lecture 18 - somatosensation

Question 1

Frank et al 1996

Answer 1

sensory deprivation is associated with problems, such as impaired growth and cognitive development, as well as elevated incidences of serious infections and attachment disorders

Question 2

Hopper and Pinneau 1957

Answer 2

found that 10 minutes of additional handling per day resulted in a significant reduction in regurgitation

Question 3

Caslet 1967

Answer 3

reported that institutionalised infants recieving an additional 20 minutes of tactile stimulation per day for 10 weeks had higher scores on developmental assessments

Question 4

4 types of receptors are sensitive only to mechanical stimulation in glabrous (hairless) skin

Answer 4

merkel’s discs, meissner’s corpuscles, fuffini’s corpuslces, pacinian corpuscles
(hairy skin contains all of these except messiners)

Question 5

Merkel’s (SA1) receptors

Answer 5

respond to low pressure or low frequency (<5Hz) vibration and spatial deformation. enable coarse texture, pattern and form perception. densley packed on the fingertips and offer acuity

Question 6

Pacinian corpuscles

Answer 6

respond to very high frequency stimilation (40-400Hz). allow fine texture perception

Question 7

Ruffini corpuscles

Answer 7

very low dynamic/temporal sensitivity but respond to sustained pressure and lateral skin stretch. detect object motion and force due to skin stretching and sensing of finger position

Question 8

Meissner

Answer 8

sensitive to high frequencies of skin deformation (5-40Hz) and spatial deformation

Question 9

dominance in different roles

Answer 9

in some tasks such as grasping and manipulation, all receptor types are active. in most tasks, pattern pattern of activity across receptor types are likely to be important

Question 10

Wilder and Penfield (1891 - 1976)

Answer 10

brain surgeon who treated patients with epilepsy. he would stimulate patient’s brain before surgery to minimise the side-effects. he mapped the motor and somatosensory cortex

Question 11

two-point thresholds

Answer 11

present participants with two objects/points touching the skin and measure how much distance is necessary for them to perceive the two objects as separate. the two-point threshold is the shortest the distance required for you to recognise two points of contact

Question 12

pressure sensitivity theresholds

Answer 12

you use different monofibres of different sizes/stiffness to measure how much pressure is required for the participants to feel something. each monofibre allows you to apply a specific amount of pressure. it means the peak-force threshold has been achieved and a relatively consistent force is continued by the filaments until they contact or are severely curved. the pressure sensitivity threshold corresponds to the minimal pressure required for participants to feel something

Question 13

localisation thresholds

Answer 13

present participants with one stimulus, then another one. ask them whether the stimuli were in the same or different locations. the localisation threshold is when the participants can just detect the two stimuli being presented on two different places

Question 14

tactile recognition by active touch - Lederman and Klatzky (1987)

Answer 14

examined how we actively interact with objects in our environment and proposed a set of exploratory procedures (EPs). which EPs are used and in which order depends on the task and users hypothesis

Question 15

tactile recognition by passive touch

Answer 15

simple or familiar shapes can be recognised by passive touch

Question 16

Johnson and Philips (1981)

Answer 16

applied raised letters to stationary fingertip and found that 30% of participants can correctly identify the letter when the height was 3mm, but over 80% when the height was 8mm

Question 17

passive touch and pattern recognition - Jones et al 2009

Answer 17

used tactors and presented participants with tactile patterns on their forearms. ps presented with different tactile patterns. sequence of 115Hz pulses that lasted 500ms before a 500ms gap.

