An attempt to the modern knowledge of the genomic expression of the nervous system (NS) is done but the authors do not want do demonstrate the evolutive espeçts of the embrionary-fetal development of the NS of man, but stress the "neurological equipament" which we were born with and how we get to maturity. Maturation and learning are focalized. In the subject of maturation the aspects of function and structure are shown. As to the second aspect - learning - many theories, are reviewed, being emphasized Pavlov's condicio-nement. After the revision of these basis the neurophenotype of children is divided in 3 types: 1) permanent manifestations with which the children are born and that are constant and practically do not modificate during their evolution (uncondicionated reflexes and the primitive sensibilities); 2) transitory reflex manifestations are archaic or reflex manifestations which disappear with the evolution returning just in pathological situations (tonic-neck assymetric reflex of Magnus-De Kleijn, Moro's reflex, Laudau's reflex and cutaneous-plantar in extension); 3) evolutive reflex manifestations - with which children are born, reflexes or automatics in the beginning, and which disappear with the evolution being replaced by the same activities, although in voluntary character, passing or not through a nitid inhibiting phase; lately some of these activities are automatized constituting in secondary automatisms (suction, prehension, automatic march, reflex of swimming). Myra y Lopez interpretate these functions in his terminology as "deflexes". The neurophenotype of the normal term NB is characterized by the following items, according to Lefèvre and Diament's works: 1 - Asymmetric attitude determined by the asymmetric tonic-neck reflex pattern; 2 - generalized hypertonia of the flexor muscles of the 4 limbs and of the thigh adductors; 3 - more frequent myotatic reflexes: patellar, adductor, tricipital and naso-palpebral, being necessary the symmetry of the responses; 4 - the plantar cutaneous reflex in extension of the hallux with or without spreading of the other toes present in 100% of the RN; 5 - automatic or reflex activities present in 100% of the RN; assymetric tonict-neck reflex (fragmentated in 70%, complete in 30%), reflex walking, automatic plantar support, suction; 6 - reflex of the "doll's eye" in 100%; 7 - photomotor reflex in 100%. The key-ages of the neurological evolution of the normal lactent determinated by us in 1967, are also expression of the normal neurophenotype and may be summarized as follows; A-1) from the RN until the end of the lst month: Vocal expression: inarticulated cry; initiation of the lallaction after the 1st month. Posture: asymmetric attitude, with or without asymmetric tonic-neck reflex: general hypertonia in flexion; hypotonia of the paravertebral muscles. Myotatic and superficial reflexes: more liverliness myotatic reflexes; the plantar-cutaneous reflex in extension of the hallux with or without spreading of the other toes: Primitive motor manifestations: the more frequent in the NB of normal term are suction, grasping of fingers and toes, Magnus-De Kleijn's TNR pattern, Moro's, walking reflex and plantar support. Ocular reflexes: photomotor reflex and doll's-eye proof. A-2) from the beginning of the 2nd month until the end of the third: Vocal expression: evident lallation. Posture: loss of asymmetric attitude; beginning of the symmetric attitude, head supine, recumbent position; beginning of complete and uncomplete upholding of the head; persistence of the hypertonia; general flexor hypertonia, although less pronounced. Superficial and myotatic reflexes: reduction of the liveliness of myotatic reflexes; persistence of the plantar-cutaneous reflex in extension of the hallux with or without spreading of the hallux. Archaic reflexes: persistence of the following primitive motor manifestations; suction, prehension of fingers and toes, Moro's plantar support and walking reflex; loss of Magnus-De Kleijn's reflex; beginning of higher incidence of Landau's reflex (I and II). Ocular reflexes: loss of answer to the doll's-eye proof from the end of the 3rd month on. A-3) from the beginning of the 4th month until the end of the 6th month: Vocal expression: estabilization of the lallation. Posture: beginning of the attitude 3 (or change of decubitus) and of the attitude 4 (change of position from laying to sitting); complete upholding of the head was observed in all examined children at the end of the 4th month; start sitting with support; beginning of the orthostatic position with support; reduction of the hypertonia in flexion. Locomotion: starting the voluntary walking with support in the 5th month. Coordenation; estabilization of the voluntary palmar prehension; beginning of the hand-handkerchief and hand-object coordination; beginning of the pincer's prehension in the 6th month. Superficial reflexes: beginning of cutaneous-plantar reflex in inconstant extension of the hallux. Archaic reflexes: loss of Moro's reflex not complete until the end of the 6th month; loss of the palmar prehension reflex until the beginning of the 6th month; loss of the plantar support until the beginning of the 5th month; loss of the walking reflex until the end of the 4th month; estabilization of the Landau's reflex I and II. Ocular reflexes: following the light stimulus from several direction in 100% of the children up to the 5th month. A-4) beginning at the 7th until the end of the 9th month: Vocal expression: beginning of the first words and phrase-words at the 8th month; gradual loss of lallation. Posture: spontaneous attitude related with the decubite (attitude 4); sitting without support in 100% from the 9th month on; evolution of the orthostatic position with support; stabilization of the normal tonus for the age or "phisiological hypotonia"; loss of hypertonia on generalized flexion of limbs starting in the beginning of the 7th month. Locomotion: beginning of crawling starting in the 8th month; beginning of walking with support. Coordenation: stabilization of the coordination hand-handkerchief on the face and hand-object; stabilization of prehension in pincers until the end of the 9th month. Superficial reflexes: stabilization of the plantar-cutaneous reflex in inconstant extension of the hallux and beginning of the answer in flexion in the 9th month. A-5) from the beginning of the 10th month until the 12th: Vocal expression: diseppearance of the lallaction at the end of the 11th month; predominance of the first words. Posture: spontaneous attitude (nº 4) respecting decubits; stabilization of the orthostatic position with support; beginning of the orthostatic position without support at the 11th month; predominance of "physiological hypotonia". Locomotion: stabilization of crawling; stabilization of walking with support; beginning of walking without support in the 11th month. Superficial reflexes: predominance of the plantar-cutaneous reflex in flexion at the 12th month. Archaic reflexes: disappearance of prehension reflex in the toes at 12 months; disappearance of palmar prehension at the end of the 11th month; stabilization of the prehension in pincers. Finally the conclusions of the Evolutive Neurological Examination of the group of Lefèvre showing important correlations between the maturation and certain functions, mostly regarding the proprioceptive and gnostic sensibilities are reported.