Term
| Describe the cerebral cortex |
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Definition
- The ‘seat of consciousness’ and higher brain functions.
- Layer of grey matter that covers the entire cerebrum – approximately 1.5-2m2.
- Very large in humans – approximately 1010 neurones. |
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Term
| How is the cerebrum split? |
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Definition
| The cerebrum is the rostral-most and largest part of the brain. It is clearly split down the middle into two cerebral hemispheres, separated by the deep sagittal fissure. |
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Term
| What is the right cerebral hemisphere concerned with? |
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Definition
| the right cerebral hemisphere receives sensations from, and controls movements of, the left side of the body |
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Term
| What is the left cerebral hemisphere concerned with? |
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Definition
| with sensations and movements on the right side of the body |
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Term
| How are cerebral hemispheres connected? |
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Definition
Corpus callosum: massive white area full of axons
Anterior commissure: connects the temporal lobes |
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Term
| What techniques are used to study the cerebral cortex? |
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Definition
- Staining techniques: e.g. Nissl staining.
- Lesion studies |
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Term
| What lesions studies have been used? (4) |
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Definition
- experimental animals – lesion parts of the cortex (cut bits out) and see effect on behaviour.
- Humans – examine behaviour after pathology, surgery and/or accidents.
- Electrophysiology: electroencephalogram (EEG), electrical stimulation on surface of brain (Penfield).
- Imaging studies: non-functional (CT and MRI scans) and functional (PET and fMRI) imaging |
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Term
| Which cortex type is the most common and how many layers does it have? |
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Definition
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Term
| How many layers does the hippocampus have? |
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Definition
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Term
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Definition
regions of the cerebral cortex defined by its cytoarchitecture that can be analysed histologically based on laminar distribution
50 areas |
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Term
| For example, describe areas that receive sensory input |
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Definition
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Term
| For example, describe areas that send out motor input |
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Definition
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Term
| Which Brodmann areas are associated with somatosensory sensation? |
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Definition
| 1, 2, 3 (post-central gyrus) |
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Term
| Which Brodmann areas are associated with fine motor control? |
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Definition
| 4 - primary motor cortex (pre-central gyrus) |
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Term
| Which Brodmann areas are associated with conscious visual sensation? |
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Definition
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Term
| Which Brodmann areas are associated with auditory sensation? |
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Definition
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Term
| Which Brodmann areas are associated with speech production? |
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Definition
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Term
| Describe the cells in lamina I |
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Definition
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Term
| Describe the cells in lamina II and III |
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Definition
| small pyramidal cells (project to other cortical areas). |
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Term
| Describe the cells in lamina IV |
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Definition
| stellate cells (receive from thalamus). |
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Term
| Describe the cells in lamina V |
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Definition
| large pyramidal cells (output cells) |
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Term
| Describe the cells in lamina VI |
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Definition
| pyramidal cells (project to thalamus) |
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Term
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Definition
- Triangular-shaped cell body (soma)
- Single axon.
- Large apical dendrite.
- Multiple basal dendrites.
- Presence of dendritic spines.
- Have conical or pyramidal shaped cell bodies
- Found mainly in layers III, V, and VI. |
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Term
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Definition
- have star-shaped cell bodies.
- Layer IV is rich in stellate neurones.
- Mainly glutamatergic (excitatory).
- receive input from the thalamus |
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Term
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Definition
- can innervate different layers or be confined to a single layer.
- Are inhibitory GABAergic neurones and can brake responses
- Multipolar with free-branching dendrites. |
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Term
| Describe the cerebral cortex |
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Definition
- The ‘seat of consciousness’ and higher brain functions.
- Layer of grey matter that covers the entire cerebrum – approximately 1.5-2m2.
- Very large in humans – approximately 1010 neurones. |
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Term
| Where does the thalamus input? |
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Definition
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Term
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Definition
| Broca encountered a patient who could understand language but could not speak. Broca found a lesion in the left frontal lobe therefore he knew that lesion was associated with the inability to speak. |
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Term
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Definition
| measures electrical activity of large groups of neurones in the cortex |
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Term
| What does ECG activity frequency depend on? |
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Definition
behavioural state
therefore differences in epilepsy, coma and sleep can be seen |
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Term
| What are the 'rhythms' or waves categorised by? |
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Definition
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Term
| Name the 4 waves from fastest to slowest |
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Definition
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Term
| What frequency are delta waves and what are they associated with? |
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Definition
- anything smaller than 4Hz.
- these are often large in amplitude
- characteristic of deep sleep |
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Term
| What frequency are theta waves and what are they associated with? |
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Definition
- these are about 4-7Hz
- and occur during (some) sleep states. |
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Term
| What frequency are alpha waves and what are they associated with? |
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Definition
- 8-13Hz
- associated with quiet, relaxed, waking states. |
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Term
| What frequency are beta waves and what are they associated with? |
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Definition
anything greater than 14Hz.
