cycles Seasonal of plasma steroids and reproductive behavior See steroids that become elevated during the prenesting period- have to do with way of making effects and build nervous system so that they can make and hear those calls. So this helps orchestrate all the events involved in the production of the gametes and important behaviors. Female during pre-nedsting time, the ovaries are large and after, in the non reproductive stage, they are almost nonexistent For the males the sonic muscle is huge and very vascularized, not the case with the female. These muscles are attatched to the gas filled swim bladder. This swim-bladder is an outcropping of the pharynx Calling makes have higher steroid levels than non callers. These toad fish are active at day and at night. Play speakers that play natural calls they respond to it right away. When you transplant males that do not originally call to areas where with calling males, they will then call. When exposed- these are the baseline breeding levels and the control is the baseline nonbreeding. Can experience fluctuations based on the social situation. So this can play an energetic role a maetabolic role. Looked at cortisol levels and 11 KT levels. Play sounds in the tank- immediate response, think that theyre responding to what they think is a real fish and theyre ready to battle it. Detecting differences in duration of the signal. Diff signal length, diff number of response- took blood sample to see cortisol and 11 KT levels. Cortisol was consistently high while 11 KT was progressively increasing with the increase in the tone length up to the 275 ms mark. Females use auditory sense to detect and locate vocalizing males. Videotaping fish. In clear plexiglass tank, lit with red light. Speaker plays the hum- and the female moves toward the speaker in a desperate attempt to find the male. . Grunt- not interested in that. Growl- female moves away slightly. They didnt appreciate white noise or music. This was a female that was full of eggs. When a female that no longer has eggs is placed in the tank, she doesnt care for the sound. Length of the time that the sound is on matters. Shorter duration, less of a response. Neuromodulation of vocal-acoustic Mechanisms They use their sacculus, which we use to detect acceleration etc Nerver that goes to the epithelium called the eighth nerve and goes into the brain, can record the activigty of individual ganglia Record the response of an auditory primary afferent neuron and then look the at auditory stimulus, look atht the time between spikes= rate code. Handout. First set of graphs. The dark line is the phase locking. Any family ofcalls can be broken down into different sinusoidal curves and you can play each of these on their own and see the response. VS vector strength synchronization- 1 means perfect less that that is less of a correlation.
This is looking at the female nervous system. They respond sometimes, and then not other times, Is this due to huge changes in nervous system? Well they change from one auditory state to another due to the loss of their eggs. Humans : estrogen receptors in ears. Can hear higher sounds with more estrogen, so hear these sounds better when pre-menopausal. What is the point of this? Steroid- Dependent Auditory PlasticityL couples frequency encoding to frequency spectrum of male advertisement. So theres the fundamental frequency ((see figure B in the handout in the lower right of the sheet) So we see that females are picking up on the higher frequency due to the estrogen, and then find the calls. Their auditory system has changed to capture this energy and then produce a behavioral response. All estrogens made from testosterone.- they use aromatase to make estradiol. Aromatase is higher in bony fishes by an entire order of magnitude, and these levels of aromatase change seasonally. So they crash during winter and upregulate during the spring. The red stains all neurons and the green stains the glial cells that stain the outside of the fish and then the vocal nucleus- which is bathed in estrogen. Estrogen receptorsand alpha mRNA. Estrogen resceptor alpha also localized in the sacculus. Use in situ hybridization to show their locations in the sacculum, and then theres the haircells staned. The tips = stereocilia. Aromatase is also found in the ganglion cells of the eight nerver that feed. . Steroids locally produced in ear, local pool that affects the hearing. Were interested in the natural behavior but this can also be included in understanding human medical conditions. Model systems- we want to look where something is exaggerated because then the system is magnified. Maybe hearing loss has to do with steroids. Neuroendocrine coupling of reproduction nd vocal-acoustinc function. The neural machinery is greatly affected by the steroids. So this most likely happens in humans too. We usually focus on the gonads, but the brain itself also manufactures neurosteroids. Rapid effects (Within five minutes).