The Brain and Behaviour

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The Brain and Behaviour
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The central nervous system

• The central nervous system is one of the two
  major divisions of the human nervous system.
• The central nervous system comprises the brain
  and spinal cord. The spinal cord connects the
  brain and the peripheral nervous system.
• The peripheral nervous system includes all parts
  of the nervous system that lie outside the brain
  and the spinal cord.

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The Brain

• It is encased in a hard, protective skull and
  weighs, on average, around 1.5 kg in adults.
• It has the consistency of firm jelly and is
  covered by a strong plastic like membrane.
• There is a small gap between the brain and the
  skull, which is filled with fluid.

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The Cerebral Cortex

• The cerebral cortex is the convoluted outer layer
  or covering of the two cerebral hemispheres.
• The surface area of the cerebral cortex bends and
  folds inwards so that its surface area can fit
  into the limited amount of space available in the
  skull.
• If flattened out the cerebral cortex would cover
  about 4 A4 pages.
• The cerebral cortex is involved with
  information-processing activities such as
  perception, language, learning, memory, thinking,
  problem-solving as well as the planning and
  control of voluntary body movements.

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• Some areas of the cerebral cortex are dedicated
  to specific functions.
• The areas of the cerebral cortex and their main
  functions can be can be organised into three
  broad categories
• 1. The various sensory cortex areas which receive
  and process information from our different senses
  
• 2. The motor cortex area which receives,
  processes and sends information about voluntary
  body movements
• 3. Association cortex which integrate sensory,
  motor and other information and are involved in
  the more complex mental abilities, such as
  perceiving, thinking and problem-solving.
• It is believed that the larger the size of the
  cerebral cortex, the more intelligent the
  organism will be.

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Cerebral Hemispheres

• The cerebral cortex is described as having two
  halves, called cerebral hemispheres.
• The cerebral hemispheres are two almost
  symmetrical brain structures that appear to be
  separated by a deep groove (known as the
  longitudinal fissure) running from the front to
  the back of the brain.
• Although the hemispheres appear to be separated,
  they are connected at several points by strands
  of nerve tissue. The largest and most important
  of these strands is the corpus callosum.
• The left hemisphere receives information from the
  right side of the body just as the right
  hemisphere receives information from the left
  side of the body.

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Remember!! Contralateral Organisation

• Left hemisphere controls movement on the right
  side of the body.
• Right hemisphere controls movement on the left
  side of the body.

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Corpus Callosum

• The interaction between the two hemispheres of
  the brain occurs mainly through the corpus
  callosum.
• The corpus callosum is a strand, or bridge of
  nerve tissue that connects the left and right
  cerebral hemispheres and serves as the main
  communication pathway between them.
• This means that information can be exchanged
  between the two hemispheres when performing their
  many functions as we think, feel and behave
  throughout everyday life.

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Four lobes of the cerebral cortex

• The cerebral cortex of each hemisphere can be
  divided into four anatomical regions called
  cortical lobes.
• Cortical lobes are areas of the brain associated
  with different structures and functions. The four
  lobes are named after the bones of the skull that
  cover them.
• Frontal lobe
• Parietal lobe
• Occipital lobe
• Temporal lobe

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• The lobes contain areas of the cortex that have
  specialised sensory or motor functions, as well
  as areas of the cortex generally referred to as
  association cortex.
• The sensory areas of the lobes receive and
  process information from sensory receptors in the
  body.

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• The sensory area that receives and processes
  visual information is called the primary visual
  cortex. It is located in the occipital lobe.
• The sensory area that processes auditory
  information is called the primary auditory cortex
  and is located in the temporal lobe.
• Sensory information from the skin and from
  skeletal muscles is processed in the
  somatosensory cortex located in the parietal
  lobe.

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• The motor areas receive and process information
  about voluntary body movements that is
  intentional movements such as when you scratch
  your nose.
• There is only one primary motor area in the
  brain. This is called the primary motor cortex
  and is located in the frontal lobe.

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• The association areas of each lobe integrate
  information from different brain areas and are
  mainly involved in complex cognitive processes
  such as perceiving, thinking, learning,
  remembering, reasoning and so on.
• Association areas are located on all four lobes
  of each hemisphere and may receive and process
  information from sensory and/or motor areas, as
  well as from other structures or other
  association areas of the brain in other lobes.

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Frontal Lobe

• The frontal lobe is the largest of the four
  lobes and occupies the upper forward half of each
  cerebral hemisphere, right behind your forehead.
• In the forward section of each frontal lobe are
  association areas that receive information from
  other lobes to enable us to perform complex
  mental functions.
• The frontal lobes are also involved in
  personality, the control of emotions, and
  expression of emotional behaviour.

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Primary Motor Cortex

• Located at the rear of each frontal lobe and
  running roughly across the top of your head is a
  strip of neural tissue called the primary motor
  cortex.
• The primary motor cortex is specifically involved
  in controlling voluntary bodily movements through
  its control of skeletal muscles.
• The motor cortex in the left frontal lobe
  controls voluntary movements on the right side of
  the body and vice versa.
• The amount of cortex devoted to a particular body
  part corresponds to the complexity or fineness of
  its movements.