Question 18

what did Jones 2009 find

Answer 18

the mean accuracies for up, up/right and up/left = 37% and for left and right = 87%. this showed that recognition for patterns moving across the arm is better that for patterns moving along the arm

Question 19

Geldard and Sherrick 1972

Answer 19

presented 3 tactors (A,B and C) seperated by a 10cm gap on the forearms of participants. 5x 2ms pulses were presented at each tactor with a 40-80ms gap. the spatiotemporal patterns of taps administered to the arm with templates showing how stimuli are typically percieved

Question 20

Blankenburg et al 2006

Answer 20

measure the activation of s1 when presenting participants with three actors (A, B and C) along the forearm. they found that s1 is involved in the conscious experience of rabbit

Question 21

Light et al 2005

Answer 21

showed that the reported frequency of physical contact (hugs) with partners was correalted with elevated oxytocin levels and lowered blood pressure in women

Question 22

oxytocin

Answer 22

is related to pair-bonding behaviour of mammals, and it also has analgesic and reward properties

Question 23

endorphin

Answer 23

plays a well understood role as part of the mechanisms of pain control

Question 24

types of pain

Answer 24

nociceptive, inflamatory and neuropathic

Question 25

nociceptive pain

Answer 25

activation of nocic receptors

Question 26

inflamatory pain

Answer 26

damage to tissues and inflamations to joints or by tumour cells

Question 27

neuropathic pain

Answer 27

lesion or other damage to the nervous system

Question 28

Melzack and Wall 1965

Answer 28

showed that pain signals are sent directly from the skin to the brain

Question 29

other factors can alter pain

Answer 29

mental state, focus of attention

Question 30

phantom limb pain

Answer 30

having a tingling feeling and a definite shape that resembles the real limb before amputation. burning, cramping or shooting pain. can be occasional and mild to continuous and severe

Question 31

Jensen et al 1983, 1985

Answer 31

found that 72% of amputees had phantom limb pain days after amputation. 65% had it 6 months later. 60% has it 2 years later

Question 32

phantom limb therapy

Answer 32

in the long run, only 7% of patients are helped by the more than 50 types of therapy used to treat phantom limb pain

Question 33

Katz and Melzack 1990

Answer 33

proposed that in addition to nerve deafferentation (and damage), there are somatosensory pain memories that may be received after an amputation and can lead to phantom limb pain. implicit and explicit memory may contribute to the experience of phantom limbs and phantom limb pain

Question 34

Culp and Abdi 2022

Answer 34

found that deep brain stimulation (DBS) has been proven to be highly effective with minimal side effect profiles

Question 35

DeWied and Verbaten 2001

Answer 35

found that pain tolleance scores were higher as a function of picture pleasantness. in another condition they found that participants who viewed pictures without pain cues tolerated the cold water for a longer period of time than those who viewed pictures that contained pain-related information

Question 36

Derbyshire et al 2004

Answer 36

showed that brain activity during physically induced (PI) and hypnotically induced (HI) and imagined pain overlap in some regions

Question 37

two dimensions to pain

Answer 37

sensory-discriminate dimension and affective-motivational dimension - these two dimension of pain involve distinct neural pathways

Question 38

sensory-discriminative dimension

Answer 38

refered to as "intensity" or given the label "sensory", includes the spatial and temporal characteristics and quality of pain

Question 39

affective-motivational dimension

Answer 39

referred to as "unpleasantness" or given by label "affective", captures how bad/unpleasant pain is. it also captures the motivational aspect of pain

Question 40

dysmenorrhea

Answer 40

describes menstrual pain. primary = pain without an underlying condition. secondary = pain due to conditions like endometriosis or fibroids

Question 41

Eisenberg 2012

Answer 41

suggested that experiences of social rejection, exclusion or loss are generally considered to be some of the most "painful" experiences that we endure

Question 42

social pain

Answer 42

emerging evidence suggests that experiences of social pain (the painful feelings associated with social disconnection) rely on some of the same neurobiological substrates that underlie experiences of physical pain

Question 43

Eisenberg et al 2004

Answer 43

found that increased activity in the dACC and AI (both associated with affective physical pain) when participants were excluded

Question 44

experiences of social pain

Answer 44

rely on brain regions associated with the affective component of pain in order to warn against and prevent the dangers of social harm

Question 45

Fauchon et al 2017

Answer 45

found that empathetic feedback from the observer has a positive influence on pain appraisal and that this effect may surpass the negative effect of unempathetic remarks. negative remarks can either trigger feelings of guilt or induce imitation/anger with antagonisitc effects on pain