Associative learning in the box jellyfish Tripedalia cystophora.

Associative learning, such as classical or operant conditioning, has never been unequivocally associated with animals outside bilatarians, e.g., vertebrates, arthropods, or mollusks. Learning modulates behavior and is imperative for survival in the vast majority of animals. Obstacle avoidance is one of several visually guided behaviors in the box jellyfish, Tripedalia cystophora Conant, 1897 (Cnidaria: Cubozoa), and it is intimately associated with foraging between prop roots in their mangrove habitat. The obstacle avoidance behavior (OAB) is a species-specific defense reaction (SSDR) for T. cystophora, so identifying such SSDR is essential for testing the learning capacity of a given animal. Using the OAB, we show that box jellyfish performed associative learning (operant conditioning). We found that the rhopalial nervous system is the learning center and that T. cystophora combines visual and mechanical stimuli during operant conditioning. Since T. cystophora has a dispersed central nervous system lacking a conventional centralized brain, our work challenges the notion that associative learning requires complex neuronal circuitry. Moreover, since Cnidaria is the sister group to Bilateria, it suggests the intriguing possibility that advanced neuronal processes, like operant conditioning, are a fundamental property of all nervous systems.

Chronic anorexia nervosa: Patient characteristics and treatment approaches. / Chronicznie chory pacjent z jadlowstretem psychicznym i jego leczenie.

Anorexia nervosa constitutes amajor challenge to medical practitioners, especially clinicians, due to a high rate of chronicity and a very serious risk of relapse. One of the underlying causes of this state of affairs is the ego-syntonicity of the disorder, which differentiates it from similar conditions, and which is responsible for the patient's denial and lack of motivation for treatment (resulting in frequent instances of therapy refusal or drop-out). The paper outlines different approaches to defining chronic anorexia nervosa. Thisform of anorexia and its therapeutic implications are discussed through the lens of clinicians and other medical professionals. Furthermore, the patients'experiences of chronic anorexia nervosa are described. The dilemmas concerning palliative care for this group of patients are addressed and treatment options and relapse prevention strategies are recommended, with a focus on the latest developments in this respect. The paper is concluded with an optimistic report of complete recovery from this diagnosis, including an analysis of the factors underlying the positive therapeutic outcome.

Vision Made Easy: Cubozoans Can Advance Our Understanding of Systems-Level Visual Information Processing.

Animals relying on vision as their main sensory modality reserve a large part of their central nervous system to appropriately navigate their environment. In general, neural involvement correlates to the complexity of the visual system and behavioural repertoire. In humans, one third of the available neural capacity supports our single-chambered general-purpose eyes, whereas animals with less elaborate visual systems need less computational power, and generally have smaller brains, and thereby lack in visual behaviour. As a consequence, both traditional model animals (mice, zebrafish, and flies) and more experimentally tractable animals (Hydra, Planaria, and C. elegans) cannot contribute to our understanding of systems-level visual information processing-a Goldilocks case of too big and too small.However, one animal, the box jellyfish Tripedalia cystophora, possesses a rather complex visual system, displays multiple visual behaviours, yet processes visual information by means of a relatively simple central nervous system. This-just right-model system could not only provide information on how visual stimuli are processed through distinct combinations of neural circuitry but also provide a processing algorithm for extracting specific information from a complex visual scene.

Hunting in Bioluminescent Light: Vision in the Nocturnal Box Jellyfish Copula sivickisi.

Cubomedusae all have a similar set of six eyes on each of their four rhopalia. Still, there is a great variation in activity patterns with some species being strictly day active while others are strictly night active. Here we have examined the visual ecology of the medusa of the night active Copula sivickisi from Okinawa using optics, morphology, electrophysiology, and behavioral experiments. We found the lenses of both the upper and the lower lens eyes to be image forming but under-focused, resulting in low spatial resolution in the order of 10-15°. The photoreceptor physiology is similar in the two lens eyes and they have a single opsin peaking around 460 nm and low temporal resolution with a flicker fusion frequency (fff) of 2.5 Hz indicating adaptions to vision in low light intensities. Further, the outer segments have fluid filled swellings, which may concentrate the light in the photoreceptor membrane by total internal reflections, and thus enhance the signal to noise ratio in the eyes. Finally our behavioral experiments confirmed that the animals use vision when hunting. When they are active at night they seek out high prey-concentration by visual attraction to areas with abundant bioluminescent flashes triggered by their prey.

Vesicular stomatitis virus enables gene transfer and transsynaptic tracing in a wide range of organisms.

Current limitations in technology have prevented an extensive analysis of the connections among neurons, particularly within nonmammalian organisms. We developed a transsynaptic viral tracer originally for use in mice, and then tested its utility in a broader range of organisms. By engineering the vesicular stomatitis virus (VSV) to encode a fluorophore and either the rabies virus glycoprotein (RABV-G) or its own glycoprotein (VSV-G), we created viruses that can transsynaptically label neuronal circuits in either the retrograde or anterograde direction, respectively. The vectors were investigated for their utility as polysynaptic tracers of chicken and zebrafish visual pathways. They showed patterns of connectivity consistent with previously characterized visual system connections, and revealed several potentially novel connections. Further, these vectors were shown to infect neurons in several other vertebrates, including Old and New World monkeys, seahorses, axolotls, and Xenopus. They were also shown to infect two invertebrates, Drosophila melanogaster, and the box jellyfish, Tripedalia cystophora, a species previously intractable for gene transfer, although no clear evidence of transsynaptic spread was observed in these species. These vectors provide a starting point for transsynaptic tracing in most vertebrates, and are also excellent candidates for gene transfer in organisms that have been refractory to other methods.

