1. Chapter 4: Sex Differences in Behavior: Animal and Human Models Examining the Neural and Neuroendocrine aspects of the Brain.

2. 4.2 Synapses may form either on dendritic spines or on the shaft of a dendrite

3. 4.5 Cichlid fish show changes in neuronal cell size in response to social conditions

4. 4.8 Singing in female songbirds falls along a broad continuum

5. Santiago Ramon Y. Cajal (1852-1934) Founding Scientist in the Modern Approach to Neuroscience. Received Nobel Prize in 1906

6. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.1: The nervous system’s functions, p. 388. Sensory input Motor output Integration

7. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.2: Levels of organization in the nervous system, p. 389. Central nervous system (CNS) Brain and spinal cord Integrative and control centers Sensory (afferent) division Somatic and visceral sensory nerve fibers Conducts impulses from receptors to the CNS Motor (efferent) division Motor nerve fibers Conducts impulses from the CNS to effectors (muscles and glands) Autonomic nervous system (ANS) Visceral motor (involuntary) Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands Sympathetic division Mobilizes body systems during activity Parasympathetic division Conserves energy Promotes housekeeping functions during rest Peripheral nervous system (PNS) Cranial nerves and spinal nerves Communication lines between the CNS and the rest of the body Somatic nervous System Somatic motor (voluntary) Conducts impulses from the CNS to skeletal muscles = Structure = Function Key: Central nervous system (CNS) = Sensory (afferent) division of PNS = Motor (efferent) division of PNS Key:Brain Spinal cord Skin Visceral organ Skeletal muscle Peripheral nervous system (PNS) Motor fiber of somatic nervous system Somatic sensory fiber Sympathetic motor fiber of ANS Parasympathetic motor fiber of ANS Visceral sensory fiber (a) (b)

8. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.3: Neuroglia, p. 390. (a) Astrocyte (d) Oligodendrocyte (e) Sensory neuron with Schwann cells and satellite cells (b) Microglial cell (c) Ependymal cells Schwann cells (forming myelin sheath) Cell body of neuron Satellite cells Nerve fiber Capillary Neuron Nerve fibers Myelin sheath Process of oligodendrocyte Fluid-filled cavity Brain or spinal cord tissue

9. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.4: Structure of a motor neuron, p. 392. (b) (a) Dendrites (receptive regions) Cell body (biosynthetic center and receptive region) Nucleolus Nucleus Terminal branches (telodendria) Nissl bodies Axon (impulse generating and conducting region) Axon terminals (secretory component) Axon hillock Neurilemma (sheath of Schwann) Node of Ranvier Impulse direction Schwann cell (one inter- node) Neuron cell body Dendritic spine

10. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.5: Relationship of Schwann cells to axons in the PNS, p. 394. (a) (b) (c) (d) Schwann cell cytoplasm Axon Neurilemma Myelin sheath Schwann cell nucleus Schwann cell plasma membrane Myelin sheath Schwann cell cytoplasm Neurilemma Axon

11. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.6: Operation of gated channels, p. 398. (a) Chemically gated ion channel Na + K+K+ K+K+ (b) Voltage-gated ion channel Na + Receptor Neurotransmitter chemical attached to receptor ClosedOpen Membrane voltage changes ClosedOpen Chemical binds

12. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.7: Measuring membrane potential in neurons, p. 399. Voltmeter Microelectrode inside cell Plasma membrane Ground electrode outside cell Neuron Axon

13. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.8: The basis of the resting membrane potential, p. 399. Na + K+K+ K+K+ K+K+ K+K+ Cell interior Na + 15 mM K + 150 mM Cl – 10 mM A – 100 mM Na + 150 mM A – 0.2 mM Cell exterior K + 5 mM Cl – 120 mM Cell exterior Cell interior Plasma membrane Na + –K + pump Diffusion K+K+ Na + Diff us ion -70 mV

14. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.9: Depolarization and hyperpolarization of the membrane, p. 400. Depolarizing stimulus Membrane potential (voltage, mV) Time (ms) 0 –100 –70 0 –50 +50 1234567 Hyperpolarizing stimulus Membrane potential (voltage, mV) Time (ms) 01234567 –100 –70 0 +50 Inside positive Inside negative (a)(b) Resting potential Depolarization Resting potential Hyper- polarization

15. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.10: The mechanism of a graded potential, p. 401. (b) Depolarized regionStimulus Plasma membrane Depolarization Spread of depolarization (a)

16. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.11: Changes in membrane potential produced by a depolarizing graded potential, p. 402. Distance (a few mm) –70 Resting potential Active area (site of initial depolarization) Membrane potential (mV)

17. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.12: Phases of the action potential and the role of voltage-gated ion channels, p. 403. 01234 –70 –55 0 +30 Membrane potential (mV) Time (ms) Relative membrane permeability Na + K+K+ K+K+ Outside cell Inside cell Outside cell Inside cell Depolarizing phase: Na + channels open Repolarizing phase: Na + channels inactivating, K + channels open Action potential P Na PKPK Threshold Na + K+K+ K+K+ Outside cell Inside cell Outside cell Inside cell Inactivation gate Activation gates Potassium channel Sodium channel Resting state: All gated Na + and K + channels closed (Na + activation gates closed; inactivation gates open) Hyperpolarization: K + channels remain open; Na + channels resetting 2 2 3 4 4 1 1 1

18. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.13: Propagation of an action potential (AP), p. 405. –70 +30 (a) Time = 0 ms(b) Time = 2 ms(c) Time = 4 ms Voltage at 2 ms Voltage at 4 ms Voltage at 0 ms Resting potential Peak of action potential Hyperpolarization Membrane potential (mV))

19. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.14: Relationship between stimulus strength and action potential frequency, p. 406. Time (ms) Voltage Membrane potential (mV) –70 0 +30 Threshold Action potentials Stimulus amplitude

20. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.15: Refractory periods in an AP, p. 406. Stimulus Membrane potential (mV) Time (ms) –70 0 +30 012345 Absolute refractory period Relative refractory period Depolarization (Na + enters) Repolarization (K + leaves) After-hyperpolarization

21. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.16: Saltatory conduction in a myelinated axon, p. 407. Node of Ranvier Cell body Myelin sheath Distal axon

22. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.17: Synapses, p. 409. (a) (b) Cell body Dendrites Axon Axodendritic synapses Axoaxonic synapses Axosomatic synapses Axosomatic synapses Soma of postsynaptic neuron Axon

23. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.18: Events at a chemical synapse in response to depolarization, p. 410. Synaptic vesicles containing neurotransmitter molecules Axon of presynaptic neuron Synaptic cleft Ion channel (closed) Ion channel (open) Axon terminal of presynaptic neuron Postsynaptic membrane Mitochondrion Ion channel closed Ion channel open Neurotransmitter Receptor Postsynaptic membrane Degraded neurotransmitter Na + Ca 2+ Action Potential 1 2 3 4 5

24. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.19: Postsynaptic potentials, p. 412. Threshold Membrane potential (mV) Time (ms) +30 0 –70 –55 1020 (a) Excitatory postsynaptic potential (EPSP) Threshold Membrane potential (mV) Time (ms) +30 0 –70 –55 1020 (b) Inhibitory postsynaptic potential (IPSP)

25. Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings. Figure 11.24: Types of circuits in neuronal pools, p. 422. (a) Divergence in same pathway (e) Reverberating circuit (f) Parallel after-discharge circuit (b) Divergence to multiple pathways (c) Convergence, multiple sources (d) Convergence, single source Input Output Input Output Input Output Input 1 Input 2Input 3 Output Input

26. Why Study Bird Song? Bird song has been a classic behavioral response studied in animals to help us understand sexually dimorphic differences in brain organization. By studying bird song and the neural and neuroendocrine basis of bird song, we can better understand the principles of how the brain organizes itself during development. This information about bird song can then be used to understand and/or predict aspects of organization of the brain of other animals including in humans.

27. Major Regions of the Bird Brain Associated with Song: HVC = higher vocal center RA = robust nuclusu of the archistriatum nXIIts = hypoglossal nerve DM = dorsomedial region of the nucleus intercollicularis ICo = intercollicularis Syrinx = the vocal organ in birds that produces sound (equivalent to our larynx)

28. A typical bird syrinx.

29. 4.9 The neural basis of bird song Note that in birds with sexually dimorphic song abilities, these brain regions are typically much larger in males than in females of the species.

