Adult Neurogenesis

Question 1

How can radioactive nucleotide analogues be used to visualise newly-generated neurons?

Answer 1

Inject

Taken up into DNA - during cell replication and division

Question 2

What are the advantages of radioactive nucleotide analogues to visualise newly-generated neurons?

Answer 2

Permanent tracing
Trace whole population of dividing cells
Birth dating

Question 3

What are the disadvantages of radioactive nucleotide analogues to visualise newly-generated neurons?

Answer 3

Only visualises cell nucleus - do not know cell type

Label incorporation may be due to DNA repair

Question 4

Name a radioactive nucleotide analogue

Answer 4

BrdU

Question 5

Which 2 techniques can be used to visualise newly-generated neurons?

Answer 5

Radioactive nucleotide analogues

Genetic marking by retroviruses

Question 6

How can genetic marking by retroviruses be used to visualise newly-generated neurons?

Answer 6

Integrate after cell mitosis

Labels dividing cells

Question 7

What are the advantages of genetic marking by retroviruses to visualise newly-generated neurons?

Answer 7

Permanent tracing
Birth dating
Whole-cell visualisation - modify virus to express GFP

Question 8

What are the disadvantages of genetic marking by retroviruses to visualise newly-generated neurons?

Answer 8

Only few cells marked

Invasive - must be injected into dentate gyrus

Question 9

Where does adult mammalian neurogenesis occur?

Answer 9

Subgranular zone

Subventricular zone

Question 10

Where do subventricular zone-generated cells go and via which migratory streams?

Answer 10

Rostral migratory stream - to olfactory bulb

Medial migratory stream - to ventromedial PFC

Question 11

Where do subgranular zone-generated cells go?

Answer 11

Into dentate gyrus granule cell layer

Question 12

What are the steps of new neuron development in the dentate gyrus?

Answer 12

Progenitors migrate into granule cell layer
Make local connections
Grow dendritic tree - receives contacts from EC
Grow axon - project to CA3

Question 13

Name factors that increase new neuron proliferation/survival

Answer 13

Exercise
Enriched environment
Learning tasks involving hippocampus
Brain damage - seizures, ischaemia
Antidepressants

Question 14

Name factors that decrease new neuron proliferaton/survival

Answer 14

Stress
Depression
Brain damage - PD
Ageing
Alcohol, nicotine, opiates

Question 15

In which brain area does neurogenesis occur in songbirds and what is the role of this area?

Answer 15

Higher vocal centre

Enables new song learning every year

Question 16

What is a disadvantage of radiation and chemical neurogenesis KO methods?

Answer 16

Also have non-specific detrimental health effects - may affect behaviour

Question 17

What is an advantage of genetic neurogenesis KO methods?

Answer 17

Temporally and spatially restricted

Question 18

What is the role of the dentate gyrus?

Answer 18

Pattern separator
Similar inputs from EC activate different neuronal patterns in DG
Less likely for memory overlap between similar events

Question 19

What are the 2 possible explanations for the need for neurogenesis in the dentate gyrus?

Answer 19

Increase hippocampal memory capacity

Increase capacity for pattern separation

Question 20

What does the time-tagging of memories theory suggest for the purpose of dentate gyrus neurogenesis?

Answer 20

Newer cells more excitable - set up connections to CA3 preferentially
Temporal pattern separation - separate memories in time