PYB204 study guide Flashcards
williams syndrome
Patients with Williams syndrome have difficulty processing visuospatial information. However, they can learn repeated routes better than age-matched healthy individuals
early philosophy of cognitive psychology
nativism: knowledge is innate.
empiricism: knowledge s acquired through experience (aristotle, bacon, berkely, locke, hume, and mill)
Cognitive revolution
During world war 2, research on human performance was intensively conducted.
Information processing approach
theorises that humans actively process the information they receive from their senses, like a computer does.
input —> mind (where process of info occurs) —> output
two key principles of vision
- Perception is dynamic – we perceive change
- We perceive constancies in a changing environment
Fovea
at the back of the eye, focuses the light that we are directly looking at.
Saccades
spazzing wobbling to keep the eye moving. if the retina stabalises on an image, it will disappear as the photons stop firing and the brain fills the missing space.
ciliary muscles
they control the shape of the lens to accomodate for near or far targets. the ciliary muscles relax to focus near, and tighten to focus far. they sit on the top and bottom of the lens to stretch or relax the shape.
cones
High acuity, low dark sensitivity, fast dark adaptation
rods
Rods have low acuity, slow dark adaptation, high dark sensitivity
Vergende and stereopsis
the two eyes converge to produce two different, but aligned images of the same target.
duplex retina theory
Schultze proposed that rods and cones form two separate visual systems:
1. Photopic = bright light vision via cones
2. Scotopic = dim light vision via rods
ganglion cells
Act like a lens, capturing an image over an area of the retina (called the receptive field). This effect is due to a process of lateral inhibition between adjacent receptors using microelectrode recording
receptive fields
Ganglion cells have both excitatory and inhibitory connections within their receptive field. Some ganglion cells can be excited by light inside the receptive field.
the tectopulvinar system
purpose is to be the basic relay systems through the brain to respond to seeing things and acting on them. Van essen 1985, ungerleid and mishkin 1982 found several functions;
localisation of objects in space
guidance of eye movements
gross pattern perception.
some optic tract fibres project to the superior colliculi and then on the pulvinar and lateral posterior nuclei
where is the tectopulvinar system located
these structures are located in the thalamic region called the tectum. receiving back projections from the cortex.
blindsight
weiskrantz 1977, 1992 found that some people with damage to the focal system can still react to visual stimuli although they claim that they can not see them.
sensation
how our sensory organs (eyes, ears, etc) convert physical information into signals that our nervous system understands
perception
how we process environmental information to form internal representations of the environment
cognition
how we use internal representations to do more complex things
types of thresholds
difference thresholds: the smallest change in a stimuli can be detected. Weber’s law.
absolute thresholds: the minimum intensity of a stimuli that can be detected. Fechner’s law
absolute threshold
the minimum intensity of a stimulus that can be detected
the outer ear
pinna –> increases the sound amplitude. External canal provides protection and increases amplitude
ear drum –> tympanic membrane vibrating in response to sound waves, moves bones in middle ear.
the middle ear
ossicles –> the smallest bones in the body, transmit vibrations from the ear drum to the cochlea. provides protection from high amplitudes.
ossicles are made up of malleus, incus, and staples
inner ear
cochlear –> contains auditory sensory receptors
the inner ear contains the cochlear, with three canals: vestibular canal, tympanic canal, and cochlear duct
central auditory pathways
nerve fibres from each cochlea synapse in a number of sites on the way to the primary auditory cortex
The cochlear nucleus
The superior olivary nucleus
The inferior colliculus
The medial geniculate nucleus
The signal arriving at the cochlear nucleus splits and goes to each of the superior olivary nuclei. Beyond this point, input from both ears is present in both hemispheres.
frequency coding
sounds are made up of a mixture of sine wave components, the auditory system isolates and identifies the frequencies of these components. This is known as fourier analysis. The basilar membrane is about 30mm long and varies in stiffness and width alone its length. Travelling waves move along the basilar membrane and peak at a different point depending on the frequency of the sound.
cochlear implants
can do the maths of frequency coding for the ear and stimulate the cochlear based on the frequency of sounds
the auditory neurons
are arranged in an orderly manner in the primary and secondary auditory cortex.
central auditory pathways
the cochlear nucleus
the superior olivary nucleus
the inferior colliculus
the medial geniculate
agnosia
the impairment of object recognistion. they can identify elements of the object but not the object as a whole