Origins of behavioural neuroscience Flashcards
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HAVE NOTES BY SIDE THROUGHOUT AS LOTS OF DIAGRAMS
the nature of behavioural neuroscience
Behavioral neuroscience is a combination of psychology and physiology – combination of neuroscience and behaviour
The methods and the theories of these two fields are combined to try and explain how biology gives rise to psychology.
These combined methods and theories have been applied to the topics we cover in this series: Consciousness, sleep, reproduction, emotion, feeding, learning and memory, neurological disorders, mental illness, and addiction.
Reductionism and generalisation
The utility of laboratory models
Extract once process and study it – discover principle (reductionist) and generalised to a broader context
- E.g. Pavlovian conditioning
history of behavioural neuroscience
Descartes produced the first reductionist (mechanistic) account of movement
Spiritualism
Hydraulic pressure moves statue – underlying principle of Descartes theory
Balloonist theory – heat withdrawal reflex – heat causes fluid in pipes to expand – causes pressure to change up the pipe into the brain – brain channels pressure to correct location which causes muscles to move
Bit like heart/pump
How does it explain other processes? – e.g. withdrawal of hand from something cold
neural conductance
Galvani (1737-1798)
Gross anatomy in frogs
Electricity makes contact wit sciatic anatomy in legs – leg twitches
Static electricity could produce heat
Emerging theories of electricity at the time
Volta (1745-1827)
“Electrochemistry”
Produced same leg twitch with electricity from battery – no heat involved
neuron theory
Golgi (1843-1926)
Printing on clothes etc. very common at the time
Applied to brain tissue
Dye sticks to cells and enable to see more clearly what was there
Microscope also invented
Repeated pattern of highly organised structure
Diff functional roles played by different cells
doctrine of specific nerve energies
How can the same electrical impulse (in different cells) give rise to different sensory experience?
Diff parts of brain use same mechanisms but separated in functions to give rise to diff sensory experiences
Kinaesthesia – crossing of sensory experiences
lesions and neural basis of behaviour
Flourens (1794-1865)
Cut part of brain to test functionality – what behaviour is affected – correlation
Very unethical experiments
e.g. cut frontal brain – reduced movements
Cut cerebellum – lose balance and smoothness of movement
Cut brainstem = death as controls phys
cog neuroscience
Broca (1824-1880)
Diagnostic and clinical diagnoses
Know what part of behav missing
Post mortem to see where damage in brain was
Correlation
Lots of noise in the data
Impairment in ability to produce speech but comprehension still in tact
Just left of motor strip that controls tongue, face and lips – why speech production disrupted
Specialised part of the motor strip that extends beyond part of the face
somatotopic organisation
Circa (1870)
Dogs have skull removed but alive and pinned with pegs to washing line
Prod parts of the brain see which parts of the body moved
alien hand syndrome
Characterized by a limb that seems to perform meaningful acts without being guided by the intention of the patient
alien hand
foreign/unco-op behav of hand - name for syndrome and all of components
posterior alien hand
AHS that may follow posterior lesions, char by levitation and abnormal postures
magnetic apraxia/repellent apraxia
instinctive grasping/avoiding w/ abnormal posture
compulsive manip of tools
manip objects by abnormal hand against patients own will - used mainly in Japanese lit
anarchic hand
autonomous behav of limb w/o denial of ownership
strangers hand sign
detail of ownership of limb
strange hand sign
original meaning of alien hand sign - failure to recognise abnormal hand as own
autocriticism, interhem autocricism
expression of astonishment w/ behav of hand
diagnostic dyspraxia
conflict between desired act and perf act
intermanual conflict
hands act cross-purposes to each other
agonistic dyspraxia
compulsive automatic execution of orders by one of hands when patient asked to perf movement w/ other hand
Goldstein
described the case of a 57-year-old woman who suffered a stroke and thereafter perceived her left hand as having a will of its own.
On one occasion, the hand grabbed her by the throat and choked her, requiring great effort to pull it off…
Upon the woman’s death, Goldstein (1908) examined her brain and found lesions in the right hemisphere and in the corpus callosum, the large fibre bundle connecting the right and left hemispheres.
Corpus callosum – communication channel
AHS and corpus callosum
Often due to damage to the anterior (front) corpus callosum
Disruption in communication between the two sides of the brain
Pressure in area where blood leaked out but also lack of blood to rest of brain leads to death of cells
Unpredictable how the damage pattern will occur
AHS and anterior CC
Lesions of the anterior corpus callosum disconnect the two frontal cortical regions.
Primary motor cortex = sensory part – receive info from all parts of the body
Sensation and movement are interconnected but on diff sides of the channel
Premotor – origin of consciousness – activation ramps up before movement occurs
More complex decision making regions further forwards
AHS and premotor and primary motor areas
Due to disconnection of the premotor and primary motor areas between the two hemispheres?
Damage around motor cortex during stroke
AHS and descending pathways
Descending pathways from the motor cortices remain intact enabling control of muscles – goes into the striatum – then thalamus (junction box of the spine)
AHS and basal ganglia
Basal ganglia motor circuit is complex and we will cover it in a later lecture.
- Between striatum and thalamus
- Decision making and movement control
AHS and descending motor pathway
Descending motor pathway continues through the brainstem: Midbrain, pons, circuits the cerebellum (for fine motor refinement) then back out to medulla and into the spine.
- Lots of fibres
- Pons – ‘mini separate brain’
- Contralateral
- Fibres cross at the thalamus
AHS and cerebellum
Cerebellum turns jerky movement into smooth movement
AHS and somatotopic organisation
The somatotopic organisation in the motor cortex is preserved in the descending motor pathway, so that specific motor cortical regions control specific body parts.
Neurons for different areas exist at different spinal vertebrae.
AHS and consciousness
alien hand can afflict either hand equally
If consciousness was only on one side alien hand syndrome would only occur on one side
Can occur on either side
Information not exchanged with other side
Not going to consciousness on the other side - mis-match - doing stuff without being consciously aware
Consciousness resides in one side or the other - not just one side
Assume localisation theory
Emerges from totality of system
Consciousness produced by communication between 2 sides – lesion – no more communication
