Lecture 23- Ways to study brain function Flashcards
How should the brains be studied?
-Neuroscientists are usually seeking reductionist, causal mechanistic explanations of how systems interact to produce system behaviours -key part of neurological diagnosis is to localise the location of damage by examination of site–specific functions
How can one localise the location of brain damage?
-general observations (consciousness, vital signs…) -patient reports -specific functional tests 1. Motor/sensory motor 2.Sensation 3.Cognition
What is 1. Motor /sensory motor functional test to localise brain damage?
-test segmental reflexes (stretch) -test primitive reflexes (Babinksi) -measure strength of muscles, compare the symmetry, see if there is palsy -test balance, posture and gait -cranial nerves (eye movement)
What are segmental reflexes?
-reflexes that go through just one segment of the spinal cord (stretch, clasp knife, cross extension reflex)
What are primitive reflexes?
-reflexes exhibited by babies but not normal adults (due to inhibition from the higher centers) eg. Babinksi sign
What is palsy?
-paralysis involving loss of feeling and uncontrollable movements (shaking)
How is sensation useful as a diagnostic test?
-use pin prick and cotton ball -can determine if Brown Sicard syndrome or any damage in the pain and touch pathways
How do you test cognition to localise brain damage?
-language, orientation and memory tests
What are cranial nerves?
-12 pairs, always left and right of each -rostral to caudal axis -important for clinical diagnosis (determining location of brain damage) -go from the periphery straight to the brain (brainstem, except fro cranial nerve I =olfactory that goes via the olfactory bulb)
What are the two types of cranial nerves?
-sensory and motor (some have autonomic component too)
What is cranial nerve I and what does it do?
-Olfactory nerve, sensory -sense of smell
What is cranial nerve II and what does it do?
-Optic nerve, sensory -vision
What is cranial nerve III and what does it do?
-Oculomotor nerve, motor -eye movements; papillary constriction and accommodation; muscles of eyelid
What is cranial nerve IV and what does it do?
-Trochlear nerve, motor -eye movements
What is cranial nerve V and what does it do?
-Trigeminal nerve, motor and sensory -somatic sensation from face, mouth, cornea; muscles of mastication
What is cranial nerve VI and what does it do?
-Abducens nerve, motor -eye movements
What is cranial nerve VII and what doe sit do?
-Facial nerve, sensory and motor -controls the muscles of facial expression; taste from anterior tongue; lacrimal and salivary glands
What is cranial nerve VIII and what does it do?
-Vestibulocochlear (auditory) nerve, sensory -hearing; sense of balance
What is cranial nerve IX and what does it do?
-Glassopharyngeal nerve, sensory and motor -sensation from pharynx; taste from posterior tongue; carotid baroreceptors
What is cranial nerve X and what does it do?
-Vagus nerve, sensory and motor -autonomic functions of gut; sensation from pharynx; muscles of vocal cords; swallowing
What is cranial nerve XI and what does it do?
-Spinal accessory nerve, motor -shoulder and neck muscles
What is cranial nerve XII and what does it do?
-Hypoglossal nerve, motor -movements of tongue