Dim-light colour vision in the facultatively nocturnal Asian giant honeybee, Apis dorsata.

We discovered nocturnal colour vision in the Asian giant honeybee Apis dorsata-a facultatively nocturnal species-at mesopic light intensities, down to half-moon light levels (approx. 10-2 cd m-2). The visual threshold of nocturnality aligns with their reported nocturnal activity down to the same light levels. Nocturnal colour vision in A. dorsata is interesting because, despite being primarily diurnal, its colour vision capabilities extend into dim light, while the 'model' European honeybee Apis mellifera is reported to be colour-blind at twilight. By employing behavioural experiments with naturally nesting A. dorsata colonies, we show discrimination of the trained colour from other stimuli during the day, and significantly, even at night. Nocturnal colour vision in bees has so far only been reported in the obligately nocturnal carpenter bee Xylocopa tranquebarica. The discovery of colour vision in these two bee species, despite differences in the extent of their nocturnality and the limitations of their apposition compound eye optics, opens avenues for future studies on visual adaptations for dim-light colour vision, their role in pollination of flowers at night, and the effect of light pollution on nocturnal activity in A. dorsata, a ubiquitous pollinator in natural, agricultural and urban habitats in the Asian tropics and sub-tropics.

Spatial resolution and sensitivity of the eyes of the stingless bee, Tetragonula iridipennis.

Stingless bees are important pollinators in the tropics. The tremendous variation in body size makes them an excellent group to study how miniaturization affects vision and visual behaviours. Using direct measurements and micro-CT, we reconstructed the eye structure, estimated anatomical spatial resolution and optical sensitivity of the stingless bee Tetragonula iridipennis. T. iridipennis is similar in size to the Australian stingless bee Tetragonula carbonaria and is smaller than honeybees. It has correspondingly small eyes (area = 0.56 mm2), few ommatidia (2451 ± 127), large inter-facet (3.0 ± 0.6°) and acceptance angles (2.8°). Theoretical estimates suggest that T. iridipennis has poorer spatial resolution (0.17 cycles degree-1) than honeybees, bumblebees, and T. carbonaria. Its optical sensitivity (0.08 µm2 sr), though higher than expected, is within the range of diurnal bees. This may provide them with greater contrast sensitivity, which is likely more relevant than the absolute sensitivity in this diurnal bee. Behaviourally determined detection thresholds for single targets using y-maze experiments were 11.5° for targets that provide chromatic contrast alone and 9.1° for targets providing chromatic and achromatic contrast. Further studies into microhabitat preferences and behaviour are required to understand how miniaturization influences its visual ecology.

Visual detection thresholds in the Asian honeybee, Apis cerana.

To understand how insect pollinators find flowers against complex backgrounds in diverse natural habitats, it is required to accurately estimate the thresholds for target detection. Detection thresholds for single targets vary between bee species and have been estimated in the Western honeybee, a species of bumblebee and in a stingless bee species. We estimated the angular range of detection for coloured targets in the Asian honeybee Apis cerana. Using a Y-maze experimental set up, we show that targets that provided both chromatic and green receptor contrast were detected at a minimum visual angle of 7.7°, while targets with only chromatic contrast were detected at a minimum angle of 13.2°. Our results thus provide a robust foundation for future studies on the visual ecology of bees in a comparative interspecific framework.

Complex multi-modal sensory integration and context specificity in colour preferences of a pierid butterfly.

Innate colour preferences in insects were long considered to be a non-flexible representation of a floral 'search image' guiding them to flowers during initial foraging trips. However, these colour preferences have recently been shown to be modulated by multi-sensory integration of information. Using experiments on the butterfly Catopsilia pomona (common emigrant), we demonstrate that cross-modal integration of information not only affects colour preferences but also colour learning, and in a sex-specific manner. We show that spontaneous colour preference in this species is sexually dimorphic, with males preferring both blue and yellow while females prefer yellow. With minimal training (two training sessions), both males and females learned to associate blue with reward, but females did not learn green. This suggests that the aversion to green, in the context of foraging, is stronger in females than in males, probably because green is used as a cue to find oviposition sites in butterflies. However, females learned green after extensive training (five training sessions). Intriguingly, when a floral odour was present along with green during training, female colour preference during the subsequent choice tests resembled their innate preference (preference for yellow). Our results show that multi-sensory integration of information can influence preference, sensory bias, learning and memory in butterflies, thus modulating their behaviour in a context-specific manner.

Radiological protocol in spinal trauma: literature review and Spinal Cord Society position statement.

