Final answer:
The polysynaptic part of the reflex is known as the interneuron reflex, which involves multiple synapses with one or more interneurons.
Step-by-step explanation:
The polysynaptic part of the reflex is also known as the interneuron reflex. Polysynaptic reflexes involve multiple synapses with one or more interneurons between the sensory neuron and the motor neuron. These reflexes are a contrast to monosynaptic reflexes which involve just a single synapse.
Examples of polysynaptic reflexes include reflexes that occur within the spinal cord or brain stem for a more complex and coordinated response, unlike in autonomic reflexes where the short circuit might bypass the central nervous system (CNS) completely through a sensory neuron directly causing a ganglionic neuron to activate the target effector.
In contrast, a somatic reflex, such as the withdrawal reflex, involves rapid communication between the sensory and motor pathways in the CNS and occurs to protect the body from harmful stimuli.