cerebral cortex

Question 1

types of fibres in cerebral white matter

Answer 1

association fibres- connect areas in same hemisphere commisural fibres- connect left to right hemisphere eg corpus callosum projection fibres- cortex to lower brain structures eg brainstem, spinal cord eg corticospinal tract

Question 2

layers of grey matter

Answer 2

layer 1 acellular, 2-3 cortico-cortical connections, layer 4 input from halamus (2-4 mainly stellate), layer 5-6 connections with brainstem/spinal cord ie output- mainly pyramidal (layer 5 has upepr motor neurones called Betz cells)

Question 3

organisation of cortex

Answer 3

cortex arranged in layers as well as COLUMNS- neurons with similar properties are in same column

Question 4

how is neocortex (cerebral cortex) divided DIAGRAM

Answer 4

into primary cortices (eg primary motor cortex, visual etc)- whose functions are predictable, and organised topographically also into association cortices (prefrontal association area- character, behaviour, decision making, motor association area, sensory association area, and visual/auditory association areas), whose function NOT predictable, NOT organised topographically

Question 5

testing function of brain

Answer 5

fMRI, ERP, PET, SPECT and lesions analyse entire brain, microscope and extracellular/intracellular recording look at brain in more detail

Question 6

visual association cortex DIAGRAM

Answer 6

important for interpreting info going to primary visual cortex, dorsal stream goes to parietal lobe for the WHERE pathway (where in space), venteal steam goes towards temporal lobe for WHAT pathway (identification, colour)

Question 7

lesion of visual association areas

Answer 7

inability to recognise familiar faces- PROSOPAGNOSIA

Question 8

frontal cortex lesions

Answer 8

lack of decision making, aggressive, sexually inappropriate as well as damage to voluntary movements

damage to brochas area in motor assciation area- can’t say stuff (but can understand)

Question 9

parietal cortex lesions DIAGRAM

Answer 9

association area creates spatial map of where you area- can lead to disorientation (getting lost), hemispatial neglet (unaware of contralateral side ie damage to right parietal lobe= left side not processed- see diagram)

Question 10

temporal cortex lesions

Answer 10

where hippocampus is- leads to issues with MEMORY

wernickes area damange- can speak but NOT understand

problems with auditory cortex

Question 11

split brain

Answer 11

can occur when corpus callosum removed, hence hemispheres can’t communicate with each other - thus if person sees word FACE, he can able to draw it, but can’t SAY what he saw, as left side for drawing, right more for speaking- due to HEMISPHERIC SPECIALISATION

Question 12

tractography

Answer 12

looks at connection between different white matter tracts using water diffusion

Question 13

transcranial magnetic stimulation vs transcranial direct current stimulation+ which helps with motion sickness

Answer 13

certain areas of brain can be stimulated by causing neuronal firing using this method or inhibited, to determine what function that area has vs INCREASE/DECREASE in firing of that area (helps with motion sickness)

Question 14

PET scanning vs fMRI

Answer 14

put a ligand into brain and certain areas light up eg in parkisons, areas where dopamine metabolism should occur doesn’t light up- looks at blood FLOW changes (not oxygen) vs looking at soft issue, dependent on changes of blood OXYGEN

Question 15

MEG/EEG

Answer 15

uses magnetic fields vs electric currents