Cerebral cortex Flashcards
What is the neocortex?
Area of the cerebrum with 6 layers of cells, covering thebulk of the hemispheres.
What are cell types make up the 6 layers of the cortex? What neuronal communication do they provide?
- Cortico-cortical | Neuropil
- Cortico-cortical | Pyramidal cells
- Cortico-cortical | Pyramidal cells
- Thalamic input | Stellate neurones
- Connections to subcortical/brainstem/cord | Pyramidal neurones (axons leave cortex)
- Connections to subcortical/brainstem/cord
How is the cortex arranged vertically?
Dense columns - neurones with similar properties grouped into columns - providing the basic for topographic organisation.
DIagram to show cortical areas and relevant processes.
How do primary and association cortices differ?
Primary - topographical organisation + left/right symmetry.
Association - no topographical organisation. Left/right symmetry absent. Cerebral cortex outside the primary areas.
What are the primary cortices? What areas of the brain are they associated with?
Primary motor (frontal)
Primary somatosensory (parietal)
Visual (occipital)
Auditory (temporal)
Gustatory (taste - temporal)
Olfactory (smell - temporal)
List the association cortices and give their roles.
Motor association (skeletal muscle movement and motor planning)
Sensory association (sensory from skin, MSK, viscera and taste buds)
Visual association (vision)
Auditory association (hearing)
Prefrontal association (coordinates info from other areas and some behaviours/personality)
What are association fibres. What is their role?
short fibres that run between adjacent parts of the cortex - connecting areas within same hemisphere
What are commissural fibres? What is their role?
Connect left to right hemisphere (biggest is corpus callosum, with smaller anterior and posterior pathways)
What is the role of projection fibres?
connect cortex with lower brain structures such as thalamus, stem and cord
Identify association, commisurial and projection fibres.
What is hemispheric specialisation? How do the left/right hemispheres specialise when this occurs?
Split brain lateralised defects.
Left hemisphere - language dominant
Right hemisphere - spacial processing
What parts of the cerebral cortex are linked to speech?
Broca’s and Wernicke’s area.
What is diffusion tensor imaging? explain it.
structural imaging using movement of water molecules in the brain to infer underlying white matter structure and hence pathways/connections - shows integrity of functional pathways
What is transcranial magnetic stimulation? Explain it.
magnetic field used to induce electric current in cortex, causing neurones to fire - can test specific areas for function.
What is transcranial direct current stimulation? Explain it.
neuromodulation via low direct current via electrodes on the head.
Change local neurone excitability to change firing rate. No direct induction of neurones.
What is PET scanning. Explain it.
positron emission tomography - uses radioactive tracer molecules to locate brain areas where particular molecules such as dopamine are being absorbed to the brain - has good spatial resolution and specificity
What is magnetoencephalopgrahy?
measures magnetic fields - mapping brain activity by recording fields produced by natural electrical currents
What is electroencephalography?
electrophysiological monitoring method to record electrical activity - using electrodes placed on scalp or invasive electrodes during neurosurgery
explain fMRI.
functional MRI - measure brain activity by detecting changes associated with blood flow.
(coupled with neurone activation).
List the lobes of the neocortex.
Occipital. Parietal. Temporal. Frontal.
What deficits are associated with damage to each lobe?
Occipital: visual perception
Parietal: disorientation, inability to map read, apraxia, hemispatial neglect
Temporal: agnosia, receptive aphasia
Frontal: planning deficits and inappropriate behaviour
Visual posterior association area: prosopagnosia (cannot recognise or learn new faces)
What is the function of the occipital lobe?
visual association cortex - analyses attributes of visual image,
form/colour along ventral pathway and spatial relationships/movement along dorsal pathway.
What is the role of the parietal lobe?
posterior parietal association cortex - creates spatial map of body in surroundings from many information modalities
What is the role of the temporal lobe?
Language, object recognition, memory, judgement.
What is the role of the frontal lobe?
judgement, foresight, personality, appreciation of self.
