Darkthorn’s Blog

Mammalian Models

- Primates – very similar to humans, and have large brains. Live for long periods of time, need lots of living space, and are expensive to keep.

- Large mammals – less similar to humans, and still live for long periods of time.

- Small mammals – still similar to humans, but brain size is a lot smaller. Life-span is still a little long, but relatively cheap to maintain.

- Rodents – can have prominent differences from humans, but are cheap to keep with very short life-spans and breeding schedules.

Specialised models are used to study different aspects of neuroscience

- Birds – auditory

- Amphibians

- Flies/worms/yeast

- Sea creatures

Specific Studies

- Squid

o giant axon, size gives it speed (not mylinated)

o stellate ganglion has many axons to innervate mantle and musculature to provide a coordinated response

o used to study: movement of ions through channels, transport of proteins along axon, how cellular pH is maintained

- Frog

o Specifically the African Clawed Frog

o Use oocytes for detecting recombinently expresses proteins (via electrophysical recordings

- Torpedo Rays

o Use a localised electrical charge to stun prey

o Originally used to determine structure of nicotinic acetylcoline receptors (linear array)

- Aplysia

o Sea snail/slug/hare

o Most neurons are large and readily identifiable, as well as being unique in function (used for studying reflexes)

o Can be used to understand simple forms of learning and experience (non-associative learning and habituation/sensitisation of gill-withdrawal reflex)

- C. Elegans

o Nematode (worm), self-fertilising hermaphrodite with a very short lifespan

o Limited number of cells (302 neurons, 959 somatic cells)

o Morphology, position and connectivity of neurons is definite (118 classes of neuron)

o The genome has been sequenced, so we know how to alter gene expression

o Their bodies are clear, so can watch protein expression while still alive

o Mutations of particular genes can cause alterations in behaviour/movement: check GABAergic and dyrein malfunction

- Fruit-fly

o Very small, prolific and has a short lifespan

o Studies of genetics and development

o Different neurotransmitters are involved in different types of learning (dopamine in aversive memory formation)

o Neuropharmological models are studied to see the effects of drugs in improving genetic neuropathologies and drug interferences