CH8
CH8
Terms
undefined, object
copy deck
- coding
- rules by which AP's in sensory system reflect phsyical stimulus (ex. #/freq of AP)
- what are the 3 subsystems of the somatosensory system?
- Exteroceptive cutaneous system (Mechanical Stimuli (touch)Thermal stimuli (temperature)Nociceptive stimuli (pain)), Proprioception system(Monitors position of body), Interoceptive system (Informs about internal information)
- because the intensity of AP of (ear/eye) is greater than the max rate of firing (1200AP/sec) how do we detect intensity?
- multiple receptor cells act in parallel manner providing broader range for coding the intensity of stimulus (intensity represented by # of active cells)
- free nerve endings
- in dermis and have no specialized structures; respond to temp. and chemicals
- during suppression what do accessory structures do?
- can reduce level of input in sensory pathway (ex. less light, less sound)
- receptive field
- stimulus region anf eatures that cause max. response of cell in sensory system
- what cortical region plays an important role in attention?
- part of posterior parietal lobe
- why do sensory systems emphasize change in stimuli?
- changes are more likely to be significant for survival
- dorsal column system
- somatosensory system that delivers touch stimuli via dorsal columns of spinal white matter to brain
- transutaneous electrical nerve stimluation (TENS)
- delivery of electrical pulses attached to skin, excite nerves and supply region in pain (often relieves pain by closing spinal gate)
- stimulus
- physical event that triggers a sensory response
- central modulation of sensory information
- process in which higher brain centres such as cortex and thalamus suporess sources of sensory info and amplify others
- neuropathic pain
- pain caused by damage to peripheral nerves (difficult to treat)
- range fractionation
- a hypothesis of stimulus intensity stating that certain receptor cells will fire at diff. thresholds (low/mid/high)
- which part of the brain do most senses reach first? then where do they go?
- thalamus; cortex
- sensory receptor organ
- an organ specialized to receive particular stimuli (ex. eye/ear)
- adequate stimulus
- type of stimulus which a given sensory organ is particularly adapted
- somatosensory 2
- maps both sides of body in registered overlay (left/right representations occupy same part of 'map)
- attention
- state or condition of selective awareness or perceptual receptivity
- analgesia
- loss of pain sensation
- what has the cingulate cortex been though to do with attention?
- motivational aspects of attention
- specific nerve energies
- doctrin that the receptors and neural channels for the different senses are independent and operate in own special ways and can only produce one sensation each
- anterolateral system/spinothalamic system
- transmits sensation of pain/temperature
- tonic receptors
- show slow/nonexistent decline in frequency of AP's as timulation is maintained (show little adaptation)
- threshold
- stimulus intensity that is adequate to trigger nerve impulse in axon
- what do the two types of fields tell us about objects?
- make it easier to detect edges and discontinuities on objects we fell
- pacinian corpuscle
- skin receptor cell that detects vibration
- what is the sequence of excitatory events for corpuscles?
- 1. mechanical stimulation deforms corpuscle, 2. this leads to mechanical stretch of tip of axon, 3. stretching axon opens mechanically gated ion channels in membrane allowing sodium ions to enter, 4. potential reaches threshold produces action potential
- labeled lines
- brain recognizes diff. senses because the action potentials travel along distinc nerve paths
- what do the frontal eye fields located in frontal cortex seem to be involved in regarding attention?
- visual exploration of space
- somatosensory 1
- brain receives touch info from opposite side of body
- receptor cell
- located in specific organ that detects stimuli and converts them into 'language' of nervous system (electrical signals)
- how does pain help us (4)?
- teaches how to avoid injury, causes us to withdraw from source, long lasting pain promotes behaviours of recuperation (sleep, feeding etc), social signal to other animals (elicits caregiving)
- dermatome
- strip fop skin innervated by particular spinal root
- adaption
- receptors show progressive loss of response with stimulation is maintained over period of time
- what two types of fields do somatosensory receptors have?
- excitatory center/inhibitory surround OR inhibitory center/excitatory surround
- what do bilateral receptor systems do to convey info?
- relative time of arrival of stimulus to two receptors, or intensity is related to location of stimulus (info arrives at diff times possibly)
- what are the three layers that make up the skin?
- outer=epidermis (thinnest)/ middle=dermis (contains nerve fibers and blood vessels)/ inner=hypodermis (anchor for muscles, contains Pacinian corpuscles, shapes body)
- sensory transduction
- receptor cell that converts exposure from stimulus into a change in electrical potential across its membrane
- sensory pathway
- each sensory modality (touch,vision etc) has distinct heirarchy of tracts and stations in brain
- what 4 receptors relate tactile information?
- fast adapting Meissners corpuscles (respond to change), slow adapting merkels discs (inhib. surround--responsive ot edges/points (braille)/ BOTH FOR LIGHT TOUCH; slow adapting Ruffini's endings which detect stretching of skin; Pacinian corpuscle
- synesthesia
- stimuli of one sense evokes involuntary experience of another sense at same time (hear tone, taste appears in mouth)
- what is this initial stimulus for paint?
- destruction/injury of tissue near certain nerve fibers
- what are the 8 different things that compose psychology of pain?
- Cultural determinants, Pain thresholds, Past experience, Meaning of situation, Attention/anxiety, Feeling of control, Suggestion and placebos, Hypnosis
- phasic receptors
- rapidly decrease frequency of action potentials when stimulus is maintained (show adaptation)
- what are 3 things do receptive fields differ in?
- size/shape/quality of stimulation that activates them (light touch/cold etc)
- polymodal
- involving several sensory modalities (intersensory interactions)
- nociceptors
- respond to noxious stimulation
- somatosensory
- body sensation referring to touch and pain
- what are the 6 aspects of sensory processing?
- coding, adaptation, pathways, suppression, receptive fields, attention
- generator potential
- local change in resting potential of recptor cell that mediates between impact of stimuli and initiation of nerve impulses
- what kind of energy do all senses 'use'?
- action potentials