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Reaction times calculation

Sensory information has to travel from the eye to the sensory cortex then to the motor cortex and then down to the spinal cord to activate motorneurones, which innervate the muscles in the fingers (a distance of about 1 metre). Assuming the nerve conduction velocity is 50m/s and there is a minimum of 4 synapses involved (delay of 2ms per synapse), what should the reaction time be?

Why do you think reaction times are longer than this and where does most of the delay occur in reaction times?

I can't think straight and I have no idea how to go about the calculation. I think most of the delay would occur in processing the information in the brain and deciding whether or not to react to it, not too sure where most of the delay occurs though.
Reply 1
Avatar for Artymess
Artymess
16
So a distance of 1m, and velocity is 50m/s. t=d/s, so 1/50 = 0.02s or 20ms, then there's a delay of 2ms per synapse, of which there are 4. so +8ms.

I get 28ms minimum but it may be worth checking my maths.
Bear in mind the question only outlines the nervous pathway, It doesn't mention the reactions or interactions (myosin/actin binding) in the muscles, which will also take time.
Reply 2
Avatar for Eloades11
Eloades11
OP
17
Original post by Artymess
So a distance of 1m, and velocity is 50m/s. t=d/s, so 1/50 = 0.02s or 20ms, then there's a delay of 2ms per synapse, of which there are 4. so +8ms.

I get 28ms minimum but it may be worth checking my maths.
Bear in mind the question only outlines the nervous pathway, It doesn't mention the reactions or interactions (myosin/actin binding) in the muscles, which will also take time.


Thanks a lot :biggrin:

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