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Brocas Area

• A specific cortical area located in the left
  frontal lobe next to the motor cortex areas that
  control the muscles of the face, tongue, jaw and
  throat is an area called Brocas area.
• Brocas area is responsible for the production of
  articulate speech, coordinating movements of the
  muscles required for speech and supplying this
  information to the appropriate motor cortex
  areas.
• Brocas area is also involved in understanding
  the meaning of words and the structure of speech
  such as adjectives, prepositions and
  conjunctions. It is also involved in
  understanding the grammatical structure of
  sentences.

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Damage to Brocas Area

• Damage to Brocas area often produces speech that
  is very deliberate, consisting of a few words
  with very simple grammatical structure, but
  damage rarely results in the total loss of
  speech.
• This type of speech impairment is known as
  Brocas aphasia.
• Aphasia is a form of language loss or impairment
  due to brain damage, injury or disease.

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• In Brocas aphasia speech consists of very short
  sentences, typically three or four words, and
  these words are mainly verbs and nouns.
• The smaller parts of speech are often ommitted
  such as to and the, as are proper grammatical
  endings of words such as ing and ed.

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Parietal Lobe

• The parietal lobe is located behind the frontal
  lobe and occupies that upper back half of the
  brain, but not the rear-most area.
• The parietal lobe in each hemisphere receives and
  processes sensory information from the body and
  skin senses and other sensory areas in the brain.
  It also sends information to other areas of the
  brain.
• Located at the front of each parietal lobe, just
  behind and parallel to the primary motor cortex
  in the frontal lobe, is a strip of cortex called
  the primary somatosensory cortex.

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• The primary somatosensory cortex receives and
  processes sensory information from the skin and
  body, enabling us to perceive bodily sensations.
• Different areas of the primary somatosensory
  cortex are involved with sensations of touch
  received from specific body parts. Furthermore,
  the amount of cortex devoted to a particular body
  part corresponds to the sensitivity and amount of
  use of the body part.

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Occipital Lobe

• The occipital lobe is located at the rear-most
  area of each cerebral hemisphere that is at the
  back of your head.
• The occipital lobe is primarily involved in
  vision.
• Damage to the occipital lobe can produce
  blindness, even if the eyes and their neural
  connections to the brain are normal.
• The primary visual cortex is located at the base
  of each occipital lobe and this is where visual
  information from the two eyes is received and
  processed.

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Temporal Lobe

• The temporal lobe is located in the lower,
  central, area of the brain, above and around the
  top of each ear.
• The temporal lobe in each hemisphere is primarily
  involved with auditory perception, but also plays
  an important role in memory, in aspects of visual
  perception such as our ability to recognise faces
  and identify objects, and in our emotional
  responses to sensory information and memories.
• The primary auditory cortex in each temporal lobe
  receives and processes sounds from both ears,
  receiving and processing different features of
  sound and therefore playing a vital role in the
  identification of sounds.

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• The two main features of sound are frequency
  (which we perceive as pitch) and amplitude or
  intensity (which we perceive as loudness).
• Verbal sounds such as words are mainly processed
  in the primary auditory cortex of the left
  hemisphere and non-verbal sounds (such as music)
  are mainly processed in the primary auditory
  cortex of the right hemisphere.
• Damage to the temporal lobe as a result of a
  stroke or severe blow to the head can level a
  person with the ability to describe someones
  facial features, to identify their sex, and to
  judge their approximate age, but without the
  ability to recognise the person as someone that
  they know, even if it is their mother.

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Wernickes Area

• A specific area in the temporal lobe of the left
  hemisphere only, next to the primary auditory
  cortex and connected to Brocas area by a bundle
  of nerves is called Wernickes area.
• Wernickes area is involved with comprehension of
  speech more specifically, with interpreting the
  sounds of human speech.
• When a word is heard, the auditory sensation is
  processed by the primary auditory cortex of the
  left temporal lobe, but the word cannot be
  understood until the information has been
  processed by Wernickes area.
• This area is also thought to be involved with not
  only understanding words, but also for locating
  appropriate words from memory to express intended
  meanings when we speak or write.

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Hemispheric Specialisation
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Hemispheric Specialisation

• Overall, the two cerebral hemispheres appear to
  be two replicas of each other in terms of size,
  shape and function.
• The function of the sensory and motor areas of
  the left and right hemispheres are generally the
  same, however, each hemisphere does have some
  specialised functions which are not duplicated by
  the other hemisphere.
• Hemispheric specialisation The idea that one
  hemisphere has greater control over a particular
  function.

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How do we know what we know??

• The earliest evidence of hemispheric
  specialisation came from observations of people
  who had suffered a stroke or an injury affecting
  one hemisphere but not the other.
• It was observed that damage to the LEFT
  hemisphere often resulted in difficulties with
  language related activities (VERBAL TASKS) such
  as understanding speech, talking fluently,
  reading and writing. It also noted that the left
  hemisphere processes information in a step by
  step and analytical way.

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• Damage to the RIGHT hemisphere often resulted in
  difficulties with visual and spatial tasks not
  dependent on language (NON VERBAL TASKS), such as
  reading a map.

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What is each hemisphere specialised in?

