Biopsychology Year 13 (Paper 2)

Question 1

Localisation of the brain function

Answer 1

During the 19th century it was discovered that certain areas of the brain had particular functions. This is known as ‘localisation of brain function’

Question 2

The two hemispheres

Answer 2

Activity on the left-hand side of the body is controlled by the right hemisphere and the right-hand side of the body is controlled by the left hemisphere

Question 3

Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe

Answer 3

Frontal lobe –consciousness, speech production, movement
Parietal lobe –perception
Occipital lobe –vision
Temporal lobe– speech recognition, hearing

Question 4

Motor area
Somatosensory area
Visual area
Auditory area

Answer 4

Motor area- a region of the frontal lobe involved in regulating movement. Outgoing info.

Somatosensory area – an area of the parietal lobe that processes sensory information such as touch. Incoming info.

Visual area – a part of the occipital lobe that receives and processes visual information

Auditory area – located in the temporal lobe and concerned with the analysis of speech-based information.

Question 5

Case study: Phineas Gage (1848)

Answer 5

– First patient from whom we learned something about the relation between personality and the function of the front parts of the brain
– Phineas Gage was the foreman of a railway construction gang. On September 13, 1848, an accidental explosion of a charge he had set blew his tamping iron through his head.
-The tamping iron was 3 feet 7 inches long and weighed 13 1/2 pounds. 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

Question 6

Phineas Gage: Before and After accident

Answer 6

Amazingly, he still remained conscious and physically recovered.
• Before the accident:
– capable and efficient foreman – Well-balanced
– Shrewd, smart businessman
– Sociable
• After the accident:
– Fitful, disrespectful
– Profane
– Impatient and stubborn
– Unable to create and stick to future plans – His friends said he was “No longer Gage.”

Question 7

Motor cortex

Answer 7

-Responsible for generation of voluntary motor movements
-Located in frontal lobe along the bumpy region (!) the precentral gyrus
-On both hemispheres – motor cortex on right hemisphere controlling muscles on left side of body and vice versa
-Damage to this area may result in loss of control over fine movements
-Different parts of the motor cortex control different parts of the body
-These are arranged logically – the region that controls the foot is next to the region that controls the leg

Question 8

Somatosensory Cortex

Answer 8

-Detects sensory events from different regions of the body
-In parietal lobe, separated from the motor area by the ’valley’ called central sulcus
-Dedicated to the processing of sensory info related to touch; different areas of the body have more receptors than others making them more sensitive such as the skin.
-Uses sensory info from skin to produce sensations such as touch pressure, pain, temperature which it then localises to specific body regions
-The amount of somatosensory area devoted to a particular body part denotes its sensitivity. For example receptors in our face and hands occupy over half of the somatosensory area.
-Both hemispheres have a somatosensory cortex
-The cortex on one side of the brain receives sensory info from the opposite side of the body

Question 9

Visual centres

Answer 9

-Located in the visual cortex in the occipital lobe
-Visual processing begins in retina (light enters and strikes the photoreceptors (rods and cones))
-Nerve impulses from the retina travel to areas of the brain via the optic nerve
-Some travel to areas of the brain involved in coordination of circadian rhythms
-Most terminate in the thalamus, this acts as a relay station passing info to visual cortex
-Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex. This means damage to the left hemisphere can produce blindness in the right visual field of both eyes.
-Visual cortex contains different areas that process different types of visual info such as colour, shape and movement.

