Week 4- Brain and Behaviour Flashcards

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1
Q

What methods are used to examine the structure of the brain?

A
  • Performing dissections of deceased people (invasive)
  • Brain imagine (passive)
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2
Q

Outline electoencephalogram (EEG) including strengths and limitations

A
  • Test that detects electrical activity in the brain, using small metal discs (electrodes) attached to the scalp. Activity shows up as wavy lines on an EEG recording. Detect electrical activity in brain
  • Limitations:
    • Poor spatial resolution (does not receive entire picture from across the brain, has access limit)
    • Post synaptic potentials generated in superficial layers of cortex dendrites have far less contribution to EEG signals
  • Strengths:
    • Good temporal resolution (time resolution of a millisecond)
    • Measures brain activity directly
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3
Q

Outline functional magnetic resonance imaging (fMRI) including strengths and limitations

A
  • Detects changes within the blood flow
  • Relies on fact that cerebral blood and neural activation are linked. Non invasive
  • Strengths:
    • Good spatial accuracy (reliability, robustness and ability to reproduce are increased)
  • Limitations:
    • Temporal responsive blood supply is poor relative to electrical signals
    • Expensive (limits accessibility)
    • Claustrophobic (limited ecological validity)
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4
Q

Outline magnetoencephalography (MEG) including strengths and limitations

A
  • Functional neuroimaging technique
  • Maps brain activity by recording magnetic fields produced by electric currents occurring naturally in the brain
  • Uses sensitive magnetometers. Used primarily as measurement of time courses
  • Strengths:
    • can resolve events within 10 milliseconds or faster
    • accurately pinpoints sources of primary auditory, somatic sensory and motor areas
    • can create functional maps out of human cortex during complex tasks
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5
Q

Outline positron emission tomography (PET)

A
  • Functional imaging technique using radioactive substances (radiotracers) to help visualise and measure changes in metabolic processes and other physiological activities
  • Used heavily in imaging of tumours and clinical diagnosis of different brain diseases (e.g. dementia)
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6
Q

Outline lesions as a research method

A
  • Observe people with conditions which have caused lesions (e.g. MS)
  • Cannot cause lesions for study purposes
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7
Q

Outline deep brain stimulation as a research method

A
  • Aim is to stimulate areas of the brain with electrodes
  • Neurosurgical procedure involving placement of brain pacemaker, which sends electrical impulses through electrodes to targets in brain nuclei to treat movement disorders e.g. Parkinson’s and OCD
  • DBS changes brain activity in a controlled manner
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8
Q

Outline single cell recordings as a research method

A
  • Used to observe changes in voltage or current in a neuron
  • Usually used on animals
  • Microelectrode inserted into skull into a neuron in the area of the brain of interest
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9
Q

Outline electrocorticography (ECoG) as a research method

A
  • Electrophysiological monitoring
  • Uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex
  • Looks like a circuitboard
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10
Q

Summarise the structure and function of the central nervous system

A
  • Consists of brain and spinal cord
  • The spinal cord relays information from the brain to neurons in the peripheral nervous system
  • Can provide rapid responses to stimuli through the spinal reflex
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11
Q

Outline how the structures of the central nervous system are protected

A
  • The brain, a part of the CNS, is protected by the skull
  • The spinal cord is surrounded by bones called your vertebrae, or backbone
  • Between these bones is a type of multilayered tissue, called meninges, which further protect your spinal cord
  • Inside the channel formed by the meninges is the cerebral spinal fluid
  • Cerebral spinal fluid is in the brain as well as the vertebrae, and the fact that the brain floats in this liquid prevents excessive injuries from brain trauma
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12
Q

Define ventricles and outline those involved in the CNS

A
  • Ventricles are a communicating network of cavities filled with cerebral spinal fluid
  • Two lateral ventricles, third ventricle, cerebral aqueduct, fourth ventricle
  • Opens out to subarachnoid space, between the skull and the brain
  • Cerebral fluid can circulate freely and protect from head injury (with skull)
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13
Q

List and define parts of the hindbrain

A
  • Medulla oblongata- regulates physiological functions
  • Pons- contains fibres connecting medulla and cerebellum with upper brain
  • Cerebellum- “little brain”. Located at the back of the brain
  • Reticular formation- neuron network from hindbrain to midbrain
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14
Q

Describe the role of the medulla oblongata

A

Regulates:
* Breathing
* Heartbeat and respiration
* Blood flow, muscle tone and reflexes

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15
Q

Describe the role of the pons

A

Regulates:
* Respiration
* Sleeping, including waking and dreaming

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16
Q

Describe the role of the cerebellum

A

Regulates:
* Fine muscle movement, coordination of smooth muscle

Assists with:
* Balance
* Learning, particularly low level relationships between sensory info and motor outputs

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17
Q

Describe the role of the reticular formation

A
  • Assists in maintaining consciousness
  • Regulates arousal
  • Modulates activity
  • Involved in integrating info from different pathways e.g. sound and visual input
  • Contributes to blocking out info that happens when we fall asleep
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18
Q

