SENSORY SYSTEMS : INTRO Flashcards
Do all sensory receptors generate APs?
NO! Some neurons are NON spiking therefore rate of neurotransmitter release is proportional to the membrane potential (more depolarised= more neurotransmitter release)
What controls the amount of light entering the eye?
Eyelids, cornea, lens and pupil
What are opsin molecules and what do they do?
Absorb photons of light (change shape based on light)
- HYPERPOLARISATION in mempot
Do chemical receptors in taste and smell need APs?
NO! Because structures don’t have to send info over a long distance so its graded potenitals (non spiking and unmyelinated)
What are examples of non spiking, unmyelinated receptors?
Taste receptors, photoreceptors and hair cells in cochlea
What was mullers law right in saying?
Info from different sensory receptors remains segregated
In sensory systems do we care a lot about the peak amplitude decaying overtime or rising just before APs?
NO!!! Only care about the spiking RATES
What is rate code theory?
Suggesting only the NUMBER of spikes within a certain time window is important
What is temporal coding theory?
Suggests that precise timing of APs is INFORMATIVE- can possibly encode difference between stimuli
What does a peristimulus time histogram (PSTH) do?
Plots the mean spike response against time
What can be observed in the brain moving from rostral (front) to caudal (back) ?
Move from lower frequencies to higher frequencies in primary and secondary AUDITORY cortex
