Lecture 21 - Brains

Question 1

What are the three parts of a typical neuron?

Answer 1

axon
dendrites
cell body (soma)

Question 2

What are the different kinds of brain maps?

Answer 2

Somatosensory
Visual pathways
Mapping sound

Question 3

What is the path of a typical reflex arc?

Answer 3

Sensory neuron -> Interneuron -> Motor neuron -> Effector

Question 4

In order for a neuron to be triggered it has to?

Answer 4

depolarize enough to reach the threshold

Question 5

Monosynaptic reflex arc

Answer 5

simplest network possible. goes straight from sensory to motor neuron no interneuron.

Question 6

Polysynaptic reflex arc

Answer 6

reflex arc that does involve interneuron

Question 7

What are the two ways of processing and integrating neuron signals?

Answer 7

Feed forward and Feed back neural circuits

Question 8

feed forward convergence

Answer 8

take information from multiple neurons to a single neuron

Question 9

feed forward divergence

Answer 9

information from one neuron splits across multiple neurons.

Question 10

what are the two kinds of feedback

Answer 10

feedback inhibition(reduce signal) 
positive feedback(increase signal)

Question 11

What are the different levels of Nervous system organisation?

Answer 11

Network (no ganglia)
Ventral ladder (ganglia)
Dorsal tube (enlarged frontally)
Encephalisation: Brain

Question 12

What is the enlarged mass at the end of the Dorsal nerve cord

Answer 12

brain

Question 13

What are the primary vesicles of brain?

Answer 13

Prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)
spinal cord

Question 14

What are the major divisions of the tripartite brain?

Answer 14

Forebrain
Brainstem
- Midbrain
- Hindbrain

Question 15

what is the purpose of the cerebellum?

Answer 15

motor coordination

Question 16

what is the purpose of the Optic lobe / tectum?

Answer 16

sensory integration

Question 17

what is the purpose of the Thalamus?

Answer 17

sensory relay centre

Question 18

In what groups is the Cerebrum most developed?

Answer 18

Most developed in birds and mammals

Question 19

What is the Cerebrum divided into?

Answer 19

Paleocortex (rhinencephalon)
Limbic system, e.g. hippocampus (spatial learning,
memory)
Neocortex (cerebral cortex)

Question 20

What is the Ratio of brain:spinal cord in fish, humans and amphibians?

Answer 20

Fish and amphibians 1:1
Humans 55:1

Question 21

What is the disadvantage of having a large brain?

Answer 21

‘Expensive-tissue hypothesis’
The brain is very metabolically demanding to run

Question 22

Are sensory and motor areas close to each other encoded close to one another on the brain? What species demonstrates this?

Answer 22

yes most of the time
star nose mole

Question 23

does light go through the nerves or the photoreceptors first?

Answer 23

nerves

Question 24

What processing of information is done before the signal reaches the brain in the visual pathway?

Answer 24

Colour vision(different cones detect different wavelengths)
Contrast enhancement
-Lateral inhibition
Conversion of many receptors to larger
receptive field
-comparison
-conversion

Question 25

What is the purpose of lateral inhibition?

Answer 25

edge detection detecting the movment of light

Question 26

How does lateral inhibition work?

Answer 26

Question 27

Layers of information processing in visual pathway?

Answer 27

**Retina** Photoreceptor Bipolar cell Ganglion cell **Tectum / Thalamus** Lateral geniculate nucleus (LGN) **Primary visual cortex** Left side of both eyes to left side of visual cortex

Question 28

What is the LGN?

Answer 28

Lateral geniculate nucleus

Question 29

What part of the LGN is colour processed?

Answer 29

parvocellular

Question 30

What part of the LGN is movement and brightness processed?

Answer 30

magnocellular

Question 31

How doe you dect location of sound?

Answer 31

the difference in signal between ear