Prakrati differentiates into antahkarana (the psychic apparatus ) , indriyas (senses) and bhutas (matter). ´Antahkarana (the psychic apparatus ) has Buddhi, Ahamkara, and Manas.
(14) Buddhi – ascertaining intelligence (vyavasayatmika), external object reflected through eye and internal images built out of samskaras ( impressions on the mind)
(15) Ahamkara – product of Buddhi is the I-consciousness and the power of self-appropriation
(16) Manas – product of Ahamkara. It cooperates with the senses in building up perceptions, and it builds up images and concepts.