Sensation and Percepton Chapter 4

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Most of the signals from the retina travel out of the eye in the optic nerve to the lateral g_____ nucleus (LGN) in the thalamus. Signals then travel to the primary visual receiving are in the occipital lobe of the cortex. Also called the _____ cortex then signals are transported via two pathways one to the occipital lobe and the other to the parietal lobe.

geniculate, straite
are involved in controlling eye movement and other visual behaviors that recive about 10 percent of the fibers from the optic nerve.
superior colicli
first major area where visual signals are received. / major function is not to create new receptive field but to regulate neural information proerites as it flows from the retina to the visual cortex / 90 of the optic nerve fibers travel here and the other 10 pecent travel to superior colliculus
one LGN on one side of the brain and one LGN on the other. One cross section reveals ___ layers. à each layer only receives signals from one eye
bilateral structure
, 6

Layers 2, 3, and 5 recive signals from the ______ eye (eye on the same side of the body)


Layers 1, 4, and 6 receive signals from the ______ eyeà the eye on the opposite side of the body of the lGN

a map in which each point on the LGN corresponds to a point on the retina
retintopic map
receptive fields side by side (exchitatory and inhibitory)
simple cortical cells

relationship between orientation and firing ( exitaroy field excitatory response)

orientation tuning curve
more than _____ perecent of the cortex responds to visual stimuli

Hubel and weasel found that many cortical neurons respond best to moving _____ stimule (complex cells)

fire to moving lines of specific liength or to moving corners or angles
end stopped cells
simple, complex, and end-stopped cells respond to specific features of a stimulus such as oritentation or direction of movement
feature detectors

respond best to small spots

Optic nerve fiber (ganglion cell)-
center surround receotive fields very similar to the ganglion cell
Lateral geniculate
reponds best to bars of particular orientation
simple cortical
respond est to a particular direction of movement to the bar
complex cortical
responds to corners, angles, or bars of a particular length moving in a particular length
end stopped cortical
if neurons fire long enough, they become fatigued or adapt
selective adaptation
selective adaptation causes what two effects
1) nueorns firing rate decreases 2) neurons fire less when that stimulus is immediately presented again

Example: presenting a vertical line causes neurons that respond to vertical lines to respond, but as these presentations continue, these neurons will eventually begin to fire less to vertical lines

selective adaptation

If these adapted neurons have anything to do with perception then adaptation of neurons that respond to vertical should result in perceptual effect of becoming less sensitive to verticals but not to other orientations.

selective adaptation
measured through grating stimuli and constant threshold
selective adaptation
are alternating bars
rating stimuli
the difference in intensity at which the bars can just barely be seen
onstant threshold

if an animal is reared in an environment that contain sonly certain types of stimuli, the neurons that respond to these stimuli will become more prevalent

selective rearing
the idea that response properties of neurons can be shaped by perceptual experience Example: raising a cat in an environment that contains only vertical lines should result in the animals visual system having neurons that respond predominantlely to vertical lines / “Use it or lose it”
Neural plasticity/experience-dependent plasticity

In the Blakemore and Cooper experiment with the kitten reared in the vertical line enviroement has many neurons that respond to vertical lines but almost none that respond to _______ lines

indicates that information about objects near each other in the environment is processed by neurons near each other in the eniviroment
reintopic mapping
The fovea only accounts for 0.01 percent of the retinas area, signals from the fovea account from to 10 percent of the reintoptopic map on the cortex this is called
cortical magnefication factor
person is injected with a small dose of a radioactive tracer that enters the blood stream and indicates the volume of blood flow. Basic idea is that activity in the brain are accompanied by changes in blood flow and monitoring the radioactivity of the injected tracer provides a measure of this blood flow.
allowed researchers to track changes in blood flow to determine which areas of the brain are being activated. To use this tool researchers developed the subtraction technique.

