Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MTB x > Week 1 > Flashcards

Week 1 Flashcards

1
Q

What did Hebb try to come up with?

A

Underlying mechanism of behaviour at the neural level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What were the key discoveries made in neuroscience prior to 1949?

A
  1. Giant squid axon
  2. Neurotransmitters
  3. Structure of neurons/synapses
  4. Neuron doctrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Giant squid axon

A

Hodgkin and Huxley
Shape about the action potential
They recorded across the membrane
Insert electrodes inside axoplasm and measure the membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Neurotransmitters

A

Discovered including ACH
Concept of chemical neurotransmission
Electrical signals were relayed across synapses via release of neurotransmitters
Complexity of neurotransmitters not known

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Structure of neurons/synapses

A

Electron microscopes were beginning to be invented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Neuron doctrine: Cajal and Golgi

A

Staining methods to find anatomy of neurons
Idea that neurons are distinct entities
Cajal conclusion: each neuron is like any other cell - has distinct membrane bound structure - but with lots of processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 3 postulates of Hebb’s theory

A
  1. Hebbian learning
  2. Cell assemblies
  3. Phase sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Hebbian learning

A

Connections between neurons increase in efficacy in proportion to the degree of correlation between pre- and post-synaptic activity

Idea that history of presynaptic activity can alter the future activity by causing a change in that connection between two cells

Information could be encoded in the nervous system in the form of changes in the strength of synaptic communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Brains are made up of millions of neuron

A

Learning and memory don’t just involve changes at 1 synapse but multiple synapse = Hebbian synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cell assemblies

A

Group of neurons which tend to fire together

The brain basis of mental representation (images,ideas) is group or assemblies of neurons that tend to be active at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Phase sequence

A

Thinking is the sequential activation of sets of cell-assemblies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Henry Gustav Molaison

A

Feb 26 1926 - Dec 2 2008
Bicycle accident age 9
Epilepsy
1953 - William Scoville - Hartford Hospital
Scoville localised epilepsy to right and left medial temporal lobes
Had chunks of medial lobe removed
Surgery effective in reducing occurrence of seizures -however side effects
Lost ability to form new long term memories but remembered events before the surgery
Able to learn new motor skills

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Types of memory proposed by what people?

A

Psychologist William McDougall

Philosopher Gilbert Ryle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Psychologist, Willi McDougall

A

Implicit memory - automatic and reflexive
Memory for skills, habit and behaviours (riding a bike)

Explicit memory - conscious remembering of the past
Memory of facts or events/ spatial memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Philosopher Gilbert Ryle

A

Knowing how = memory without record

Knowing what = memory with record

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Region of brain effected by the brain is the cortex, what did it effect?

A

Hippocampus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hippocampus

A

Conversion of short term memory to long term memory

Curved structure - seahorse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

MRI scan of HMs 🧠

A

Donated body to science - study the impact on the surgery on his brain

Loss of cortical region of hippocampus

Half of the posterior region of HM’s hippocampus was intact

Only 5cm of the medial temporal lobe had been removed

The posterior parahippocampal gyrus was mostly spared

The anterior portions of parahippocampal gyrus, most of the perirhinal and most of all of the entorhinal cortices was removed

Remaining portions H.M. Hippocampi were atrophied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The case of Clive Wearing

A

Contracted virus cause only cold sores but in Wearings case attacked the brain (Herpes simplex encephalitis)
Unable to store new memories
Unable to control emotions and associate memories well
Profound case of total amnesia as a result of his illness
Unable to form long lasting new memories
His memory only lasts between 7 and 30 seconds
The encephalitis’s caused damage to Clive Wearings hippocampus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Drawing of Ramon Y Cajal - neural circuitry

A

Produced 1922 of hippocampus section
Modified version of technique of Golgi
Technique that selectively stains just some neurons
If all stained - image would be black
The beauty - allows you to see the complete anatomy of individual neurons and also see certain pathways
Individual neurons and connections between neurons were evident in drawing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Hippocampal trisynaptic circuit

Trisynaptic loop

A

Relay of synaptic transmission in hippocampus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 major cell groups of trisynaptic loop

A

Granule cells
CA3 pyramidal neurons
CA1 pyramidal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does the first projection of the hippocampus gyrus occur

A

Between entorhinal cortex and dentate gyrus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the entorhinal cortex transmit?

