BEHAVIOURAL NEUROSCIENCES NOTES
LECTURE 1-Definitions and history...................................................................................................... 2
LECTURE 2-Approaches and methods ................................................................................................. 7
LECTURE 3- Communication at the synapse I ................................................................................... 14
LECTURE 4– Communication at the synapse II .................................................................................. 21
LECTURE 5-Movement control .......................................................................................................... 28
,LECTURE 1-Definitions and history
1-Definitions
• Behaviour: anything that a living creature does in reaction to environmental stimulation.
• Neuroscience: The scientific study of the nervous system (brain, spinal chord, sensory neurons).
Neuroscience includes different approaches to study the molecular, cellular, regional, developmental (how NS
develops and critical periods), structural, functional (what are different areas responsible for), evolutionary,
computational, and medical aspects (treatment of damage) of the nervous system.
• Behavioural neuroscience: Studies the neural mechanisms underlying behaviour (Behavioural psychology,
biopsychology, psychobiology): when the environment produces any kind of stimuli that acts on our organism. What
is going on in the nervous system that leads to a behaviour being produced. Environment→brain→behaviour.
2-History
The underlying theme for all these areas is the idea of localisation i.e. can certain behaviours or functions be attributed to
particular areas of the brain, or not?
2.1-Early attempts
1st step in localization: Are functions localised to the brain at all?
Egyptian medical records: perhaps the earliest written record on the effects of head injuries. Best
example: Edwin Smith surgical papyrus (treatment of battle wounds), whose original author is
estimated to have lived 2780 BCE.
Contains records of head injuries that led to deficits on the opposite side of the body from the head
injury (contralateral connections).
However, the heart was considered at this time the seat of consciousness and intelligence: the cardiocentric model, where unlike
the heart and other organs, the brain was not preserved in the mummification process.
This model has been seen across many different cultures like ancient China.
The Hippocratic Revolution (5th century BCE-348 BCE):
• Alcmaeon (5th Century BCE): the brain as the site of sensation and cognition. Did dissections and discovered the
optic nerve (from eyes to the brain)→the brain must be important for sensations.
• Hippocrates (460-370 BCE): “Man ought to know that from nothing else but the brain come joys, delights,… sorrows,
griefs, despondency and lamentations” Hippocratic Corpus. The brain is the controlling organ of the body
• Plato (428-348 BCE): The triune soul, where soul splits into brain, heart and gut. The brain was associated with
intellect, the heart with anger, fear and pride; and the gut with greed, desire and lower passions. Only the intellectual
soul (that in the brain) is immortal to the body.
Aristotle (384 B.C.- 322 B.C.):
Follower of Plato but rejected the idea of the brain as the organ of
intellect and function. Proposed the heart as the seat of these
functions. The heart is warm (sign of sensation, animation); the
brain is cool; therefore, the heart is of primary importance and the
brain is an elaborate cooling system in case the heart or the rest of
the body get overheated disrupting rational thinking from
happening. He lacked the clinical approach- there is no evidence
he studied humans with brain damage (his dissection was limited
to animals- the majority of which were cold-blooded biasing his
conclusions).
https://journals.sagepub.com/doi/pdf/10.1177/107385849500100408
Galen (130-200 AD):
Follower of Hippocrates and Aristotle- but completely disagreed with Aristotle on the role of the heart (against cardiocentric
model). For him, the brain was the organ of the mind and the seat of the soul. ‘Animal spirits’ and vital spirits: vital spirits
produced in the left ventricle of the heart were carried to the brain where they were transformed into animal spirits (possibly in
the ventricles of the brain or in the rete mirabile, miraculous net at the base of the visual cortex in some animals). These animal
,spirits passed through hollow nerves to initiate action or mediate sensation. Galen could not use human dissection, only animals
(cows, sheep, apes and ‘at least one elephant’)
He also worked on the role of the nervous system and made a distinction between the sensory and motor nerves. The basic
components of intellect were imagination, cognition and memory, whose localisation wasn't to the substance of the brain itself,
but to the ventricles of the brain- anterior, middle and posterior ventricles).
Bishop Nemesius and the ventricular doctrine (390 AD):
Galen´s follower. He assigned each component of the intellect to one ventricle: perception-anterior ventricle, cognition-middle
ventricles and memory-posterior ventricles.
Later accounts suggest injury studies were used to support this localisation (Posidonius of Byzantium). So, for hundreds of
years, both in Europe and Middle East, the ventricle doctrine was held as accurate.
The Renaissance:
In the 14th C, there was a move away from ventricular doctrine and focus on Galen’s work.
Vesalius (1514-1564) was an anatomist who believed that human dissections should be the main teaching tool for physicians.
He was the first to note that Galen would have been working from animal studies and correct some of the anatomical errors
that had persisted as a result. Rejected of the idea of ventricular doctrine, because human ventricles did not differ greatly from
other mammals, who could not be considered to have higher reasoning skills.
2.2-Bigger step forward in localisation
18th Century:
Localisation in the Spinal Cord: spinal cord has two types of nerves emerging from it:
• Dorsal (posterior) nerve carries sensory information into the spinal cord.