) an intial condition before the stimulus of interest is presented 2) test condition in which the stimulus of interest is presented

Example: intial condition would be when an individual is holding an object in their hand the test condition would be when the individual is manipulating the object

Then you subtract the activity record in the intial condition from the activity in the test condition to indicate the brain activation connected with manipulating the object

Functional magnetic resonane imaging (fMRI)- based on the measurement of blood flow because hemoglobin which carries oxygen in the blood contains a ferrous molecule and therefore has magnetic properties presenting a magnetic field to the brain causes the hemoglobin molecules to line up like tiny magnets.

subtraction techique
the receptive fields of neurons 1, 2, 3, and 4 are all located about the same place on the reina / all neurons within a location column have their receptive fields at the same location as on the retina
location columns
each column containg cells that respond best to a particular orientation
orientation columns
most neurons respond better to one eye than the other and neurons with the same ocular dominance are organized into ocular dominance columns in the cortex
ocular dominance columns
hubel and wesel proposed that all three types of columns could be combined into one larger unit called a hypercolumn (ice cube model) / they thought of it as a processing module thay processing information about any stimulus that falls within the location of the retina served by the hyercolumn. The hypercolumn has every kind of orientation column so what stimulus falls on it it is activated.
the cortical representation of stimulus does not have to resemble the stimulus; it just has to conatin information hat ______ the stimulus.
transmit information from the striate cortex to other areas in the brain / introduced in 1982 by Ungerleider and Mishkin (used a technique called ‘ablation’ to study this / described two different streams with two different functions
the destruction or removal of tissue in the nervous system / it can be physically removed or chemically.
Underleider and MIshkin used ______ in the experiment because their visual system is the most closely similar to humans.

first the area of the brain in interest is measured then destroyed. Then, the monkey is restrained to determine which perceptual capacities remain

-The monkeys were presented with two tasks 1) ______ discrimination 2) ______ discrimination problem

object and landmark

a monkey was shown one object “a rectangle solid” then presented with a two choice task “the rectangle object and a triangle shape object”

object discrimination
the monkeys task was to remove the food well cover that was closest to the small cylinder
landmark discrimination
one ablation the temporal lobe (____ discrimination problem) was removed and the other the parietal lobe (_____ discrimination problem) was removed.
object and landmark

-the temporal lobe is responsible for the objects identity the “_____ pathway”

-parietal lobe is reposbile for the “where” making it the “____ pathway”

what and where
the what and where pathways were also called the dorsal (_____) and ventral (_____) pathways
what and where
they found properties of the dorsal and ventral streams are established by two types of ganglion cells in the retina which transmit signals to different areas of the LGN. Thus, the cortical dorsal and ventral streams can actually can actually be traced back to the _____ and _____
retina and LGN
the “backward” flow of information provides information from the higher centers that can influence the signals flowing from the systems.

Milner and Goodale suggested rather than the pathways be called the “what” and “where” they should be called the “_____” and “____”

what and how

the ventral stream they argue is for perceiving objects

-they propose the dorsal stream is for taking _____ such as picking up an object taking this action would involve knowing knowing the location of the object but it also involves a physical interaction with the object

the most dramatic evidence supporting the idea of a dorsal “action” stream comes from “________” – the study of the behavioral effects of brain damage in humans

Brain damage is studied via _____ and _______dissociation – theses are instances when one function is present while the other is not

single and double
the two small lines inside titled squares appeared slighted tiltied in opposite directions even though they are parallel vertical lines
rod and frame illusion

-Dyde and Milner presented the observers with two tasks- a matching task and a grasping task

-observers adjusted the ______ stimulus , a rod located in an upright square until it appeared to match the orientaition of the vertical rod in the tilted square

-the _____ task—observers grasped a rod in the titled square between their thumb and forefinger.

matching and grasping
a structure that is specialized to process information about a particular type of stimulus (there is a great deal of evidence that there are specific areas in the temporal lobe that respond best to specific types of stimuli

Rolls and Tovee measured the response of monkeys _______ cortex—when they presented faces and pictures of non-face stimilu the neurons fired bect to faces.


Kanwisher first used ______ to determine brain acitivity in reposnse to pictures of faces and other objects

-they found ________ (FFA) which is located in the fusiform gyrus on the underside of the brain directly below the IT cortexà they interpreted that the FFA is specialized to respond to faces

fmri and fusiform face area

Damage to the speicialized perception are for faces causes _________-difficulty recognizing the faces of other people

is activated by pictures depicted indoor and outdoor scenes
parahippocampal place area (PPA)
activated by pictures of body but not parts of bodies
extrastriate body area (EBA)
genetically based chaarcteristics that enchance an animals ability to survive and therefore reproduce will be passed to future generations
theory of natural selection

The FFA not just reponds to faces but other complex stimuli. The objects these neurons respond to are established by ______ with those objects