Awesome brain - core principles to new therapies Flashcards
What are some factors to neuronal disorders in the CNS?
Neurons are sensitive to a lack of O2 (3 mins to death) and toxic aggregate proteins
Prone to ‘degenerative process’
Poor regenerative powers
1/6 people affected by near disorder in UK, massive problem, high morbidity. but lack of effective treatments
Describe a neuron
multiple inputs at dendrites to cell body and nucleus, 1 axon that is the single output
What happens in the grey matter?
Processing occurs in the gray matter - there’s collections of neurons, synapses and processes in here
What happens in the white matter?
Communication occurs in the white matter - collections of nerve fibres surrounded by myelin sheaths. Connects motor cortex with spinal cord
What does the CNS do?
CNS takes in sensory info from the world via the PNS, processes and learns formulating a response which again is delivered via the PNS
How do we describe the direction/ location of the CNS?
Rostral caudal (nose to tail) axis with ventral and dorsal
What key characteristics would you see in a CT of the midbrain?
aqueduct in the middle at the top of image and two bulges which are the peduncles at the bottom of the image
What key characteristics would you see in a CT of the upper medulla?
IV ventricle at top of image, 4 bulges at bottoms, described as 2 olives and 2 pyramids
What key characteristics would you see in a CT of the pons?
IV ventricle at top image, 2 budges on either side, one central bulge at bottom of image and middle cerebellar peduncles
What key characteristics would you see in a CT of the lower medulla?
Nothing special just looks like a circle
What is the order of parts in brain stem so far?
Mid brain, Pons, Upper medullar, lower medulla
Why are functions in specialised regions of the brain?
Functions of the brain such as movement, sensation, vision, memory are in specialised regions of the CNS in the grey matter. This is known as localised function
This is much more efficient than spreading out these functions for each muscle group etc as we would need lots more connections and space for our CNS.
The regions must communicate to work effectively and so white matter pathways are important in neurology, ee.g region communicates with spinal cord
Why are the locations of functions in the brain important to know?
Knowing the locations of functions and pathways between key areas allows us to be able to locate disease/lesions.
If a stroke occurs at the level of the internal capsule in the brain what would you expect to see?
if it happened at the level of the internal capsule in the brain you would get paralysis due to interruption of corticospinal tract and/or rigid and hyperflexic as this is an upper motor neuron lesion and the inhibitory pathway and plasticity has been interrupted in the spinal cord.
If a stroke occurs at the level of the lower brainstem what would you expect to see?
Paralysis or flaccid - inhibitory pathways intact
extremely rare
How does the movement system - normal basal ganglia loop work?
The basal ganglia listens to the cortex planning, feedback appropriate actions via the thalamus (thalamus is constitutively active and basal ganglia inhibits).
How does the movement system - normal basal ganglia loop work in those with Parkinson’s?
There is a lesion in the basal ganglia that leads to inappropriate/excessive information transfer to the thalamus. Too much and abnormal patterns of activity (burst and oscillations) - basal ganglia puts the brakes on the thalamus
Inhibited and distorted thalamus affects the cortex by paucity of movement, increased tone and tremor
Without dopamine being produced, the basal ganglia is excessive and abnormal patterns of activity occurs and it blocks the thalamus output to cortex which explains the low amount of movement in Parkinson’s.
