Complete the passage describing a feedback mechanism. In a feedback mechanism, produces an initial change in a variable that is detected by . The input information is transmitted to where it is integrated, along with any other available, relevant information from the body, to form a response. The output information is then sent to where a response to the initial change in the variable can be either counteracting or reinforcing. The continually monitors the variable for changes and feeds this information back to the which modifies the response accordingly.