Local anesthetics, like lidocaine and novocaine, reduce the perception of pain by:. A. blocking transmission of impulses from the spinal cord to thalamus B. preventing the formation of nerve impulses in the first-order sensory neuron C. reducing the transmission of impulses from thalamus to cortex D. inhibiting the stimulus from activating the receptor

The correct option is A.

A. blocking transmission of impulses from the spinal cord to thalamus

Explanation:

Local anesthetics, like lidocaine and novocaine, reduce the perception of pain by blocking transmission of impulses from the spinal cord to thalamus because local anesthetics they first bind to ion channel in the nerve cell and then inhibit function of the ion channel present in the membrane of nerve cell known as sodium channel. This later cause blockage of nerve impulses at the site where the injection was given from the spinal cord.