Question 10

Auditory centres

Answer 10

-In temporal lobes on both sides of brain
-Begins in cochlea in inner ear, sound waves are converted to nerve impulses
-These travel via the auditory nerve to the auditory cortex
-Pit stop at the brain stem where basic decoding happens .Then on to thalamus which acts as a relay station and carries out further processing of auditory stimulus
-Last stop is at the auditory cortex
-Sound has already been largely decoded by this point, in the auditory cortex it is recognised and may result in an appropriate response.
-Damage may produce partial hearing loss; the more extensive the damage, the more extensive the hearing losses

Question 11

Karl Lashley (1950)

Answer 11

-Higher cognitive functions such as processes involved in learning, are not localised but distributed in a more holistic way in the brain.
-In his experiment, he removed the cortex of rats and put them in a maze before and after the cortex was removed
-No matter what part of the cortex was removed, rats kept at least partial memory of the maze.
-Lashley concluded that memory did not lie in specific parts of the brain, or resides in a number of locations within the cortex, or maybe outside of the cortex completely.
-No area was proven to be more important than any other.

Question 12

Brocas Area

Answer 12

-Located in the frontal lobe of the LEFT hemisphere only
-Area to do with production of articulate speech, clear and fluent
-Moves the muscles that are required to speak
-Involved in analysing the grammatical structure of sentences, helps us extract meaning from language

Question 13

Broca’s Aphasia

Answer 13

-Damage to Broca’s area=
-Trouble with speech production, speech consists of very short and simple sentences, mainly verbs and nouns
-Reading and writing not as effected (can be in some cases)
-Deaf people can sometimes have difficulty signing if Brocas effected. Although this depends on whether they were death from birth

Question 14

Language centres- Broca

Answer 14

-Treated a patient called ‘Tan’ – unable to speak other than this one word (but did understand language)
-Studied 8 other patients who similar language deficits, along with lesions in their left frontal hemisphere
-Patients with damage to their right frontal hemisphere did not have the same problems
-This lead him to identify the existence of a language centre in the back portion of the frontal lobe of the left hemisphere believed to be critical for speech production

Question 15

Wernicke’s area

Answer 15

-Loactated in the temporal lobe of the left hemisphere only, next to the primary auditory cortex
-Involved in the interpretations of speech, referred to as the language comprehension centre
-Vital for locating appropriate words from memory to express meaning

Question 16

Wernickes’s aphasia

Answer 16

-Damage to Wernickes’s area=
-Trouble with speech comprehension. Also can’t produce meaningful sentences, can string words together but what they say is nonsensical

Question 17

Turk et al (2002)

Answer 17

-Discovered a patient JW, who suffered damage to the left hemisphere but developed the capacity to speak in the right hemisphere, eventually leading to the ability to speak about the information presented to either side of the brain.
-This suggests that perhaps localisation is not fixed and that the brain can adapt following damage to certain areas.

Question 18

Hemispheric lateralisation

Answer 18

Hemispheres of the brain are not the same

Question 19

Split-brain research: Sperry

Answer 19

-Research on people who’ve had their brains split in half – severing the corpus callosum due to epilepsy
-Corpus callosum allows both areas of brain to communicate with each other
-11 patients (small sample)
-Asked participants to look at picture of naked man
-They laughed as they knew it was funny photo but could not say what it actually was
-Right hemisphere couldn’t tell left hemisphere what its seen
-Men couldn’t therefore say what they’ve seen as left hemisphere isn’t receiving the information and this hemisphere is to do with language production

Question 20

Lateralisation

Answer 20

The idea that the two halves of the brain are functionally different and that each hemisphere has functional specialisations

Question 21

Brain plasticity

Answer 21

Refers to the brains ability to change and adapt because of past experience or trauma.

Question 22

Plasticity in infancy

Answer 22

During infancy, the brain experience a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 by the age of 2-3 years old. Twice as much as adults

Question 23

Synaptic connections/Neural pathways

Answer 23

Each time you learn something new, synaptic connections and neural pathways are formed. The less you use a neural pathway the weaker it gets. It eventually gets deleted known as synaptic pruning. This demonstrates how the brain is constantly changing and how we learn and forget.