• LEFT
• Verbal Task (involve the recognition of words)
  eg. Reading, writing, understanding of speech
• Analytical tasks (involve breaking down a task
  into its key parts and then approaching it in a
  step by step way) eg, following instructions on
  how to bake a cake.
• Left hemisphere receives and processes sensory
  information from the right side of the body.
• Controls voluntary movement on the right side of
  the body

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• Right
• Non verbal tasks (tasks that are not dependent on
  language skills) eg. Completing a jigsaw puzzle.
• Spatial and visual thinking eg. Reading a map,
  visualising a place in your mind, recognising
  faces.
• More involved in recognising emotions from facial
  cues (signals), such as raised eyebrow and
  smiling.
• Right hemisphere receives and processes
  information from the left side of the body and
  controls voluntary movements on the left side of
  the body.

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The Reticular Activating System (RAS) and Thalamus

• Two other important brain structures are involved
  in our ability to be awake and alert and to
  attend to stimuli in our internal and external
  environments.
• These are the reticular activating system and the
  thalamus.

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Reticular Activating System (RAS)

• Before incoming sensory information (neural
  impulses sent from outside the body to the brain)
  reaches the cerebral hemispheres, it must pass
  through the reticular activating system.
• The reticular activating system is a network of
  neurons that extends in many directions from the
  top of the spinal cord up to the thalamus. It
  influences our state of physiological arousal and
  alertness.

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• Nerve fibres from sensory neurons have side
  branches into the RAS, which filter incoming
  sensory information, sorting it into important
  and unimportant categories.
• These side branches stimulate the RAS to send its
  own nerve impulses upward toward the cortex,
  arousing it to a state of alertness and activity.
  
• This stimulation keeps the cortex alert and
  active which we then experience as being in a
  state of consciousness awareness.

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• Once alerted to the fact that new information is
  on its way, the brain is ready to process the
  sensory information.
• Unimportant information is ignored.
• This is what we know as selective attention-
  our ability to voluntarily redirect our attention
  to a specific stimulus while ignoring others.
• Eg. When you are trying to cross a busy road
  without traffic lights the RAS allows you to
  filter out unwanted sensory information and
  concentrate on what is important.

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• The RAS is not only involved in keeping us alert
  when we are awake- it is also involved in the
  control of sleeping and waking, and is often
  referred to as the brains arousal centre.
• Experiments in which researchers have removed the
  RAS from animals show that without it they cannot
  be awakened, due to lack of arousal. If the RAS
  is electrically stimulated in sleeping animals
  they will awaken immediately.

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• Damage to the RAS will profoundly disrupt the
  sleep-wake cycle and can result in coma or a
  vegetative state.
• Many general anaesthetics work by reducing the
  activity of the RAS, making the patient
  unconsciousness.

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The thalamus the sensory switching station

• The thalamus is a structure that sits on top of
  the brain stem and acts as a sensory relay
  station.
• Information from all senses (except smell) pass
  through this structure.
• The thalamus is a brain structure that filters
  information from the senses and transmits the
  information to the cerebral cortex.

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• Eg. Information from the eyes enters the thalamus
  and is relayed to the primary visual cortex in
  the occipital lobe.
• The flow of information is not one way- there is
  a constant flow of information between the
  thalamus and other cortical areas.
• In addition to incoming sensory information, the
  thalamus receives information about our state of
  arousal from the reticular formation.
• This means the thalamus also has a crucial role
  in influencing our level of alertness.

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• The thalamus also appears to play a role in
  attention.
• It filters the vast amounts of information that
  need to be attended to and highlights some while
  de-emphasising others.
• This is crucial when we are in need of resting
  the brain (eg sleep) as the thalamus stops
  information from passing through to the cortex.

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The spinal cord

• The spinal cord is a long column of nerve tissue
  that extends from the base of the brain and is
  encased in the spinal column which runs from the
  skull to the lower back.
• The bones of the spinal cord are called
  vertabrae.
• The two main functions of the spinal cord are

To pass motor information from the brain to the
Peripheral Nervous System so that the appropriate
actions can be taken.
To pass sensory information from the Peripheral
Nervous System to the brain.
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• When the spinal cord is damaged, the brain loses
  both sensory input from and control over the
  body.
• The spinal cord is the linking pipeline that
  integrates the central nervous system and
  peripheral nervous system, which work together to
  transmit information around the body.
• This information is transmitted via NEURONS.

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TYPES OF NEURONS

• There are three main types of neurons, each of
  which has a different role in the nervous system.
  
• These are
• Sensory neurons
• Motor neurons
• Interneuron's
• Sensory neurons and motor neurons are found
  primarily in the PNS, whereas interneurons are
  only found in the CNS.

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SENSORY NEURONS

• Sensory neurons (also called afferent neurons)
  are specialised cells that receive information
  from both the external environment and from
  within the body and transmit the information to
  the CNS.
• Their main role is to help us sense the external
  world and changes within our body.
• Generally there are different types of sensory
  neurons, each of which is specialised to respond
  only to a particular type of stimulation. Eg. The
  sensory neurons in the ears respond to sound
  waves, but not light.

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MOTOR NEURONS

• Motor neurons (also called efferent neurons)
  transmits messages from the CNS to the muscles,
  glands and organs.
• They enable muscles to move, cause glands to
  secrete chemicals and activate internal organs
  such as the heart, lungs and intestines.