Ocular and extraocular expression of opsins in the rhopalium of Tripedalia cystophora (Cnidaria: Cubozoa).

A growing body of work on the neuroethology of cubozoans is based largely on the capabilities of the photoreceptive tissues, and it is important to determine the molecular basis of their light sensitivity. The cubozoans rely on 24 special purpose eyes to extract specific information from a complex visual scene to guide their behavior in the habitat. The lens eyes are the most studied photoreceptive structures, and the phototransduction in the photoreceptor cells is based on light sensitive opsin molecules. Opsins are photosensitive transmembrane proteins associated with photoreceptors in eyes, and the amino acid sequence of the opsins determines the spectral properties of the photoreceptors. Here we show that two distinct opsins (Tripedalia cystophora-lens eye expressed opsin and Tripedalia cystophora-neuropil expressed opsin, or Tc-leo and Tc-neo) are expressed in the Tripedalia cystophora rhopalium. Quantitative PCR determined the level of expression of the two opsins, and we found Tc-leo to have a higher amount of expression than Tc-neo. In situ hybridization located Tc-leo expression in the retinal photoreceptors of the lens eyes where the opsin is involved in image formation. Tc-neo is expressed in a confined part of the neuropil and is probably involved in extraocular light sensation, presumably in relation to diurnal activity.

Swim pacemaker response to bath applied neurotransmitters in the cubozoan Tripedalia cystophora.

The four rhopalia of cubomedusae are integrated parts of the central nervous system carrying their many eyes and thought to be the centres of visual information processing. Rhopalial pacemakers control locomotion through a complex neural signal transmitted to the ring nerve and the signal frequency is modulated by the visual input. Since electrical synapses have never been found in the cubozoan nervous system all signals are thought to be transmitted across chemical synapses, and so far information about the neurotransmitters involved are based on immunocytochemical or behavioural data. Here we present the first direct physiological evidence for the types of neurotransmitters involved in sensory information processing in the rhopalial nervous system. FMRFamide, serotonin and dopamine are shown to have inhibitory effect on the pacemaker frequency. There are some indications that the fast acting acetylcholine and glycine have an initial effect and then rapidly desensitise. Other tested neuroactive compounds (GABA, glutamate, and taurine) could not be shown to have a significant effect.

Fixational eye movements in the earliest stage of metazoan evolution.

All known photoreceptor cells adapt to constant light stimuli, fading the retinal image when exposed to an immobile visual scene. Counter strategies are therefore necessary to prevent blindness, and in mammals this is accomplished by fixational eye movements. Cubomedusae occupy a key position for understanding the evolution of complex visual systems and their eyes are assumedly subject to the same adaptive problems as the vertebrate eye, but lack motor control of their visual system. The morphology of the visual system of cubomedusae ensures a constant orientation of the eyes and a clear division of the visual field, but thereby also a constant retinal image when exposed to stationary visual scenes. Here we show that bell contractions used for swimming in the medusae refresh the retinal image in the upper lens eye of Tripedalia cystophora. This strongly suggests that strategies comparable to fixational eye movements have evolved at the earliest metazoan stage to compensate for the intrinsic property of the photoreceptors. Since the timing and amplitude of the rhopalial movements concur with the spatial and temporal resolution of the eye it circumvents the need for post processing in the central nervous system to remove image blur.

Antennular sensory organs in cyprids of balanomorphan cirripedes: standardizing terminology using Megabalanus rosa.

Cirripedes are one of the major groups of fouling organism in the marine environment. The cyprid can, before a permanent attachment, actively explore and walk on the substratum using its antennules in a bipedal fashion without leaving the surface. Studying the structure of the cyprid antennule is therefore important for understanding the events that culminate in biofouling by barnacles. There are at present no complete, standardised accounts of the structure of the cyprid antennules in thoracican barnacles, and moreover, the existing accounts vary in their use of terminology. This article describes the cyprid antennule of the barnacle Megabalanus rosa. This barnacle species is common in E Asia, and the cyprids have previously been used in several biofouling studies. All externally visible setae on the antennules have been mapped; these comprise both chemosensors with a terminal pore, a putative aesthetasc-like seta and mechano-sensory setae. More setae were found on the attachment disc than in previous scanning electron microscope-based studies, but not all structures that can be seen with transmission electron microscopy were visible. The disc itself seems to have a variable surface area, which could assist in exploring rough surfaces. The various lengths of the antennular setae, coupled with the disposition of the segments, enable the cyprid to cover a wide swath of substratum during exploratory walking. A new terminology is proposed for cyprid antennular setae, which will form a basis for future comparative and functional studies of cirripede settlement.

