Chapter 5 Flashcards
what is sensation
brings information to the brain that arises in the reality outside our bodies
- upset stomach, etc
- begins with the interaction between a physical stimulus and our biological sensory systems
what is perception
the process of interpreting sensory information
- individual differences
the gateway to perception is the process of attention of our narrow focus on consciousness
what is synesthesia
a condition where the stimulation of one sensory pathway leads to the simultaneous automatic stimulation of another sensory pathway
- differences in perception
- may see letters as specific colours
what is transduction
before you can use info from your senses, it must be translated into a form the nervous system can understand
- the process from translation from stimulus to neural signal = transduction
what is sensory adaptation
the reduced response to an unchanging stimulus
- when the smell of food is barely noticeable after a while
- high intensity stimuli like bright lights or loud noises are things such as nearby explosions and have consequences for our safety
what is bottom up processing
the brains use of incoming signals to construct perceptions
- visual reality from information about light that is sent from the eye to the brain
- when we read a sentence that is spelled wrong, we use this type of processing to bring the sensations of the letter shapes to our brain and we use our knowledge and previous knowledge to make sense of the individual worlds
what is the top-down processing
we use knowledge gained from prior experience with stimuli to perceive them
- a skilled reader has no trouble reading the a jumbled sentence
what is psychophysics
gustav fechner developed methods which was used for studying the relationships between stimuli and perception of those stimuli
- used to establish the limits of awareness or thresholds for each of our sensory systems
what is the absolute threshold
the smallest possible stimulus that can be detected at least 50% of the time
what is the difference threshold
the smallest difference between 2 stimuli that can be detected at least 50% of the time
- the amount of difference that can be detected depends on the size of the stimuli being compared
- larger stimuli = larger differences by the observer
EX: you are eating salty chips, friend is eating lightly salted chips but if we were to add equal amounts of salt to both bags, your friend would notice because it is passing their difference threshold since yours are already very salty
- being able to detect the difference between two different weights
what is a signal detection
it is a two-step process involving the actual intensity of the stimulus - which influences the observes belief that the stimulus did occur, b) and the individual observers criteria for deciding whether the stimulus occurred
- EX: a jurys decision on whether a person is guilty - weighing their concerns
define vision
the processing of light reflected from objects - is one of the most important sensory systems in humans
- cerebral cortex processes visual information
light moves in ____
waves
wavelength = distance between each peak
amplitude = height of the wave
large amp = brighter light
humans can only see a small fraction of the electromagnetic spectrum
what is the cornea - part of the eye
toward the front of the eye - outer layer covering becomes clear
- begins process of bending light to form an image on the back of the eye
what is the pupil - part of the eye
the light that travels through the cornea and into the pupil which is surrounded by the iris (which can be coloured)
- the pupil opening can adjust in response to the amount of light present in the environment and to signal from the autonomic nervous system
- arousal = dilated, relax = constricted
what is the lens - part of the eye
directly behind the pupil and iris is the main optical instrument of the eye
- muscle attached to the lens can change its shape, allowing us to accommodate or adjust our focus to see near or distant objects
- muscles relax = lens flatten = focus on distant objects
- muscles contract = lens becomes spherical = focus on near objects
what is the retina
behind the lens - the main ball in your head
a thin but complex network of neurons specialized for processing light
- located in deep of the retina = specialized receptors - light is passed for information
- before it hits the receptor, it hits the vessels and neurons but we cannot see them
- the retina sees things upside down and reversed due to diffraction
what are rods and cones in the eye
responsible for different aspects of vision
rods = more sensitive to light than cones, they excel at seeing dimmed light
- your peripheral vision does a better job at viewing dim light than your central vision does
cones = red, blue, green
- function best under bright light and provide the ability to see both sharp images and colour
what is the optic nerve
the nerve exiting the retina of the eye
- the axons from the final layer of the cells leave the back of the eye to form this nerve
- at the optic chiasm - the axon closest to the nose cross over to the other hemisphere
(focusing straight means that everything on the left side is processed by the right hemisphere) = helps seeing depth
what are optic tracts
nerve pathways travelling from the optic chiasm to the thalamus, hypothalamus and midbrain
axons in the optic tract synapse in the thalamus - which sends info to the amygdala and the primary visual cortex and the occipital lobe
- the amygdala uses visual info to make quick emotional judgements - about harmful stimuli
- the rest of the optic tract fibres connect with the hypothalamus - where their input provides information about light needed to regulate sleep wake cycles
what are the two major pathways radiating from the occipital cortex
- dorsal stream - extends upward from the primary visual cortex - this is pathway that helps us process movement and localize objects in space
- ventral system - extends downwards from the V1 in the occipital lobe to the temporal lobe - this is the pathway that responds to the shape and colour and contributes to our ability to recognize objects and faces
what are the three primary colours in the world of light
red, blue, green - in the world of light
but the primary colours of paint = red, blue, yellow
what is the trichromatic theory
a theory of colour vision based on the existence of different types of cones for the detection of short (blue), medium (green) and long wavelengths (red)
high wavelength = low freq
what is the opponents process theory
the theory of colour vision does a better job than the trichromatic theory in explaining these colour afterimages. This theory proposes the existence of colour channels: a red–green channel and a blue–yellow channel. We cannot see a colour like reddish green or bluish yellow because the two colours share the same channel. The channels are “opponent” or competing. Activity in one colour group in a channel reduces activity in the other colour group.