• Ventral (anterior) nerve carries motor signals to the muscles to produce
movement.
The Bell-Magendie Law (1811-1822):
Previously, it was suggested that both sensory and motor messages passed along both types of nerve, they were bidirectional.
It was thought that impulses could pass in both directions at once.
• Bell (1774-1842): (Scottish) showed the motor functions of the ventral roots via dissection studies in 1811.
• Magendie (1783-1855): (French) researched those, and the sensory functions of the dorsal roots, using vivisection
studies. More spreader findings than Bell.
Despite researching this independently, both are credited in the name of the law. In Bell’s 1811 pamphlet, he suggests that
other parts of the brain could be assigned to sensory or motor roles- but strong localisation ideas didn’t really start to emerge
until Franz Gall.
Franz Gall (1758-1828) and phrenology (1795):
Suggested that regions of the brain relate to specific functions and traits, so appearance therefore indicates psychological
characteristics at that time. An individual who is skilled in those functions will show well developed brain regions. This will
be seen in the development of the skull- bumps and dips will correspond to the development of the brain beneath (the skull fits
the brain like a hand in a glove). The more spiritual the trait, the higher on the skull it is (closer to God).
How did Gall determine these areas? Examples:
• Destructiveness: indicated by development above the ear. Gall
knew an apothecary who became an executioner, who had a
well developed destructiveness region. Also, wild animals
have a strong development here too.
• Acquisitiveness: upper front of the squamous structure. This
area seemed large among the pickpockets Gall knew.
Non-scientific conclusions: based on observations of people that he
knew.
, Cortical equivalence: alternative to phrenology
Even during phrenology's heyday, (1802-1838) there were a lot of criticisms of the approach. One of the most vocal opponents
was Marie-Jean-Pierre Flourens (1794-1867). He stated that the cortex functions as a whole- all parts are responsible for
intelligence, the will and perception. He used lab and animal studies to demonstrate that functions could be recovered after
parts of the brain were destroyed.
Much of his work was on animals with lower cortical dependency than mammals (frogs, hens, etc.). While he did work with
cats, dogs and mice, these specimens may have been young: hence more plasticity to the injury. Finally, his own biases against
phrenology (and therefore the idea of localisation in general) may have led him to play up certain findings and play down
others.
2.3-The shift towards localisation
Broca and Broca´s area:
Localisation became more accepted with Paul Broca’s discovery, presented in 1861. A patient (Patient
‘Tan’) with damage to the left inferior frontal cortex showed intact language understanding, but
impaired speech production. Broca was not the first to identify such a region- but previous researchers
had associations with phrenology, which made them unreliable.
Broca had not been an advocate for phrenology, so the change was noted, he was reliable and
respected and also provided a detailed case history for Patient ‘Tan’ (also, the site of the injury did
not relate to the area suggested by phrenologists for speech).
Carl Wernicke (1848-1905):
Wernicke’s discovery came 10 years later (1874). The lesion was located in the left posterior temporal lobe and the patient had
difficulty understanding language but could produce it (although not coherently). This provides the second part of the double
dissociation that localises language related functions to the left hemisphere.
2.4-Phineas Gage
https://slate.com/technology/2014/05/phineas-gage-neuroscience-case-true-story-of-famous-frontal-lobe-patient-is-better-than-textbook-accounts.html
He is psychology’s favourite curiosity: he appears in 60% of all textbooks of psychology, neuropsychology and the
neurosciences.
” …an anecdote about Gage is like an "ace [up] your sleeve. It's just like whenever you talk about the French Revolution you
talk about the guillotine, because it's so cool. “- Peter Ratiu
He was also strong evidence for localisation of function: the index case for personality change due to frontal lobe damage.
Pre accident: a construction foreman for the Rutland and Burlington railroad in New England who held a position of
responsibility, described as intelligent and socially well adapted. A blasting accident shot a 3cm thick iron bar through his skull,
entering below the left cheekbone and exiting through the top of his head. Gage survived the accident, but the injury caused a
change to his personality: he became unreliable, disrespectful, lost his sense of social conventions and responsibility. Friends
and acquaintances described him as ‘no longer Gage’.
There’s a lot of misreporting around Gage’s case: Malcolm Macmillan has spent years collecting information about Gage, and
has found this great tendency to exaggerate his physical symptoms: in 1852, Gage actually became a long-distance stagecoach
driver in Chile, a job that would have required planning and self-regulation, as well as the sensory-motor and cognitive skills,
evidence perhaps for a social recovery, aided by the structure his new job required of him (it´s suggested that he went through
ha kind of social recovery). False information (gambling, family abuse, etc.) comes from second and third hand accounts of
Gage, not those who actually knew him, revealing the importance of primary sources.
In context:
At the time of the accident, phrenology (and thus localisation) was controversial. Harlow’s (1848) first report of Gage doesn’t
go into much detail about the psychological effects. Bigelow (1848) states there was a full recovery, both mental and physical
(supported cortical equivalence).
