Prenatal Development of Behavior How and where is embryonic behavior first produced? Is it myogenic? orвЂ¦ Is it neurogenic? What part(s) of the body move first? Functions of Embryonic and Fetal Behavior Necessary for normal anatomical and physiological development Serves adaptive functions as a behavior Serves as practice for future behavior Is an epiphenomenon of no particular importance CoghillвЂ™s View of Behavioral Development Earliest movements are spontaneous rather than elicited From the beginning, movements are вЂњmass actionsвЂќ вЂњMass actionsвЂќ become вЂњindividuatedвЂќ into more localized and discrete movements Summary 1. The behavior pattern develops as a regular, orderly sequence of movements, which is consistent with the order of development of the nervous system and its parts. 2. In a relatively precise manner physiological processes follow the order of their embryological development in the functions of aquatic and terrestrial locomotion and feeding. 3. Behavior develops from the beginning through the progressive expansion of a perfectly integrated total pattern and the individuation within it of partial patterns which acquire various degrees of discreteness. WindleвЂ™s View of Behavioral Development First movements are forelimb proprioceptive reflexes other local reflexes follow (oral reflexes appear next) Complex behaviors emerge as local responses become integrated with each other Conceptions of Behavioral Development Coghill behavior is sculpted from undifferentiated precursor, much like a sculptor chips away all of the stone that is unwanted, leaving the final, differentiated form Windle behavioral development is achieved by putting together small pieces, much the way a machine is assembled Why do Coghill and Windle disagree? species differences experimental artifacts types of behaviors studied WhoвЂ™s right? Can their positions be reconciled? How would Coghill respond to Windle? Which view is more consistent with what you have learned already? How can you reconcile CoghillвЂ™s and WindleвЂ™s positions? Who cares? Why is the distinction between the views of Coghill and Windle important? Are there implications beyond the appearance of embryonic behavior? Behavior of the Duck Embryo (Video) Classes of avian embryonic behavior 1. Type 1 behavior вЂњjerky, uncoordinatedвЂќ movements of the limbs found from the onset of motility until pre-hatching 2. Type 2 behavior startle-like behavior found from the onset of motility throughout incubation 3. Type 3 behavior pre-hatching, hatching highly organized, not predictable from Types 1 and 2 occurs only in the days immediately prior to hatching Comparative Embryology of the Chick, Rat and Human (Handout) Human Crown-Rump Lengths The Appearance of Fetal Movements in Early Pregnancy Movement Gestation of First Appearance (wks) Heartbeat 6 Any movement (lateral head movement) 7 Startle 8 Generalized movements 8 Hiccups 8 First cutaneous sensitivity (cheek) 8 Isolated arm movements 9 Head retroflexion 9 Hand-face contact 10 Breathing 10 Jaw opening 10 Stretching 10 Head anteflexion 10 Swallow 10 Cutaneous sensitivity (palms) 11 Yawn 11 Suck 12 Cutaneous sensitivity (soles) 12 From De Vries et al. (1982). The emergence of fetal behaviour. I. Qualitative aspects. Early Hum Dev; 7: 301-22 The Appearance of Fetal Movements in Early Pregnancy Movement Lateral head movement Startle Generalized movements Hiccups Isolated arm movements Head retroflexion HandвЂ”face contact Breathing Jaw opening Stretching Head anteflexion Yawn Suck and swallow First Appearance (Wks. Gestation) 7 8 8 8 9 9 10 10 10 10 10 11 12 Note. From De Vries et al. (1982). The emergence of fetal behavior: I. Qualitative Aspects. Early Hum. Dev., 7, 301-322. Embryonic stages: conception to 8 wks de Vries, J.I.P. & Fong, B.F. (2006) Normal fetal motility: An overview. Ultrasound in Obstetrics and Gynecology, 27, 701-711. Pillai, M. & James, D. (1990) Development of fetal behavior: A review. Fetal Diagn. Ther. 5, 15-32. Other examples: Sleep; ingestive behavior; thermoregulation; locomotion; cognition? Fetal Yawning More Yawns http://www.layyous.com/ultasound/ ultrasound_video.htm Maturation of Sensory Functions in Humans Somatosensation 7 wk 8-9 wk 11 wk 15 wk 13-14 wk first responses to upper lip peribuccal free nerve endings found 8-9 wk face, palmar, plantar trunk whole body responds 20-25 wk vestibular 4 wk 11 wk 20-30 wk trigeminal (somatosensation) ciliated receptors functional olfaction 12 wk taste buds 4 wk 8 wk 18-20 wk 20 wk 20-25 wk 23-29 wk 24-28 wk 27-28 wk 33 wk cochlea begins to differentiate organ of Corti begins to develop organ of Corti begins to function cochlea appears mature first cardiac responses to sound first responses obtained first responses to vibro-acoustic stimuli first responses to pure tones inner ear mature 30-32 d 13 wk 20 wk optic vesicles form rods, cones, begin to form, not complete until after birth eyes open Proprioception Chemosensation Olfaction Gustation Audition Vision Gottlieb, G. (1971) Ontogenesis of sensory function in birds and mammals. In E. Tobach, L.R. Aronson & E. Shaw (Eds.) The Biopsychology of Development. N.Y.: Academic Press. What Role(s) Does Experience Play? Facilitation Maintenance Achievement 25 No Experience 20 15 10 5 0 Age Experience Induction No Experience 35 Achievement 30 25 20 15 10 5 0 Age Experience Facilitation and Maintenance Tees, R.C., (1974) Effect of visual deprivation on development of depth percepton in the rat. Journal of Comparative and Physiological Psychology, 86, 300-308.