The brain through the ages Flashcards

week 1

You may prefer our related Brainscape-certified flashcards:
1
Q

what is neuroscience?

A
  • Looks at the neurones and what links them all together (brain, CNS/PNS)
  • The scientific study of the nervous system
  • Interdisciplinary:
  • biology,
  • physiology
  • psychology,
  • computer science,
  • mathematics,
  • physics,
  • philosophy,
  • medicine
  • The study of how our nervous system controls behaviour, thoughts and emotions.
  • BPS fundamental
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2
Q

what is the nervous system?

A
  • Network of neurones in the brain, spinal cord and periphery
  • Central Nervous System (CNS)
  • Brain and Spinal Cord
  • Peripheral Nervous System (PNS)
  • Nerves (Cranial and Spinal)
  • Ganglia (a mass of nerve cell bodies)
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3
Q

what are neurones?

A

building blocks of the nervous system

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4
Q

what are the functions of dendrites in a neurone?

A

to pick up information from pre-synaptic neurones or the environment to send it along the axon.

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5
Q

what is the function of the nucleus of a neurone?

A

supports the dendrite cells by generating an impulse throughout the axon.

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6
Q

what is the function of the cell body of a neurone?

A

supports the system of the cell as it contains genetic information, maintains the neuron’s structure, and provides energy to drive activities.

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7
Q

what is the function of the myelin sheath of a neurone?

A

helps with the conductivity along the axon by allowing electrical impulses to transmit quickly and efficiently along the nerve cells.

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8
Q

What is the function of the Schwann cells in a neurone?

A

two types: myelinated and non-myelinated that both play a pivotal role in the maintenance and regeneration of axons of the neurones in the PNS.

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9
Q

what is the function of the node of Ranvier in a neurone?

A

transfers electrical impulses along the myelin sheath as they cannot travel across it otherwise (generation ion fast electrical impulses)

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10
Q

what is the function of the axon terminals in a neurone?

A

allows the neuron to conduct electrical impulse down to another neuron or another type of cell by the release of signals into the synapse.

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11
Q

why is neuroscience an essential part of modern psychology?

A
  • Behaviour is initiated by the nervous system
  • Neuroscience can therefore be used to help understand behaviour
  • Want to see more or less of certain behaviours
  • What are the adaptive/maladaptive behaviours of well being?
  • Psychologists who study biological bases of behaviour…
  • Behavioural neuroscientists
  • (AKA: Biological Psychologists, Biopscychologists)
  • Use physical measurements of brain function
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12
Q

what are the origins of neuroscience?

A

human prehistory (500BCE)
ancient Egypt (4000-30BCE)
Ancient Greece (450-300BCE)
Roman Empire (30BCE- 500CE)

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13
Q

What occurred during the human prehistory period of neuroscience?

A
  • Stone Age/ Bronze Age/ Iron Age.
  • neolithic period
  • Blunt force cranial trauma
  • Cranial trepanation
  • “5-10% of all skulls found from the Neolithic period were trepanned with single or multiple skull openings of various sizes”
  • Release of evil sprits for diseases such as epilepsy (trephining and trepanning).
  • Drilled holes in left side of head when issues with right side of body (cross-lateralisation of the brain).
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14
Q

what occurred during the Ancient Egyptian times of neuroscience?

A
  • First recorded/written language that we can relate to.
    • Earliest written reference to the brain (17th Century BCE)
      ○ the Edwin Smith Surgical Papyrus (hieroglyphics from doctors at the time that informed the procedure of the operation)
    • Body and most organs were preserved (mummified) after death… but not the brain
    • Brain not considered to be the centre of human functioning.
    • Heart was central to human functioning.
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15
Q

during the Ancient Greek times, what did Hippocrates suggest?

A

○ Father of modern medicine
○ the theory of the four humours (black bile, yellow bile, phlegm, blood)
§ If out of balance we would have illness
§ First to suggest that the soul and mind were controlled by the brain.
○ “… the source of our pleasure, merriment, laughter and amusement, as of our grief, pain, anxiety, and tears is none other than the brain”

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16
Q

during the ancient greek times, what did Aristotle suggest?

