An Ethnographic Filmflam: Giving Gifts, Doing Research, and Videotaping the Native Subject/Object

Using the discussion of self-reflexivity as an organizing principle, this article examines how mobilizing digital video technology during fieldwork opens up empirical and theoretical space for reconceptualizing the relationship between anthropologists and informants. Placing the field of visual anthropology into critical conversation with long-standing theoretical arguments about the objectivist limitations of native anthropologists, I argue that the slipperiness of nativity as an anthropological designation helps to provide analytical tools for examining filmmaking as a kind of gift-giving process between native ethnographic filmmakers and the subjects of their films. This article highlights some of the ways in which my own filmic and videographic exploits in Harlem, New York, mark integral connections between seeing and being the proverbial other, probing social exchanges predicated on the usefulness of low-budget digital technology as a means of fostering politically and epistemologically valuable ethnographic collaborations.     

“How” and “what” matters: Sampling method affects biodiversity estimates of reef fishes

Understanding changes in biodiversity requires the implementation of monitoring programs encompassing different dimensions of biodiversity through varying sampling techniques. In this work, fish assemblages associated with the “outer” and “inner” sides of four marinas, two at the Canary Islands and two at southern Portugal, were investigated using three complementary sampling techniques: underwater visual censuses (UVCs), baited cameras (BCs), and fish traps (FTs). We firstly investigated the complementarity of these sampling methods to describe species composition. Then, we investigated differences in taxonomic (TD), phylogenetic (PD) and functional diversity (FD) between sides of the marinas according to each sampling method. Finally, we explored the applicability/reproducibility of each sampling technique to characterize fish assemblages according to these metrics of diversity. UVCs and BCs provided complementary information, in terms of the number and abundances of species, while FTs sampled a particular assemblage. Patterns of TD, PD, and FD between sides of the marinas varied depending on the sampling method. UVC was the most cost‐efficient technique, in terms of personnel hours, and it is recommended for local studies. However, for large‐scale studies, BCs are recommended, as it covers greater spatio‐temporal scales by a lower cost. Our study highlights the need to implement complementary sampling techniques to monitor ecological change, at various dimensions of biodiversity. The results presented here will be useful for optimizing future monitoring programs.     

Opsin gene sequence variation across phylogenetic and population histories in Mysis (Crustacea: Mysida) does not match current light environments or visual-pigment absorbance spectra

The hypothesis that selection on the opsin gene is efficient in tuning vision to the ambient light environment of an organism was assessed in 49 populations of 12 Mysis crustacean species, inhabiting arctic marine waters, coastal littoral habitats, freshwater lakes ('glacial relicts') and the deep Caspian Sea. Extensive sequence variation was found within and among taxa, but its patterns did not match expectations based on light environments, spectral sensitivity of the visual pigment measured by microspectrophotometry or the history of species and populations. The main split in the opsin gene tree was between lineages I and II, differing in six amino acids. Lineage I was present in marine and Caspian Sea species and in the North American freshwater Mysis diluviana, whereas lineage II was found in the European and circumarctic fresh- and brackish-water Mysis relicta, Mysis salemaai and Mysis segerstralei. Both lineages were present in some populations of M. salemaai and M. segerstralei. Absorbance spectra of the visual pigment in nine populations of the latter three species showed a dichotomy between lake (λ(max) =554-562 nm) and brackish-water (Baltic Sea) populations (λ(max) = 521-535 nm). Judged by the shape of spectra, this difference was not because of different chromophores (A2 vs. A1), but neither did it coincide with the split in the opsin tree (lineages I/II), species identity or current light environments. In all, adaptive evolution of the opsin gene in Mysis could not be demonstrated, but its sequence variation did not conform to a neutral expectation either, suggesting evolutionary constraints and/or unidentified mechanisms of spectral tuning.     

Behavioral modification in choice process of<Emphasis Type="Italic">Drosophila</Emphasis>

In visual operant conditioning ofDrosophila at the flight simulator, only motor output of flies—yaw torque—is recorded, which is involved in the conditioning process. The current study used a newly-designed data analysis method to study the torque distribution ofDrosophila. Modification of torque distribution represents the effects of operant conditioning on flies’ behavioral mode. Earlier works^[10] showed that, when facing contradictory visual cues, flies could make choices based upon the relative weightiness of different cues, and it was demonstrated that mushroom bodies might play an important role in such choice behavior. The new “torque-position map” method was used to explore the CS-US associative learning and choice behavior inDrosophila from the aspect of its behavioral mode. Finally, this work also discussed various possible neural bases involved in visual associative learning, choice processing and modification processing of the behavioral mode in the visual operant conditioning ofDrosophila.     