PURPOSE: The Spinal Cord Society constituted a panel tasked with reviewing the literature on the radiological evaluation of spinal trauma with or without spinal cord injury and recommend a protocol. This position statement provides recommendations for the use of each modality, i.e., radiographs (X-rays), computed tomography (CT), magnetic resonance imaging (MRI), as well as vascular imaging, and makes suggestions on identifying or clearing spinal injury in trauma patients. METHODS: PubMed was searched for the corresponding keywords from January 1, 1980, to August 1, 2017. A MEDLINE search was subsequently undertaken after applying MeSH filters. Appropriate cross-references were retrieved. Out of the 545 articles retrieved, 105 relevant papers that address the present topic were studied and the extracted content was circulated for further discussions. A draft position statement was compiled and circulated among the panel members via e-mail. The draft was modified by incorporating relevant suggestions to reach a consensus. RESULTS AND CONCLUSION: For imaging cervical and thoracolumbar spine trauma patients, CT without contrast is generally considered to be the initial line of imaging and radiographs are required if CT is unavailable or unaffordable. CT screening in polytrauma cases is best done with a multidetector CT by utilizing the reformatted images obtained when scanning the chest, abdomen, and pelvis (CT-CAP). MRI is indicated in cases with neurological involvement and advanced cervical degenerative changes and to determine the extent of soft tissue injury, i.e., disco-ligamentous injuries as well as epidural space compromise. MRI is also usually performed when X-rays and CT are unable to correlate with patient symptomatology. These slides can be retrieved under Electronic Supplementary Material.

Foraging strategies and physiological adaptations in large carpenter bees.

Large carpenter bees are charismatic and ubiquitous flower visitors in the tropics and sub-tropics. Unlike honeybees and bumblebees that have been popular subjects of extensive studies on their neuroethology, behaviour and ecology, carpenter bees have received little attention. This review integrates what is known about their foraging behaviour as well as sensory, physiological and cognitive adaptations and is motivated by their versatility as flower visitors and pollinators. This is evident from their extremely generalist foraging and adeptness at handling diverse flower types as legitimate pollinators and as illegitimate nectar robbers. They purportedly use traplining to forage between isolated patches and are long-distance flyers over several kilometres suggesting well-developed spatial learning, route memory and navigational capabilities. They have a broad range of temperature tolerance and thermoregulatory capabilities which are likely employed in their forays into crepuscular and nocturnal time periods. Such temporal extensions into dim-light periods invoke a suite of visual adaptations in their apposition optics. Thus, we propose that carpenter bees are an excellent though understudied group for exploring the complex nature of plant-pollinator mutualisms from ecological and mechanistic perspectives.

A comparative analysis of colour preferences in temperate and tropical social bees.

The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees' responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees' preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.

Vertebral and Intraspinal Anomalies in Indian Population with Congenital Scoliosis: A Study of 119 Consecutive Patients

STUDY DESIGN: Retrospective case study by clinical and radiological data analysis. PURPOSE: To analyze different types of vertebral anomalies and the incidence of associated intraspinal anomalies in the Indian population. OVERVIEW OF LITERATURE: This is the largest study of congenital scoliosis and associated intraspinal anomalies in Indian population. Incidence of intraspinal anomaly in this series is 47% which is higher than previous literature. Hemivertebra was the most common anomaly as seen in previous studies. METHODS: A total of 119 patients with congenital scoliosis who underwent surgery between December 2006 and December 2012 were studied. Data was reviewed with medical records, plain radiographs, and magnetic resonance imaging (MRI) scans. RESULTS: Thoracolumbar curve was most common, seen in 43.6% of patients. In addition to scoliotic deformity, kyphosis was seen in 26% of patients. Failure of formation, the most common vertebral anomaly, was seen in 51.2% of patients, failure of segmentation was seen in 19.3% of patients, and there were 29.4% patients having both formation and segmentation anomalies. Hemivertebra was the most common vertebral anomaly seen in 66.3% of patients and for whom 63.2% were in thoracic spine. Intraspinal anomalies were associated with 47% of patients with congenital scoliosis. Tethered cord was the most common intraspinal abnormality and was found in 48.2% patients with intraspinal anomalies. The patients with failure of segmentation and mixed deformities were found to have a significantly higher incidence of intraspinal anomalies (65% and 57%, respectively) than those with failure of formation (34%). Out of 31 patients with kyphotic deformity 29% had intraspinal anomalies, and amongst them tethered cord was the most common anomaly seen in 66% patients. Out of 12 patients with neurocutaneous markers, 83% patients had intraspinal anomaly. CONCLUSIONS: Intraspinal anomalies were seen in 47% of patients with congenital scoliosis in the Indian population. Tethered cord was the most common intraspinal anomaly, seen in 48% cases of congenital scoliosis. Hemivertebra was seen in 66% cases and was the most common vertebral defect. Hence MRI imaging of whole spine should be done in all cases of congenital scoliosis before any surgical intervention. Special attention should be given to physical examination and visualization of any neurocutaneous markers, which are associated with a higher incidence of intraspinal anomalies; absence of a neurocutaneous marker, however, does not rule out intraspinal anomaly.

Motion cues improve the performance of harnessed bees in a colour learning task.

