S P TEST 2 QUESTIONS TOUCH INTRO 1 the perception of the position WHERE movement of our limbs in space 2 perception mediated by kinesthetic vestibular receptors 3 In premature babies touch has effects on 4 Area of brain for movement 5 Where are touch receptors 2 places 6 knowledge of the world that comes from sensory receptors in skin muscles tendons joints Action for perception Later perception for action 7 Anesthetize skin receptors work receptors don t subject can t maintain stable grasp of objects they must manipulate 8 Preattentive feature detection you can before using selective attention to identify a particular feature No need to some features just pop out 9 Haptic recognition relies on not Good for handling objects to identify them Opposite visual system which would be good at horizontal vs vertical 10 Can haptic field of view read more than 1 finger at a time 11 Very sensitive area of body small densely packed more cortical area processing touch from that area 12 Meissner Pacinian Action Pot rapidly adapting Merkel Ruffini AP slowly adapting 13 Pacnian corpuscle RAPIDLY adapting only or force can deflect membrane channels become leaky to receptor potential 14 Merkel receptor perception 15 Meissner frequency vibration across skin RAPIDLY adapting 16 Receptors with receptive fields are closest to skin surface Merkel Meissner Of those 1 is rapidly adapting other is slowly adapting 17 Which are deeper Warm receptors or cold receptors 18 What is the normal skin temp range Thermoreceptors respond to changes 19 channels non selective cation channels in cell membrane How many of these do we have for temp all different 20 convey rate at which muscle fibers are changing in length Fires upon of a muscle Reflex leads to CONTRACTION of muscle 21 stretch reflex muscle contracts in response to its being quickly stretched Too fast for brain involvement Involves with 1 synapse btwn them 1 sensory port of a motor neuron la and II afferents and 1 motor neuron Knee jerk reflex hamstrings standing 22 Used as a reflex when something too heavy causes a muscle to relax 23 Touch receptors brain 24 Cuneate nucleus half of body Gracile nucleus half of body 25 know what something is by touching it 26 Mechanoreceptors thalamus cortex 27 Info regarding stimuli takes a separate pathway to the brain spinothalamic tract 28 The nerve joins medial lemniscus STT General sensory conveys info from stretch receptors from chewing muscles 29 gets info from medial lemniscus STT via thalamus Then S2 association cortex 30 Stimulation of S1 contralateral 31 Somatosensory association cortex DORSAL Somatosensory association cortex VENTRAL 32 S1 is important for Position sense 2 point discrimination Sterognosis Graphestheia Perception of stimuli Pereption of 33 Sporadic activity in can cause perception of missing limb 34 When blindfolded for 5 days activity in decreased activity in primary visual cortex increased Visual cortex started processing somatosensory info Plasticity 35 inability to identify objects by touch damage to Woman couldn t identify objects explored by her right hand but COULD if explored by left hand or visually damage to left parietal lobe She could gather info even w impaired hand but couldn t go from perception to what that perception represented 36 Haptic object localization needs a for coordinated system used to define locations in space The center of the frame is the 37 TOP DOWN control if you know you will be touched somewhere you voluntarily direct you attention to that place BOTTOM UP control reflexive direction of attention to abrupt stimulus 38 Experiment worst performance touch stimulus but visual auditory stimulus presented instead 39 Experiment When bar height diff btwn vision touch perceived height falls somewhere in the MIDDLE w weighted more heavily However if visual cues made less reliable more weight given to 40 Lego experiment VISION vs TOUCH modality as learning took place recognized best if presented in modality from learning recognized best if orientation was same orientation reversed 180 41 can read Braille determine location orientation of slot on head of screw report feeling pressure TEXTURE PERCEPTION When something 1st touches skin or when it also touches something else single fiber stim buzz HIGH FREQ VIBRATION DETECTION Movement across the skin Single fiber stimulation wobble or flutter LOW FREQ VIBRATION DETECTION Grasp an object like a mug more than 1 fiber must be stimulated to perceive touch FINGER POSITION STABLE GRASP 42 Merkel receptors only known somatosensory receptor that isn t part of a adapting receptive field 1 fiber braches synapses w many Merkel cells Basal layer of of hairy glabrous skin 43 Meissner corpuscle in glabrous skin epidermis receptive field adapting When does it fire APs Thin outer capsule w stack of within capsule Abundant in Good for 44 Pacinian corpuscle Where receptive field adapting Layers of thin epithelial cells w btwn layers When does it fire APs Bad for good for OR 45 Ruffini endings In receptive field adapting Capsule traversed by strands of connective tissue Tension applied to one or both Respond to 46 Find key with Grasp key with Grasp harder with inserting into lock Know when hit end of key hole with 47 Muscle spindles detect When the muscle is stretched the are stretched 48 2 types of intrafusal muscle fibers 1 fibers 2 fibers 49 2 types of sensory endings 1 Primary large axon sensitive to of muscle stretch less activity during of stretch 2 Secondary flower spray NOT so sensitive to of muscle stretch Maintains activity during stretch 50 Motor innervation motor neurons aka fusimotor neurons NOT for force of Regulates sensitivity of so responds even during contraction 51 Golgi tendon organs detect tension Thin capsule surrounding bundles adapting since collagen is not elastic threshold for response 52 How much myelin do visceral receptors have Most act subconsciously through Nociceptors Silent nociceptors only sensitive when organ is or 53 Posterior for perception and action for perceptual recognition and learning PAIN 54 Is pain a subjective experience CHEMICALLY stimulate nociceptors threshold Respond to intense control 55 Then action potential in primary afferent synapse in of spinal cord Pathway to brain spinothalamic tract part of Anterolateral System Concious awareness change level of attention autonomic response emotion pain 56 Anterior cingulate cortex ACC processing of pain 57 1 watching videos of people being injured
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