A

○ “… the brain is not responsible for any of the sensations at all, the correct view is that the sear and source of sensation is the region of the heart”
§ Agreed with ancient Egyptians
§ Hook out brain and preserve other organs except the heart which would be mummified with the body.
□ Our behaviours and emotions were controlled by the heart where the brain was for the blood to “cool off”.
○ Socrates tutored Plato who tutored Aristotle
§ Socrates and Plato did not write their ideas down but Aristotle did- why he is most known for the ideas.

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17
Q

what did Galen suggest? (Roman Empire)

A
  • Furthered Hippocrates work.
    ○ Used the idea of the 4 humours.
    • Leading physician of the Roman Empire
      ○ Lots of his work occurred on the battle field
    • Saw the brain as the ruling organ of the body
    • Common sense, cognition and memory were all functions of the brain
    • Discovery of ventricles fitted with Hippocrates’ theory of humourism
    • Talked about the ventricles- idea that they were in the brain.
      ○ Idea that they were the source of behaviour
    • Used apes, pigs etc
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18
Q

when were the dark ages and what happened during them?

A

~ 500-1000 AD
* Not much occurred here
* Beginning of Christianity in the western world.

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19
Q

who were the influential figures during the renaissance period for neuroscience?

A
  • Leonardo da Vinci (1452-1519)
    ○ Sensation, cognition and memory attributed to the “3” ventricles
    ○ Discussed idea of the correct proportions of the human body.
    • Andreas Vesalius (1514-1564)
      ○ Added more detail to the understanding of brain structure
      § Regional functions of the areas in the brain
      ○ Found errors in Galen’s anatomy (200 accounts= blood flowing from left to right sides of the heart)
      ○ Father of modern anatomy
    • René Descartes (1596-1650)
      ○ Fluid-mechanical theory of brain function
      ○ Reflexive theory
      § Reflexes and movements of people touching objects with unvoluntary movements.
      § E.g.: touching a hot object
      ○ Cartesian Dualism
      § The mind and body are one but controlled by two separate things.
      § Inherently different.
20
Q

what are the 4 key insights into neuroscience during the 18th and 19th century?

A
  1. nerves are wires
  2. localisation of specific brain functions
  3. the neuron
  4. evolution of the brain
21
Q

what is meant by “nerves are wires”?

A
  • nerves are electrical in functioning (action potentials)
22
Q

what did Luigi Galvani suggest about nerves are wires?

A

○ Stimulation of nerves in frogs caused muscle contractions
§ Legs would still move with electrical stimulation even when head not on body

23
Q

what did Herman Von Helmholtz suggest about nerves are wires?

A

○ Human physiology is subject to the laws of nature
§ Human physiology
§ Laws of conservation
§ Laws of energy
○ Measured the speed of nerve conduction
§ Of the signals across the body
○ ~90 ft/sec
○ Slow – not just electrical, but physiological
§ Did his work on eels and squids- long neurones.

24
Q

what is meant by “localisation of specific brain functions” ?

A
  • brain having different functions in different areas?
25
Q

what did Johannes Müller suggest about the localisation of specific brain functions?

A

○ Proposed the “law of specific nerve energies”
○ German
○ Sesnory input, all nerves are the same in function and what they are translating
○ Each go to different parts of the brain
○ LOCALISATION OF FUNCTIONING

26
Q

what did Marie-Jean Pierre Flourens suggest about the localisation of specific brain functions?

A

○ Experimental ablations
§ Scull ablation- e.g.: Phineas Gage
§ Used stroke victims
§ Remove part of the brain
□ Will have lots of different effects of the body
§ Trans-magnetic stimulation: temporarily deadens part of the brain
○ Intellect = cerebral cortex
○ Lower brain = vital bodily functions
- Cerebellum = coordination and motor control

27
Q

what did Paul Broca suggest about the localisation of specific brain functions?

A

○ Damage to left frontal cortex = difficulties in language production
§ Known for localisations in functioning
○ Patient called Tan
§ Had stroke in left region of the brain
○ Broca’s region
§ Autopsies and dissections

28
Q

what did Gustav Fritsch & Eduard Hitzig suggest about the localisation of specific brain functions?

A

○ Muscle contractions contralateral to brain hemisphere
○ First ones to really nail down lateralisation of functioning
○ Echoed in previous history
○ Understood the hemispheric differences
○ Left brain controlled right motor functioning of the body. (opposite for the right part of the brain)

29
Q

what is meant by “the neurone” as an insight of neuroscience?

