PSYCHOBIOLOGY // LECTURE 1 MEERLO // PSYCHO-
BIOLOGY IN A HISTORICAL PERSPECTIVE // CHAPTER 1
// 6-5-2021
➢ What is psychobiology?
Google: The study of the biological foundations of the mind, emotions, and mental
processes.
→ The study of biochemical foundations of thought, mood, emotion, affect, and behavior.
→ The use of biological methods to study normal and abnormal emotional and cognitive
processes.
→ Psychobiology or biopsychology or behavioral neuroscience
➢ Main aims of the course
→ Understanding the neurobiological and physiological mechanisms underlying complex
behavior, emotion and cognitive functions:
• Brain mechanisms → The brain doesn’t only regulate and drive peripheral processes, but
these peripheral processes can have profound effects on brain systems and the functional
output of the brain in terms of behavioral cognition and emotion
→ A stressful event is associated with the perception of a potential threat / danger (snake)
which then involves activation of brain mechanisms and that drives emotional responses and
behavior → That is associated with peripheral mechanisms necessary to support this
behavioral response
• Peripheral nervous system
• Hormones → Some of the hormones released during stress have a strong influence on the
brain → Hormones that provide a break on the stress systems in the brain or solved the
situation, but also hormones that promote formation of memory of this stress situation
which allows to build up experience and next time you better deal with the similar situation
• Immune system (cytokines)
→ Interaction between the brain and peripheral factors
→ Understanding the neurobiological and physiological mechanisms underlying behavioral
dysfunction and psychopathology:
- From psychobiology to psychopathology:
• From functional stress responses and emotional responses to posttraumatic stress
disorder, anxiety disorders and depression.
• From normal social behavior to violence or autism.
• From regulation of feeding behavior to anorexia and obesity.
→ Understanding the process of behavioral neuroscience: reasoning behind research
questions, experiments and conclusions.
,→ Problem-based learning assignment
• Formulating a scientific question
• Designing experiments
• Writing a research proposal
➢ A little bit of history
Our understanding of mechanism underlying complex behavior, emotion and cognitive
functions strongly depend on technological advances in neuroscience.
→ Psychobiology is a dynamic and rapidly developing scientific discipline: “The facts of
today are tomorrow’s artifacts”
➢ Ancient Greek philosophers on psychobiology
→ The mind-body question
→ Are mind and body separate? Or are they one and the same?
→ Aristotle (384-322 BC): “It is not necessary to ask whether the soul and body are one,
just as it is not necessary to ask whether the wax and its shape are one”
→ Dualism: The body and mind are different entities
→ Monism: The body and mind were 1 thing
→ Within the monism different variations developed about how body and mind are
integrating with each other
→ Hippocrates and humourism: Temperament and mental health depend on the balance
between four distinct bodily fluids or “humors”
→ The 4 fluids were blood, yellow bile, black bile and phlegm and were associated with
organs or tissues in the body, but also with certain physical qualities (cold, hot, wet, dry) and
also with the 4 elements (air, earth, fire, water)
→ Ultimately somebody’s mental state and temperament were the result of complex
interactions between the bodily fluids and all these other elements
→ The word humor is derived from Greek and it means something like fluid
→ Hippocrates assumed that mood and disorders of mood has physiological bases
➢ The dawn of experimental science
→ Galenus (131- ca. 201~217 A.D.)
→ Galenus was one of the most prominent medical researchers in that time and made
important contributions to various scientific disciplines → He wrote documents and books
on his studies and discoveries and his work has dominated western medical science
→ His leading medical views were based on extensive and anatomical research on animals
and humans and it helped that he was a physician and therefore could rely on an
inexhaustible research of study objects in the shape of wounded or dead gladiators
,→ The wounded gladiators had a much higher chance of survival under his care than
otherwise
→ Nerve ligation experiments
→ The brain controls motions of the muscles
→ Anatomical studies were often performed on dead animals / humans, but Galenus also
sometimes practiced on living animals
→ During one of those demonstrations on a tie down but loudly screaming pig Galenus
accidently cut through the nerve projecting to the voice box in the throat → The pig
immediately ceased all sound and became quiet even though he was alive and struggling
with the ropes → So Galenus had discovered the. nerve action from the brain to the muscle
that in part is responsible for the production of sound
→ This research of Galenus demonstrated that the brain through the nervus projections was
responsible for muscle contractions and movement → He demonstrated that the brain
regulated behavior
➢ Psychobiology as a scientific discipline
→ William James (1842-1910)
→ Scientific study of psychology should be grounded in an understanding of biology.
→ William James & Carl Lange
→ James-Lange theory of emotion: Emotions arise from physiological responses to stimuli
→ Our emotions are physiological responses
→ Knight Dunlap (1875-1949)
→ Writer of the book “An outline of Psychobiology”
→ Editor of the scientific journal “Psychobiology”
→ On the interconnection of mental and physiological functions
→ Cesare Lombroso (1835-1909)
→ Anthropological criminology
→ Relationship between certain physical characteristics of the skull and jaw (sloping
foreheads, jutting chins) and criminal behavior.
