L1 Techniques in bio

Question 1

What is optogenetics?

Answer 1

A biological technique that involves the use of light to control cells in living tissue, typically neurons, that have been genetically modified to express light-sensitive ion channels. Used in rats. Channels change the flow of electrical charge and activate or silence the neurons. Light is delivered by a thin optical fibre implanted into the brain

Question 2

What is deep brain stimulation?

Answer 2

Involves implanting very fine wires, with electrodes at their tips, into the brain.
When the device is switched on, the electrodes deliver high frequency stimulation to the targeted area. Used in Parkinson’s Disease.

Question 3

What is Transcranial Magnetic Stimulation?

Answer 3

Pulse of magnetic field applied to brain
Briefly disrupts neural functioning - Like very brief lesion/ stroke
Localisation of function (involved in a task) e.g. affects speech.

Question 4

What is a voxel?

Answer 4

A volumetric pixal - the best brain scans have the smallest voxels.

Question 5

What is a Computerised tomography (CAT) scan?

Answer 5

Measures the structure of the brain by taking pictures of slices. Can see brain abnormalities.

Question 6

What is MRI scanning and what advantage does it have over CAT scans?

Answer 6

Magnetic Resonance Imaging. More detailed image - measures density.

Question 7

Name two types of structural imaging.

Answer 7

CAT and MRI scanning.

Question 8

Name 3 types of functional imaging.

Answer 8

1. Positron Emission Tomography (PET scan)
2. Functional magnetic resonance imaging (fMRI)
3. Magnetoencephalography (MEG)

Question 9

How does PET scanning work?

Answer 9

Tracer (radioactive substance injected) and detectors map where the substance goes. Often radioactive glucose as brain regions most active take up most glucose (i.e. can map active regions).

Question 10

Can PET scanning trace neurotransmitter pathways?

Answer 10

Yes but not good spatial resolution so can’t look at really small brain regions. Also slow so difficult to measure quick changes.

Question 11

How does fMRI work?

Answer 11

Brain activity measured indirectly from levels of oxygen in blood. Detects increases in blood oxygen levels (BOLD signal) in response to increased neuronal activity.

Question 12

What 3 advantages does fMRI have over PET?

Answer 12

Better resolution (smaller voxels)
Faster
No radiation.

Question 13

How does MEG work?

Answer 13

Detects weak magnetic field emitted by neurons.

Question 14

Can fMRI scanning trace neurotransmitter pathways?

Answer 14

No

Question 15

What can a radial arm maze measure?

Answer 15

Short and long term memory

Question 16

What type of scan is useful for measuring drug use and transmitter activity?

Answer 16

PET scan

Question 17

What types of resolution are better with fMRI than PET scaning?

Answer 17

Temporal and spatial.

Question 18

What type of scan can detect rapid changes in neuronal activity and how long activity lasts?

Answer 18

Magnetoencephalography (MEG)