The structural theory of mind by Sigmund Freud stated of id, ego, and
superego. The ‘triune brain theory’ put forward by MacLean simply
describes the functional levels of the brain: ‘reptilian brain’,
‘paleomammalian brain’, and ‘neomammalian brain’. The neocortex gave the
capacities for higher mental functions. The aim of the study is to
formulate a model for the human mind based on the current knowledge of
neuroanatomy, physiology, and biochemistry. The anatomic substrates for
consciousness, perception, memory, language, emotions, abstraction,
social judgement and self-awareness are analysed. The consciousness is
mediated by the ascending reticular activating system. The multiple
perceptions are analysed by the association cortices. The hippocampal-
entorhinal circuitry is the site for memory processing. In the model for
language, there is a ventral infratemporal stream for semantic
comprehension, and a dorsal stream for phonological processing. The
limbic system is the neural substrate for emotions. The abstraction is
by the hippocampal-prefrontal circuitry. The prefrontal cortex is
essential for social cognition. The association fibres and the
commissural fibres connect the areas. The suprachiasmatic nucleus of the
hypothalamus is the pacemaker of the biological clock. The
neurotransmitters such as glutamate, dopamine, norepinephrine,
histamine, and gamma-aminobutyric acid are involved in the modulation of
all these.The ascending arousal system, limbic system, memory and
language circuits, association areas, and the prefrontal cortex
constitute the basic structural substrate for the human psyche. The
functions are dependent on the balance between the excitatory and
inhibitory activities of the neurotransmitters.