Lecture 1: History and Structure and function of the nervous system

Question 1

History of Cognitive Neuroscience; is there more than the brain alone.

Monism vs. Dualism

Answer 1

Monoism: The brain produces behavior, thoughts and the mind (thales, willis, la mettrie, Gall)

Dualism: The mind appears from elsewhere; its something immaterial (Decartes; res cogitans vs. res extensa)

Question 2

Does the brain work as one big organ or is it made up of different modules?

Functional specialization vs. Aggregate field theory

Answer 2

Functional specialization: different areas in the brain have different functions (Willis, Galls’ Sphrenology)

Aggregate field theory: The brain works as a whole (Flourens)

No brain area works alone!

Question 3

Electrical stimulation (Fritsch & Hitzig 1870)

Answer 3

electrical stimulation of brain areas produces characteristic movement in dogs.

Question 4

Broddmann (1909)

Answer 4

identification of 52 distinct brain areas with different cellular architectures.

Question 5

Visualization of individual neurons

Answer 5

Golgi: cells in the brain form a continuous mass of tissue

Ramon Cajal: neural doctrine; neurons are discrete entities.

Question 6

The cognitive revolution

Answer 6

not all behavior is learned (chomsky)

Question 7

Instruments of Neuroscience

Angelo Mosso (1891)

Answer 7

pulsations of the blood in the brain is directly related to mental activity.

Question 8

CNS; central nervous system

Answer 8

Brain (cerebrum, cerebellum, brainstem) + Spinal cord

Question 9

PNS; peripheral nervous system

Answer 9

Nervous system that is not the brain + Spinal cord

Question 10

The cells of the nervous system: 2

Answer 10

Neurons: transmit information
Glial cells: function depends on the type

Question 11

4 types of Glial cells

Answer 11

1. Astrocytes: blood-brain-barrier
2. Oligodendroctyes: myline sheet
3. microglial cells: remove damaged cells
4. Schwann cells: myline sheet

Question 12

Dendrites

Answer 12

receive input from other neurons at the dendritic spines

Question 13

Axon

Answer 13

outputs signal to other neurons at the axon terminals

Question 14

Neural signalling

resting membrane potential

Answer 14

when a neuron is not sending a signal, it is at rest. the neuron will have an electrical voltage of -70mV

Question 15

Intra-extra cellular fluid is made of?

Answer 15

Ions: atoms or molecules that are either positive or negative charge.
K+ potassium
Na+ sodium
Ca2+ calcium
Chloride Cl-
Organic anions A+

Question 16

ion channels

Answer 16

selectively permit one type if ion to pass. more pottasium K+ channels in cell membrane

Question 17

Ion pumps

Answer 17

active transport proteins. sodium-potassium pump. pumps 3 sodium ions (Na+) out of the cell and 2 potassium ions in the cells.

Question 18

Intracellular fluid

Answer 18

positively charged potassium ions K+ and negatively charged organic anions (A-)

Question 19

Extracellular fluid

Answer 19

consists mostly of positively charged sodium ions Na+ and negatively charged chloride ions (Cl-)

Question 20

concentration gradient

Answer 20

The difference in the concentration of Ka+ and Na+ inside and outside the cell.

Question 21

Na+ Ka+ pump

Answer 21

enzyme that actively pumps Na+ out of the cell and pumps Ka+ inside the cell

Question 22

electrical gradient

Answer 22

because the cell membrane mostly permeable to Ka+ via potassium channels, Ka+ will move from intra to extracellular space. since it is more positively charged outside the cell there is an an electrical imbalance.

Question 23

electrochemical equilibrium state

Answer 23

The concentration gradient and electrical gradient reach a electrochemical equilibrium state. In this state the difference in electrical charge is -70mV (resting membrane potential)

Question 24

The action potential

Answer 24

When a neuron is active (when it is passing information) the resting potential changes into an action potential.

The rapid depolarization and repolarization on the neurons output.

Question 25

Dendrite spines

Answer 25

Neuron receives a signal at the dendrite spines. these contain channels that open when a neurotransmitter binds to the channel receptor

Question 26

Ligand-gated channels

Answer 26

Ligand-gated channels open or close in response to the binding of specific Neurotransmitter.

