Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
|
What is a pathway?
|
A chain of connected neurons carrying the same signal (e.g. spinothalamic pathway)
|
|
|
How many cranial nerves are there?
|
12 pairs
|
|
|
How many spinal nerves are there?
|
33 pairs (Cervical= 8, Thoraic= 12, Lumbar= 8, Sacral= 5)
|
|
|
What is the corpus collosum?
|
a bridge that links cortex of two cerebral hemispheres
|
|
|
What happens if the corpus collosum is cut?
|
Individual can only name object if holding in RIGHT hand as information goes to LEFT side of brain- same side as brain as broca's area so does not have to cross to other side of brain. (sperry)
|
|
|
The dorsal root carries what type of information?
|
Sensory (afferent)
|
|
|
The ventral root carries what type of information?
|
Motor (efferent)
|
|
|
Where do most cranial nerves emerge from?
|
The brain stem
|
|
|
What part of the eye contains photoreceptors?
|
The retina
|
|
|
What do photoreceptors do?
|
Convert light energy to membrane potential
|
|
|
What type of cell links photoreceptors to ganglion cells?
|
Bipolar cells
|
|
|
retinal ganglion cells meet to form what?
|
the optic nerve
|
|
|
There are two types of photoreceptor what are these?
|
Rod and cone
|
|
|
What type of photoreceptor is more sensitive and what does this mean for its use?
|
Rods are more sensitive so work better in low light conditions (if too bright will be fully saturated and therefore could not provide any useful information)- Rods are 1000 x more sensitive than cones
|
|
|
What type of photoreceptor is less sensitive and what does this mean for their function?
|
Cones are less sensitive which means they are optimally operated in daylight
|
|
|
Where are cones concentrated?
|
At the fovea
|
|
|
Where are rods concentrated?
|
around peripheral regions
|
|
|
What type of photoreceptor converges on ganglion cells?
|
Rods- gives larger DOTS- greater sensitivity but reduced resolution
|
|
|
What type of photoreceptor displays one to one connectivity?
|
Cones- fine dots- less sensitive but better resolution
|
|
|
How many types of cones are there and how do they differ?
|
There are 3 types of cones- each is maximally sensitive to a different wave length; Blue (430), Green (530) and Red (560)
|
|
|
What is special about the three types of cones?
|
They can make any colour - trichromacy theory- relative activation of each
|
|
|
What can test for colour blindness?
|
Ishihara's cards
|
|
|
What do M type cells (10%) respond to?
|
Dark border passing across its receptive field (centre and surround)
|
|
|
How many types of retinal ganglion cells are there?
|
2 ( M- type and P-type)
|
|
|
The ganglion receptive field has two parts which work in different ways, tell me about this?
|
The ganglion receptive field is made up of centre and surround- the surround inhibits activation while the centre excites.
|
|
|
What are M type cells sensitive to?
|
White light (contrast of- not absolute luminance)
|
|
|
How to P type cells (90%) work?
|
Light of one wavelength is cancelled by another wavelength in the surround ( work in colour pairs) e.g. Red (centre) = ON, Green (surround) = OFF
|
|
|
What are the colour pars that cancel each other in P type cells?
|
red-green and blue-yellow
|
|
|
Where do the optic nerves of each eye connect?
|
at the optic chasm
|
|
|
Fibres from both eyes cross- what is this called?
|
partial decussation
|
|
|
What does the right side of the eye focus on?
|
The left visual hemifield
|
|
|
Where do the visual tracts project to?
|
The lateral geniculate nucleus (LGN) of the thalamus
|
|
|
Where does information from the left visual hemifield go?
|
the right side of the brain
|
|
|
Where does information from the right visual hemifield go?
|
the left side of the brain
|
|
|
How many layers does the lateral geniculate nucleus (LGN) have?
|
6 ( M type cells and P type cells project to different layers)
|
|
|
What layers of the lateral geniculate nucleus do M type cells project to?
|
Layers 1 & 2 - the magnocellular layers
|
|
|
What laters of the lateral geniculate nucleus do P type cells project to?
|
Layers 3 - 6 ( the parvocellular layers)
|
|
|
The layers of the lateral geniculate nucleus are divided into two overall types- what are these?
|
magnocellular and parvocellular (MAGNO AND PARVO)
|
|
|
layers 1 and 2 are what type of cell layer?
|
Magnocellular
|
|
|
layers 3 - 6 are what kind of cell layer?
|
Parvocellular
|
|
|
The separation of M type cell information from P type cell information means what?
|
information about contrast is kept separate from information about colour
|
|
|
How does information get to the primary visual cortex?
|
thalamic relay neurons from LGN terminate in level IV of primary visual cortex
|
|
|
What would a lesion of V5 (of the primary visual cortex) cause?
|
Akinetopsia. As V5 is specialised for motion analysis a lesion here would mean a patient would not be able to see moving objects
|
|
|
What would a lesions of V4 of the primary visual cortex cause?
|
Achromotopsia. As V4 is specialised for colour vision- a patient with a lesion here would only see in shades of grey
|
