• EXAM next Tuesday (no need for a blue book)• Office hours moved from today to NEXT Monday 1-3pm• NEXT week’s Discussion section—bring in 2 papers relevant to your Independent ProjectAnnouncements1• Organizational effects of hormones– occur during development–shape s adult phenotype (usually permanent)• Activational effects of hormones– require immediate presence of keyhormone for neurons to function normally– temporaryTwo different scales of Hormonal operation2Organizational Effects of Hormones Birds Other taxa?• Sexual dimorphism in number of neurons in HVC due to increased exposure to estradiol in male brain• Gonads produce T, converted to estrogen in the brain through aromatase activity3Organizational Effects of Hormonesmammals• Rat pup location in the uterus, will determine how ‘male-like’• Each pup develops in it’s own micro-uterine sac• Exposed to its own hormones as well as its neighbors• Females with 2 brothers as neighbors develop more masculine physical and behavioral features4• Exposure to sex steroids at key points in development, lead to changes in adult behavior via changes in the brain5• Organizational Effects• Activational Effects– Steroids• Alter Sensory Sensitivity• Social modulation• Can modify aggressive behaviorHormones & Behavior6MidShipman & Hormonal Effects on the Sensory System• Called midshipman fish because they have bioluminescent spots that resemble rows of uniform buttons• Females are attracted to the male's song. 7MidShipman• Midshipman migrate from the deep Pacific waters to the intertidal zone of the west coast of North America each summer to mate.• Courting males excavate nests beneath rocks in shallow water and hum to attract egg-laying females. 8The System• The ‘hum’ comes from rapidly contracting muscles on the male's swim bladder • The hum in RealAudio .au or .wav format.• Some fish species are capable of vocalizing, but virtually all fish have ears. • Playback experiments show that female midshipmen are attracted to computer-synthesized hums. • Each female deposits all her eggs for that season in one nest and swims away. • Males guard eggs until they hatch and mature & they continue singing/humming to attract more females (eggs). 9Female Tuning Curves Vary by differences in Hormones• Took Non-Reproductive Females and treated them with Estrogen (estradiol) or Testosterone• Then recorded their auditory tuning (using electrophysiology)• BOTH hormones INCREASED Females Frequency Tuning Curves• Increased the Temporal Encoding of the Male vocalizations!• Why would females/males be interested in Time Components of male calls?10How is this happening?(Searched for ER in Fish Brain)11How is this happening?(Bass and colleagues)• Fish have the HIGHEST capacity for estrogen production in the brain• Found Estrogen Receptors in the Auditory Brain area– Preoptic area – Vocalacoustic site in the hypothalamus)• Is Estrogen somehow enhancing Sensory Reception?12Social modulation of reproductive hormones13MethodsSocial modulation of reproductive hormones• Kathleen Lynch & Walt Wilczynski isolated female tungaras, exposed them to either a chorus of male calls or random tones14Estrogen significantly increases after exposure to mate chorusLynch and Wilczynski, 2006, Hormones and Behavior 50, 101-106.Results& Androgens did not15Signal reception influences hormone productionSignal detected by peripheral sense organBrain neurosecretory cells(mainly hypothalamus)PituitaryGonadsGnRHSex SteroidsLH/FSHCNS Sensory AreasOther examples?16Signal reception influences hormone production which, in turn, influences signal receptionSignal detected by peripheral sense organBrain neurosecretory cells(mainly hypothalamus)PituitaryGonadsGnRHSex SteroidsLH/FSHCNS Sensory Areasexamples?17From Lehrman 1964 Scientific AmericanInterrelationships between hormones and behaviorDaniel Lehrman181.Courtship involves vocal exchange (“nest coos”) between males and females, plus stereotyped behaviors2. Estrogen and prolactin increase in females during the interaction3. Reception of vocal signals necessary for the hormone increase in females19Cheng, M.F. (1992) Anim. Behav. 43: 1035-1044.A salient cue is the female hearing herself• Measured follicle size with following:• Sham (surg) + no playback• Devocalized + no playback• Devocalized + other female coo• Devocalized + own female’s coo• Devocalized + male coo20Hearing the communication call stimulates follicular growth. Hearing the call plus interacting with a male yields the biggest effect.21• Organizational effects of HormonesGenes &/or Environment can trigger different hormones that:(1) alter gonadal development &(2) brain regions that alter sexually-specific behavior• Activational effects– (Associative Reproduction)– (Dissociative Reproduction)– Challenge HypothesisTwo different scales of Hormonal operation22Associated Reproductive Pattern• Increases in Hormones • Gamete Production • & Sexual ActivityWhite Crown Sparrows23BREEDING SEASONS IN TEMPERATE ENVIRONMENTS24Hormonal control of behavioral prioritiesA) Hormonal changes induced by physical environment:Male red crossbills kept at constant temperature & food, but natural photoperiodDecrease of sex hormones in fall25Associative Reproductive Pattern• Seasonal change in reproductive behavior that is tightly correlated with changes in the gonads and hormones• Red Crossbills• Alaskan White Crowned Sparrows• Why not produce testosterone all year round?26An important behavioral hormone: testosteroneBENEFITS: In males, it can stimulate behavioral and physiological changes necessary for mating.COSTS: It also can have negative effects on immune system, which suggests a reason why testosterone levels cycle with breeding season27BREEDING SEASONS IN EXTREME ENVIRONMENTS28RED-SIDED GARTER SNAKES IN CANADA29Some Males don’t need Testosterone to Display Mating Behavior• Canadian red-sided Garter Snake (Thamnophis sirtalis parietalis)• Has NO testosterone circulating in its system during the Mating Season!!!• E.g. of a Dissociated Reproductive Pattern30SPRING EMERGENCE31MATING BALL32ONE FEMALE AND UP TO 50 MALES33Red-Sided Garter Snakes (Crews)• Add Hormones—No effect on Reprod Behav• Mess with their Pineal Gland/Hypothalamus •  Males don’t court in spring• These brain regions have TEMP-sensitive neurons.• Detecting TEMP changes