T/F males are more likely to have a form of red-green colour deficiency
true
the genes for pigments used by red and green cones are located on the X chromosome - this makes the deficiency sex-linked
which theory is better? the thrichomatic theory or the opponent process?
The trichromatic theory provides a helpful framework for the functioning of the three types of cones in the retina
- However, as we move from the retina to higher levels of visual analysis…
- the opponent process theory seems to fit observed phenomena neatly
- Both theories help us understand colour vision but at different levels of the visual system.
how can we recognize objects
the hierarchical model implies a reality built out of individual bars and edges
the mathematical approach suggests that we analyze patterns of lines
- grating van vary between freq and contract
- high freq = bars in a given distance and provide fine detail
- low freq = relatively few bars
- high contract = large differences in intensity between adjacent vars like black being next to white
- low contrast = gratings have subtler differences in intensity between cars like dark gray next to black
what is the fusiform face area
- FFA
- in adolescence, the visual processing of faces activates a particular area of the brain which is part of the ventral pathway located in the inferior temporal cortex
- it becomes active during the processing of faces as opposed to other objects
- faces carry special significance in the typically developing human visual system
what are the 5 Gestalt principles
- suggests that we spont divide a scene into a main figure and ground
- proximity - objects that are close together tend to be grouped together - (same thing with stimuli, similar stimuli are grouped together)
- principle of continuity - which shows that points that are close together are seen as smooth lines
- principle of closure - when people see a complete unbroken image even if there are gaps in the lines - they fill in the blanks
- principle of simplicity - suggests that
we use the simplest solution to a perceptual problem
what is the depth perception
the ability to use the 2D image projected on the retina to perceive 3D
explain monocular cues vs binocular cues
mono = one eye
- occulsion - or the blocking of images of distant objects by closer objects - to understand you need to be familiar with how big the real size of the object is
bino = two eyes
used to construct a 3D image to provide an illusion of depth in their 2D pieces
what is the retinal disparity
the most effective depth cues
- requires both eyes
- binocular cue
- they provide infor about the relative distance between 2 objects in the visual field
how is binocular depth system an advantage to predators
prey are good at hiding esp if they blend into the environment
- retinal disparity allows us to spot tiny variations in the depth of objects in the visual field
- makes animals stand out against the background
what is astigmatism
the surface of the cornea is uneven
what is audition
sense of hearing
ultrasounds and infrasounds
ultra = above the range of the human hearing
infra = below the range of the human hearing
explain the outer ear
structures that are visible outside the body
- the pinna = collects and focuses on sounds like a funnel - helps to localize sounds as being above or below the head - the sounds are chanelled through the auditory canal
explain the middle ear
the boundary between the middle and inner ear is formed by another membrane - the oval window
this gap between these 2 membranes is bridged by a series of tiny bones - the purpose of these bones is to transfer sound energy from the air of the outer and middle ear to the fluid found in the inner ear
explain the inner ear
contains 2 sets of fluid filled cavities embedded in the bone of the skull
one set = vestibular system
other set = the cochlea - specialized receptor cells that respond to vibrations transmitted to the inner ear
what is the cochlea
inner ear structure that has receptors
- 1. vestibular canal
- 2. tympanic canal
- vibrations transmitted by the bones of the middle ear to the oval window produce waves in the fluid of the vestibular canal that travels around the apex and back through the tympanic canal
between the 2 canal = cochlear duct
what is the basilar membrane
a membrane in the cochlea on which the organ of corti is located
what is the organ of corti
resting on top of the basilar membrane
- contains many rows of hair cells that transduce sound energy into neural signals
what is the auditory nerve
bending the hair cells stimulates the release of neurotransmitters onto the cells of the auditory nerve
- the basiliar membrane needs to move very little before the hair cells are stimulated
- the branches of the nerve cell can make contact with the haircells and the medulla which sound information is then sent to the midbrain
- midbrain –> thalamus which sends info to the –> primary auditory cortex
T/F the freq of sound interacts with our perception of its loudness
true
how can we tell where the sound is coming from
we localize sound to the left and right by comparing the differences between the arrival times of the sounds to our two ears
T/F our ability to localize sounds is influenced by interactions with vision and audition
true
how do we group sounds together
sounds from one location are grouped together bc we think it all came from the same source
- when we know its from diff locations we know its from diff sources
- sounds that start and stop at the same time are perceived as being the same source
what is somatosensation
provides us with information about the position and movement of our bodies along with touch, skin temp and pain
