Cortical Organisation and function Flashcards
How is the brain microscopically organised (two words)
Layers and Columns
What numbers of the Brodmann’s classification do the primary motor cortex and the primary somatosensory cortex encompass?
Somatosensory - 1,2,3 // Motor Cortex - 4
What are the 4 functions of the frontal lobe?
CALM - Cognition, Attention, Language, Memory
What are the 4 functions of the parietal lobe?
SSSS - sensation, sensory parts of language, spatial orientation, self-perception
What is the function of the occipital lobe?
Visual information processing
What are the 3 functions of the temporal lobe?
AME - auditory information processing, memories, emotions
What 4 structures are included in the limbic lobe?
Amygdala, Cingulate Gyrus, Hippocampus, Mamillary Body
What are the 5 functions associated with the limbic lobe?
learning, motivation, emotion, memory, reward
What are the 5 functions associated with the insular cortex
Visceral sensations (thirst & hunger),
Autonomic control,
Interoception (internal sensation - heartbeat),
Auditory processing,
Visual-vestibular integration
What are the two components of the internal cerebral cortex structure?
Grey matter (outside) - neuron bodies and glial cells,
White matter (inside) - myelinated neuron axons
What are the three types of fibres that connect the white matter and which structures do they connect
Association fibres - same side of brain,
Commissural fibres - homologous structures in left and right,
Projection fibres - cortex with thalamus, brainstem, spinal cord
What are the two types of fibres in the association fibres?
Short and Long fibres
What are 4 examples of association fibres?
Superior Longitudinal Fasciculus (frontal & occipital) //
Inferior Longitudinal Fasciculus (temporal & occipital) //
Arcuate Fasciculus (frontal and temporal) //
Uncinate Fasciculus - anterior frontal and temporal //// longitudinal goes to occipital, other two are frontal temporal
What are the two types of commissural fibres?
Corpus callosum,
Anterior commissure
When would the corpus callosum be severed?
To prevent severe epilepsy from travelling from one side to another
What are the two classifications for projection fibres by direction?
Afferent - towards cortex,
Efferent - away from cortex
What are a specific group of projection fibres?
Corona Radiata
radiate deep to the cortex
Where is the corona radiata found?
Internal capsule (between thalamus and basal ganglia)
How is the localisation of function different between primary cortices and secondary/association cortices?
Primary - predictable, topographical organisation, L-R symmetry.
Vice versa for secondary/association
What movements do the primary motor cortex control?
Fine, discrete, precise voluntary movements
What movements do the supplementary area control?
Complex internally cued movements - rising from chair
What movements does the premotor area control?
Planning movements (external) - respond to environment (Premotor - pre-motor actions)
What does the primary somatosensory area do?
Processes somatic sensations - fine touch, vibration, two-point discrimination, proprioception, pain, temperature
What does the somatosensory association do?
Significance of sensory information - recognising context
What does the primary visual do?
Processes visual information
What does the visual association do?
Meaning and interpretation to visual input
What does the primary auditory do?
Processes auditory information
What does the auditory association do?
Meaning and interpretation to audio input
What does the prefrontal cortex association do?
PAPAD - personality, attention, planning, adjusting social behaviour, decision making
What does Broca’s area do, and the effect of a lesion?
Production of language, expressive aphasia
What does Wernicke’s area do, and the effect of a lesion?
Comprehension of language, receptive aphasia
How are the Broca and Wernicke areas connected?
arcuate fasciculus
What is the effect of a parietal lobe lesion?
contralateral neglect - lack of awareness on contralateral side - cannot see other side etc.
e.g. doesn’t eat from left side/ shave/ wear clothes
What is the effect of a frontal lobe lesion?
Changes in personality, inappropriate behaviour
can be due to stroke and restriction of blood flow
What are the two effects of a temporal lobe lesion?
Agnosia (cannot recognise) -lateral
Anterograde Amnesia (cannot form new memories) -medial
How is the cerebral cortex damaged?
usually due to restriction of blood flow, stroke.
Transient ischaemic attack is when there is no irreversible damage. (temporary blockage)
What is the effect of a primary visual cortex lesion?
Blindness in that part of visual field
What is the effect of a lesion in visual association area?
Hard to interpret visual information - prosopagnosia (face blindness)
Three main arteries that supply the brain
Anterior, middle, posterior cerebral artery.
What two imaging scans are used for the lobes, and what for?
PET (blood flow to brain region), helpful for research
functional MRI (blood oxygen in brain region)
How would you assess electrical and magnetic signals in the brain
Electroencephalography (EEG), used for epilepsy
Magentoencepahlography (MEG)
How do you carry out signalling tests?
Evoked-potentials: place electrodes that release impulse, and detect effect on the nerve
How would you assess functional integrity of neuronal circuits?
Transcranial Magnetic Stimulation - using electromagnetic induction (for MS)
How would you detect firing rates of neurons?
Transcranial Direct Current Stimulation
low direct current over the scalp to increase or decrease neuronal firing rate
What are the two types of imaging to visualise brain connectivity?
Diffusion Tensor Imaging (using water diffusion) and DTI with tractography (to build a 3D reconstruction)
Shows water diffusion of water molecules across neurons