A

It’s signal from parahippocampal gyrus to the dentate gyrus via granule cells (perforant path)
The dentate gyrus then synapses on the pyramidal cells in CA3 via missy cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where does CA3 region fire?

A

Fires to CA1 via Schaffer collaterals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens when low frequency AP travels down Schaffer collaterals

A

Release of glutamate which binds to both AMPA and NMDA receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does AMPA receptors do?

A

Open and allow influx of Na+ into CA1 post synaptic cell resulting in slight depolarisation event in post synaptic cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Where does glutamate bind?

A

NMDA receptor but no ions pass through pore because of mg2+ blockade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the result of glutamate + AMPA receptor

A

Greater depolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does influx of Na+ cause?

A

Large depolarisation event in post synaptic cell which repels mg2+ blockade from NMDA receptor through electrostatic repulsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the consequence of NMDA receptor + glutamate

A

Allow Ca2+ and Na+ to enter through the pore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is LTP?

A

Strengthen connection between 2 neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What does influx of Ca2+ activate?

A

Secondary intracellullar cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What does increase of Ca2+ contribute to?

A

Two phases of LTP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is early phase?

A

Ca2+ binds to its binding protein and cause insertion of new AMPA receptor onto post synaptic cell membrane at CA3-CA1 synapse

Last for a few hours and require brief increase in Ca2+ level

36
Q

What is late phase?

A

Prolonged influx Ca2+ results in increase in transcription factors resulting in gene expression and new proteins to be synthesised

37
Q

What is involved in the formation of new synapses?

A

Growth factors
Basis of synaptic plasticity
Brain changes as it learns
Formed between CA3-CA1 Neurons

Last 24 hours up to life time

38
Q

Memory processing occurs in what other brain region?

A

Cerebral cortex

39
Q

What is the result of continuous activation of the same pathway?

A

Create high frequency presynaptic AP and post synaptic activation in these oath

40
Q

What does strengthening of synapse strengthen?

A

Memory

41
Q

What is Hebbs synapse

A

Both presynaptic activity is needed (release of glutamate)

And postsynaptic activity(to induct potentiation)

42
Q

Why are glutamate receptors of particular interest ?

A

glutamate is the main excitatory neurotransmitter in the human brain

Acts as an excitatory neuromuscular transmitter in insects and other Arthropods

43
Q

Special type of glutamate receptor: NMDA receptor

A

Involved in the mechanisms of synaptic plasticity in mammalian brain
Important for learning and memory

44
Q

What are types of glutamate receptors?

A

Ionotropic glutamate receptor

Metabotropic glutamate receptor

45
Q

Ionotropic glutamate receptors

A

Act as ligand-gated ion channels

Mediate fast excitatory neurotransmissioj in the brain

Receptor and ion channel all in one binds the neurotransmitter (glutamate) leading to opening of channel leading to influx of ions through

46
Q

Metabotropic glutamate receptor

A

G-protein coupled receptors that act via second messenger systems to mediate slower but often long term synaptic signalling

Act to influence ion channel activity indirectly because they lead to formAtion of second messenger systems

Bind glutamate and this links via G-protein to formation of a second messenger that influences ion channel activity

47
Q

Types of Metabotropic glutamate receptors (mGluR)

A

Relationship between Metabotropic glutamate receptors and how that leads to activation of cannabidiol receptors in the brain

GPCR - 7 transmembrane domain topology

8 identified

48
Q

What are the 8 identified of domain topology?

A 
mGluR1
mGluR2
mGluR3
mGluR4
mGluR5
mGluR6
mGluR7
mGluR8
49
Q

What is 2 types of pharmacological classification of ionotropic glutamate receptor?

A
  1. Non-NMDA
    - AMPA receptor
    - kainate receptor
  2. NMDA type receptors
50
Q

NMDA

A

Receptor type unusual in properties

Critical for mechanism and memory

51
Q

What has pharmacologist discovered?

A

Various chemicals that will selectively activate sub-group of glutamate receptors

52
Q

How can you distinguish between different types of receptors?

A

Doing experiment
Testing on neurons
Activate current in some cells and not others

53
Q

How can you isolate nicotinic receptors from organs?

A

Using snake toxin

54
Q

What strategy was used to determine the structure of glutamate receptor for the first time?

