Biopsychology Flashcards
Robert suffered a stroke at the age of 55. After the stroke he was paralysed down his right side, though he could move his left arm and leg easily. Robert could clearly understand what was said to him, but was unable to produce any speech.
Discuss how knowledge of hemispheric lateralisation and language centres in the brain has helped our understanding of cases such as Robert’s.
Refer to Robert’s case in your answer
- different parts of the brain perform different functions
- functions are specific to individual parts of the parts
what two halves is the brain divided into
the left and right hemisphere which are divided by a small gap
what is localised to the left hemisphere
language
what is localised to the right hemisphere
spatial skills
what is hemispheric lateralisation
different sides of the brain perform different functions
Patient tan lost the ability to speak. Based on your knowledge of hemispheric lateralisation, where did Tan have damage
left hemisphere
what is Contralateral organisation
is when the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.
what are both hemispheres of the brain involved in
the 5 senses and controlling our movement
what does contralateral mean
opposite side
what functions are organised contralaterally
vision, movement, touch
how do the right and left hemisphere communicate
communicate by sending nerve impulses to each other using the corpus callosum.
what is the The corpus callosum
a bundle of axons that connect the hemispheres. It acts as a bridge between the two hemispheres
what does it mean if some functions are processes by only one side of the brain
they are hemispherically lateralised
Explain what is meant by contralateral brain organisation
Contra means ‘opposite’, and lateral means ‘side’, so contralateral means that some functions of the brain controls the opposite side of the body. Contralateral brain organisation means that the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.
Which two regions of the brain are involved in the fight or flight response?
Hypothalamus, pituitary gland.
what are split brain patients
patients whose corpus callosum has been cut
what happens when he corpus callosum is cut
the two hemispheres can no longer communicate
what is the procedure used in split brain research study
- patients are sometimes asked to respond to a stimulus that has been presented to them, by pointing at the stimulus that matches the one they were shown
- patients are sometimes asked to describe a stimulus that has been presented to them
what is the method used in split brain research
1) present stimulus to left or right side of brain
2) ask patient to respond to the stimulus
what are the results of split brain research
Sperry’s study:
he concluded that language is hemispherically lateralised to the left hemisphere
patients could match the pictures whether or not it was presented to the right or left hemisphere
In Sperry’s original study, he showed split-brain patients a stimulus, to either their right or left hemisphere. He then later asked patients to point to that same stimulus, when showed a choice of four different ones. Patients could point to the correct image. Explain why this happened.
The ability to visually process and identify the image isn’t hemispherically lateralised. Therefore regardless of which hemisphere the information was presented, the participant had still processed the information and was able to point to the correct stimulus from the choice of four.
When participants were asked to respond verbally to a stimulus, their response depended on which side the information was presented to. Explain why these results occurred in Sperry’s subsequent study.
The ability to say what was processed by the left hemisphere occured because language is hemispherically lateralised to the left hemisphere. If a stimulus is presented to the right hemisphere, a split brain patient is unable to identify or describe it, because language is not processed in the right hemisphere.
What are the limitations of split-brain research?
- the study contains confounding variables
- the study has not been consistently replicated
- the study lacks generalisability
- the participants brains were abnormal
what could Danelli conclude about hemispheric lateralisation from doing a case study on EB
hemispherically lateralised functions can be taken over by the other hemisphere in some conditions
Explain one issue of using patients who have undergone split-brain surgery to study hemispheric lateralisation of normal people’s brains.
Split-brain patients have had the surgery to split their brain because they were experiencing severe seizures. So, it’s possible that these patients’ brains are organised differently to other people’s brains. Therefore this is a confounding variable in the interpretation of the study, because it may actually be their different brains that cause any results rather than their corpus callosum being severed.
what is the cortex
the outer surface of the brain
what does the motor cortex do
controls body movement on the right side of the body
what does the somatosensory cortex do
processes the feeling of touch. the somatosensory cortex in the right hemisphere controls the left side of the body. and the somatosensory cortex in the left hemisphere controls the right side of the body
where is the somatosensory cortex located
behind the motor cortex
how does the auditory cortex process sounds
by receiving nerve impulses or impulses from sensory neurones that talk to sensory receptors in the ears
where is the auditory cortex located
behind and slightly below the somatosensory cortex
what does the auditory cortex do
processes sound. There is an auditory cortex in both hemispheres, but the auditory cortex is not organised contralaterally
where is the visual cortex located
right at the back of the brain
what des the visual cortex do
processes vison. Both hemispheres are involved in processing vison. The visual cortex works by receiving nerve impulses from sensory neurones that talk to sensory receptors in your eyes. Vison is organised contralaterally
where is the brocas area located
below and slightly in front the motor cortex
what is the function of brocas area
involved in producing language, so we can say it is hemispherical lateralised to the left hemisphere
where is the Wernickes area located
behind the auditory cortex
what is the function of wernickes area
- enables us to understand written language
- enables us to understand speech
- hemispherically lateralised to the left hemisphere
what is aphasia
- when people lose the ability to produce language
- when people lose the ability to understand language
what is brocas aphasia
inability to produce language
what is Wernickes aphasia
inability to understand language
Bella was in a terrible car crash and received severe damage throughout the whole cortex of her right hemisphere.
What symptoms would we expect Bella to exhibit?
- Loss of vision to the left of her body.
- Loss of movement to the left half of her body
- Loss of sensation of touch to the left half of her body.
In a conversation, Joseph listens and can understand what people are saying. However, he struggles to express himself verbally. His dad suggested that he writes down what he thinks, or acts it out, but he struggles with this too - his left hand and arm feel like they’re not doing what he wants them to do.
Using the information above, explain what areas of Joseph’s brain might be damaged and why.
Joseph’s Broca’s area could be damaged because he is struggling to create language - he can’t find the right words to express himself. His right motor cortex may also be damaged, because he is struggling to use his left arm and hand, and his right motor cortex controls the left side of his body. Joseph isn’t having any problems with touch sensations, right side of his body or understanding language, so his somatosensory cortex, left motor cortex and Wernicke’s areas seem to be ok.
what are the limitations of localisation of function
- may be over simplified because a complex function often requires more than one brain region/ area
- ignores the importance of communication between brain regions
- it ignores individual differences in brain organisation
what are the criticism of patients tan research
Dronkers found that patient tan had damaged other regions of his brain outside of Brocas area. Dronkers supports the idea that more than one region is responsible for language production
Explain why case studies of patients like Tan support the idea of brain localisation.
Tan displayed difficulties with producing language, and after he had died a post-mortem examination showed damage to his Broca’s area. This suggests that damage to that particular area had caused Tan’s symptoms, supporting that different areas have specific functions.