List the parts of the midbrain

A
  • Tectum
  • Tegmentum
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19
Q

Describe the role of the tectum

A
  • Processes visual (via superior colliculus) and auditory (via inferior colliculus) info
  • Allows us to orient surroundings with eyes and body movements
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20
Q

Describe the role of the tegmentum

A
  • Involved in movement and arousal
  • Plays a role in learning, to produce behaviours, which minimise unpleasant and maximise pleasant consequences
  • Implicated in the role of fear and reward behaviours
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21
Q

Outline the role of the forebrain and list the structures

A
  • Forebrain is involved in complex sensory, emotional, cognitive and behavioural processing
  • Hypothalamus
  • Thalamus
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22
Q

Outline the roles of the hypothalamus and thalamus

A
  • Hypothalamus:
    • Eating
    • Sleeping
    • Sexual activity
    • Emotions
    • Detects changes in glucose levels, triggering hunger sensations
  • Thalamus:
    • Processing and transferring info
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23
Q

Outline the structures and functions of the sub-cortical structures (within cerebrum)

A
  • Basal Ganglia
    • Movement control
    • ‘Automatic responses’
  • Limbic System
    • Pleasure and fear
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24
Q

Outline the structures and functions of the limbic system (forebrain)

A
  • Septal area
    • Pleasure
    • Pain relief
    • Emotionally significant learning
  • Amygdala
    • Learning and memory of emotional events
    • Recognition of fear
  • Hippocampus
    • Storage of new memories
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25
Q

Outline the three main functions of the cerebral cortex

A
  • Sequencing voluntary movement e.g. playing music
  • Allows us to make subtle discriminations from different perceptual information
  • Allows for symbolic thought to represent objects or concepts
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26
Q

What is the cerebral cortex?

A

Outer brain layer with interneurons

27
Q

Describe the two structures which make up the cerebral cortex

A
  • Gyri- raised areas of the brain
  • Sulci- cracks in the brain
28
Q

Why is the cerebral cortex folded?

A

To optimise usage of space within the skull. Allows for larger surface area in the brain

29
Q

How are functions distributed across hemispheres?

A
  • Apart from language, most higher functions are distributed across both hemispheres
  • Lower level functions are localised to certain hemispheres
30
Q

What and where is the corpus callosum?

A

A thick bundle of nerves located in the centre which allows hemispheres to communicate

31
Q

Outline how visual information is processed (hemispheres)

A
  • Info from left and right visual fields cross over at optic chiasma and are processed in opposing hemispheres
  • Occurs for many sensory experiences
  • There are theories, but not entirely sure why
32
Q

Outline areas of the cerebral cortex and their functions

A
  • Primary areas- processes new sensory information
  • Association areas- processes complex mental processes e.g. perception, ideas and planning
33
Q

Outline the functions of the frontal lobe

A
  • Movement and attention
  • Planning
  • Social skills
  • Some aspects of personality
  • Higher order behaviours e.g. abstract thinking and memory
  • Both lobes deal with social, emotional, motor and sexual behaviour, plus problem solving
  • Left frontal lobe = language ability
  • Right frontal lobe = nonverbal aspects of communication. Auditory
  • Right frontal lobe involved in negative emotions, left involved in positive emotions
34
Q

Outline what happened to Gage and what resulted from this

A
  • Accident, iron rod driven through head, destroying frontal lobe
  • Affected personality and behaviour
  • Influenced debate of cerebral localisation, first to suggest brain’s role in determining personality
35
Q

Discuss the role of the prefrontal cortex

A
  • Help orchestrate thought and action in accordance with internal goals
  • Cognitive control may stem from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them
  • Provides bias signals to other brain structures which guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states and outputs needed to perform a given task
36
Q

Discuss the role of the motor cortex

A
  • Anterior, behind central sulcus which runs down the side of cerebral hemispheres
  • 1870, stimulated motor cortex in dogs, found it caused them to move involuntarily. Different locations caused different muscles to move
  • Primary area involved in planning and executing voluntary movements
  • Primary motor cortex involves least stimulation to induce muscle movement. Arranged so different regions control different body parts
37
Q

Discuss the role of the parietal lobe

A
  • 2 areas- one involves sensation and perception, the other is concerned with integrating sensory input, primarily visual
  • First function integrates sensory information to form a single perception cognition
  • Second function constructs a spatial coordinate system to represent the world around us
38
Q

What does left parietal lobe damage result in?

A
  • Gerstman Syndrome
    • Left-right confusion
    • Difficulty with writing (agraphia)
    • Difficulty with maths (acalculia)
    • Disorder of language (aphasia)
    • Inability to perceive objects normally (agnosia)
39
Q

What does right parietal lobe damage result in?

A
  • Condition where individual neglects parts of the body/space, impairing skills e.g. dressing
  • Difficulty in making things (constructional apraxia)
  • Denial of deficits (anosognosia)
40
Q

What does bilateral parietal lobe damage result in?