30. 4.10 Singing in zebra finches is organized by estrogens but activated by androgens

31. 4.11 The sonic organs are used by Type I male midshipman fish to attract females to their nests The sonic organs are sound producing muscles attached to the swim bladder in these fish. Type 1 males have well developed sonic organs (6x) compared to Type 2 males or females. The Type 1 male is an aggressive male. The Type 2 male has a “sneaker” reproductive behavior pattern and actually has roughly a 9x gonad:body mass ratio compared to Type 1 males.

32. 4.12 Urination postures of domestic dogs

33. 4.15 The frequency of rough-and-tumble and pursuit play (Part 1) Study of Rhesus Monkeys The pseudohermaphrodites are females who received in utero exposure to exogenous androgens.

34. 4.15 The frequency of rough-and-tumble and pursuit play (Part 2)

35. 4.16 Contributions of activational and organizational effects of hormones to behavior

37. Known Brain Differences in Humans: SDN-POA =sexually dimorphic nucleus of the preoptic area of the hypothalamus. The volume of SDN in medial preoptic area is modified by hormones, among which testosterone is proved to be of much importance. The larger volume of male SDN is correlated to the higher concentration of fetal testosterone level in males than in females. From Roger Gorski’s Lab at Yale University: Coronal rat brain sections showing the SDN-POA A: male; B: female; C: female treated perinatally with testosterone; D: female treated perinatally with the synthetic estrogen diethylstilbestrol.

38. INAH-3 = the third interstitial nucleus of the anterior hypothalamus The INAH has been implicated in sexual behavior because of known sexual dimorphism in this area in humans and because it corresponds to an area of the hypothalamus that when lesioned, impairs heterosexual behavior in non-human primates without affecting sex drive. It has been reported to be smaller on average in homosexual men than in heterosexual men, and in fact has approximately the same size as INAH 3 in heterosexual women. The above information is based on Simon Levay’s work that was published in the journal Science in 1991. LeVay S (1991). A difference in hypothalamic structure between homosexual and heterosexual men. Science, 253, 1034-1037.

39. 4.17 Average sex differences in behavior often reflect significant overlap between the sexes

40. 4.18 Congenital absence of the olfactory bulbs in Kallmann syndrome Kallmann Syndrome - hypogonadism (decreased functioning of the glands that produce sex hormones) caused by a deficiency of gonadotropin-releasing hormone (GnRH) which is created by the hypothalamus. Alternative names include: hypothalamic hypogonadism or hypogonadotropic hypogonadism Males with this condition have smaller than average testes, are infertile, and express anosmia (the inability to detect odors) This is due to incomplete development of the olfactory bulb embryologically.

41. The lack of olfactory bulb development results in the lack of GnRH cell development (the cells in the olfactory bulb normally migrate during development to the hypothalamus

42. 4.19 A possible sex difference in the corpus callosum Corpus callosum - a structure of the mammalian brain in the longitudinal fissure that connects the left and right cerebral hemispheres. It facilitates communication between the two hemispheres. This may explain certain sexually dimporphic right/left communication disorders are more prevelant in males than females….. such as ADHD, schizophrenia. This may also suggest why females may have greater verbal cognition and why some task performance skills are sexually dimorphic…

43. 4.20 Performance on certain tasks favor one sex over the other Females > Males Males > Females

44. Box 4.5 Hormones, Sex Differences, and Art (Part 1)

45. Box 4.5 Hormones, Sex Differences, and Art (Part 2)

46. Male Female with CAH Female All drawings by children aged 5-7.

47. Congenital Adrenal Hyperplasia (CAH) - an autosomal recessive disease group resulting in mutations of genes for hormone production in the brain that guid the biochemical steps of production of cortisol from cholesterol by the adrenal glands (Corticotropin Releasing Hormone (CRH) or Corticotropin Inhibiting Hormone (CRIH)) CRIH is also sometimes called Atriopeptin. Most of these conditions involve excessive or deficient production of sex steroids and can alter development of primary or secondary sex characteristics in some affected infants, children, or adults.