Evolution of the Brain

Question 1

What marks the first organism with a nervous system?

Answer 1

Glutamate receptors

Question 2

Why was the synapse the first nervous structure to appear?

Answer 2

Without synapses, axons and dendrites would have no function. Those parts evolved around the synapse

Question 3

What nervous structures are detected in early forms of life?

Answer 3

AMPA and NMDA receptors

Question 4

Define Homolog, Ortholog and Paralog

Answer 4

1. Homolog = genes or proteins that share a common ancestor
2. Ortholog = genes or proteins that share a common function in different species
3. Paralog = multiple variants of one gene in one species

Question 5

How could you describe a protosynapse?

Answer 5

Protein complexes in organisms without a nervous system (detect environment or other kinds of changes)

Question 6

What role do Tyrosine Kinase Receptors play?

Answer 6

They respond to external stimuli. Those are found in early organisms and in later organisms, they contribute to plasticity.

Question 7

What indication of a synapse is found on early organisms?

Answer 7

Similar receptors and proteins found in synapses. In very early organisms, those proteins are not used in the nervous system, but rather to sense nutrients in the environment

Question 8

What two proteins are important in the formation of one of the earliest synapses?

Answer 8

Neurexin and Neuroligin - They bind to each other to form a synapse

NMDA and AMPA are also important

Question 9

What two functions did a nervous system serve early organisms?

Answer 9

1. Movement away from predators

2. Contraction and movement for proper food intake

Question 10

what is an example of a basic nervous system?

Answer 10

A nerve net and nerve ring

Question 11

What is the advantage of symmetry of the nervous system for an organism?

Answer 11

It will enable better coordination of motor movement

Question 12

What structure allows more integration of neuronal complex signals?

Answer 12

Ganglia
Earlier organisms like worms that have a symmetrical nervous system also create ganglia to help their coordination and information processing

Question 13

What do ganglia do precisely?

Answer 13

They do local signal integration of motor and sensory input

Question 14

What aspect of the brain tells some information about the behavior of an animal?

Answer 14

For example, a nocturnal hunter would have a relatively more developed visual cortex that it uses to adapt to the nocturnal hunting style

Question 15

What brain structure is overall the most developed in mammals?

Answer 15

The cerebrum

Question 16

What could be an important factor in the rapid development of the brain size in humans, compared to other primates?

Answer 16

After humans discovered fire, they needed less space in their jaw for muscles, so they would make more space for their brain

Question 17

How are human neurons different from other animals?

Answer 17

Humans have fewer neurons, but many more synapses. The human neurons are also more complex.

Question 18

What factors might influence intelligence?

Answer 18

1. Nr of neurons
2. Types of neurons (GABA important for signal processing)
3. Nr of synapses per neuron
4. Layering of the cortex (Cortical layers are less compact - might allow more synapses)