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Incorporating service learning (SL) components can be a very powerful way to engage students, add relevance, and develop community-building skills. SL experiences can play important roles in neuroscience classes, although the roles can be different depending on the needs of the classes. In this paper, we will present two models of incorporating service learning into neuroscience courses. The first model gives an example of using SL in a non-majors course, and the second model gives an example of using SL in a neuroscience class for neuroscience concentrators. After describing the two sets of experiences, we summarize the positive aspects and the challenges involved in creating SL components in neuroscience courses, develop some keys to success, and then provide a list of additional resources.

This article describes a neuroscience outreach program developed by college undergraduates and aimed at second graders. Over a period of four weeks, twenty-five Denison students enrolled in a non-majors course on gender and the brain visited twenty-four second grade classrooms to engage a total of 464 students. We had a mission to both promote college awareness and to specifically bring some brain science into the classroom. The desire to engage students with the brain was in part a wish to celebrate brain awareness week and in part a wish to follow a feminist tenet of bridging theory and practice via activism. The college students chose six activities: a brain puzzle, a sock content guessing game, a jelly bean olfaction and taste test, mystery noises, a message transmission game, and a version of tag. During our outreach with the second graders, my students monitored student engagement and compared engagement between male and female second graders. Engagement was high for nearly all activities but girls were more engaged than boys during the brain puzzle and jelly bean activities. Effect sizes measured as Cohen's "d" statistics were small to large (0.2 to 0.93). The other four activities (mystery socks, mystery noises, message transmission and neuron chain tag) showed no difference in engagement between male and female second graders. Our program benefited the Denison students as well, introducing many to community involvement and awakening in them an interest in teaching or working with kids.

This article describes a non-majors biology class linking neuroscience and women's studies. The class had 24 students from 13 majors. We met for three classroom hours and three laboratory hours each week. We used animal and human case studies to explore issues of gender, sexuality, hormones, anatomy, biochemistry, behavior and environment to explore the differences and similarities between male and female brains. Reading focused on two major texts, Roughgarden's Evolution's Rainbow and Hines's Brain Gender, and primary literature referenced within. Student performance was assessed through exams, class participation, presentations of primary literature, and independent research projects with oral and written presentations. The cross-listing with women's studies improved the class because it led to a great richness of majors and experiences. Furthermore, these students were used to vehement discussion and careful analysis, which carried over to assessing the primary literature, to a surprising degree.

The local flow environment affects the shape of waterborne chemical signals through a variety of physical mechanisms and at several scales. Since crayfish rely on these chemical signals to extract information about predators, prey, and mates, one might expect the chemical sensors (aesthetascs) on crayfish antennules to be physically tuned to the presentation of chemical cues by the flow environment. This hypothesis was tested by comparing length, diameter, and spacing of antennules and aesthetascs among geographically distinct populations of Orconectes virilis. Crayfish were collected from the Chagrin river, Hebron hatchery, and Burt lake. In addition, antennules were sampled from 43 museum populations representing 12 lake, 10 creek, and 21 river populations from multiple states and river drainages. Mean velocities from the collection sites were either measured directly or calculated from United States Geological Survey (USGS) historical data. Structural parameters were measured using Scion Image software on Scanning electron microscope micrographs, and analyses of variance were performed using StatView. Structural parameters of aesthetascs were found to vary with flow environment. Aesthetascs from lake populations were inserted at a larger angle, extended out farther from the supporting antennule relative to the width of the antennule, and were more widely spaced than aesthetascs from creek, hatchery, and river populations.

Crayfish rely on the chemosensory neurons in their antennules to help them find food and habitat and to mediate social interactions. These structures often sustain damage from aggressive interactions or from the environment, but they have the ability to regenerate. In this study, we examine whether the effects of antennule ablation and regeneration on odor-tracking ability correlate with structural changes in the antennule that occur during regeneration. We initiated the regeneration process by removing the right antennules from 55 individuals of Orconectes sanborni. We developed a method to nondestructively sample the regenerating antennules so that we could follow the growth of new antennular tissue in the same animals over time. We used dental epoxy to make molds of the regenerating antennule after each molt. We then made resin positives, which were visualized using scanning electron microscopy. Structural parameters including aesthetasc length, diameter, segment length, and number per row were measured from scanning electron micrographs using Image J software. Crayfish were tested in a tabletop water Y-maze before and after surgery and after each molt to assess their ability to track food odors. The structural and the behavioral data indicate that the antennules possessed many aspects of their original structure by the end of the second molt. Flicking of antennules, investigation of substrate, success rate at finding the odor-containing Y-maze branch, and time to completion of Y-maze regained pre-antennulectomy values by the end of the third molt.

