Final answer:
Valium works as a GABA agonist, enhancing the activity of GABA receptors in the brain, leading to a calming effect.
Step-by-step explanation:
The neurological effect of Valium, which is a sedative drug prescribed for anxiety, is A) Increased GABA activity; calming effect. Valium is classified as a benzodiazepine, and these drugs are known for their calming effects on the central nervous system. They function as GABA agonists, which means they promote the activity of GABA receptors in the brain. GABA, or gamma-Aminobutyric acid, is an inhibitory neurotransmitter that reduces neuronal excitability throughout the nervous system, leading to decreased anxiety, muscle relaxation, and sedative effects.