A

Molecular biological approach

55
Q

What assay did they use ?

A

Xenopus oocytes as an expression system

56
Q

How did the assay work?

A

Take egg of Xenopus
Isolate them
Put them into a recording chamber
Insert electrode and measure currents across membrane
If you put glutamate onto egg of Xenopus - nothing happening at all - no current

57
Q

Why is Xenopus a good assay system?

A

It doesn’t express ionotropic glutamate receptor

58
Q

What did analysis of CDNA reveal?

A

It encoded an 889 amino-acid protein (~100 kDA)

When expressed in Xenopus - activated by kainate

this receptor was named GluK1 (now also known as GluR5)

59
Q

How many AMPA receptors are there?

A

4

GluR1 (GRIA1)
GluR2 (GRIA2)
GluR3 (GRIA3)
GluR4 (GRIA4)

60
Q

How many kainate receptors?

A

5

GluR5 (GRIK1)
GluR6 (GRIK2)
GluR7 (GRIK3)

KA1 (GRIK4)
KA2 (GRIK5)

61
Q

Historically, what are different names used for?

A

Same gene product

62
Q

What are clade of receptors activated by?

A

Kainate

63
Q

What can one infer about the phylogenetic relationship of ionotropic glutamate receptors?

A

There must have been an ancestral kainate receptor that gave rise to these multiple types

64
Q

What is nAChR?

A

Ionotropic receptors

respond to chemical stimuli

Incorporate an ion channel

Heteromultimers

N-terminus located extracellularly and loops through the membrane 4 times

C terminus located extracellularly

Pentameric (5 subunits)

65
Q

Glutamate receptor

A

N-terminus located extracellularly
Transmembrane domain
Second transmembrane domain doesn’t go through the membrane - it loops in and out again
Then there’s a second and third membrane spanning region - C terminus comes to inside

66
Q

What are many membrane proteins?

A

Glycosylated

Oligonucleotides chain attached to them

Glycosylation only occurs on extracellularly parts of protein

67
Q

How can you work out if the protein is glycosylated or not?

A

The weight is increased

Mass of the protein is bigger on SDS page gel

68
Q

What does large extracellularly region form?

A

2 part structures that form a binding site for glutamate

69
Q

What forms the lining of a pore?

A

P-loop

70
Q

Where does voltage gated Na+/K+/ca2+ have a p-loop between?

A

5th and 6th membrane spanning region

71
Q

What is the role of P-loop?

A

Forms a favourable environment for the entry of cations

72
Q

What did low resolution of ionotropic glutamate receptor indicate?

A

These proteins were tetrameric (4 subunits)

73
Q

How is a tetrameric structure formed?

A

2 subunits come together to form a diner and another 2 subunits come together to form another dimer

74
Q

What is the ultimate way of determining a protein structure?

A

X-Ray crystallography

Cryo-EM

75
Q

When was the AMPA structure determined?

A

2009
It has a tetrameric structure
Indicated by 4 colours
Each colour represents a subunit

76
Q

What are the majority of AMPA receptors in CNS?

A

Heteromers

Contain GluR2

77
Q

What does the presence of GluR2 render?

A

AMPA receptors impermeable to calcium

78
Q

In the absence of GluR2?

A

AMPA receptors are permeable to sodium, potassium and calcium

79
Q

Where are GluR2 and GluR1 predominant?

A

In the forebrain

Low levels of GluR3 and GluR4

80
Q

At most excitatory synapses in the CNS, what does AMPA receptors mediate?

A

Post-synaptic depolarisation

As a consequence of net influx of sodium ions

81
Q

Where are kainate receptors found?

A

Both pre- and post- synaptically

Have modulatory roles in synaptic transmission

82
Q

Evolutionary origin of ionotropic glutamate receptors?

A

Share little sequence similarity with ligand-gates ion channel

Channels in the nicotinic ACH/GABA/ glycine family

83
Q

Where has nicotinic ACH/GABA/glycine receptors been found?

A

Animals

84
Q

Where has genes encoding proteins ionotropic glutamate receptors found?

A

Plants

85
Q

What does glutamate receptors mediate?

A

Cell to cell communication during neurotransmission

86
Q

Genes of the glutamate receptor like (GLR) family have been implicated in defence against pathogens
reproduction
Control of stomata aperture and light signal

A

^^

MTB x (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions