It is important to be stress-free and relaxed to “make sense” of all the input we receive from the senses.
The middle brain, which is also called the Mammalian Brain, controls the emotions, sexuality and the immune and hormonal systems. It is the site of long term memory and this explains why the memory of emotionally rich events is generally long term and powerful. However, when stressed, the middle brain will not release information into the neo-cortex. The neo-cortex, or higher brain, controls our ability to reason, develop language and conceive abstract ideas. It “makes sense” of all the input we receive from the senses. For example, if you are stressed while ear training, your language won’t connect to your sensual experience of pitch and you won’t be able to connect the names of pitches to the experience of pitch.