Arborisations

Question 1

what does arbor mean

Answer 1

tree

Question 2

work of Ramon y Cajal

Answer 2

documented complexity and diversity of dendritic arbors e.g purkinje cells in the cerebellum

Question 3

desert locust

Answer 3

swarms 1200km^2
robust and predictable response to local stimuli

Question 4

electrophysiology in desert locusts

Answer 4

electrodes in metathoracic ganglion (sensory neurons terminate) and record responses in: ventral/dorsal tibia, dorsal femur

innervation causes firing (spike noise)
know: interneuron anatomy (produces spatial map)

Question 5

where is the sensory system of the drosophila

Answer 5

periphery

Question 6

how to make a tree

Answer 6

neurons need to grow in the same space and repel
repellants form trees (only sister branches repel)

Question 7

down syndrome cell adhesion molecule (DSCAM)

Answer 7

gene in drosophila and mice
large isoform diversity via alternative splicing (~38000 isoforms)
genomic DNA is multi-exonic - forms mRNA - protein (homophilic binding domain)

self-avoidance - prevents tangles due to repulsive force by homophilic binding

Question 8

DSCAM mutant

Answer 8

collapsed dendrites (no repelling)

WT: repelling

rescue: sufficient to repair

Question 9

clustered protocadherins (pcdhs)

Answer 9

in vertebrates
inform neurons of the branches’ identity
self-avoidance requires pcdhgs

Question 10

CUT

Answer 10

homeodomain protein which regulates branching in drosophila
in class IV - reduces complexity

Question 11

abrupt (ab)

Answer 11

BTB-zinc finger protein (TF) regulates branching complexity of da neurons (drosophilia)

Question 12

ab26 mutants

Answer 12

LOF - increased complexity of class I da neurons (simple cells become complex)
class IV - no change in structure
ab26 overexpression in class IV - reduces complexity

Question 13

terminal selector transcription factors

Answer 13

within post-mitotic neuron
process: regulatory inputs -> terminal selector gene ->terminal gene battery

neuron-type specific gene batteries endow cells with distinct anatomical and functional properties

Question 14

what do motor neuron dendrites form in drosophila

Answer 14

myotopic maps in the CNS (reflects layout of muscles in the periphery)

Question 15

what does the adult ventral neural cord contain (drosophila)

Answer 15

(unit for leg control)
539 ascending sensory neurons
1328 descending sensory neurons
MNs

Question 16

neuroblast (NB)
early vs late born

Answer 16

generates ~50% of leg MNs

early born: lateral to midline
late born: distal to midline

Question 17

why do dendrites have different morphologies despite trees growing at the same time

Answer 17

midline signalling molecules (act as a repellant)
receptor = Roundabout

Question 18

Robo mutants

Answer 18

Robo gain of function - repel to lateral edge
robo loss of function - medial territory
Comm gain of function - removes Robo

Question 19

what are growth cones attracted to

Answer 19

chemoattractants (DCC)

Question 20

how do class III da neurons orient growth

Answer 20

DSCAM

Question 21

does self avoidance (DSCAM/pcdh) counter the targetting of dendrites

Answer 21

use ectopic netrin
result: greater distance from cell body and altered morphology

Question 22

synaptotropic hypothesis

Answer 22

nascent synapses help growth
branches make nascent synapses

Question 23

pleural muscle motoneuron PMM

Answer 23

PMM are cells in the BS/SC
axons form branching patterns in the abdomen - contraction

Question 24

molecules required for synapse formation

Answer 24

presynaptic - NRX
postsynaptic - NLG

Question 25

synaptic activity movement

Answer 25

synaptic activity - stabilisation
no synaptic activity - retraction

Question 26

vGluT vs vGluT mutant

Answer 26

located presynaptically
vGluT - packages glutamate into vesicles, regulates amount of Glu released
vGluT mutant - no Glutamate release - no change in structure/complexity

Question 27

NLG

Answer 27

not needed for growth
Nlg1 expressed in muscles

Question 28

tips of dendritic branches

Answer 28

tips have PMM accumulation (signal/precursor for new synapses/anchoring new proteins for signalling/dynamic remodelling?)
lifetime of dots predict stability of aborisation

Question 29

NAC (neuritic adhesion complex)

Answer 29

presynaptic protein complex needed for growth of branches
accumulation of proteins at the synapse
synaptic cell adhesion molecule

Question 30

cell type specific labels for stick and grow

Answer 30

leucine-rich repeat containing synaptic adhesion molecule
neurexins
neuroligins
teneurins