

a signal that can activate or excite a response from an organism. Foods, sounds, and other triggers that cause specific behaviors or sensory experiences are stimuli.
Picture an animal cell. Maybe it’s small and rectangular, like some skin cells. Maybe it’s small and circular, like some white blood cells. Maybe it’s small and branched, like some nerve cells. Or maybe it’s big—about a meter long—and wire thin. (Wait… what?) Cells this long do exist, though they are rare. To find the longest cell that we know of, we must dive into the deep, dark depths of the ocean, and imagine looking inside of a giant squid.
Signals from the brain have been used to help scientists understand how people see, move, and make decisions. In this experiment scientists tested whether they could also use these signals to record a person's emotional state. Would they be able to detect fear, surprise, sadness, and more by looking inside the brain?
Our daily life depends on the ability to see, hear, feel, and smell at the same time, a skill that develops during childhood. In this article scientists studied how the brain develops the ability to combine sensory information.