Week 12 B Flashcards
Nigel is home alone and a cat burglar attempts to break into his house. But Nigel is clever and has set several traps for expected intruders. The cat burglar steps on a nail as they ascend stairs to the home, which causes great pain from the sole of the foot
What cortical area would be activated to perceive the pain?
somatosensory
Nigel is home alone and a cat burglar attempts to break into his house. But Nigel is clever and has set several traps for expected intruders. The cat burglar steps on a nail as they ascend stairs to the home, which causes great pain from the sole of the foot
What neural pathway/tract would the sensory signal travel to get to the cortical area
spinothalmic
Would the sensory feedback be re-afference or ex-afference
exafference
What reflexes would be activated when the cat burglar steps on the nail and what is the importance of each reflex?
flexor reflex - causes activation of the agonist muscle to pill away from pain
crossed-extensor - stabilizes body so limg can pull away
recurrent inhition is ____ feeedbacl mechanism
negative
what is recurrent inhibtion mediated by?
renshaw cells
in recurrent inihbtion _____ neurons release ___ activated by___
inhibitory interneurons release glycine onto alpha MN, activated by collateral from alpha MN
as MN actitiy increase Rensha cell acitvity ____
increases too - porportionatal
what does recurrent inhibtion allow motor nerurons to stay informed about?
allows MN to stay informed about its own activities
recurrent inhition involves inhition onto ____ and acts as a _____ to prevent ___
involves inhibition on MN pool, acts as governor or loiter to prevent overactivity of muscle
what bacteria is involve in recurrent inhbition? how?
C tetani. bacteria causing tetanus
it releases a toxin that prevents Renshaw cells from releasing glycine - prevents recurren inhbition
leads to hyperactivity of MN - severe persisiten muscle activation + tetanic spasm
draw out recurrent ihibiton
What action does the 1a afferent have
on the agonist alpha motor neuron?
A) Excitation
B) Inhibition
C) 1a afferents do not act on the alpha
motor neuron
excitation
when can recurrent inhibition occur?
anytime the alpha MN is activated - even if by Ia
what is released in pre-synaptic inhibiton? give an example of pre-synaptic inhibtion.
GABA - Ia afferents inhibited before the excite alpha MN
in pre-synaptic inhibition there is communication via what
axo-axonal synapse
how does pre-synatpic inhibition inhibit the pre synaptic neuron (3 ways)
prevents Ca2+ channels from opening,
decreases ca2+ influx in presynaptic neruon, reduces nNT releas eon psot synaptic
What ion does pre-synaptic inhibition involve ?
ca - it reduces the influx and prevents channels from oepning
are we able to train pre-synaptic inhibition to condition stretch reflec depednign on task?
yes
what did the study on monkeys and reflexes show?
that we are able to trian pre-synaptic inhibtion to condition the stretch refelx (decrase or increase refelx)
Renshaw cells are activated by the 1a afferent to inhibit alpha MN. true or false.
false - activated by alpa MN
Renshaw cells release GABA. True or false
false - glycine
tetani bacteria interfere with recurrent inhibition by exciting the ᵯ motor neuro
false - prevent relase of glycine frome renshaw cells
ecurrent inhibition prevents the ᵯ motor neuron from becoming overactive - true or false
true