Question 27

Excitatory postsynaptic potential (EPSP)

Answer 27

temporary increase in the postsynaptic membrane potential, making it more likely for a neuron to fire an action potential, typically caused by the binding of neurotransmitters to receptors on the postsynaptic neuron. One EPSP is not strong enough to elicit an action potential. EPSP decay fast

Question 28

Inhibitory postsynaptic potential (IPSP)

Answer 28

temporary hyperpolarization of the postsynaptic membrane, making it less likely for a neuron to fire an action potential, usually resulting from the binding of inhibitory neurotransmitters to their receptors on the postsynaptic neuron.

Question 29

decremental conduction

Answer 29

Decremental conduction is the gradual reduction in the amplitude of an electrical signal as it travels along a neuron

Question 30

Axon hillock

Answer 30

If there are sufficient excitatory signals, the axon hillock will initiate an electrical signal and generate action potentials when the combined input exceeds a certain threshold.

Question 31

Temporal summation

Answer 31

When the EPSP's follow is close succession , the integrated potential at the axon hillock will be large enough to trigger an action potential One

Question 32

spatial summation

Answer 32

when different EPSP's occur simultaneously at different locations, the integrated potential at the axon hillock will be large enough to trigger an action potential

Question 33

What will happen if the strength of the EPSP is as strong as that of the IPSP

Answer 33

no action potential

Question 34

voltage gated sodium channels

Answer 34

The axon hillock produces an action potential because of the voltage gated sodium channels that are present at the axon hillock. in contrast to ligand gated channels, these channels are triggered by changes in the membrane potential

Question 35

Refractory period

Answer 35

when a neuron returns to its resting membrane potential, it undershoots to a state of hyperpolarization before returning to resting potential if -70mV. during this period the neuron cant become active again

Question 36

Absolute refractory period (ARP)

Answer 36

Na+ are still closed so a new action potential cannot be generated.

Question 37

relative refractory period

Answer 37

an action potential can happen but only with larger-the-normal depolarizing currents.

Question 38

Myline sheets

Answer 38

act as insulators around the axons that allow electronic condition to travel high speeds.

Question 39

Schwann cells

Answer 39

surround the axons with a highly insulating layer

Question 40

nodes of ranvier

Answer 40

intervals of 1.5 mm of naked sections with no insulation. action potentials are only generated at the nodes of ranvier. between these nodes the signal is passively spread very fast speeding up conduction velocity to up to 150 m/s

Question 41

Multiple sclerosis (MS)

Answer 41

the immune system destroys the myeline sheets of neurons. many sensory and motor functions are impaired.

Question 42

synaptic transmissions

Answer 42

the transfer of a signal from one neuron to the other.

Question 43

how do neurons communicate?

Answer 43

via chemical synapses

Question 44

synaptic cleft

Answer 44

space between axon terminal of sending neuron and dendrite of receiving neuron

Question 45

Presynaptic neuron & postsynaptic neuron

Answer 45

releases neurotransmitters in synaptic cleft that binds to specialized receptors of the receiving or postsynaptic neuron

Question 46

vesicles

Answer 46

vesicles in the axon terminal are filled with neurotransmitter molecules

Question 47

ligand gated ion channels vs. G-protein coupled receptors

Answer 47

ligand-gated ion channels: binding of neurotransmitter with receptor directly opens the ion channel. fast signalling in ms! G-protein coupled receptors (GPCRs): indirect effect via a second messenger. slower signalling hundreds of milliseconds/seconds.

Question 48

types of neurotransmitters

Answer 48

Glutamate: most prevalent neurotransmitter. excitatory. memory, cognition and mood regulation. GABA: second most prevalent. inhibitory. slows down your brain by blocking specific signals in your CNS (calming effect) Acetylcholine: present in neuromuscular junction. excites muscles. Dopamine: motor control/cognition. substantial nigra and ventral tegmental area as production sites in the brain. (parkinson) Norepinephrine (noradrenaline): arousal. locus coeruleusas production site. fight or flight response. Serotonin: mood/cognition. raphe nucleus. (depression)