Instruction Using techniques from the course, design a set of experiments to add
ID: 265813 • Letter: I
Question
Instruction Using techniques from the course, design a set of experiments to address one of the two issues presented below. Be sure to 1) clearly state vour hvpothesis(es) and vour expected outcomes (figures can be used), and 2) pay attention to proper controls, repetitions, and how the data will be evaluated. Note: the overall design of the experiment is what is important here. Do not give details of the technical methods but rather provide a description of experiments and analyses that will test the hypothesis(es) Question Spike-frequency adaptation in neurons is usually due to the slow after-spike hyperpolarization (slow AHP). The slow AHP is a potassium current that is activated by calcium entering the cell with each action potential. Design experiments using extracellular recording of the stretch receptor axon to determine whether a calcium- dependent process is contributing to spike- frequency adaptation in the stretch receptor neuron.Explanation / Answer
Spike- Frequency adaptation is one of the important phenomenon in which when neuron is stimulated with square pulse then it shows reduction in the firing frequency of their spike. It is caused due to many biophysical mechanism.
The action potential created in neuron due to the sodium channel and it become inactive due to the depolazation and it recover slowly and thus delay to next spike increases due to the less availability of sodiun channel which therebydecreases spike amplitude.
Now voltage dependent pottasium current and slow delayed rectifier pottasium current got activated slowly on depolarization and got activated below the spike threshhold. Calcium activated pottasium current on the other hand are increased by the increase of calcium concentration in the cell and cause After Hyperpolarizing Potential(AHP).
The mechanism of spike frequency adaptation is analysed in substantia gelatinosa neuron. After adapting firing neurones generated short burst of spikes it was found that firing pattern of spike does not change after sustitution of calcium ion with cobalt,magnesium or cadmium ions which proves that calcium dependent conductance does not contribute to adapting firing.