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INTERNEURONS

• Interneurons exist only within the CNS.
• Interneurons provide neural links between sensory
  and motor neurons and have a specialised role of
  carrying and integrating messages between sensory
  and motor neurons.
• When information from a sensory neuron arrives at
  the CNS, an interneuron receives, organises and
  integrates the information. They also connect
  with the motor neurons to send messages back
  through the PNS.

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Neurons

• The major difference between sensory and motor
  neuron activity is the direction of the neural
  impulse and what happens at their destinations.

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STUDIES ON COGNITIVE PROCESSES OF THE BRAIN

• The brain is not always perfect as shown through
  perceptual anomalies or irregularities like
  when we perceive motion that doesnt actually
  occur (motion after effect), when we fail to
  notice changes that are occurring (change
  blindness) and when we involuntarily experience
  sensations that do not have a physical basis at
  that time (synethesia).

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• When looking at the irregularities of the brain
  we examine these phenomena, which are all
  experienced by people with intact, undamaged
  brains.
• Other people with brain damage experience the
  world very differently to those without damage.
• We will also look at this and the way this
  effects a persons life.
• Aphasia
• Spatial neglect
• Split-brain studies

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APHASIA

• The word aphasia is a general term used for
  clinical purposes to describe individuals with a
  language disorder.
• Aphasia refers to a language disorder apparent in
  speech (comprehension or production), writing or
  reading, produced by injury to brain areas
  specialised for these functions.

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• Aphasia is often classified into three main
  areas
• Fluent aphasias in which there is fluent speech
  but there are difficulties in either auditory
  verbal comprehension or the repetition of speech
  spoken by others
• Nonfluent aphasias in which there are
  difficulties in articulating clearly but auditory
  verbal comprehension is good
• Pure aphasias in which there are specific
  impairments in reading, writing or the
  recognition of words.
• The most common cause of aphasia is stroke,
  causing loss of blood supply to areas of the
  brain associated with language.

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• Some aphasia sufferers can speak fluently but
  they cannot read, others may understand what they
  read but cannot speak, some can write but not
  read, some can read but not write, some can read
  numbers but not letters, and others can sing but
  not speak.

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Brocas aphasia

• In the late 1800s, French physician Paul Broca
  studied patients with damage to the lower left
  frontal lobe, close to the motor cortex.
• This later became known as Brocas area.
• He discovered that while patients with damage to
  this area could understand what was said to them
  and knew what they wanted to say in response,
  they simply could not say it.

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• In Brocas aphasia a person has difficulty in
  speaking, although they continue to understand
  speech.
• A typical patient will speak slowly and
  laboriously, and use simple sentences.
• Usually only the concrete words (verbs and nouns)
  are pronounced and the connecting words are
  omitted (to, the or ing).
• Eg. Boy went beach instead of The boy went to
  the beach.
• The sentence is not articulate and incomplete.
• Some patients cannot speak at all.

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• Brocas aphasia
• http//www.youtube.com/watch?vf2IiMEbMnPM

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Wernickes aphasia

• Around the same time, German physician and
  psychiatrist Carl Wernicke studied patients with
  a different language disorder.
• This was the inability to understand speech or to
  produce coherent language.
• He identified a part of the brain in the left
  temporal lobe close to the primary auditory
  cortex as being the area responsible for language
  comprehension- Wernickes area.

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• Wernickes aphasia is a type of aphasia in which
  a person has considerable difficulty
  comprehending speech and speaking in a meaningful
  way.
• Unlike Brocas aphasia, speech is often fluent
  and grammatically correct, but what is said is
  nonsense.
• Words are used inappropriately and sometimes made
  up words are used.
• The patient often is not even be aware that what
  they are saying does not make sense.

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• Eg. When describing a picture of a woman washing
  the dishes and her two children stealing cookies
  from the cookie jar behind her the patient says
• Well, this ismother is always here working her
  work out of here to get her better, but when
  shes looking the two boys looking in the other
  part. One their small tile into her time here.
  Shes working another time because shes getting
  to. So two boys work together and one is sneaking
  around here making his work and further funnas
  his time he had.

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• Tono man
• http//www.youtube.com/watch?vFw6d54gjuvA
• Wernickes aphasia
• http//www.youtube.com/watch?vaVhYN7NTIKU

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Language functions

• There are other areas of the brain that have been
  linked to language that complement the functions
  outlined in Broca and Wernickes areas.
• It has also been found that the right hemisphere
  may also have a role in language.
• Some patients with major destruction to the left
  hemisphere may be capable of swearing or using
  emotionally charged words, or singing, and
  learning well known phrases.
• Some can sing phrases that they are unable to
  say, thereby making use of the right hemispheres
  musical function.

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Spatial neglect

• Read intro page 217.
• Spatial neglect is an attentional disorder in
  which individuals fail to notice anything either
  on their left or right side.
• They tend to behave as if one side of their world
  does not exist.
• Most commonly observed in stroke victims or
  accident victims who have extensive damage to the
  rear area of the parietal lobe of the right
  hemisphere.
• They mostly neglect the left side of their world.