A

the basic functioning unit of the brain

30
Q

what did Camilla Golgi suggest about the neurone?

A

○ Invented a new staining technique
○ Propose “reticular theory”
§ Golgi staining techniques
§ Golgi cells
^ together (with Ramon y Cajal) won the Nobel prize in 1906

31
Q

what did Santiago Ramòn y Cajal suggest about the neurone?

A

○ Worked out neural circuitry of many brain regions
○ Propose the “neuron doctrine”
§ Neurones are connected through synapses (neurotransmitters)
§ Worked on many brain regions
§ They are building blocks.
^ together (with Golgi) won the Nobel prize in 1906

32
Q

what is meant by evolution of the brain?

A

Gradual change in structure of physiology of a species- generally producing more complex organisms- as a result of natural selection

33
Q

what did Charles Darwin suggest about the evolution of the brain?

A

○ “On the origin of species” (1859) considered the foundation of evolutionary biology
○ Natural selection
§ Level of sexual selection
§ Changes in genes and lead to different characteristics that enhance our survival chances.

34
Q

who is Alfred Russel Wallace and why is he important?

A

he came up with natural selection theory alongside Darwin andethought of the idea (that Darwin had been working on in private for 20) in 1858.

35
Q

what are vertebrate brains?

A
  • Vertebrate brains are similar in organization
    • All vertebrates have a forebrain, midbrain & hindbrain
    • Brain areas may be specialised in distinct ways in response to environmental constraints
    • e.g.:
      ○ crocodiles have huge olfactory bulbs (brain area for smell)
      ○ Shrews have large hippocampi meaning they have excellent sense of direction.
36
Q

how has our brain evolved?

A
  • Brain size increased
    ○ In relation to body size and proportions.
    • Proportion of the different areas changed
      ○ Larger in animals of high social intelligence.
    • Folding of cerebral cortex increased
      ○ Increases surface area to get more neurons in the brain
      § Humans have a larger neuronal capacity
37
Q

what is the importance of brain size?

A
  • Brain size has increased
    • However… there is no link between brain size and behavioural complexity
    • E.g.:
      ○ Shrews brain area is 3.3% of body mass but humans is only 2.5%
38
Q

what are the proportions between the brain and the body?

A
  • Brain size needs to be considered alongside body size
    • There is a relationship between proportional brain size and complexity of behaviour
    • Human brain is proportionally larger than any other large animal
39
Q

how did hominids evolve?

A
  1. Australopithecus robustus
    1. Homo habilis
    2. Homo erectus
    3. Homo sapiens neanderthalensis
    4. Homo sapiens sapiens
      * The high, straight forehead of modern humans superseded the prominent brow ridges of ancestors due to expansion of cortex, especially prefrontal cortex, in our species.
      (refer to lecture notes for the diagram)
40
Q

why are there differences in brain proportions?

A
  • Proportions of parts of human brain are different than other primates
    • Differences in evolutionary development of parts of brain have more effect on behaviour than brain size
41
Q

what is the neocortex?

A
  • Size increased in primates
    • Is flexible & has almost infinite learning abilities
    • Reflects growing complexity of social lives
    • Growth of certain parts of cortex responsible for social skills (e.g., language) because they improved this ability
    • Where most changes occur and greatest growth has been in humans.
    • Developed greatly in social animals.
      ○ More white matter
42
Q

what is the prefrontal cortex?

A
  • Developed greatly in primates
    • In other species it is primarily for voluntary motor control
    • In humans: Responsible for unequalled planning & abstract reasoning abilities
      Modern research:
    • Human’ superior abilities are attributable to other specialised cortical regions & denser inter-connections between prefrontal cortex & rest of brain
43
Q

why are human brains so big?

A
  • Humans have larger volume of white matter in PFC (compared to most other primates)
    • White matter provides greater connectivity between PFC & rest of brain (compared to other species)
    • Connectivity is vital for working memory functioning
44
Q

what is the significance of having increased folding of the cerebral cortex?

A
  • Increase in cortex folding has been a major factor in brain evolution
    • Folding = cortical surface area to fit inside the skull
    • Allows better organisation of complex behaviours
45
Q

why might humans have a larger neocortex than other species?

A
  • to facilitate advanced social skills.