Male Procambarus clarkii were matched by size and largest claw length and observed interacting in pair matches before and after removal of the androgenic gland or a sham operation. Although results were not significant, trends suggested that males showed less aggression after the removal of the androgenic gland. Average bout duration did not decrease, but mean intensity of interaction decreased. This exercise was part of a student lab for non-majors. Students were positive about the lab, indicating that they learned about quantifying behavior, about hormonal involvement in aggression, and that the lab made them want to do more science.

Many students understand the electrical properties of neurons and can adequately describe the creation and transmission of electrical impulses. However, students often have difficulty when it comes to understanding how neurons have an equally important role in cell signaling. This latter function is crucial in the establishment of proper cell fate during regeneration. I have devised a lab that includes in its goals: 1) an investigation into the cell signaling role of neurons, 2) experience with non-lethal invasive surgery, 3) an opportunity for student-collected data, and 4) the chance to work with charismatic animals. In addition, the exercise provides insight into development because development and regeneration follow similar pathways. The lab also introduces the topic of stem cells. Finally, the eventual regeneration of the denervated limb can provide an opportunity to discuss the mechanisms of nerve repair. A critical event in urodele limb regeneration is the formation of a blastema. This event requires an intact nerve supply. Nerves secrete a substance called the neurotrophic growth factor(s) that appear to stimulate the reentry of blastema cells into the cell cycle, through a complex series of signaling events. In this laboratory exercise, students examine this effect by amputating both front limbs, but denervating only one. They then compare limb regeneration under and exempt from nerve control within the same animal. Students control for denervation using a behavioral assay, and monitor limb growth for six weeks. All sixteen of the surgeries were successful, and all showed the expected difference between the denervated and the control limb.

Many marine animals track odor plumes to their source. Although studies of plume-tracking behavior have been performed in unidirectional flow, benthic animals such as crustaceans live in coastal habitats characterized by waves. We compared signal encounters by odor-plume-tracking stomatopods (mantis shrimp) in wave-affected and unidirectional flow in a flume. Stomatopods are small enough that we can study their natural behavior in a flume. They sample odors by flicking their antennules. A thin sheet of laser light illuminating an odor plume labeled with dye [planar laser induced fluorescence (PLIF) technique] permitted us to measure the instantaneous odor concentration encountered by the animal's chemosensory organs (antennules) while it tracked the plume. We simultaneously measured behavior and the high-resolution odor signal at the spatial and temporal scale of the animal. We found that the navigating animal encountered odor filaments more often in wave-affected flow than in unidirectional flow. Odor filaments along the animals' antennules were significantly wider and of higher concentration in waves than in unidirectional flow.

Robots are needed to locate the sources of toxic chemical plumes. Lobsters, which track odor plumes for many ecologically crucial activities, can provide inspiration for robot designers. Before accurate search strategies for robots can be developed, how odor molecules are captured by the lobster's chemosensors must be understood. A recent study by Koehl et al. shows how lobster olfactory antennules alter the patterns of concentration in turbulent odor plumes during odor sampling.

Like many marine crustaceans, mantis shrimp rely on their sense of smell to find food, mates, and habitat. In order for olfaction to function, odorant molecules in the surrounding fluid must gain access to the animal's chemosensors. Thus fluid motion is important for olfaction, both in terms of the large scale fluid movements (currents, waves, etc.) that advect the odorants to the vicinity of the sensors, and the small-scale viscosity dominated flows that determine odorant access to the surface of the sensor. In order to understand how stomatopods interpret their chemical environment, I investigated how stomatopod chemosensory morphology and the movement of the structures bearing the chemosensors affect fluid access to the sensor surface in Gonodactylaceus mutatus. Preliminary results from new directions are presented, including mathematical modeling of molecular flux at the sensor surface, field studies of the effects of ambient flow on odor sampling behavior, and flume experiments testing the ability of stomatopods to trace odor plumes. Finally, I show how the use of multiple techniques from several disciplines leads to new ideas about the functional morphology of stomatopod antennules.