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• Read studies pg 218.
• Spatial neglect is widely considered to be a
  disorder involving failure of attention, and not
  due to impairment of memory processes, the visual
  system or any other sensory system.
• Its much greater occurrence with damage to the
  right rather than the left parietal lobe
  highlights the importance of this lobe in
  attention and spatial recognition.
• Many patients insist that there is nothing wrong
  with their perception of the world.
• Some do however, make a gradual recovery.

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Split brain studies

• Much of our knowledge on hemispheric
  specialisation comes from researchers Roger
  Sperry (1914-1994) and Michael Gazzaniga (1939-).
  
• These researchers demonstrated that there is more
  to hemispheric specialisation than just language
  functions.
• How is it possible to test only one side of the
  brain?

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• One way is to work with people who have had a
  split-brain operation.
• Split brain surgery involves surgically cutting
  the corpus callosum thereby disconnecting one
  hemisphere of the brain from the other.
• Another less common procedure is the WADA test in
  which a sedative is injected into an artery which
  sedates only one side of the brain.

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Split brain surgery

• In the 1940s there was very little remedy for
  people who suffered from severe epileptic
  seizures (10-15 a day).
• In recognising the need for new treatments,
  American neurosurgeon William Van Waganen decided
  to contain seizure activity by cutting the corpus
  callosum and stopping the communication between
  the two cerebral hemispheres.

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• Animals studies showed that there were no obvious
  effects of this surgery and in the 1940s the
  first of the human split-brain surgeries began.
• There was little evidence of impairment and
  patients appeared to remain normal, however
  there was little or no improvement in the
  occurrence of the seizures.
• The surgery was abandoned until the 1950s when
  Sperry and a student of his, Roger Myers
  conducted successful split brain operations with
  cats.
• Through this experimentation it was found that
  the earlier split-brain operations may have been
  unsuccessful because the corpus callosum and
  other neural connections had not been completely
  severed.

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• The split-brain surgeries were conducted on 11
  epileptic patients, completely cutting the corpus
  callosum and other nerves, leaving some patients
  virtually seizure free afterwards and with
  minimal side-effects.
• Sperry and Gazzaniga however discovered that the
  surgery had left some patients with a unique
  condition.

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Effects of having a split brain

• Surgery that cuts the corpus callosum interrupts
  the exchange between the two cerebral
  hemispheres, so information registered in one
  hemisphere is unable to be transferred to the
  other.
• This means the brain cannot integrate information
  registered separately in each hemisphere.
• Eg. Information registered in the right
  hemisphere cannot be transferred to the left
  (language centres) and therefore cannot be
  verbalised.

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• Problems arise for split-brain patients when a
  response requires information from one hemisphere
  to be integrated with information from the other
  hemisphere.
• Eg. When registering visual information, it is
  registered on the retina of each eye and travels
  to each hemisphere. Info from the right portion
  of a persons vision (right visual field) goes to
  the left hemisphere where the speech centre
  allows you to articulate this information
  verbally. If you receive information only to your
  left visual field, the information will only
  travel to your right hemisphere and if you had a
  split-brain operation it would be unable to pass
  to the left hemisphere and therefore be unable to
  be articulated verbally.

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Perceptual anomalies

• Perception occurs when sensory information
  reaching the brain is meaningfully interpreted.
• Touch, taste, smell, sight, hearing.
• This allows us to make sense of the world.
• However sometimes we make errors in our
  perceptions and this can lead to perceptual
  anomalies.
• Perceptual anomaly refers to an irregularity in
  perception. It usually involves an inconsistency
  or mismatch between the perceptual experience and
  physical reality.

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• Eg. When driving along a highway you may see a
  puddle on the road ahead. As you drive the road
  stays dry and the puddle remains in the distance.
  In reality there is not puddle it is a layer of
  hot air beneath cool air but the brain
  misinterprets it and you see it as a puddle.
• Three types of anomalies
• Motion after-effect
• Change blindness
• Synesthesia

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Motion after-effect

• Motion after-effect refers to the phenomenon that
  occurs when, after staring at a moving image for
  a period of time and then looking immediately at
  a stationary one, we perceive the stationary
  image to be moving in the opposite direction to
  the moving image.
• http//www.michaelbach.de/ot/mot_adaptSpiral/

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• One explanation for motion after-effect is that
  the neurons in the visual cortex that respond to
  the motion become fatigued over time. When you
  stare at a moving object, these cells signal
  movement in one direction. When you shift your
  attention to something else, these neurons fail
  to fire. However, as neurons that signal movement
  in the opposite direction are more active they
  therefore interpret the movement as the opposite
  direction.

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Change blindness

• Change blindness refers to a failure to notice
  changes in a visual scene.
• This failure to notice is usually because the
  changes occur at the same time as a disruption to
  our vision and, in particular, a disruption to
  our attention.
• Change blindness illustrates the importance of
  attention in cognitive processes and the
  important roles of the RAS and thalamus as a
  sensory filter.

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• http//www.youtube.com/watch?vvBPG_OBgTWg

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Inattentional blindness

• Inattentional blindness is the failure to notice
  an object in the environment, because attention
  was not focused on it.
• There is no visual disruption or reliance on
  memory.
• It is possible that these phenomena occur because
  of a failure to store the information in the
  first place. It may also occur because we are
  unable to compare the new information with the
  old information.
• http//www.youtube.com/watch?vIGQmdoK_ZfYfeature
  related

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Synesthesia

• Synesthesia is a perceptual experience in which
  stimulation of one sense produces additional
  unusual experiences in another sense.
• It is involuntary and occurs automatically and is
  consistent across time.
• Grapheme-colour synesthesia is the most common
  form and is when the experience of viewing
  letters or numbers actually produces the
  experience of colours.

