Psychoanalysis and The Unconscious by D.H. Lawrence

In asserting that the seat of consciousness in a young infant is in the abdomen, we do not pretend to suggest that all the other conscious-centers are utterly dormant. Once a child is born, the whole nervous and cerebral system comes awake, even the brain's memories begin to glimmer, recognition and cognition soon begin to take place. But the spontaneous control and all the prime developing activity derive from the great affective centers of the abdomen. In the solar plexus is the first great fountain and issue of infantile consciousness. There, beneath the navel, lies the active human first-mind, the prime unconscious. From the moment of conception, when the first nucleus is formed, to the moment of death, when this same nucleus breaks again, the first great active center of human consciousness lies in the solar plexus.

The movement of development in any creature is, however, towards a florescent individuality. The ample, mature, unfolded individual stands perfect, perfect in himself, but also perfect in his harmonious relation to those nearest him and to all the universe. Whilst only the one great center of consciousness is awake, in the abdomen, the infant has no separate existence, his whole nature is contained in the conjunction with the parent. As soon as the complementary negative pole arouses the voluntary center of the lumbar ganglion, there is at once a retraction into independence and an assertion of singleness. The back strengthens itself.