→ (This idea could not be confirmed by real data)
→ Lombroso proposed that criminal behavior in humans was partly in the genes and in
association with that also partly reflected in some physical / anatomical features
→ He assumed that criminal were a more primitive kind of people and evolutionary more
close to apes and he called them the Homo delinquens → Because of their closer
relationship with apes these people would also have more primitive anatomical features
→ Anthropological criminology
→ Relationship between certain physical characteristics of the skull and jaw (sloping
foreheads, jutting chins) and criminal behavior.
→ (This idea could not be confirmed by real data)
→ We can’t predict criminal behaviors in the basis of the size and shape of someone’s skull
and chin
, → Jose Manuel Rodriguez Delgado (1915-2011)
→ Mind control
→ Controlling behavior by electrical stimulation of specific brain regions.
→ Delgado became famous by experiments showing that electrical stimulation of certain
parts of the brain can directly affect and control behavior
→ Delgado implanted electrodes in an aggressive bull in the brain region that he thought
was involved in regulating aggression and demonstrated that he could stop the bull from
attacking by pushing the bottom of his remote electrical stimulator
➢ Modern psychobiology research
→ How do we advance our knowledge of behavioral neuroscience?
• Observations, measurements
• Experimental manipulation
→ A wide variety of tools and techniques (Chapter 5)
,PSYCHOBIOLOGY // LECTURE 2 // MOORMAN //
METHODS AND RESEARCH STRATEGIES // CHAPTER 5
// 6-5-2021
◼ Methods for measuring what’s going on in the brain under certain
experimental conditions
1. In vivo recording of neuronal / electrical activity
→ Measuring the electrical activity of single cells or groups of neurons by means of
electrodes
→ You can measure:
• Global cortical activity with macroelectrodes (electroencephalogram) → Can be done in
humans and animals
• Single cell or multi-unit activity with microelectrodes that are inserted in to the brain
→ This needs stereotactic surgery for precise location of electrodes
→ Mostly done in animals and makes use of an apparatus that’s called a stereotact
➢ Stereotactic surgery
→ Brain atlas to look up the coordinates of the target region relative to the visible sutures
of the skull
→ If you do this surgery in a standard laboratory rodent then there are brain atlases
available where you can look up the exact position and coordinates of the brain region that
you’re interested in → The atlas provides the coordinates of brain regions relative to the
connections of the different skull bones → Upper left: So if you carefully open up the skin on
the top of the hand you see the connections between the bone plates and particularly this
crossing here which we call Bregma → Then the atlas will tell exactly where a certain brain
region is relative to this Bregma point → So the atlas tells you exactly where you have to
drill your little hole and enter your electrode
→ Then you can anesthetize your rat / mouse and you place it in the stereotactic apparatus
that you see here and you can fix its head so that you can precisely insert your electrode
→ The electrode is connected to an arm which is connected to this part (cross) which can
move in all directions
→ Based on the coordinates in the atlas you can lower the electrode where you want it to be
and record the activity of the neurons
, 2. In vivo assessment of brain biochemistry by means of micro dialysis
→ Measuring concentrations of specific molecules in extracellular fluid sampled by means
of a semi-permeable dialysis membrane
→ This type also requires stereotactic surgery for precise location of micro dialysis probe
→ By this method one determines the concentration of small molecules in the extracellular
fluid surrounding the neurons → In many cases these are molecules that are released by
neurons, such as neurotransmitters that are released during synaptic signaling
→ So in a different way than electrical activity this approach can also tell you something
about activity of the brain and neurons, but it’s by chemical activity associated with synaptic
transmission and not the electrical activity that’s associated to the transfer of action
potentials across your axons
→ This method works by placing a probe / tube with a very small semi-permeable
membrane at the end and you place this at the exact location in the brain that you’re
interested in and the molecules that are floating around this semi-permeable membrane will
then enter your probe and you can take a sample and analyze the concentrations of the
molecules that you’re interested in
→ The importance of this technique relies on the fact that you can do repeated
measurements of the biochemistry of the brain in the animals in the course of an
experiment → On the other hand it’s a rather complex technique and it only allows you to
measure the molecules that are released by cells and float around in the extracellular fluid,
but you can’t measure structural molecules of neurons or molecules that are only present
inside the cell, such as mRNA → Moreover often you would like to do simultaneous
measurement at different locations in the brain which is quite difficult with micro dialysis,
because you can’t place too many of these probes at the same time
3. Collection of brain material for biochemical analysis
→ Measurement of mRNA or protein concentrations in homogenates of brain tissue
• Collecting brain material
• Homogenization of brain material (whole brains or dissected regions)
• Specific analysis procedures for the molecules that you’re interested in and this can be:
- Biochemical assays
- Polymerase Chain Reaction (PCR)
- Western blotting procedures
→ In the picture you see an example of a blotting procedure where the homogenized brain
samples are placed in an apparatus that separates the proteins on the basis of their size and
their electrical charge which determines how rapidly these proteins run through a gel and in
this gel you get bands of different proteins with a different change / weight which are not
