<P> Mammals--which appear in the fossil record after the first fishes, amphibians, and reptiles--are the only vertebrates to possess the evolutionarily recent, outermost part of the cerebral cortex known as the neocortex . The neocortex of monotremes (the duck - billed platypus and several species of spiny anteaters) and of marsupials (such as kangaroos, koalas, opossums, wombats, and Tasmanian devils) lack the convolutions--gyri and sulci--found in the neocortex of most placental mammals (eutherians). Within placental mammals, the size and complexity of the neocortex increased over time . The area of the neocortex of mice is only about 1 / 100 that of monkeys, and that of monkeys is only about 1 / 10 that of humans . In addition, rats lack convolutions in their neocortex (possibly also because rats are small mammals), whereas cats have a moderate degree of convolutions, and humans have quite extensive convolutions . Extreme convolution of the neocortex is found in dolphins, possibly related to their complex echolocation . </P> <P> There are many central nervous system diseases and conditions, including infections of the central nervous system such as encephalitis and poliomyelitis, early - onset neurological disorders including ADHD and autism, late - onset neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and essential tremor, autoimmune and inflammatory diseases such as multiple sclerosis and acute disseminated encephalomyelitis, genetic disorders such as Krabbe's disease and Huntington's disease, as well as amyotrophic lateral sclerosis and adrenoleukodystrophy . Lastly, cancers of the central nervous system can cause severe illness and, when malignant, can have very high mortality rates . Symptoms depend on the size, growth rate, location and malignancy of tumors and can include alterations in motor control, hearing loss, headaches and changes in cognitive ability and autonomic functioning . </P> <P> Specialty professional organizations recommend that neurological imaging of the brain be done only to answer a specific clinical question and not as routine screening . </P>

Which of the following structures are associated with the cns