Brain structure

Question 1

What is neuroscience?

Answer 1

It is the study of the brain as a physical system. Central to it is mathematical modelling, description of neurons and circuits in terms of equations which capture how one state of the system leads to the next

Question 2

What is the complex systems approach?

Answer 2

When elements are brought together to make a complex system, and properties emerge that none of the constituent elements have on their own.

Question 3

what is a model

Answer 3

a picture of what might be going on in the brain, if it has a wider perspective it becomes a theory

Question 4

how do you know if your model is right?

Answer 4

you can never know whether the model is right, but you can only falsify a model, which helps to understand what might actually be right.

Question 5

scientific model

Answer 5

circle making scientific progress possible, when new observations contradict the predictions > it can lead to a paradigm shift.

Question 6

Cerebral cortex

Answer 6

wrinkled layer surrounding the rest of the brain. Involved in most cognitive functions

Question 7

thalamus

Answer 7

inside: it is a relay station in the pathways from sensory receptors of the visual, auditory and somatosensory systems to the cortex. It helps controlling sleep, wakefulness, attention and consciousness.

Question 8

hypothalamus

Answer 8

regulates functions that are essential for maintaining the normal state of the body and reproduction. It controls hunger, body temperature, thirst, fatigue, sleep and hormones.

Question 9

What is the limbic system and what makes it up

Answer 9

Regulates emotion and memory > includes thalamus, hypothalamus, hippocampus, amygdala, cingulate gyrus and basal ganglia

Question 10

cerebellum

Answer 10

sensorimotor control, learning, languange and other cognitive functions.

Question 11

brainstem

Answer 11

connects the spinal cord to the brain

Question 12

Where are the four parts of the brain and what are they called and what do they do

Answer 12

frontal (decision making), temporal (down) (analysing sound), occipital (back) (visual information), paretial (above) (sensorimotor processing and sensory integration).

Question 13

difference between gyrus and sulcus

Answer 13

gyri are at the top, sulcus is the sulk

Question 14

what are the fissures called?

Answer 14

central fissure/sulcus > separates the frontal and paretial lobe
lateral/sylvial fissure > separates the temporal from the others above.

Question 15

anatomical directions:

Answer 15

rostral (frontal), caudal (posterior)
dorsal (up), ventral (down)
medial (middle), lateral (outside)

Question 16

what does the membrane of the neuron do and what’s at its interior

Answer 16

It separates the outside from the inside so that they don’t interact, it’s fatty and both outside and inside are packed with ions: positive > sodium, potassium, calcium; negative > chloride. ALL THESE REPEL EACH OTHER.

Question 17

Ion channels:

Answer 17

specialized protein structures that will let through specific ions

Question 18

Ion pumps:

Answer 18

they activeley transport ions across the membrane.

Question 19

What is the membrane potential

Answer 19

Also called resting potential, it’s at -70 mV

Question 20

What has more positive ions, outside or inside?

Answer 20

outside

Question 21

How many steps does the action potential go through? And describe them

Answer 21

1. the neuron is triggered at the axon hillock in the soma when the voltage difference in the soma becomes more positive - it POLARIZES TO THE THRESHOLD OF -55mV
2. Sodium channels open up and sodium comes into the cell causing a rapid DEPOLARISATION, that climbs to +20mV.
3. Potassium channels open up letting potassium out which leads to a REPOLARISATION back to -70mV > HYPERPOLARISATION when the potential sinks below the resting action potential.
4. The membrane goes back to its resting stage > RESTING POTENTIAL

Question 22

How long does the spike last

Answer 22

Around 5ms

Question 23

what is the synapse?

Answer 23

connection between the two neurons - the neuron who signals is pre-synaptic, the receiver is post-synaptic.

Question 24

What happens in the synaptic terminal?

Answer 24

It containes the neurotransmitters. The depolarisation makes them be reseased into the synaptic cleft. From there they attach themselves to receptors in the receiving neuron. This makes ion channels open and changes the membrane potential of the receiving neuron.

Question 25

what is a synaptic current

Answer 25

flow of ions caused by synaptic activity

Question 26

what happens in an excitatory synapse?

Answer 26

it depolarises the post-synaptic cell

Question 27

what happens in an inhibitory synapse?

Answer 27

it lowers the membrane potential

Question 28

Present the two synaptic currents:

Answer 28

primary current > current flowing along the dendrite.
Some of the current leaks via the LEAK CHANNELS into the extracellular space. There we have ions being pulled towars the neuron and ions being pushed away. This extracellular movement is called: secondary current or volume current