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• Although the causes of synesthesia are yet to be
  clearly determined, there are some factors that
  are associated closely with synesthesia
• It is most likely to run in families, suggesting
  a genetic link
• It is most common in drug users (LSD)
• People with one type of synesthesia are more
  likely to have another form
• Creative people are more likely to have
  synethesia
• Synesthesia can develop over the course of a
  lifetime, not everyone is born with it.

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• http//www.youtube.com/watch?vveoN1mh7RME

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Brain research methods.

• Neuroimaging can capture detailed images of the
  living intact brain as people engage in different
  mental processes or make behavioural responses.
• Functional neuroimaging refers to scanning
  techniques that provide views of some particular
  aspect of brain function by showing images of the
  brain at work.

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Brain research methods

• Summarising brain research methods.docx

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Ethical principals in brain research

• Psychologists are not medically qualified and
  therefore are not legally or ethically permitted
  to administer any medical procedures.
• Any neuroimaging device involves medical
  procedures and can therefore not be administered
  by a psychologist.
• A psychologist may work on a team with medical
  experts to administer these kinds of treatments.

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THE HUMAN NERVOUS SYSTEM
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• Central Nervous System
• The Central Nervous System (CNS) comprises the
  brain and spinal cord. The spinal cord connects
  the CNS with the Peripheral Nervous System.
• The roles of the CNS are to integrate and
  coordinate all incoming neural information and to
  initiate messages sent to different parts of the
  body, the CNS does not have direct contact with
  the outside world.
• The CNS relies on the Peripheral Nervous System
  to provide it with information about both the
  external world and the bodys internal
  environment, and to carry messages from the CNS
  to various parts of the body.

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• Peripheral Nervous System
• The Peripheral Nervous System (PNS) is the entire
  network of nerves located outside the Central
  Nervous System.
• It extends from the top of the head, throughout
  the body to the tips of the fingers and toes and
  to all parts of the skin.
• The PNS has two main functions
• To carry information from the sensory organs to
  the CNS
• To convey information from the CNS to the
  muscles, organs and glands.
• It enables communication to occur between the CNS
  and all other parts of the body outside the brain
  and spinal cord.

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Human Nervous System

• In the human nervous system, messages can only
  travel in one direction along the neuron. To
  accommodate this, the PNS has two different
  pathways for communicating information to and
  from the CNS.
• One of these pathways consists of a set of
  neurons- the sensory neurons- that carry
  information from the sensory organs, muscles and
  glands to the CNS.
• The other pathway consists of a set of neurons-
  motor neurons- that carry instructions or
  messages from the CNS to muscles, organs and
  glands.

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You are able to feel the heat of a wood fire
because of the coordination of the and the .
The heat given from the fire is received by the
neurons of the skin, which are part of the
. The sensory neurons then transmit the
information to the . The brain then organises
and interprets the information in a meaningful
way, which enables you to know how hot the flame
is. If you decide it is too hot, the brain sends
messages via the neurons which are part of the
to the muscles in your legs to move a few steps
away from the fire.
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The peripheral nervous system can be subdivided
into two quite distinct nervous systems, each of
which has different functions- the somatic
nervous system and the autonomic nervous system.
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THE SOMATIC NERVOUS SYSTEMThe Somatic Nervous
System is a network of sensory (afferent) nerves
that carry information received by sensory
receptors in the body to the CNS, and motor
(efferent) nerves that carry information from the
CNS to control voluntary movements of skeletal
muscles.The Sensory function of the SNS is
activated when you sense or feel something on
your skin for example and the SNS sends signals
from that point to your brain via the spinal
cord, resulting in you experiencing the
sensation. The motor function of the SNS is
demonstrated whenever you voluntarily move a body
part.
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• THE AUTONOMIC NERVOUS SYSTEM
• The Autonomic Nervous System is a network of
  nerves that connects the CNS to the bodys
  internal organs and glands providing feedback to
  the brain about their activities.
• The ANS is called autonomous because many of the
  organs, glands and processes under its control
  are self-regulating and not usually under
  voluntary control.
• Eg. Heartbeat, digestion, perspiration.
• Regardless of our level of awareness or
  alertness, the ANS keeps the vital organs and
  systems of our body functioning thus maintaining
  our survival.

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• Divisions of the ANS
• The ANS is made up of two distinct divisions, the
  sympathetic and parasympathetic nervous systems.
• The sympathetic nervous system is responsible for
  increasing the activity of most visceral muscles,
  organs and glands in times of vigorous activity,
  stress or threat.
• The parasympathetic nervous system is responsible
  for decreasing the activity of most visceral
  muscles, organs and glands, and keeping the body
  functioning in a normal state.
• While the two nervous systems are both active at
  the same time, one system usually dominates the
  other at any given time.

