methods for studying brain structure and function

Question 1

Franz Gall

Answer 1

observed people with excellent verbal memories and bulging eyes- so said brain area concerned with verbal memory was located behind the eyes

Question 2

phrenology

Answer 2

bulges and depressions on skull correspond to specific behaviours
BUT
- usually based on indiviuals with behavioural quirks
- skull shape has little relationship to brain anatomy

Question 3

techniques for observing the anatomical structure of the brain- historical procedures

Answer 3

brain slices selectively stained and viewed under microscope to identify key features
stains= 1. cell body stains- violet, more densley concentrated cell bodies, 2. myelin stains- colour myeline sheath, 3. membrane stains- silver- interacts with axon membranes and shows dendrites.

Question 4

histochemical techniques

Answer 4

-looks at location and direction of specific neurons and neurotransmitters

Question 5

immunocytochemical techniques

Answer 5

• takes advantage of immune reaction (body producing antibodies to bind to specific antigens)
• brain slices placed in solution contained ab
• if specific protein present in brain it will bind to ab

Question 6

problems with staining techniques

Answer 6

• invasive- most likely have to be dead as uses brain slices

Question 7

CT/CAT scans

Answer 7

xrays passed thru patients head and 2d image produced
the whiter the image the denser the tissue
commonly used for diagnosis of tumours, strokes, blood clots, neural degeneration

Question 8

MRI

Answer 8

• uses powerful magnet to observe magnetic radiation from hydrogen atoms
• shows key structures through showing different hygrogen concentrations
• looks at brain from 3 anatomical planes- horizontal, saggital, coronal

Question 9

fMRI

Answer 9

uses similar process to mri
demonstrates structure and function
measures metabolic activity
when active, brain areas consume o2
so fmri measures level of o2 consumption
colder colours- less activity
warmer colours- greater activity

Question 10

PET scans

Answer 10

• radioactive glucose injected into patient
• this is taken up by metabolising cells
• can look during rest and during activity to see the difference of glucose consumption as its radioactively labelled
• can compare healthy and diseased brains- diseased would have less glucose consumption

Question 11

advantages of brain imaging

Answer 11

• relatively non invasive
• can be used to compare healthy vs diseased brains and activity during rest and activities
• good spatial resolution

Question 12

disadvantages of brain imaging

Answer 12

• risks from xrays and radiation
• noisy
• claustraphobic
• expensive
• lots of equipment
• not portable
• poor temporal resolution- not good at linking events to real tie changes in images

Question 13

recording electrical activity

Answer 13

tells us which structures used in particular functions

Question 14

microelectrodes

Answer 14

• implanted into brain to record neural activity
• can be used to monitor activity of individual neurons
• highly invasive
• records very precise activity

Question 15

macroelectrodes

Answer 15

more suitable for humans than microelectrodes
used in EEG

Question 16

EEG

Answer 16

active electrodes attached to scalpi areas of expected neural activity
indifferent electrodes attached to neural areas
shows differences in electrical activation between active and neural electrodes measured

Question 17

beta waves

Answer 17

show person actively attending to events and aware of surroundings

Question 18

alpha waves

Answer 18

awake but is not actively processing info (daydreaming)

Question 19

theta waves

Answer 19

related to light sleep

Question 20

delta waves

Answer 20

related to deep sleep

Question 21

advantages of macroelectrodes

Answer 21

• fairly non invasive
• can differntiate between diff neurological conditions

Question 22

disadvantages of macroelectrodes

Answer 22

• time consuming
• interpretaion requirs considerable experience