lecture 1- definitions and a brief history Flashcards
what is behaviour?
behaviour is anything that a living creature does in reaction to some kind of environmental stimulation
what is neuroscience?
neuroscience is the study of the nervous system (the brain, the spinal cord, the sensory/motor neurons) there are multiple approaches to take when studying this area.
-functional: what do these areas do?
-development: how does the nervous system develop over the lifetime?
-anatomically: at the molecular level, the cellular level, the level of different brain regions and structures
-medical: what happens when things go wrong, and how can they be treated?
heart or head?
- 2780 BCE: egyptian medical records
- links injuries to the head with deficits in the body
- against the key theory of the time
what is the cardiocentric model?
the heart is the key organ of the body
the Hippocratic revolution 5th century BCE - 348 BCE
- Alcmaeon (5th century BCE): the brain as the site of sensation and thought
- Hippocrates (460-370 BCE): the brain is controlling organ of the body
- Plato (428-348 BCE): the triune soul- brain, heart and gut
-the brain= intellect
-the heart= anger, fear and pride
-the gut= greed, desire and lower passions - the intellectual soul (that in the brain) is immortal
Aristotle 384-322 BCE
but why aristotle?
- observations limited to animals
- the majority of which were cold-blooded
- and small
-no clinical experience - a ‘pure’ biologist, rather than an applied one
Galen 130-200 AD
- the most influential physician of the roman empire
- dissected a wide range of animals including mamals
- the first to number the cranial nerves, and suggest some might be motor functions and some for sensory functions
- sensation and perception results from the conversion of vital spirits (in the heart) into animal spirits (in the brain)
- these spirits flow through the nerves and cause action/sensation
Galen and localisation
-the basic components of intellect: imagination/perception, cognition and memory
-these components were dependant of each other
-but for now, no further attempt at localisation
Bishop Nemesius and the ventricular doctrine (360 AD)
- suggested the ventricles as the home of the three components
- perception= anterior ventricle
- cognition= middle ventricles
- memory= posterior ventricles
- widely accepted idea
- supported by early dissociation studies
- damage to specific region= loss of that function
the renaissance and hands on experience
-Andreas Vesalius (1524-1564)
-anatomist and author
- studied in Padua: access to human bodies
-highlighted multiple instances where the human brain did not fit Galens descriptions
- urged study of anatomy via dissection
- rejected the ventricular doctrine
localisation in the spinal cord- what two types of nerves does the spinal cord have 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
- Bell (1774- 1842): motor functions of the ventral roots
- Magendie (1783-1855): sensory functions of the dorsal roots
- The bell-magendie law:
- the anterior nerves contain only motor fibres, the posterior roots only sensory fibres
Franze Gall (1758-1828) and extreme localisation
- regions of the brain relate to specific functions and traits
- greater skill= larger area/development
- greater development in the brain= matching development in the skill
phrenology
- the more spiritual the trait, the higher on the skull it is
- destructiveness: indicated by development above the ear
-apothecary turned executioner- also. wild animals
-acquisitiveness: upper front of the squamous structure - well developed in pickpockets
-early pop psychology
-and quickly commercialised
- also. wild animals
- and a component of 19th century scientific racism
- remnants of phrenology in modern phrases
- highbrow vs lowbrow
cortical equivalence
- marie-jean-pierre flourens (1794-1867)
-the cortex function as a whole - all parts are responsible for intelligence, the will and perception
- animals studies: subjects recover abilities after destruction of cortical areas
- animal subjects; eg frogs, hens
- lower cortical dependency
-use of younger subjects
-greater possibility?
- lower cortical dependency
- possibility of bias in interpretations?
the shift towards localisation
- paul broca and patient tan (1861)
- left inferior frontal cortex damaged
- language understanding: functional
- language production: impaired
- evidence for localisation of language functions… accepted?
- paul Broca
-right person, right time - no previous ties to phrenology
- proposed site did not fit with phrenological theories
- an extremely detailed case study provided
phineas gage - pre accident
- pre accident: railroad construction foreman
- seen as responsible, intelligent, social
- 1848- blasting accident: damage to frontal cortex
phineas gage- post accident
- changes in personality
- unreliable, disrespectful, lost his sense of social conventions and responsibility
- ‘no longer gage’
phineas gage
- evidence for localisation of function:
- the index case for personality change due to frontal lobe damage
- initial reports on his case:
-no mention of cognitive changes- (harlow,1848) - ‘the patient is not well’- (Bigelow, 1848)
the importance of primary sources
- initial support for theories of cortical equivalency
- support for theories of localised function
- early evidence for psychosocial adaptation/social recovery?
cytoarchitecture
- theodor meynery (1833-1892)
- the cellular architecture of the brain
- noted variations in the historical structures, according to the regions (1876)
visualising cells
- Franz Nissl (1860-1919): The Nissl method
- stains the cell body highlighting different structures
- allowed examination of internal cell details
visualising cells cont.
-Camillo Golgi (1843-1926)
- silver nitrate staining solution
- stains selected cells in their entirety
- visualising of axon, dendrite, and the length of neuron possible
neuron doctrine
- santiago ramon y cajal (1852-1934)
- modification of the golgi stain
- nerve cells are individual structures
- no physical connection between them
neuron doctrine (1906)
- the brain is made up individual units (cells)
- units are specialised depending on function
- they are connected by sites of contact (the synapse), not shared cytoplasm
- each synapse releases only one type of transmitter
- updates
- electrical synapses: are connected by cytoplasm
- contransmission is very common
localisation: where are we now?
- brain regions can be related to specific functions/behaviours
- but no one part of the brain is an island
- vast interconnections between the regions and structures
- the connections are similarly important in understanding how behaviours may be affected/controlled
- neither extreme view suits what we observe- and other factors will influence behaviour and development as well
what are the 3 recent ideas in biological psychology?
- lateralisation of functions
- neuroplasticity
- neuroethics
lateralisation of function
- localisation of certain functions to either the left or right hemisphere
- broadly:
- language localised to the left hemisphere (LH)
- face recognition localised to the right hemisphere (RH)
- emotion localised to the RH
neuromyth: left brain vs right brain
- extreme lateralisation:
- left hemisphere= rational/logical/masculine
- right hemisphere= creativity/intuition/feminine
- educational programs
-right brain dominant children- require different styles of teaching
-evidence
- little to suggest anything as extreme as this division
