Most drugs that influence behavior do so by which of the following mechanisms?

• A. Directly changing the structure of DNA in neurons
• B. Blocking all electrical activity in the nervous system
• C. Altering neurotransmitter activity at synapses
• D. Increasing the number of neurons in the brain

Answer: (C)

Verified step by step guidance

1. Understand that drugs influencing behavior typically act on the communication system within the brain rather than altering the physical structure of neurons or DNA.
2. Recall that neurons communicate through chemical messengers called neurotransmitters, which transmit signals across synapses (the gaps between neurons).
3. Recognize that altering neurotransmitter activity at synapses can change how signals are sent and received, thereby influencing behavior.
4. Eliminate options that involve direct DNA changes or increasing neuron numbers, as these are not typical mechanisms for most behavior-influencing drugs.
5. Conclude that the primary mechanism is altering neurotransmitter activity at synapses, which can involve increasing, decreasing, or mimicking neurotransmitter effects.