Experience‐dependent regulation of TrkB isoforms in rodent visual cortex

Within primary visual cortex (V1), brain‐derived neurotrophic factor (BDNF) signaling through its high‐affinity receptor TrkB is important for normal development and experience‐dependent plasticity. TrkB is expressed in several alternatively spliced isoforms, including full‐length TrkB (TrkB.FL), and several truncated isoforms (TrkB.T1, TrkB.T2, and TrkB.T4) that lack the intracellular tyrosine kinase domain. These isoforms are important components of BDNF signaling, yet little is known about the developmental or experience‐dependent regulation of their expression. Using immunohistochemistry, we found TrkB.FL and TrkB.T1 expressed in interneurons and pyramidal neurons within V1, but not in cortical astrocytes. We used real‐time PCR to quantify the changes in mRNA expression of BDNF, the four TrkB isoforms, and the low‐affinity receptor P75^NTR during normal development, and in response to visual deprivation at two different ages. BDNF expression increased between postnatal days 10 (P10) and P30, and was rapidly down‐regulated by 3 days of visual deprivation during both the pre‐critical period (P14‐P17) and the critical period (P18‐P21). Over the same developmental period, expression of each TrkB isoform was regulated independently; TrkB.T1 increased, TrkB.FL and TrkB.T2 decreased, and TrkB.T4 showed transient changes. Neither brief visual deprivation nor prolonged dark‐rearing induced changes in either TrkB.FL or TrkB.T1 expression. However, TrkB.T4 expression was reduced by brief visual deprivation, whereas TrkB.T4, TrkB.T2 and P75^NTR were up‐regulated by prolonged dark‐rearing into the critical period. Our data indicate that TrkB isoform expression can be selectively regulated by visual experience, and may contribute to experience‐dependent cortical plasticity. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009     

Visual fields,foraging and collision vulnerability in Gyps vultures

The visual fields of vultures contain a small binocular region and large blind areas above, below and behind the head. Head positions typically adopted by foraging vultures suggest that these visual fields provide comprehensive visual coverage of the ground below, prohibit the eyes from imaging the sun and provide extensive visual coverage laterally. However, vultures will often be blind in the direction of travel. We conclude that by erecting structures such as wind turbines, which extend into open airspace, humans have provided a perceptual challenge that the vision of foraging vultures cannot overcome.     

Visuomotor transformations: early cortical mechanisms of reaching

Recent studies of visually guided reaching in monkeys support the hypothesis that the visuomotor transformations underlying arm movements to spatial targets involve a parallel mechanism that simultaneously engages functionally related frontal and parietal areas linked by reciprocal cortico-cortical connections. The neurons in these areas possess similar combinations of response properties. The multimodal combinatorial properties of these neurons and the gradient architecture of the parieto-frontal network emerge as a potential substrate to link the different sensory and motor signals that arise during reaching behavior into common hybrid reference frames. This convergent combinatorial process is evident at early stages of visual information processing in the occipito-parietal cortex, suggesting the existence of re-entrant motor influences on cortical areas once believed to have only visual functions.     

Morphology of the retina in deep‐water fish Nezumia sclerorhynchus (Valenciennes, 1838) (Gadiformes: Macrouridae)

Using light microscopy, we examined the retina of benthopelagic fish Nezumia sclerorhynchus. Although the retina is typical of other vertebrates, having three nuclear and two synaptic layers, it presents some features associated with the animal's deep‐sea habitat. A stratum argenteum containing iridescent crystals is located in the choroid. The pigment cell layer shows bulky cells filled with melanin granules but without the typical apical processes. The visual cells, consisting of a big population of rods, are arranged in several banks. No cones were observed. The outer segments are very long and cylindrical, and the inner segments are constituted by a small ellipsoid at the proximal end. The outer nuclear layer contains several rows of oval nuclei, and the spherules in the outer plexiform layer have less regular outlines than nuclei. The inner retina is characterized by very large horizontal cells, and presumable bipolar and amacrine cells separated by large spaces that are occupied by neuronal processes. Finally, the low density of ganglion cells produces a thin nerve fibre layer. The results of this study suggest that the retina of Nezumia sclerorhyncus exhibits high visual sensitivity and that vision is a sense that plays an important role in its behaviour.