Task 8- Lobes, hemispheres... Flashcards
Beliefs of the Ancient Egyptians
- Edwin smith papyrus:
- papyrus that contains short descriptions of symptoms and treatment of Brian injuries
- illustrates how physicians treated soldiers and came convinced of importance of head in controlling behavior
-in wider society: scholars convinced that heart was seat of the soul
Soul - Ancient Greece -Plato
Soul divided in 3 parts
1) brain -> reasoning, immortal, separated from body, controlled body
2) heart -> sensation, mortal
3) liver -> Appetite
Aristotle - soul
- heart as seat of soul -> heat
- brain -> cold, tempered the heat
- > functional unit
Galen
- 6 centuries after Aristotle
- Greek physician
- demonstrated that voice come from brain, not heart
- dissected brains and published drawing (used ox brains)
- believed that soul resided inside brain
-Animal spirits:
Spirits that travel over the nerves between ventricles in brain and body
-Ventricles:
Thought to contain perceptions, memories and thoughts
-> seat of animal spirits st
Developments in the renaissance
- Galen’s view norm until well into 18th century
- Andreas Vesalius established that there were 3 ventricles
1) front -> receive info from senses, called common sense, fantasy, imagination
2) middle -> thought and judgement
3) back -> memory
-observations by Johann Schenk von Grafenberg -> after brain damage patients sometimes could no longer speak b
Developments in 17th and 18th century (2)
1) brain instead of vesicles
- British anatomist Thomas Willis-> first to implicate grey part in functions of memory and will
2) increased interest in reflexes
- Galen noticed that animals perform involuntary acts
- Descartes -> mechanistic view
Breakthroughs of 19th century (5)
1) discovery of the cerebrospinal axis
2) Growing impact of the reflexes
3) localization of brain functions
4) the discovery of the nerve cell
5) disentangling communication in the nervous system
1) Discovery of the cerebrospinal axis
- understanding that spinal cord is an integral part of CNS
- involved in control of many functions
- body remains functioning when cerebral hemispheres are disconnected
- some animals have a spinal cord but no brain
2) Growing important of reflex
The reflex arc:
- introduced by Marshall Hall
- describing process underlying a reflex
Reflex arc as basis of mental functioning:
- Ivan Sechenov claimed that all higher functions of brain were of a reflex nature
- > influenced Pavlov (his student)
3) Localisation of brain functions
-shift from brain equipotentiality theory to localisation theory
4) Discovery of the nerve cell
- better microscopes
- techniques to stain brain tissue
- > innovations for breakthrough
5) Disentangling communication in the nervous system (3 findings)
1) individual neurons instead of continuous network
- > communicate with each other without being attached
- Golgi
- Cajal
2) electricity within neurons
- Luigi Galvani -> evidence for electricity in nervous system
- operating frogs
- Reymound: firmly established that nerve signals involved electricity (50 years later)
- Helmholtz: measure speed of signal transmission, 1852
3) The synapse
- Neurotransmitter, chemical substance
William James (USA) and reflex arc
- > ambivalent opinion
- reflex arc was considered as a model of brain functioning in the US
John Dewey
- ambivalence
- reflex concept as too elementaristic and mechanistic
Equipotentiality theory
- all parts of brain have equal significance and are involved in each task
- > first thought to apply to whole brain, then limited to cerebral hemisphere
Localisation theory
- brain processes are localized
- > only part of the brain underlies a particular mental function
Findings of language production
Jean Baptiste Bouillaud 1825:
- student of Gall
- evidence that speech was controlled by front parts of brain
Paul Broca 1861:
- more cases showing importance of frontal lobes for language production
- claimed only left hemisphere involved
Brocas are: speech production
Wernickes are: speech comprehension
Golgi
- straining technique
- 1873
Santiago Roman y Cajal
- neuron doctrine
- network of neurons composed of individual cells
- > communicate with each other without being attached
- after Golgi and Wernicke
Emergence of neuropsychology in 20th century
-localization studies in WW: Gorden Homes (1876-1965): case studies -> vision problems after gun shot wounds at the back of the head
Joachim Bodamer (1847): described soldiers who lost ability to recognize faces -> prosopagnosia
-> psychologists became involved in study of behavioral consequences of brain injury, calling themselves neuropsychologists
A change of focus: cognitive neuropsychology
- 70/80s: neuropsychologist were dissatisfied because
1) Localisation on basis of human brain injuries was difficult
2) results went rarely beyond a list of symptoms
-> neuropsychologists should investigate functional implications of injuries
New name : cognitive neuropsychology
-aimed at understanding and treating the behavioral consequences of brain damage within the information processing models proposed by cognitive psychologists
One of first topics addressed by new approach: Deep dyslexia
-sting impaired reading after brain injury -> reading out semantically related words
- made distinction between
1) logogen system
2) cognitive system
1) logogen system
- contained all words known to patient, no information about meaning
- visual logogen system -> recognition of written words
- auditory -> spoken words
- output -> production of speech
2) cognitive system
-stored meaning of words with which logogen system interacted
- for normal reader: 3 routes to name a written word
- patients with dyslexia: 2 routes are severed and only one remaining route
- > the one via cognitive system -> gives rise to semantically related errors
Brain imaging studies and the turn to neuroscience
-from post-mortem analyses to single cell recording -> to non-invasive techniques
Criticism cognitive neuroscience
-findings of fMRI etc. are more comparable to localisation efforts of traditional neuropsychology than testing of cognitive models using neuropsychology
Defence of cognitive neuroscience (3)
1) difference between showing! And speculating about brain regions involved in a particular task
2) Localisation of brain activity while performing a task -> provide info about the processes involved
3) recognized that tasks require interaction of several areas
Broadman
…
Thomas Willis
-17th century
-coined words ‘hemisphere’ and ‘lobe’
-attention to difference between outer layer and cerebral hemispheres
-first to implicate grey part in functions of memory and will
-
Franz Joseph Gall (1758-1828)
- phrenonology
- bumps etc -> cognitive skills
- first one to link behavior and brain regions together
Broca
- 1824-1880
- patient who always said TAN
- Broca’s area
Wernicke
1848-1905 -> after Broca
cognitive neuropsychiatry
- end of 20th century
- researchers argued that same approach could be used in study of faulty thinking in mental disorders
-> in particular delusions:
Strong erroneous beliefs that are not supported by empirical evidence
Case study of Joseph Capgras
- a women had long list of mental problems
- delusions!
- Capgras first interpretation:
- delusion as result of discrepancy between rationally recognizing the family member and no longer feeling any sense of familiarity
Capgras advanced explanation - inspired by Freud
- source of delusion: incestuous desire for father
- > led to ambivalence in feelings for other relatives -> resulting in mix of love and hate
- if conflicts escalated too much:
- ‘solved’ by making dissociation between the real, beloved person and the look-alike that could be hated
Capgras delusion -> cognitive neuropsychiatry
- cognitive neuropsychiatry grew interested in Capgras delusion when it became clear that delusion sometimes started after brain injury
- Capgras delusion attracted further interest because cognitive models of face processing pointed to conclusion, that face recognition involved two different routes ( and that one routes is severed in people who have delusions)
Galvani
- frog studies
- 1786
Raymond
- 1808
- fish experiments, research
Helmholtz
-1852
Broca
-1861
Bouilland
- 1825
- speech controlled by frontal lobes
Marshall hall
- reflex arc
- 1832
- described the process underlying a reflex
Gall & spurzheim
-Localisation , phrenology