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The Sympathetic Nervous System

• Enhances survival by providing an immediate
  response, in a split second, to any kind of
  emergency.
• When an emergency is perceived, neurons in the
  SNS activate target organs and glands to respond
  in the required way. The result is that
• heart rate and blood pressure increase,
• breathing rate increases so more oxygen can be
  taken in,
• sugar and fat are released from storage to
  provide instant energy to the skeletal muscles,
• the pupils dilate to allow more light to enter
  the eye and enhance vision,
• and sweat glands increase their production of
  sweat which cools the body.

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The Parasympathetic Nervous System

• The PNS generally has the effect of
  counterbalancing the activities of the SNS.
• It has two main functions
• 1. It keeps the systems of the body functioning
  efficiently and in times of minimal stress and in
  the absence of threats, helps it to maintain the
  internal body environment in a steady, balanced,
  state of normal functioning (homeostasis).
• 2. It also restores the body to a state of calm,
  once the need for activity of the SNS has passed.
  
• The PNS dominates the SNS most of the time as it
  is involved in basic everyday functioning.

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Description Function
Somatic Network of sensory nerves that carry info to the CNS received by sensory and motor nerves that carry info from the CNS to control voluntary movements of the skeletal muscles. Initiates all skeletal muscle activity enabling you to perform voluntary actions such as scratching your head, talking, riding a bike, dancing, chewing and wriggling your toes.
Autonomic The Autonomic Nervous System is a network of nerves that connects the CNS to the bodys internal organs and glands providing feedback to the brain about their activities. Heartbeat, digestion, perspiration. Regardless of our level of awareness or alertness, the ANS keeps the vital organs and systems of our body functioning thus maintaining our survival.
Sympathetic Enhances survival by providing an immediate response, in a split second, to any kind of emergency. When an emergency is perceived, neurons in the SNS activate target organs and glands to respond in the required way heart rate and blood pressure increase, breathing rate increases so more oxygen can be taken in, sugar and fat are released from storage to provide instant energy to the skeletal muscles, the pupils dilate to allow more light to enter the eye and enhance vision, and sweat glands increase their production of sweat which cools the body.
Parasympathetic The PNS generally has the effect of counterbalancing the activities of the SNS. It dominates the SNS most of the time as it is involved in basic everyday functioning. It keeps the systems of the body functioning efficiently and in times of minimal stress and in the absence of threats, helps it to maintain the internal body environment in a steady, balanced, state of normal functioning (homeostasis). It also restores the body to a state of calm, once the need for activity of the SNS has passed.
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• OLD COURSE

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Research on hemispheric specialisation

• There are 3 main approaches to conducting
  research on hemispheric specialisation
• 1. Studying individuals with brain damage
• 2. Studying people who have had a split brain
  operation.
• 3.Studying people with intact, and damaged
  brains.

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1. Studying people with brain damage

• People who have suffered brain damage include
  those who have suffered a stroke, have suffered
  head injuries through a car or sporting accident,
  or for a medical reason, have had to have part of
  their brain surgically removed.
• This research has been crucial in localising the
  functions of each hemisphere. For example,
  Broca's and Wernickes pioneering studies on
  damage to the specific parts of the left
  hemisphere that are involved in speech production
  and speech comprehension. Their research clearly
  showed that language and language- dependent
  verbal tasks are a specialised function of the
  left hemisphere.

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• Similarly, the role of the right hemisphere in
  spatial tasks is evident in people with Neglect
  Syndrome, a disorder caused by damage to the
  right hemisphere. Sufferers behave as if the
  left side of their world does not exist. For
  example, they may eat all the food on the right
  side of their plate.

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Case Studies

• Sometimes one of the best methods of brain
  research is to conduct a case study.
• Case study A detailed account of a single
  individual
• Eg. Phineas Gage, Albert Einstein
• Advantages Rich source of information and detail
• Disadvantages Time consuming, problems with
  generalising as cases are extraordinary.

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• Phineas Gage is probably the most famous patient
  to have survived severe damage to the brain.  He
  is also the first patient from whom we learned
  something about the relationship between
  personality and the function of the front parts
  of the brain.

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• The tamping iron was 3 feet 7 inches long and
  weighed 13 1/2 pounds.  It was 1 1/4 inches in
  diameter at one end and tapered over a distance
  of about 1-foot to a diameter of 1/4 inch at the
  other.  The tamping iron went in point first
  under his left cheek bone and completely out
  through the top of his head, landing about 25 to
  30 yards behind him.  Phineas was knocked over
  but may not have lost consciousness even though
  most of the front part of the left side of his
  brain was destroyed.  Dr. John Martyn Harlow, the
  young physician of Cavendish, treated him with
  such success that he returned home to Lebanon,
  New Hampshire 10 weeks later.

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• Some months after the accident, probably in about
  the middle of 1849, Phineas felt strong enough to
  resume work.  But because his personality had
  changed so much, the contractors who had employed
  him would not give him his place again.  Before
  the accident he had been their most capable and
  efficient foreman, one with a well-balanced mind,
  and who was looked on as a shrewd smart business
  man.  He was now fitful, irreverent, and grossly
  profane, showing little deference for his
  fellows.  He was also impatient and stubborn, yet
  impulsive and indecisive, unable to settle on any
  of the plans he devised for future action.  His
  friends said he was "No longer Gage."

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2. Studying people who have had a split brain
operation.

