Final answer:
The amygdala, a structure within the limbic system, is responsible for processing the feeling of fear, such as the fear experienced when an insect crawls on your arm.
Step-by-step explanation:
The sensation of fear that you experience when you feel something like an insect crawling on your arm can be attributed to the work of the amygdala. The amygdala is a structure within the limbic system that processes emotional responses, including fear. Research by scientists like Joseph LeDoux has shown that the amygdala is critical for these responses.
A fear stimulus is first perceived in the thalamus and then it can either travel directly to the amygdala for a quick response or go through the cortex before reaching the amygdala for a more processed reaction. The amygdala's involvement in the sensation of fear is crucial, as it regulates emotions and can trigger the fight-or-flight response by signaling to the hypothalamus upon detecting fear stimuli.