COGS 100 FINAL EXAM STUDY
The neuron has dendrites, axons, a cell body, a myelin sheath, and nodes of ranvier. The dendrites
receive input from axons. The axons take that input and send it out to other dendrites. The cell body
conducts the electricity the neuron needs to send the signal. The myelin sheath insulates the axon so that it
is protected from its surroundings, and is able to send signals faster. The nodes of ranvier allow the nerve
impulses to move along the neuron by de-polarisation and re-polarisation of the nerve membrane.
The brain has four lobes. There is the parietal lobe, which is responsible for the senses of touch.
There is the temporal lobe that is responsible for hearing. Then there is the occipital lobe that works in
vision. And there is the frontal lobe, which does the planning, thinking, and other cognitive processes.
The main functional areas of the cortex are the sensory areas, cortex areas, and association areas.
The sensory areas make you aware of sensation, the association areas give meaning to those sensations,
and the motor areas allow you to act upon that sensation.
The somatosensory and motor areas both have dedicated areas for different body parts. The more
sensitive and intricate a body part is, the more space is allocated for them on the somatosensory and
motor strips. The motor cortex sends output for your body to move, and the sensory cortex deals with the
information you get from touch stimuli.
Retinotopic mapping is the preservation of order on an image as it is being transduced from the
retina to the brain. Different parts of the retina process different parts of the visual field.
When light enters the eye, it passes through the cornea, the aqueous humour, and the pupil before
entering the lens and the large chamber with its vitreous humour. It then goes through the retina. After the
retina, the photoreceptors (rods and cones) then convert the light into electrochemical signals, which are
transmitted to the brain via the optic nerves. Each optic nerve is a bundle of long axon fibers of the
ganglion cells in the retina. These axons make contact with the neurons of the LGN in the thalamus. From
there, the axons of the LGN neurons send the signals up to the primary visual cortex.
Cornea>aqueous humour>pupil>lens>vitreous humour>retina>photoreceptors>electrochemical
signals>optic nerve>LGN in thalamus> primary visual cortex
A typical receptive field of a retinal neuron is donut shaped. It has a centre-surround field. This is
where the stimulation of the centre has an antagonistic effect to the stimulation of the surround. The
receptive field may be “on-centre” or “off-centre.” These are measured in intensity. For on-centre, if light
hits the centre of the field, there is an intense response. If it hits the surround, there is little to no response.
However for off-centre, it is the opposite. Light that hits the centre of the field give little to no response,
but light that hits the surround gives an intense response.
Magno-cellular neurons are larger neurons, and have longer dendrites. Parvo-cellular neurons are
smaller neurons, and have shorter dendrites. Magno-cellular neurons deal with your periphery. They
respond to movement and work very fast. However, parvo-cellular neurons are more focused on the
centre of your vision. They enable you to discriminate patterns, structures, colours, details, and space.
They also work at a slower rate than magno-cellular neurons do.
The dorsal stream is at the back of the brain; the parietal lobe. It is the “where” pathway, or now
more known as our vision for action (action being something like hand-eye coordination. It tells us the
locations of our surroundings. The ventral stream is at the belly of the brain; the temporal lobe. It is the
“what” pathway, now more known as our vision for identification. It identifies the things in our
environment. For example, when I look at my hand, I know I’m holding a pencil because of this stream.
Scientists know they are distinct because they studies brain-damaged patients. They observed that
when patients had damages dorsal streams, they had difficulties locating things. And when patients had
their ventral streams damaged, they had problems identifying things. COGS 100 FINAL EXAM STUDY
Chomsky’s look at the theory of grammar as a theory of mind is related because Chomsky looks
at them both like they’re Turing Machines. He thinks that language can mechanically be explained, and so
can the human mind. For him, they both operate algorithmically.
By calling his theory of grammar a computational theory, he means that language is “computed.”
He uses the theory of transformational grammar to explain this. There are rules (algorithms) to make a
deep structure of a sentence. Then there are transformational rule