Question 24

Maguire et al (2000)

Answer 24

-London taxi drivers have to memorise the streets of London and the streets just outside London to pass the test and officially become a Black Cabbie
-This demands good long term memory and spatial reasoning
-In brain scans of 16 Cabbies they showed a large posterior hippocampus showing that the brain adapts when we learn more
-The longer they were taxi drivers the more grey matter they had (size)

Question 25

Draganski (2006)

Answer 25

-Investigated medical students revising for
exams.
-Students were given periodical MRI scans.
-They found during intense periods of revision and exams the grey matter increased significantly, having a larger parietal cortex and hippocampus.
-Three months later no further structural changes were seen.

Question 26

Functional recovery

Answer 26

Functional recovery is the transfer of functions from a damaged area of the brain after trauma to other undismayed areas.

Question 27

Biological Rythms

Answer 27

-They are cyclical patterns within biological systems that have evolved in response to environmental influences, e.g. day and night
3 types: Circadian, Infradian and Ultradian

Question 28

Circadian rhythm

Answer 28

-24 hour rhythm
-AKA the body clock
-Example = the sleep wake cycle, last over 24 hours with around 16 of being awake and 8 of being asleep
-Repeated every day

SIFFRE
-2 months in cave without any exogenous zietgabers (no way to tell time)
-When he came out it was a month earlier than the 2 months. He thought he was in there longer than he actually was

Question 29

Infradian rhythm

Answer 29

-Lasts longer than 24 hours and can be weekly, monthly or annually
-A monthly Infradian rhythm is the female menstrual cycle, regulated by hormones that either promote ovulation or stimulate the uterus for fertilisation

Case study
-Women with irregular menstruated cycles
-Got pheromone from womens sweat by cotton bud
-It’s then treated with alcohol and frozen then put on upper lip of other participant
-68% of women’s cycle became more similar to their donors
-Pheromones acted as exogenous zeitgebers

Question 30

Ultradian Rhythms

Answer 30

-Lasts less than 24 hours
-Example = pattern of human sleep
-5 stages to the pattern of sleep
-Stage 1- Light sleep, muscle activity slows down, occasional muscle twitching
-Stage 2- Breathing pattern and heart rate slows, slight decrease in body temperature
-Stage 3- Deep sleep begins, brain begins to generate slow delta waves
-Stage 4- Very deep sleep, rhythmic breathing, limited muscle activity, brain produces delta waves
-Stage 5- Rapid eye movement, brainwaves speed up and dreaming occurs, muscles relax and heart rate increases, breathing is rapid and shallow

Question 31

Endogenous pacemakers

Answer 31

-Internal mechanisms that govern biological rhythms, in particular the circadian sleep wake cycle
-Light provides primary input to the system
-Detected by the eye which sends message to the SCN
-SCN then uses the information to coordinate the activity of the entire circadian system
-Sleeping and wakefulness are not determined by the circadian rhythm alone, but also by homeostatsis

Question 32

Exogenous Zeitgebers

Answer 32

-External mechanisms that govern biological rhythms, in particular the circadian sleep/wake cycle
-Social cues such as meal times and social activities, but the most important zeitgeber is light, which is responsible for resetting the body clock each day, keeping it on a 24 hour cycle

Question 33

Ways of investigating the brain

Answer 33

1. FMRI
2. POST MORTEM
3. EEG
4. ERP

Question 34

FMRI

Answer 34

-Brain scan in a chamber, scan for blood flow oxygenated activity in area

Strengths
-Good spatial resolution
-Scientific
-Non invasive
Weaknesses
-Lacks temporal resolution
-Ppl with claustrophobia may struggle

Question 35

POST MORTEM

Answer 35

-Analysis of brain in deceased patient

Strengths
-Determine what irregularities/damage causes behaviour e.g. TAN allowed us to see where language was produced (Brochas area)

Weaknesses
-Damage may be caused in death or the cause of death meaning results can’t be generalised

Question 36

EEG

Answer 36

-Electrical activity is measured by placing electrodes on scalp

Strengths
-Good temporal resolution (quick to complete)
-Cheaper than other methods

Weaknesses
-Poor spatial resolution (can’t pinpoint exact locations)