Anatomy of Neural Circuits Flashcards

1
Q

how could you section the brain?

A
  • sliced across 2 planes (front to back) can see 2 hemispheres
  • along the horizontal axis (2 parts of the brain are symmetrical)
  • sideways (not symmetrical)
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2
Q

what would a mid sagittal section look like?

A
  • forebrain compromises of cerebral hemispheres and diencephalon (CNS)
  • lower hind bran structures are the pons, medulla and cerebellum (CNS)
  • motor nerves (PNS)
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3
Q

what is the diencephalon?

A

thalamus and hypothalamus

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4
Q

how does an MRI work?

A
  • nuclei of hydrogen atoms act as spinning magnets
  • strong magnetic field to align protons
  • burst of radio waves temporarily flips the protons out of alignment (return to state and emit energy)
  • energy is detected
  • hydrogen in different types of tissue have slightly different realignment rates
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5
Q

what does the brain stem include?

A

the medulla, midbrain and bons

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6
Q

what is the brain stem?

A
  • evolutionary oldest brain regions
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7
Q

what is the function of the brain stem?

A
  • automic
  • digestion, respiration, heart rate, blood pressure, swallowing
  • site of entry for sensory information
  • mediates arousal
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8
Q

what does the pons do?

A

relays information from the cerebral cortex to the cerebellum

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9
Q

what is the function of the cerebellum?

A
  • recieves input of motor task to be performed and progress of ongoing skills
  • provides corrective skills and fine tunes movement
  • learning of motor skills
  • controls fine movement
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10
Q

what is the structure of the cerebellum?

A
  • organised into 3 layers of cells
    1. granular layer
    2. purkinje layer
    3. molecular layer
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11
Q

what is the cerebellum?

A

10% of brain volume but 50% of neurons

- evolutionary ancient

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12
Q

how can the cerebellums function be tested?

A

activation of the cerebellum during a bilateral finger tapping task which can be visualized by MRI –> fMRI activity superimposed

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13
Q

what does fMRI stand for?

A

functional MRI

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14
Q

what is fMRI?

A
  • depends on the fact that haemoglobin in blood distorts MRI properties of the spinning H atoms
  • amount of distortion depends on whether haemoglobin is carrying oxygen or not
  • measures areas where there are higher levels of oxygenated blood in the brain
  • increase blood flow to parts of the brain that are active
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15
Q

what is the cerbral cortex?

A
  • most evolved brain structure (humans have a large cerebral cortex)
  • heavily wrinkled to allow lots of neurons
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16
Q

what is the structure of the cerebral cortex?

A
  • 4 different lobes: frontal lobe, parietal lobe, occipital lobe, temporal lobe
  • organised into (6) cell layers which organise inputs and outputs
  • neurons of the brain are organised into circuits
17
Q

what is the function of the frontal lobe?

A

planning future action (pre-frontal cortex)

control of movement (motor cortex)

18
Q

what is the function of the parietal lobe?

A

somatic sensation

touch, pain and pressure

19
Q

what is the function of the occipital lobe?

A

vision

20
Q

what is the function of the temporal lobe?

A

hearing
deep lying structures eg the hippocampus - learning and memory
emotion - amygdala
- regulating motor performance - basal ganglia

21
Q

what is the function of the cerebral cortex?

A
  • responsible for high order functions

- know more about neurons involved in sensory and motor than in processing language, memory or emotion

22
Q

why are neurons organsied into circuits?

A

so that the neurons for one particular function are in one neural system

23
Q

what diseases do problems in the basal ganglia lead to?

A

parkinsons or huntigdons disease

24
Q

what does emotion influence?

A

motivation behaviours

25
Q

what are the key components of emotion?

A
  1. physical sensation

2. conscious feeling

26
Q

what structures are responsible for physical sensation?

A
  • Peripheral, autonomic, endocrine and skelomotor response

- Amygdala, hypothalamus and brain stem

27
Q

what ares structures are responsible for conscious feeling/perception?

A
  • Cortical structures: orbital and medial frontal lobes (prefrontal cortex)
28
Q

what is function of the amygdala?

A
  • required for fearful and pleasurable response
  • generates memories associated with emotional experiences
  • recieves information from the thalamus and sensory cortex
29
Q

which structures does the amygdala work with for physical manifestation?

A

thalamus and brain stem

30
Q

which structure does the amygdala work with for conscious feeling?

A

pre-frontal cortex

31
Q

which structure does the amygdala work with for memory of the context?

A

hippocampus

32
Q

how do you test fear conditioning?

A
  • pair a sound with an electric shock
  • rat will learn to feat the sound
  • an associative memory
  • rodents with lesions in amygdala lack a conditioned fear response
33
Q

who is patient SM?

A
  • damaged amygdala but intact hippocampus
  • tested ability to rate intensity of human facial expressions
  • failed to recognize fear
  • damage was caused by Urbach-Weithe condition
34
Q

what motivation and reward be driven by?

A
  1. drive states directed towards maintaining physolical homeostasis (eg apeptite)
  2. motivational states driven by rewarding/pleasurable and reinforcing stimulus (eg dont want bland food)
35
Q

what is the reward pathway?

A
  • stimuli signal the presence of reward by activating dopaminergic neurons in the VTA that project to the NuccAcc
  • this is the reward pathway
36
Q

what is the VTA?

A

ventral tegmental area

37
Q

what is the NucAcc?

A

nucleus accumbens

38
Q

what acts on the reward pathway?

A

all addictive substances or behaviors activate this pathway