Thalamus: it lies just below the cerebrum. It serves as a relay centre between various parts of brain and spinal cord. It also receives modified and sensory impulses before they travel to cerebrum. Thalamus also involved in pain perception and consciousness.
Hypothalamus: It lies above midbrain and just below cerebrum. In humans it is roughly the size of an almond.one of the most important function of hypothalamus is to link nervous system and endocrine system. It controls the secretion of pituitary glands. It also controls feelings such as rage, pin, pleasure and sorrow.
Cerebrum: It is the largest part of forebrain. It controls skeletal muscles, thinking, intelligence and emotions. It divided into two cerebral hemispheres. The interior parts of cerebral hemispheres are called olfactory bulb which receives impulses from olfactory nerves and create the sensation of smell. The upper layer of cerebral hemispheres consists of grey matter. The grey matter of nervous system consists of cell bodies and non-myelination axons. Beneath this layer is present the white matter. The white matter of nervous system consists of myelinated axons. Cerebral cortex has a large surface and is folded in order to fit in skull.