t/f having a high pain tolerance cant lead to premature death
true because the impaired pain reception affect our ability to respond to injury and assess our circumstances
how does somatosensory stimuli arise
within the body or making contact with its surface
- these stimuli provide an organism with little time to react
somatosenses provide essential feedback needed for movement, speech, safety
what is the vestibular system
the system in the inner ear that provides information about body position and movement
contain sensitive hair cells that are bent back and forth within their surrounding fluids when the head moves and when the movement stops the fluids can reverse
the movement of the hair cells result in the production of a signals in the auditory nerve - the same nerve that carries info about sound
the axons form connections in the medulla and in the cerebellum
the medulla receives input from the visual system, the cerebellum and other somatosenses
- vestibular information travels from the medulla to the thalamus, the primary somatosensory cortex or the parietal lobe and then the primary motor cortex
what is the sensory homunculus
demonstrates the areas of the body that are represented based on their sensitivity rather than their size
- how the human body is represented in the brain
T/F different receptors in the skin help us sense pressure, vibration, stretch or pain
true
t/f those with autism have different sensory worlds
true
- oversensitive touch
t/f some pain receptors respond to mechanical damage only
false
some can do mechanical damage and respond to temperature or chemicals
what are the two types of fibers that bring info about pain to the brain
- fast, myelinated axons - for sharp ouch sensations
- slower, unmyelinated axons that are responsible for dull, aching sensations
where does the pain info get sent to in the brain
pain fibres form synapses with the spinal cord cells, send message to thalamus, send message to the anterior cingulate cortex and the insula (which manage the emotional qualities of pain) and to the somatosensory cortex in the parietal lobe (intensity of pain)
what is the gate control theory
helps explain the various psychological and physical factors that contribute to pain perception by proposing that rather than pain signals being automatically sent to the brain
- these signals must first pass through neurological gates at the spinal cord. If the gate is open, pain signals travel to the brain and are perceived; if the gate is closed, it’s possible that the pain may not be perceived at all (child too excited at a bday party to let an injury bother them)
why does the forebrain structure form connections with the periaqueductal grey of the midbrain
this area is rich in receptors for our natural opioids, the endorphins. The periaqueductal grey is a major target for opioid painkillers, such as morphine. Electrical stimulation of the periaqueductal gray produces a significant reduction in the experience of pain.
t/f even when people are told they’re receiving a placebo the pain relief can occur as long as they are told that placebo effects can be powerful
true
what is olfaction
the sense of smell
- provides information from a distance
- taken in thru the nostrils and circulated within the nasal cavities where it interacts with the olfactory receptors
- receptors are located in a thin layer of cells within the nasal cavity = olfactory epthelium
what is gustation
the sense of taste
- involves info from contact with the body
- the tongue has receptors for carbohydrates and capsaicin (equally distributed)
what is the olfactory nerve
a nerve carrying olfactory information from the olfactory receptors to the olfactory bulbs
what is the olfactory bulbs
information is brought from the olfactory nerves
- the nerve fibres synapses in one of the two bulbs which is located just below the mass of the frontal lobes
these bulbs proceed to the olfactory cortex and to the amygdala
- the cortex makes connections with the thalamus which sends info to the conscious awareness of odours
what is a papillae
small bumps on the tongue that contain taste buds
what are taste buds
a structure found in papillae that contains taste receptor cells
- in each taste bud = receptor cells which extend like tiny hairlike cilia into the saliva that interact with dissolved taste stimuli
- info travels from the mouth/tongue to the medulla which turns communication with the thalamus and to the other places, ending up in the orbitofrontal cortext where emotional pleasantness/unpleasantness in stimuli is processed
T/F chemical senses interact to provide the perception of flavour
true
- having a reduced sense of smell = blocked nose = less taste
T/F as we age, out sensitivity to smell decreases
true
- bc olfaction and taste interact to form the flavour of foods, decreased sensitivity in both senses might overal affect appetite as we age
T/F the loss of olfaction may contribute to deficits in other senses
true
like gustation and input from tthe trigeminal nerve
T/F females are more sensitive to smell than makes
true
how does olfaction and PTSD relate
close association between olfaction and memory allows certain smells to trigger ptsd
how does the sense of smell/taste related to different cultures
different cultures may relates scents for religious, medicial or personal purposes
- body odour in some countries is not harmful or offensive
- everyone has different taste preferences
T/F the loss of one sense gives us the greater ability to interact with other senses
true
- loss of hearing = responds highly to touch, visual info
