T1L11 global brain activity

Question 1

brain rhythms

Answer 1

eg sleep and wake, steps of walking, menstruation

Question 2

electroencephalogram (EEG)

Answer 2

• lots of electrodes all over your head
• pyramidal cells generate small fields
• only detectable if large population of neurons activated in synchrony
• this population must be aligned in parallel so they summate rather than cancel each other out

Question 3

synchronous activity

Answer 3

• amplitude of EEG signal partly depends on how synchronous underlying activity is
• number of cells, timing, total excitation

Question 4

brain rhythms

Answer 4

learn this I guess - s10

Question 5

generation of synchronous rhythms

Answer 5

one neuron oscillator:

Thalamic cells have a set of voltage-gated ion channels that allow each cell to generate rhythmic, self-sustaining discharge patterns, even in the absence of external inputs.
The rhythmic activity of each thalamic pacemaker neuron then becomes synchronised with many other thalamic cells via a hand-clapping kind of collective interaction.

Question 6

function of brain rhythms

Answer 6

• maybe meaningless byproduct of other shit
• activity of coordination
• sensory input

Question 7

sleep

Answer 7

• reduced motor activity
• decreased response to stimulation
• stereotypic postures
• easily reversible

functions:

• conservation of energy
• cognition
• thermoregulation
• neural maturation and mental health

Question 8

3 functional states of sleep

Answer 8

• awake
• non REM
• REM

see s17

Question 9

other imaging techniques than eeg

Answer 9

1. structural
   - CT (computerised tomography)
   - MRI
2. functional
   - PET (positron emission tomography)
   - fMRI

Question 10

ct

Answer 10

• based on xray absorption
• bone white, csf black
• diagnose tumours or haemorrhaging

radiation

Question 11

mri

Answer 11

• completely safe
• better spatial resolution
• better discrimination between white and grey matter
• can be adapted to detect changed in blood flow fMRI

magnetic field aligns protons and the spin produces a measurable mr

Question 12

pet

Answer 12

• blood volume
• radiation
• sensitive to whole brain
• can use tracers
• spatial resolution 10 mm

all functional imaging is comparison with baseline

Question 13

BOLD (fMRI)

Answer 13

• blood oxygen
• no radiation
• 1mm spatial res
• some regions hard to image eg near sinus

all functional imaging is comparison with baseline

Question 14

BOLD signal

HRF

Answer 14

blood-oxygen-dependant contrast

HRF- haemodynamic response function (changes of BOLD signal over time)