Well, imagine that you have a toy car that you can control with a remote. When you push the buttons on the remote, the car moves in different directions, right?
Now, your body is like the remote and your brain is like the toy car. The brain is responsible for making your body do things, like move your arms and legs or think about stuff. But sometimes, people like to use drugs to change the way their brain works.
When humans take psychoactive drugs like alcohol, marijuana, or cocaine, it can affect the way their brain communicates with the rest of their body. It can make them feel happy, relaxed, or energetic. Sometimes, it can even make them see things that aren't really there.
Now, animals also have brains, so drugs can affect them too. When animals are given drugs, scientists can study how it changes their behavior. For example, if a mouse is given a drug that makes it run faster in a maze, the scientists can tell that the drug is affecting its brain in a certain way.
However, we have to be very careful when studying the effects of drugs on animals. We can't ask them how they're feeling, so we have to look for other signs that they might be uncomfortable or in pain. And, just like with humans, using drugs can be dangerous for animals too. If they take too much of a certain drug, it could even be deadly.
So, in short, just like with toys and remotes, drugs can affect the way our brains work, and scientists study the effects on animals too, but we have to be very careful and make sure the animals are safe.