[The effect of some factors on medical student specialty choice of non-primary care--a synthesis of the literature]. / Wplyw wybranych czynników na wybór waskich specjalizacji medycznych przez studentów wydzialów lekarskich.

The paper analyses the literature on non-primary care specialty choice. The motives for studying medicine and influences on medical student career choice have been presented. The stability of this selection has also been examined. Several predictors of specialty choice such as: demographics, academic performance, income, social status and personality attributes have been identified. Moreover, the influence of prestige, intellectual content, ability to provide sophisticated technology on preferences of non-primary care specialty has been analyzed. Association between empathy and medical specialty choice has been evaluated. What is more, it is presented that internal medicine residents are more likely to be introverted, attentive, to have deeper intellectual curiosity, higher aspiration levels and to be interested in mental stimulations. Furthermore, the surgery residents are more likely to be interested in modern technology, prestige, higher income and to be assertive and extroversive. In addition, students attracted to gynecology like contact with (mostly healthy) patients and express strong believes on reproductive issues. Besides, psychiatry students seem to be sensitive, unstable and impulsive. The analyses of Polish students' attitudes to non-primary care specialties are also presented. There is a positive perception of non-primary care and hospital medicine specialties. The specialties are more attractive because of foreseeable higher income, prestige, opportunities for research and possibilities for mastering skills and knowledge.

[Determinants of primary care specialty choice]. / Determinanty wyboru specjalizacji medycznej w podstawowej opiece zdrowotnej przez absolwentów wydzialów lekarskich.

This paper analyzes and synthesizes the literature on primary care specialty choice. Motivation for choosing medicine and its impact on recruitment to different types of medical work has been presented. Factors that influence medical students and young doctors to change specialty preference have also been explored. Variables, such as gender, martial status, age, income expectations and prestige, that affect medical students' specialty selection decisions for primary care, have been examined. Personality profiles of primary care physician have been evaluated and the influence of communication skills and knowledge of social psychology on his/her work have been analyzed. It is presented that other traits, such as patient-centeredness, needs to serve society and value orientation, is also associated with increases in numbers of students choosing primary care. The analyze shows that the preference for primary care is connected with being interested in diverse patients and health problems and also with being people-orientated. A survey conducted into Polish medical students' attitudes to primary care and family medicine is presented. There is a negative perception of family medicine among Polish students and doctors because of its long work hours and less time for family, insufficient diagnostic possibilities and monotony It is chosen because of lack of other possibilities, difficulties in employment and opportunity to become 'a specialist' in short time.

[Female and male medical students differences in self-concept and aspirations]. / Zwiazek plci z obrazem siebie i poziomem aspiracji u studentów wydzialu lekarskiego akademii medycznej.

UNLABELLED: This study was designed to investigate the connection between medical students' gender and their self-concept and aspirations. MATERIAL AND METHODS: The sample of 199 students was obtained from Medical University of Lódz, 124 were female and 75 were male. Distribution by class was 45.23% fifth year and 54.77% sixth year. They had demographic survey and reliable tests performed: Aspirations Questionnaire by B. Galas and G. H. Gough and A. B. Heilbrun Adjective Check List. RESULTS: In the research medical students' gender was associated with medical students' aspirations and self-concept. Man scored higher in material aspirations (p = 0.002) and lower in familiar aspirations (p = 0.026) and religious aspirations (p = 0.007). Women scored higher (ACL) in endurance (p = 0.024), self-control (p = 0.030) and military leadership (p = 0.032). Whereas men scored higher (ACL): in affiliation (p = 0.006), heterosexuality (p = 0.034), personal adjustment (p = 0.008), feminine attributes (p = 0.021), free child (p = 0.006), high origence-low intelligence (p = 0.008) and in high origence-high intelligence (p = 0.004). CONCLUSION: Medical students gender is associated with their aspirations and self-concept.

[Differences in medical specialty choice and in personality factors among female and male medical students]. / Zwiazek plci z preferowana specjalizacja medyczna oraz wybranymi cechami osobowosci studentów wydzialu lekarskiego.

UNLABELLED: This study was designed to investigate the connection between medical students' gender and their medical specialty preference, empathy and personal values. MATERIALS AND METHODS: The sample of 199 students was obtained from Medical University of Lódz, 124 were female and 75 were male. Distribution by class was 45.23% fifth year and 54.77% sixth year. The mean age of the students was 24.07 years (SD = 0.92). They had demographic survey and reliable tests performed. Empathy was examined with Empathy Questionnaire by A. Weglinski and personal values by Allport-Vernon-Lindzey Study of Values and Scheler's Personal Values Scale by P. Brzozowski. RESULTS: In the research medical students' gender was associated with medical students' specialty preference (p < 0.001). Men favoured surgery whereas women preferred gynaecology and internal medicine. In this study female students scored higher in empathy (p < 0.001) and in the Religious Values (p < 0.01). Male students scored higher in the Economic Values (p < 0.05). There was no significant association between medical students' gender and other personal values. CONCLUSIONS: There is the connection between medical students' gender and their medical specialty preference. Medical students gender is associated with their empathy, religious values and economic values.