of sugars increases in areas that are active. Radioactive sugars are injected into a patient that will emit gamma rays when metabolized by the brain. These rays can be detected and an image can be produced that shows localized brain activity.

Strengths – gives a colorful and dynamic picture of brain activity; shows structural changes that indicate problems before they can show up on MRI or CT scans

  • Weaknesses – not as precise as a fMRI; health problems can occur with the injection of radioactive substances.
what do we know
What do we know?
  • Localization of brain function is not set,
  • continually under study and subject to revision as new information comes available.

sample exam question paper 1
Sample exam question – Paper 1
  • Explain how one study demonstrates localization of function in the brain.
  • Wernicke
  • Broca
  • Damasio
1 phineas gage
1 – Phineas Gage
  • Author: Damasio et al. 1994
  • Type: Case Study, single subject, non-random sample, instrumental – it sought to construct/confirm a hypothesis regarding localization of inhibition in the brain as well as explaining the phenomena of his changed behaviour by what his brain injury turned out to be once they could perform an autopsy.
  • Aims: To discover the nature of the injuries to Gage’s brain and correlate those injuries with the changes in his behaviour reported from the period – disinhibition
  • Method: Using modern technology, researchers reconstructed the injury to Gage’s skull and compared those to historical accounts of his behaviour before and after the injury.
  • Conclusions: The reconstructed injury based on the skull of Gage indicated damage to the pre-frontal lobe of the brain which corresponds with prior knowledge of the localization of inhibition in the brain. This correlates positively with the changes in behaviour of the subject described by the historical accounts.
the endocrine system
The Endocrine System
  • Closely related to neurotransmitters, hormones are chemical substances that have an effect on structures elsewhere in the body.
  • While neurotransmitters work across the synaptic cleft 1/10,000mm wide, hormones work across the entire body. They can have an immediate and important impact on behaviour.
role of hormones
Role of hormones
  • Hormones are released by endocrine glands and have specific effects on the body based on the body’s need to maintain homeostasis and development.
master gland
Master gland
  • The hypothalamus regulates the pituitary gland which sends out a variety of hormones for growth and development. It is the “central command” for other endocrine structures.
  • Eg. Gonadotrophins – direct the formation of external sexual organs in the developing fetus.
glands and their function
Anterior pituitary

Posterior pituitary


Islets in the pancreas

Often called the body’s master gland because it triggers hormone secretion in many of the other endocrine glands.

Prevents loss of water through kidney

Affects metabolic rate

Affects utilization of glucose

Glands and their function
glands and their function1
Adrenal cortex

Adrenal medulla



Various effects on metabolism; some effects on sexual behaviour

Increases sugar output of liver; stimulates various internal organs in the same direction as the sympathetic branch of the ANS.

One set of hormones (estrogen) produces female sex characteristics and is relevant to sexual behaviour.

Another hormone (progesterone) prepares uterus for implantation of embryo.

Produces male sex characteristics. Relevant to sexual arousal.

Glands and their function