5. • Penjelasan biologis perilaku
• Filosof dan neuroscientist yakin bahwa mindbrain adalah satu. Mengapa dan bagaimana
otak berhubungan dengan kesadaran masih
tanda tanya
• Ekspresi gen tergantung pada lingkungan dan
interaksi antar gen
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8. Mengapa mempelajari otak?
• Otak adalah ‘tempat’ perilaku
• Banyak masalah psikologis berasal dari
masalah biologis dan kadang-kadang)
membutuhkan intervensi biologis mis
• mis. Alzheimers, Parkinsons, epilepsi,
schizophrenia, depresi, ketergantungan obat
• Pemahaman tentang biologi membantu untuk
menjelaskan fenomena psikologis (mis.
persepsi)
10. Some questions
• How does anatomy help us understand brain function?
• What can studies of patients with brain damage tell us about
normal brain function?
• What can studies of animals with brain damage tell us about brain
function?
• Can we learn about brain function by non-invasive study of
normal humans?
• What can we learn from micro-electrode recording?
• How do chemistry and physics of nerve cells influence
psychological processes?
• Will fMRI and PET scanners make other techniques for the study
of brain function obsolete?
11. perilaku
• We can often deduce a lot about brain function
simply from behaviour
• It’s cheap and non-invasive and should be the
starting point for most studies
14. Behaviour (e.g. Interferensi ingatan)
• Could measure the independence of different
memory systems
• e.g. measure recalled words from a memory
test after reading a passage versus recalled
words after doing maths
• Then measure recalled numbers after
reading a passage versus doing maths
16. Luka di otak
• Mengukur pengaruh kerusakan otak (luka,
lesions)
• Disebabkan oleh
• Disease, trauma, stroke
• Surgery (frontal lobotomies,
commisurotomies…)
• misalnya
• Paul Broca
• Phineas Gage (pasien frontal lobe)
• Patient ‘HM’ (anterograde amnesia)
17. Masalah dan luka • We can only study what we get!
• Lesions terjadi biasanya pada daerah tertentu (mis. dimana
saluran aliran darah tertentu berjalan)
• Biasanya daerah luas dan multiple rusak
• Kadang-kadang neuron rusak
• Jarang terjadi (small n)
• Recovery
• Otak dapat menyambung kembali (apalagi ketika masih muda)
• Individu belajar strategi kognitif baru
• Hard to know what the original function was
18. Lesions – pada binatang
• Secara sengaja membuat lesion
• Secara kimiawi, electrikal atau dengan didinginkan
• Memilih daerah yang ingin dipelajari
• Secara selektif
• Regional
• Chemical
• Repeatability
• Lesi yang sulit terjadi pada manusia
• Kelemahan
• Perbedaan antar spesies
• Invasive
19. Lesions - TMS
• Transcranial Magnetic Stimulation (TMS) involves
creating a strong focal magnetic field over the scalp of
a (healthy) subject
• Creates a disturbance of activity near the probe, which
goes away when the probe is turned off!
• Pros:
• Reversible, repeatable and (relatively) non-invasive
• Cons:
• Not clear what its doing or exactly where the ‘disruption’ is
20. Anatomi
• Mempelajari lapisan otak dari post-mortem
• Menggunakan pelacak untuk mengetahui
daerah mana yang saling berhubungan
• Anterograde: travels forward showing which area this
cell projects to
• Retrograde: travels back showing where inputs are
coming from
• Both help us know about the function of an area
• Dengan ‘electron microscopes’ yang sangat
kuat, dapat dipelajari anatomi sel saraf secara
individual
21. Electrophysiology (neurophysiology)
• With electrophysiology we can insert
microelectrodes into the brain and record
form individual neurons, or clusters of them
• By measuring the rate at which it releases
action potentials we can determine what the
cell is used for
• e.g. a motor neuron might fire during a handmovement, a visual neuron during the
presentation of a particular stimulus…
22. Electrophys – pros and cons
• Pros
• The firing of neurons, ultimately is often what
we want to know about
• Can be used to study almost any area of the
brain
• Cons
• Invasive
• Animal work
• If a cell responds to a stimulus is it necessarily
needed for that stimulus? (interpretation is
harder than it sounds sometimes)
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23. Electrophys and microstimulation
Animal’s Response
• Microelectrodes can also be used for
stimulation
• Can simulate the response of a neuron
• e.g. in a motion detection task (below) we can
bias which direction the dots appear to move
by microstimulation (of neurons that prefer
with
that motion)!!
Salzman et al (1992)
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without
Stim correl
24. Imaging
• Computerised Axial Tomography (CAT/CT)
• Basically just X-ray, rarely used now
• Positron Emission Topography (PET)
• Inject with radioactive isotope (!) and measure where it goes
• Electro-encephalography (EEG)
• Measure the local electrical activity with scalp electrodes
• Magneto-encephalography (MEG)
• Measure magnetic field and infer where electrical activity occurs
• (Functional) Magnetic Resonance Imaging (fMRI)
• Measure the amount of oxygenated blood in an area
26. Imaging – EEG
• Pros:
• Very good temporal resolution (no delay at all)
• Non-invasive (but a bit uncomfortable)
• Useful for measuring patterns in activity (e.g.
sleep research)
• Also for measuring ‘Event-Related Potentials’
(ERPs)
• Cons:
• Poor spatial resolution (a few cm around the
electrode)
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27. Imaging - fMRI
• Magnetic Resonance Imaging (anatomical scans)
• fMRI – same basic technique to measure Blood
Oxygenation Level Dependent (BOLD) signal
• BOLD signal is related to activity in the brain
(presumably increased metabolism in active areas?)
• E.g.:
Subject
imagining finger
movement
Subject making
finger movement
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29. fMRI – pros and cons
• Non-invasive and can repeat measures for a
subject
• Good spatial resolution (measure activity in
voxels of ~1mm3)
• Not great temporal resolution (BOLD signal
lags around 6secs behind activity)
• We aren’t really sure what the BOLD signal
represents
30. Other methods
• Genetics
• Family studies
• Genetic mutation
• Microdialysis
• Insert small porous probe into the brain and
measure local fluid concentrations
31. Multidisiplin
• Idealnya menggunakan beragam metode
• Measure the behavioural characteristics of a
phenomenon
• Use fMRI (or patients) to see which brain
structures are involved
• Use electrophysiology to see what the
responses of the cells are like
• Then use anatomy to see how they are
interconnected
