At which synapse in the knee-extension reflex would you expect to find an inhibitory postsynaptic potential (IPSP) ? a. the synapse between the sensory neuron and the interneuron b. the synapse between the sensory neuron and the extensor muscle motor neuron c. the synapse between the interneuron and the flexor motor neuron d. the synapse between the extensor muscle motor neuron and the extensor muscle

c. the synapse between the inter-neuron and the flexor motor neuron

Explanation:

- Knee-extension reflex is a mono-synaptic reflex. Is is also referred as simple reflex.

- It involves a single sensory and a single motor nerve fiber.

- Other examples are biceps-extension reflex

- Thus whenever there is an action potential generated in sensory neuron it causes excitatory postsynaptic potential (EPSP) in the motor neuron which is extensor motor nerve fiber.

- We also see that the same sensory neuron synapses with a inter-neuron.

- This inter-neuron is in synapse with the flexor motor nerve fiber.

- An action potential generated in inter-neuron causes inhibitory postsynaptic potential (IPSP) in the motor neuron which is flexor motor nerve fiber.