75. Which neuronal circuit is likely to fire the longest after the input stimulation ceases? A)
parallel after-discharge circuit B) converging circuit C) reverberating circuit D) diverging circuit
E) all produce the same kind of output
Solution
Answer: (C) Reverberating circuit
Explanation: The neurons in reverberating circuit act in a sequential pattern. For example, a
series of neurons, viz 1-2-3-4-5 act in sequence with the stimuli flowing from neuron 1 towards
5. When neuron 3 fires, it stimulates neuron 4, while simultaneously restimulating neuron 1 by
sending a signal back (a type of feedback mechanism) such that neuron 1 can fire again. The
process of stimulation and restimulation continues until one of the neurons stops firing or a
inhibitory signal comes into play. Thus, the reverberating circuit fires the longest after the input
stimulation ceases.
In case of converging and diverging circuit, the firing is short lived after the input stimuli ceases.
In parallel after-discharge circuit, each neuron has different number of synapses, thus differing in
synaptic delay. The signals from different synapses soon converges to a single output. Unlike
reverberating circuit, parallel after-discharge circuit does not follow a feedback phenomenon. So
firing stops as soon as all the neurons have fired. Parallel after-discharge circuit can act for
longer periods compared to converging and diverging circuits, but shorter compared to
reverberating circuit.
parallel after-discharge circuit B) converging circuit C) reverberating circuit D) diverging circuit
E) all produce the same kind of output
Solution
Answer: (C) Reverberating circuit
Explanation: The neurons in reverberating circuit act in a sequential pattern. For example, a
series of neurons, viz 1-2-3-4-5 act in sequence with the stimuli flowing from neuron 1 towards
5. When neuron 3 fires, it stimulates neuron 4, while simultaneously restimulating neuron 1 by
sending a signal back (a type of feedback mechanism) such that neuron 1 can fire again. The
process of stimulation and restimulation continues until one of the neurons stops firing or a
inhibitory signal comes into play. Thus, the reverberating circuit fires the longest after the input
stimulation ceases.
In case of converging and diverging circuit, the firing is short lived after the input stimuli ceases.
In parallel after-discharge circuit, each neuron has different number of synapses, thus differing in
synaptic delay. The signals from different synapses soon converges to a single output. Unlike
reverberating circuit, parallel after-discharge circuit does not follow a feedback phenomenon. So
firing stops as soon as all the neurons have fired. Parallel after-discharge circuit can act for
longer periods compared to converging and diverging circuits, but shorter compared to
reverberating circuit.