A critical step in the process of olfaction is the movement of odorant molecules from the environment to the surface of a chemosensory structure. Many marine crustaceans capture odorant molecules with arrays of chemosensory sensilla (aesthetascs) on antennules that they flick through the water. We developed a model to calculate molecule flux to the surfaces of aesthetascs in order to study how the size, aesthetasc spacing, and flick kinematics of olfactory antennules affect their performance in capturing molecules from the surrounding water. Since the three-dimensional geometry of an aesthetasc-bearing antennule is complex, dynamically-scaled physical models can often provide an efficient method of determining the fluid velocity field through the array. Here we present a method to optimize the incorporation of such measured velocity vector fields into a numerical simulation of the advection and diffusion of odorants to aesthetasc surfaces. Furthermore, unlike earlier models of odorant interception by antennae, our model incorporates odorant concentration distributions that have been measured in turbulent ambient flows. By applying our model to the example of the olfactory antennules of mantis shrimp, we learned that flicking velocity can have profound effects on odorant flux to the aesthetascs if they operate in the speed range in which the leakiness of the gaps between the aesthetascs to fluid movement is sensitive to velocity. This sensitivity creates an asymmetry in molecule fluxes between outstroke and return stroke, which results in an antennule taking discrete samples in space and time, i.e. "sniffing". As stomatopods grow and their aesthetasc Reynolds number increases, the aesthetasc arrangement on the antennule changes in a way that maintains these asymmetries in leakiness and molecule flux between the outstroke and return stroke, allowing the individual to continue to take discrete samples as it develops.

Many crustaceans detect odors from distant sources using chemosensory sensilla (aesthetascs) on their antennules. The greater the flow of water through arrays of aesthetascs, the faster the access of odorant to receptors inside the aesthetascs. Stomatopods facilitate odorant access by flicking their antennules, thus increasing the relative velocity of the water reaching their aesthetascs. We used dynamically scaled physical models to investigate how aesthetasc size and spacing and antennule flicking velocity affect flow penetration into the simple aesthetasc arrays of the stomatopod Gonodactylaceus mutatus. Particle image velocimetry of flow fields near models of juvenile and adult antennules revealed that velocity gradients around the aesthetascs are steeper during the outward part of the flick than during the return stroke and that the velocity gradients are steeper at the aesthetasc tips than at their bases. More fluid per unit time flows between aesthetasc rows during the outward stroke than during the return stroke, ensuring that odor sampling is pulsatile. During flicking, velocity gradients are steeper near adult aesthetascs than near juvenile aesthetascs, and adults process more fluid per unit time than juveniles. The resulting differences in odorant access can be related to size- and age-dependent changes in stomatopod ecology.

The fertilisation of free-spawning invertebrates, mainly sea urchins, has been studied extensively during the last hundred years. However, results obtained from in vitro experiments do not always reflect what happens in the real world. Organisms in their natural habitats have a complex set of challenges, cues and behaviours to contend with during fertilisation and early development, factors that are normally not considered in the laboratory setting. This review examines recent work on fertilisation ecology and discusses the relevance of these results to the findings gleaned from laboratory research. Emphasis is placed on stresses associated with fertilisation in situ, and how responses to environmental stresses (such as from turbulence, oxidative stress, ultraviolet radiation and pathogens) might affect the fertilisation process.

Life in the highly turbulent surf zone poses a severe challenge to reproduction in free-spawning animals. Not only can breaking waves quickly dilute the gametes shed by spawning organisms, but turbulence-induced shear stresses may limit fertilization and interfere with normal development. A Couette cell was used to re-create some of the effects of turbulent water motion to study effects of environmentally relevant shear stresses on fertilization in the purple sea urchin (Strongylocentrotus purpuratus). Although low shear stresses improved fertilization success (presumably by increasing mixing), exposure to high shear stresses (of the magnitude found in the surf zone) substantially decreased fertilization success, probably by interfering with contact between egg and sperm. Furthermore, eggs fertilized at high shear stresses often showed abnormal development and low survival of eggs through the blastula stage.