A
  • Balint’s Syndrome: a visual and motor syndrome
    • Inability to voluntarily control the gaze
    • Inability to integrate components of a visual scene
    • Inability to accurately reach for an object with visual guidance
41
Q

Outline the functions of the somatosensory cortex

A
  • Responsible for processing somatic sensations. Sensations arrive from receptors positioned throughout the body, for touch, proprioception (position of the body in space), nociception (pain) and temperature
  • When sensation is detected, info is sent to thalamus and then primary somatosensory cortex
42
Q

Outline the functions of the temporal lobe

A
  • Specialised for hearing and language
  • Primary cortex receives sensory info from ears
  • Association cortex arranges info into meaningful speech
  • Wernicke’s area in left hemisphere is crucial for language comprehension
43
Q

What is the result of damage to Wernicke’s area?

A
  • Aphasia- produces ‘word salad’, where one might speak fluidly and expressively but content has no meaning
44
Q

Outline the functions of the occipital lobe

A
  • Specialised for vision
45
Q

Outline the functions of the primary visual cortex

A
  • Low level visual processing
  • Receives raw sensory and visual info from thalamus
46
Q

Outline the functions of the visual association cortex

A
  • Extensions to other lobes where visual info can be combined with other senses to create perceptions of the world
47
Q

List left brain functions

A
  • Speech
  • Reading
  • Arithmetic
  • Visual memory
  • Language
  • Sounds
  • Complex movement
  • Right side of body/motor movements
48
Q

List right brain functions

A
  • Emotional content
  • Direction, distance
  • Nonverbal memory
  • Faces, patterns
  • Music, non-language sounds
  • Movement in spatial patterns
  • Left side of body/motor movements
49
Q

Discuss traumatic brain injury (TBI)

A
  • Alteration to brain functioning caused by external force
  • The external force can result in either a closed injury (non penetrating) or open (penetrating)
50
Q

Discuss non traumatic brain injury (NTBI)

A
  • Also called acquired injury
  • Causes damage to the brain by internal factors
  • Can occur as a result of strokes, aneurysm, infectious diseases, lack of oxygen and tumour
51
Q

Describe a closed brain TBI

A
  • Can cause large areas of damage due to bruising, bleeding, sheering or nerve fibres and swelling
  • Severe injuries may cause post traumatic amnesia
  • Severity of injury linked with memory loss duration
52
Q

Define coup injury

A

Damage caused by movement of head after impact

53
Q

Define countercoup injury

A

Damage caused by movement of head after impact

54
Q

What is the impact of a NTBI?

A

Difficulties in the following areas:

  • Physical
  • Cognitive
  • Communicative
  • Psychological
  • Psychosocial
55
Q

Outline locked-in syndrome

A
  • Rare neurological disorder characterised by complete paralysis of voluntary muscles, except those controlling eyes
  • People with locked-in syndrome are conscious and can think and reason, but are unable to speak or move
  • Vertical eye movements and blinking can be used to communicate
56
Q

What causes locked-in syndrome?

A
  • Brain stem stroke
  • Traumatic brain injury
  • Tumours
  • Circulatory system diseases (bleeding)
  • Diseases that destroy the myelin sheath surrounding nerve cells (e.g. multiple sclerosis)
  • Infection
  • Medication overdose
57
Q

Discuss laterality of brain function

A
  • The two different hemispheres of the brain show different dominance for different functions
  • Sensory information received on left side of body is processed by the right hemisphere and vice versa
  • Same for motor control
58
Q

Define contralateral

A

Refers to the opposite side of the body

59
Q

Define ipsilateral

A

Refers to the same side of the body

60
Q

Describe how and why split brain treatment is used

A
  • Corpus callosum is cut, cutting off communication between hemispheres (corpus callosotomy)
  • Used to alleviate epileptic seizures for those with intractable epilepsy, who haven’t responded to other treatments e.g. medication
  • Split brain patients can reveal which functions are controlled by which hemisphere
61
Q

Describe the experiment used for split brain patients

A
  • Language in the left hemisphere
  • Split brain patient is sitting looking straight ahead, focused on the fixation point in screen’s middle (dot)
  • Picture of spoon flashes to right of dot, visual info about the spoon crosses the optic chasm and ends up in the left hemisphere. When person is asked what the picture was, can identify spoon
  • If spoon were flashed to left of dot, visual info would have travelled to right hemisphere. If asked what picture was, person will see nothing, but when asked to pick spoon, pick correctly, as touch info from left hand crosses to right hemisphere
  • If asked again what object is, even in person’s hand, cannot say, as right hemisphere cannot talk. Ability for language is nonverbal
62
Q

Define neuroplasticity

A

The brain is constantly evolving structure that changes structurally and functionally in response to its environment, stimulation and condition (damage)

63
Q

Define the two mechanisms whereby the brain may experience functional improvement after injury

A
  • Recovery- restoration of neural tissue and restoration of prior performance
  • Compensation- recruitment of new neural circuits and training of new movements or activity
64
Q

Outline rat neuroplasticity experiment

A
  • Brain can change in response to learning
  • Rats reared in enriched environment have heavier cerebral cortexes, thicker synaptic contacts and up to 20% more dendritic branching
  • Can use it to direct learning