Principles of Neuroscience Lecture 23 Looking at Brain Function Flashcards
What are cranial nerves?
How can clinicians detect problems with individual cranial nerves?
These are nerves that exit the CNS at brain level, not spinal cord
There are tests for each cranial nerve; we can discriminate and detect exactly where there is a problem
What a the two ways that we can look at brain function?
- Clinical tests
2. Brain imaging technology
What are the two functions of cranial nerves?
Sensory and motor
Describe how the cranial nerves are involved in sensation
Vision Taste Hearing Somatic sensation on face Smell Balance Carotid baroreceptors Vagus nerve
Describe how the cranial nerves are involved with movement
Eye Neck Shoulders Face Mastication Tongue Gut
Describe what specific tests an tell us about cranial nerves
Each nerve has a specific test that can check to make sure everthing is in order with that nerve
Eg. Eye test, gag reflex etc
By looking at vision, what can we infer?
By seeing how vision is affected, we can infer whereabouts the problem in the visual tract has occured
By examining the localisation of facial palsy, what can we determine?
By seeing how much of the facial movement is affected, we can tell where a lesion has occured.
Eg.
Upper motor neurons lesion: only a quadrant of the face will be affected: ipsilateral projection will still be intact
Lower motor neuron lesion: half of the face will be affected
What does the mono synaptic stretch reflex tell the clinician?
If that particular joint is functioning
From which point down is there damage?
What do abnormal gait patterns tell the clinician?
If there is damage to the spinal locomotor pattern generators
What do brain scanning technologies allow a clinician to do?
To looks directly at the brain to see where there may be damage
Describe the process of EEG
Describe the spatial and temporal resolution
Describe the invasiveness
What can this technology show the clinician?
Electrodes are placed on the skull, and the electric potentials are measured
Good temporal resolution
Poor spatial resolution
Non invasive
We can see the brain waves, so we can tell if the person is asleep of awake.
Describe the different brain waves present during sleep and awake
Awake & REM sleep: alpha and beta waves
Low amplitude and high frequency
Asleep: delta waves
High amplitude and low frequency
More synchronous
Describe the process of CT scanning
Describe the spatial and temporal resolution
Describe the invasiveness
What can this technology show the clinician?
A person is put in a machine and X rays are sent through the head
A computer analyses the attenuation through the head
Fairly non invasive, but it uses X rays which are harmful.
We can see large structures or abnormalities such as bleeds or distortion
Describe the process of PET scanning
Describe the spatial and temporal resolution
Describe the invasiveness
What can this technology show the clinician?
Tagged substance administered intra venously
Gamma rays are fired at the head
When the positron and electron collide, a photon is emitted
The computer can detect the origin of the photon, thus the localisation of the substance is detected
Poor temporal and spatial resolution
Quite invasive, because we are using gamma rays
We can see the activity of the brain
