Some people believe that we can understand consciousness if we can capture brain activity in more detail. Others believe that we can never understand consciousness. The question, of course, is how consciousness is related to the brain. To answer this question, a certain kind of research can be used, namely the research into 'the neural correlates of consciousness' (NCC). In this way aspects of neural functioning can be studied and it can be checked whether these correspond to the conscious experiences that people express. Unfortunately, it is not yet clear what aspect of neural functioning should be investigated for this. It is important to remember that the NCC is about the correlation between neural functioning and conscious experiences. Therefore, no statements can be made on the basis of NCC about cause-effect relationships between the brain and consciousness. A human brain consists of 100 trillion neurons connected to each other by synapses together with glial cells. The brainstem, consisting of the medulla, punch and midbrain, is essential for survival because it performs many important functions (cardiac, respiratory and sexual functions and the maintenance of sleep and waking). Behind the midbrain is the cerebellum that has an important function in motor control. Between the midbrain and the cerebellum is the thalamus that receives sensory input.The cortex is the outer layer of the brain and contains many structures that play a role in consciousness - the hippocampus, the amygdala, the hypothalamus and the cingulate gyrus. The neocortex is the part of the brain that developed last during human evolution. The two hemispheres are related to each other by white matter from the anterior commissure and by the corpus callosum. The definition of an 'unconscious person' is someone who lives but is not responsive...