They signal an activated cortex (mental activity) |
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Term
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Definition
| activity not of the cerebral cortex. Blink artefacts are as a result of the eyes blinking. |
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Term
| How can the activity of one neurone be measured? |
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Definition
- Tungsten mini electrode/multiunit array is placed into cortex
- observe how activity changes with a stimulus/cognitive break |
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Term
| Name 2 non-functional imaging techniques and what they are used for |
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Definition
CT and MRI
Non-invasive technique to detect structural changes in brain (tumour/shrinkage/swelling) |
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Term
| How does CT imaging work? |
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Definition
| - uses computer-processed X-rays to produce tomographic images or 'slices' of specific areas of the body |
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Term
| What is the downside of CT imaging? |
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Definition
| the subject is exposed to high energy radiation that can cause cancer. |
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Term
| How does MRI imaging work? |
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Definition
| - uses strong magnetic fields and radio waves to produce images based on the hydrogen content (water) of body tissues |
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Term
| What is the downside of MRI imaging? |
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Definition
none
good images and no radiation |
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Term
| Name 2 functional imaging techniques |
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Definition
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Term
| What do functional imaging techniques detect? |
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Definition
| changes in blood metabolism and blood flow as active neurones need more glucose and oxygen - a radioactive glucose can be used |
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Term
| What are the association cortices? |
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Definition
occupies 75% of the brain
integrates information received from other brain areas and plans appropriate responses |
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Term
| Name the association cortices |
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Definition
1. Parietal association cortex
2. Temporal association cortex
3. Frontal association cortex
4. Occipital association cortex |
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Term
| What are the inputs to the association cortices? |
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Definition
| main input is from cortico-cortical connections. It also has input connections from the primary/secondary sensory and motor cortices. Other association areas in both hemispheres include the thalamus and the brainstem. |
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Term
| What are the outputs of the association cortices? |
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Definition
| hippocampus, basal ganglia/cerebellum, thalamus and other association cortices. |
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Term
| Give a short flow diagram of general connections from cortical areas to association areas |
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Definition
| primary sensory areas > higher order sensory areas > association areas > premotor areas > primary motor areas |
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Term
| What are the roles of the association cortices? |
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Definition
| cognition (the process by which we come to know the world) i.e. ability to attend to external stimuli or internal motivation, identify the significance of such stimuli and plan meaningful response to them. |
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Term
| What are the effects of a lesion to the parietal association cortex? |
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Definition
Lesions lead to deficits of attention e.g. ‘Contralateral Neglect Syndrome’:
- Inability to perceive and attend to objects, or even own body, in part of space.
- Patients deny the existence of the side of the body opposite the lesion.
- Patients do not respond to stimuli presented to side of body opposite the lesion. |
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Term
| What are the effects of a lesion to the temporal association cortex? |
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Definition
| Lesions lead to deficits of recognition |
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Term
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Definition
| also called face blindness, is a disorder of face perception where the ability to recognise faces is impaired, while other aspects of visual processing (e.g. object discrimination) and intellectual functioning (e.g. decision making) remain intact. It is caused by lesions to the temporal lobe. |
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Term
| What are the effects of a lesion to the frontal association cortex? |
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Definition
| cortex is associated with planning, therefore, lesions cause subjects unable to perform tasks. The prefrontal cortex contains ‘planning’ or ‘delay- specific’ neurones. |
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Term
| Define hemispheric lateralisation |
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Definition
| Each of the two cerebral hemispheres is responsible for specific functions that are not ordinarily performed by the opposite hemisphere. |
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Term
| In most people, what is the left area associated with? |
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Definition
- the left hemisphere contains the general interpretive and speech centres and is responsible for language-based skills, e.g. reading, writing and speaking are dependent on processing done in the left cerebral hemisphere.
- the premotor cortex involved with the control of hand movements is larger on the left side of the brain for right-handed individuals than for left-handed ones – ‘kag-handed’.
- The left hemisphere is also important in performing analytical tasks such as mathematical calculations and logical decision-making.
For these reasons it has been called the dominant hemisphere. |
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Term
| In most people, what is the right area associated with? |
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Definition
| The right cerebral hemisphere analyses sensory information and relates the body to the sensory environment. |
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Term
| Where is Broca's area? What do lesions cause? |
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Definition
frontal association area
A person with damage to Broca’s area can make sounds but not words. Some affected individuals have difficulty speaking although they know exactly which words to use; others talk constantly but use all the wrong words and make no sense at all. |
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Term
| Where is Wernicke's area? What do lesions cause? |
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Definition
temporal association cortex
Damage affects the ability to interpret what is seen or heard, even though the
words are understood as individual entities. It also affects your ability to name objects, even though you recognise them. Speech is fluent but makes little sense. |
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Term
| Are areas used for speech/processing the same in bilinguals and monolinguals? |
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Definition
| depends on whether someone is an ‘early’ bilingual or ‘late’ bilingual. |
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Term
| What's the case if you're an 'early' bilingualist? |
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Definition
| speech areas overlap for both languages and are strongly lateralised (only one hemisphere performs this specific function). |
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Term
| What's the case if you're an 'late' bilingualist? |
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Definition
| speech areas don’t overlap and are much less lateralised. |
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