• A split brain operation involves surgically
  cutting the corpus callosum, the main bundle of
  nerves/tissue that connects the two hemispheres.
• This procedure was first used in the 1940s to
  minimise or stop recurring seizures in severe
  cases of epilepsy that could not be treated by
  any other means. By severing the corpus callosum,
  the seizures were unable to pass over the
  hemispheres.

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• Important information gained from split-brain
  research is how the left and right hemisphere
  function when they cannot exchange information,
  and therefore cannot communicate together. For
  example, Sperry (1974) found that a split brain
  patient can recognise a picture of an object but
  not name it.

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3.Studying people with intact and damaged brains.

• This refers to the study of people who have not
  undergone brain surgery and do not have a brain
  injury or disease.
• New technology allows the study of brain
  functions ie
• - Electrical stimulation of the brain (ESB)
• Electroencephalograph (EEG)
• Computerised Axial Tomography (CAT)
• Positron emission tomography (PET)
• Magnetic Resonance Imaging (MRI)
• Functional Magnetic Resonance Imaging (fMRI)
• The Wada test

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Electrical Stimulation of the Brain (ESB)

• ESB involves precisely regulated electric current
  to stimulate a specific area of the brain leading
  to either activation or inhibition of stimulated
  area.
• Wilder Penfield mapped the brain using numbered
  tags, and by eliciting either a physical,
  emotional or experiential response.

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Electrical Stimulation of the Brain (ESB)

• Advantages
• -Identifying function and location.
• -hemispheric specialisation.
• -Disadvantages
• -Only useful for people undergoing brain surgery.
• -Invasive risks.
• -Generalisation difficult.

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• The Wada test
• The Wada test is used on patients with intact
  brains before surgery to find out in which
  hemisphere the language centres are located.

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The WADA test

• Sodium amytal (a fast acting barbiturate) is
  injected into either the left or right carotid
  artery (an artery in your neck)
• These arteries send blood primarily to the
  cerebral hemisphere on the same side as the
  injected artery
• ie. Injecting the left artery results in
  anaesthetising the left hemisphere (and so the
  right side of the body)

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The WADA test

• What happens?
• Patients are asked to put both arms in the air
  and count backwards from 100.
• The arm on the opposite side of the injection
  will fall limp (indicating that the anaesthesia
  has taken effect)
• If patients continue to count backwards the
  language centre must be on the other side from
  the injected artery.
• If the patient stops counting, the language
  centre must have been anaesthetised and is on the
  same side as the injection.

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Electroencephalograph (EEG)

• EEG is a device that detects, amplifies and
  records general patterns of electrical activity
  of the brain.
• Described in rhythms or patterns as alpha, beta,
  delta, theta.
• Used to diagnose brain-related medical conditions

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Electroencephalograph (EEG)

• Advantages
• -Non invasive
• -Less expensive than PET and MRI, can be used
  widely and over long periods
• Disadvantages
• -Doesnt provide detail on specific brain
  structures.

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Computerised (axial) Tomography (CAT)

• A CT is a neuroimaging technique that produces a
  computer enhanced image of a cross section
  (slice) of the brain from X-rays taken at
  different angles.
• Needs a radiologist.
• Contrast/iodine injected into the bloodstream to
  highlight brains blood vessels with no ill
  effect.

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Computerised (axial) Tomography (CAT)

• Advantages
• -Non invasive
• -precisely locates brain damage.
• Disadvantages
• -Only structural, not functional information.

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Positron Emission Tomography (PET)

• PET produces a computer-generated image that
  provides information about brain function and
  activity during various tasks.
• Tracks blood flow and detects increased neural
  activity as a result of glucose consumption.
• Harmless radioactive substance injected.
• Colour coding- red is most active

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Positron Emission Tomography (PET)

• Advantages
• -Detailed images of brain functioning.
• -Use on people without brain damage
• -More sensitive than CAT/MRI
• -Colour coding easy to analyse.
• Disadvantages
• -Injection
• -Session must be kept short
• -Cant eliminate other causes of brain activity
  at time of the scan

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Magnetic Resonance Imaging (MRI)

• MRI is a neuroimaging technique that uses
  harmless magnetic fields and radio waves to
  vibrate atoms in the brains neurons to produce
  an image of the brain.
• Coloured image assembled by computer indicates
  high and low level activity.

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Magnetic Resonance Imaging (MRI)

• Advantages
• -Identifies structural abnormalities.
• -Detects very small changes.
• -Can detect prosopagnosia (identifying faces but
  not objects) and akinetopsia (lack of motion
  perception)
• -No x-rays or radioactive substances.
• Disadvantages
• -No metallic devices can be present.
• -Still does not assess brain function.

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Functional Magnetic Resonance Imaging (fMRI)

• fMRI is a neuroimaging technique that enables the
  identification of brain areas that are
  particularly active during a given task by
  detecting changes in oxygen levels in the blood
  flowing through the brain.
• Colour variation reflects degree of activity.
• Can take numerous images in succession leading to
  more detailed, precise images.
• 3D displays.

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Functional Magnetic Resonance Imaging (fMRI)

• Advantages
• -No radiation.
• -More detail than PET.
• -Colour coding
• Disadvantages
• -Still cannot eliminate other influences on brain
  activity of brain at a given point.