Hoofdstuk 6 Flashcards
Sensation
Basic processes by which sensory organs respond and the nervous system respond to stimuli in the environment and to the elementary psychological experiences that result from those processes.
Perception
Refers to more complex organizing of sensory information within the brain and to the meaningful interpretations extracted from it-> brain, thought and memory.
Sensory receptors
Are specialized structures that respond to physical stimuli by producing electrical changes that can initiate neural impulses in sensory neurons.
Sensory neurons
Specialized neurons that carry information form sensory receptors into the central nervous system, with their own unique pathways.
Sensory coding
The preservation of the information about the physical stimuli to which they are responding.
Quantitative variation
The amount or intensity of energy.
Qualitive variation
The precise kind of energy.
Transduction
The neural process by which a receptor cell produces an electrical change in response to physical stimulation-> occurs in way that information about the quantity and quality of the stimulus is preserved in the pattern of action potentials send to the brain.
Sensory adapatation
The change in sensitivity that occurs when a given set of sensory receptors and neurons is either strongly stimulated or relatively unstimulated for a length of time. Dependent on the amount of stimuli, the sensory system can become more or less sensitive.
Psychophysics
The study of relationships between physical characteristics of stimuli and the sensory experiences (judgement of a stimuli) produced by those stimuli.
Absolute threshold
The faintest detectable stimulus of any given type; lower= more sensitive.
Difference threshold or just-noticeable difference (jnd)
The minimal difference in magnitude (or intensity) between to stimuli that is required for the person to detect them as different.
Weber’s law
The jnd for stimulus magnitude is a constant proportion of the magnitude of the originals stimulus. Jnd= kM (M=magnitude, k= proportionally constant).
Signal detection theory
Proposes that the detection of a sensory stimulus is dependent upon both the physical intensity of the stimulus and the psychological state (including expectation, motivation and alertness) of the perceiver.
Olfaction
Smell
Odorants (geurstoffen) can reach the olfactory epithelium trough 2 routes
(1) Through the nostrils (neusgaten) and (2) Trough the nasal pharynx-> connects the back of the mouth cavity with the nasal cavity.
Pheromones
A chemical substance that is released by an animal and acts on other members of its species to promote some specific behavioural or physiological response.
Vomeronasal organ
Contains receptor cells specialized for reponing to pheromones.
What are the six primary tastes?
- Sweet
- Sour
- Salty
- Bitter
- Umami (savoury/delicious)
- Fat
In which two ways is pain a ‘’body’’ sense?
- Pain receptors exist over the whole surface of the skin and in many other bodily tissues.
- The experiences comes from within your own body.
In what way is pain an emotion?
Pain can overwhelm, it has facial expressions.
In what way is pain an drive?
Pain motivates both to reduce the pain and to avoid behaviour in the future that caused the pain.
2 types of pain sensory neurons
- C fibres-> slow, second (dull, burning) pain.
- A-delta fibres-> fast, first (sharp, highly localized) pain.
Three components of pain experience:
- The sensory component: depends largely in the somatosensory cortex, the area of the parietal lobe that receives input for touch and temperature as well as pain-> crucial for the ability to perceive pain as an sensation, to describe its intensity and qualities, and to locate it in a particular portion of the body.
- The primary emotional and motivational component: experienced immediately, depends on the cingulate cortex and the insular cortex, portions of the limbic system. Damage to the insula gate and insular cortex; asymbolia for pain-> people can describe and perceive a pain stimulus, but is doesn’t bother them.
- Secondary emotional and motivational component (more cognitive): worry about the future or the meaning of the pain. Brain area; prefrontal lobe-> planning and concern about the future.
Gate-control theory
Explain the variability in the experience of pain a person has, referring to other conditions than only the physical stimulus-> experience depends on the degree to which input form pain sensory neurons can pass through a neural ‘’gate’’ and reach higher pain centre in the brain. Conditions can increase or decrease pain by opening or closing the gate.
Phantom-limb pain
Pain occurs, even when the pain pathways entering the brain from the spinal cord are destroyed (amputation for example)-> so brain’s mechanisms can be activated, even without sensory input from that part of the body-> in fact the lack of sensory input might trigger phantom-limb pain.
How does injury produce a localized increase in pain sensitivity?
(1) Changes in free nerve endings of C fibres and A-delta fibres that are induced by chemicals released from damaged cells-> now the sensitized sensory neurons respond to much weaker stimuli, than they would have before the injury. (2) Second-order pain neurons in the spinal cord and brainstem become sensitized by intense activation (minutes to weeks).
Endorphins
Chemicals produced by the body that act like morphine. How do they work? (1) brain/spinal cord serve as neurotransmitters to alter the activity or exbibility of neurons to which they bind. (2) Secreted for the pituitary gland and adrenal glands as hormones, they enter the bloodstream.
Stress-induced analgesia
The decreased pain sensitivity that accompanies highly stressful situations.
Amplitude
The sound’s intensity, the total pressure exerted by the molecules of air. Usually measured in decibels (dB).
Frequency
The sound’s pitch. The rate at which the molecules of air or another medium move back and forth. Frequency is measured in hertz (Hz)-> the number of complete waves/cycles per second generated by the sound source. Humans: 20-2000 hertz.
Outer ear
Consist of the pinna, visible portion of the ear and the auditory canal.
What are the functions of the outer ear?
It functions as a funnel for receiving sound waves and transporting them inward. The vibration of air causes the auditory canal to vibrate, which in turn, causes the eardrum to vibrate.
Middle ear
Air-filled cavity, separated from the outer ear by the eardrum. 3 tiny bones, called; ossicles (hammer, anvil and stirrup). Which are linked to the eardrum at one end to another membrane called the oval window at the other end.
When sound causes the eardrum to vibrate, the ossicles vibrate and push against the oval window.
What are the functions of the middle ear?
To increase the amount of pressure that sound waves exert upon the inner ear so that transduction can occur.
Inner ear
Consist primarily of the cochlea, a coiled structure where transduction takes place.
Basilar membrane
Forming the floor of the inner duct, on which are located receptor cells for hearing, hair cells.
2 categories of deafness:
- Conduction deafness; occurs when the ossicles of the middle ear become rigid and cannot carry sounds inward from the tympanic membrane to the cochlea-> these people can hear vibrations by other routes than the middle ear.
- Sensorineural deafness; result from damage to the hair cells if the cochlea or damage to the auditory neurons (loud sounds).
How do the two kinds of deafness differ in their physiological bases and in possible treatment?
Conduction-> conventional hearing aids.
Sensorineural-> surgically implanted hearing aid called a cochlear implant.
How does the traveling wave form a basis for frequency coding?
(a) A rapid firing in neurons that come from the proximal end of the membrane, accompanied by little or no firing in neurons coming from more distal parts, is interpreted by the brain as a high-pitch sound.
(b) Rapid firing in neurons coming from a more distal portion of the membrane is interpreted as a lower-pitched sound.
How does the traveling-wave theory explain the pattern of hearing loss that occurs as we get older?
More hearing loss for high frequencies, than low frequencies. Cause; by the wearing out hair cells with repeated use.
Why do we lose our ability faster to hear high frequencies?
Because the cells coding for high frequencies are acted upon by all sounds, while those coding low frequencies are acted upon only by low-frequency sounds.
Phonemes
The individual vowel and the consonant sounds that make up words, and phonemic restoration is an illusion in which people hear phonemes that have been deleted from words or sentences as if they were still there.