The proboscis extension conditioning (PER) is a successful behavioural paradigm for studying sensory and learning mechanisms in bees. Whilst mainly used with olfactory and tactile stimuli, more recently reliable PER conditioning has been achieved with visual stimuli such as colours and looming stripes. However, the results reported in different studies vary quite strongly, and it remains controversially discussed how to best condition visual PER. It is particularly striking that visual PER leads to more limited performance as compared to visual conditioning of free-flying bees. It could be that visual PER learning is affected by the lack of movement and that the presence of visual motion cues could compensate for it. We tested whether bees would show differences in learning performances when conditioned either with a colour and motion stimulus in combination or with colour alone. Colour acquisition was improved in the presence of the motion stimulus. The result is consistent with the idea that visual learning might be tightly linked to movement in bees, given that they use vision predominantly during flight. Our results further confirm recent findings that successful visual PER conditioning in bees is achievable without obligatorily removing the antennae.

Improving levels of evidence in studies published in spinal journals from 1983 to 2011.

INTRODUCTION: The evidence basis for spinal surgical practice is closely related to the quality of clinical studies published. In the hierarchy of study designs, the quality of evidence from a randomised controlled trial (RCT) and meta-analysis are considered better than other types of prospective and retrospective study designs. We assessed the level of evidence in studies published from 1983 to 2011 in 4 journals, publishing predominantly on spine related topics. METHODS: Computerised search of the Medline database was undertaken to evaluate the articles published in 4 'spinal' journals (Spine, European Spine Journal, Journal of Spinal Disorders and Techniques and Spinal Cord) from 1983 to 2011. The numbers of RCTs, meta-analyses and other clinical trials (non-RCT) over the time periods 1983-7, 1988-92, 1993-7, 1998-2002, 2003-7 and 2008-11 were compared. RESULTS: From a total number of 21775 articles evaluated, there were 888 (4.1%) RCTs, 93 (0.4%) meta-analyses and 1355 (6.2%) other clinical trials. Overall, comparing the time periods 1983-7 with 2008-11, there were increases in the proportion of RCTs (1.6% to 5.1%), meta-analysis (0% to 0.6%) and other clinical trials (0.9% to 6.3%) and a decrease in the proportion of other articles published (97.6% to 88.1%). These changes appear to have plateaued after 2003-7. CONCLUSIONS: Although RCTs, meta-analysis and other clinical trials form a small proportion of the studies published in leading 'spinal' journals, there have been an encouraging increase in their proportion over the years. This is comparable with other larger surgical specialities and provides a better evidence basis for clinical practice in spinal disorders.

Anterior thoracic foraminotomy through mini-thoracotomy for the treatment of giant thoracic disc herniations.

STUDY DESIGN: A retrospective review of a case series. OBJECTIVES: Giant thoracic disc herniations remain a surgical challenge and historically have been associated with significant complications. While neurological outcomes have improved with the abandonment of decompressive laminectomy, the attempt to minimize surgical complications and associated morbidities continues through less-invasive approaches. With the current study, we describe a surgical technique to treat giant thoracic disc herniations while minimizing approach-related morbidity. METHODS: Demographic and radiographic data; clinical outcome and perioperative complications were retrospectively analysed for patients with single-level giant thoracic disc herniations who underwent mini-thoracotomy and selective microsurgical anterior spinal cord decompression without instrumented fusion. RESULTS: Between 2007 and 2012, 7 consecutive patients with giant thoracic disc herniations were treated (average age of 53 years; range 45-66 years). The average canal encroachment was 73.2 % (range 40-92 %) with 5 grossly calcified discs of which 3 had transdural components. All patients had gradual myelopathic progression. The average Nurick grade was 3.5 (range 2-5). All patients were successfully treated with anterior microsurgical decompression without instrumentation. Uninstrumented fusion with rib graft was performed only in one patient with advanced degenerative changes. Average time of surgery was 337.8 min (range 220-450 min). The average length of hospital stay was 7.4 days (range 6-11 days). The average neurological status at follow-up (average 23.5 months; range 9-36 months) using the modified Nurick grading scale was 1.28. No vertebral collapse or loss of spinal alignment developed. There were no neurological complications. One patient developed an acute headache and diplopia, 10 days after surgery, following sneezing associated with a post-operative thoracic cerebrospinal fluid leakage requiring revision. Two patients suffered an approach-related complication in form of intercostal neuralgia; one was persistent. CONCLUSIONS: Anterior decompression using a mini-transthoracic approach provides sufficient exposure for microsurgical decompression of giant thoracic disc herniations without disrupting the stability of the spine. Microsurgical decompression without instrumentation does not appear to lead to vertebral collapse or spinal malalignment.

Improvement of persistent developmental stuttering after surgical excision of a left perisylvian meningioma.

Persistent developmental stuttering (PDS) has been treated by speech and language and psychotherapy with limited success. We report the case of a 69-year-old with PDS since the age of five. A left perisylvian meningioma was successfully resected following investigation for generalised seizure. Spontaneous significant improvement in stuttering after surgery in the perisylvian area to the best of our knowledge has not been reported.

Thoracic intradural extramedullary capillary haemangioma.

The authors report a rare case of thoracic intradural extramedullary capillary haemangioma, the clinical presentation of which was similar to any other intraspinal mass. Magnetic resonance imaging does not always distinguish this entity from others, but the presence of enlarged vasculature is often a useful clue. Complete resection is the treatment of choice of this hamartomatous lesion.