Oculomotor Function Research Articles

A central mesencephalic reticular formation projection to the supraoculomotor area in macaque monkeys.

The central mesencephalic reticular formation is physiologically implicated in oculomotor function and anatomically interwoven with many parts of the oculomotor system's premotor circuitry. This study in Macaca fascicularis monkeys investigates the pattern of central mesencephalic reticular formation projections to the area in and around the extraocular motor nuclei, with special emphasis on the supraoculomotor area. It also examines the location of the cells responsible for this projection. Injections of biotinylated dextran amine were stereotaxically placed within the central mesencephalic reticular formation to anterogradely label axons and terminals. These revealed bilateral terminal fields in the supraoculomotor area. In addition, dense terminations were found in both the preganglionic Edinger-Westphal nuclei. The dense terminations just dorsal to the oculomotor nucleus overlap with the location of the C-group medial rectus motoneurons projecting to multiply innervated muscle fibers suggesting they may be targeted. Minor terminal fields were observed bilaterally within the borders of the oculomotor and abducens nuclei. Injections including the supraoculomotor area and oculomotor nucleus retrogradely labeled a tight band of neurons crossing the central third of the central mesencephalic reticular formation at all rostrocaudal levels, indicating a subregion of the nucleus provides this projection. Thus, these experiments reveal that a subregion of the central mesencephalic reticular formation may directly project to motoneurons in the oculomotor and abducens nuclei, as well as to preganglionic neurons controlling the tone of intraocular muscles. This pattern of projections suggests an as yet undetermined role in regulating the near triad.

Oculomotor neurocircuitry, a structural connectivity study of infantile nystagmus syndrome.

Infantile Nystagmus Syndrome (INS) is one of the leading causes of significant vision loss in children and affects about 1 in 1000 to 6000 births. In the present study, we are the first to investigate the structural pathways of patients and controls using diffusion tensor imaging (DTI). Specifically, three female INS patients from the same family were scanned, two sisters and a mother. Six regions of interest (ROIs) were created manually to analyze the number of tracks. Additionally, three ROI masks were analyzed using TBSS (Tract-Based Spatial Statistics). The number of fiber tracks was reduced in INS subjects, compared to normal subjects, by 15.9%, 13.9%, 9.2%, 18.6%, 5.3%, and 2.5% for the pons, cerebellum (right and left), brainstem, cerebrum, and thalamus. Furthermore, TBSS results indicated that the fractional anisotropy (FA) values for the patients were lower in the superior ventral aspects of the pons of the brainstem than in those of the controls. We have identified some brain regions that may be actively involved in INS. These novel findings would be beneficial to the neuroimaging clinical and research community as they will give them new direction in further pursuing neurological studies related to oculomotor function and provide a rational approach to studying INS.

Cortical and thalamic projections to cytoarchitectural areas 6Va and 8C of the marmoset monkey: connectionally distinct subdivisions of the lateral premotor cortex.

We studied the afferent connections of two cytoarchitectural subdivisions of the caudolateral frontal cortex, areas 6Va and 8C, in marmoset monkeys. These areas received connections from the same set of thalamic nuclei, including main inputs from the ventral lateral and ventral anterior complexes, but differed in their patterns of corticocortical connections. Areas 8C and 6Va had reciprocal interconnections, and received similar proportions of afferents from premotor areas 6M and 6DC, and from the prefrontal cortex. However, area 8C received stronger inputs from frontal areas that have been implicated in oculomotor functions, whereas area 6Va received stronger projections from the primary motor area. Somatosensory projections to area 6Va were generally stronger than those to area 8C, and originated from several areas; in contrast, only the second somatosensory area (S2) sent major inputs to area 8C. Finally, although both 6Va and 8C received major inputs from the rostral posterior parietal cortex (putative homologs of areas PE, PF, and PFG), area 8C also received a variety of smaller connections from posterior midline, caudal posterior parietal, and extrastriate areas. Statistical analyses revealed that the pattern of connections of area 8C is more akin to that characterizing a premotor area, rather than a prefrontal area. We conclude that cytoarchitectural area 6Va in the marmoset is similar to ventral premotor areas identified in other simian primates, and that area 8C corresponds to a specialized subdivision of the caudal premotor complex where visual information for the guidance of movements is likely to be emphasized.

Abnormal White Matter Blood-Oxygen-Level-Dependent Signals in Chronic Mild Traumatic Brain Injury.

Concussion, or mild traumatic brain injury (mTBI), can cause persistent behavioral symptoms and cognitive impairment, but it is unclear if this condition is associated with detectable structural or functional brain changes. At two sites, chronic mTBI human subjects with persistent post-concussive symptoms (three months to five years after injury) and age- and education-matched healthy human control subjects underwent extensive neuropsychological and visual tracking eye movement tests. At one site, patients and controls also performed the visual tracking tasks while blood-oxygen-level-dependent (BOLD) signals were measured with functional magnetic resonance imaging. Although neither neuropsychological nor visual tracking measures distinguished patients from controls at the level of individual subjects, abnormal BOLD signals were reliably detected in patients. The most consistent changes were localized in white matter regions: anterior internal capsule and superior longitudinal fasciculus. In contrast, BOLD signals were normal in cortical regions, such as the frontal eye field and intraparietal sulcus, that mediate oculomotor and attention functions necessary for visual tracking. The abnormal BOLD signals accurately differentiated chronic mTBI patients from healthy controls at the single-subject level, although they did not correlate with symptoms or neuropsychological performance. We conclude that subjects with persistent post-concussive symptoms can be identified years after their TBI using fMRI and an eye movement task despite showing normal structural MRI and DTI.

The nucleus prepositus hypoglossi contributes to head direction cell stability in rats.

Head direction (HD) cells in the rat limbic system fire according to the animal's orientation independently of the animal's environmental location or behavior. These HD cells receive strong inputs from the vestibular system, among other areas, as evidenced by disruption of their directional firing after lesions or inactivation of vestibular inputs. Two brainstem nuclei, the supragenual nucleus (SGN) and nucleus prepositus hypoglossi (NPH), are known to project to the HD network and are thought to be possible relays of vestibular information. Previous work has shown that lesioning the SGN leads to a loss of spatial tuning in downstream HD cells, but the NPH has historically been defined as an oculomotor nuclei and therefore its role in contributing to the HD signal is less clear. Here, we investigated this role by recording HD cells in the anterior thalamus after either neurotoxic or electrolytic lesions of the NPH. There was a total loss of direction-specific firing in anterodorsal thalamus cells in animals with complete NPH lesions. However, many cells were identified that fired in bursts unrelated to the animals' directional heading and were similar to cells seen in previous studies that damaged vestibular-associated areas. Some animals with significant but incomplete lesions of the NPH had HD cells that were stable under normal conditions, but were unstable under conditions designed to minimize the use of external cues. These results support the hypothesis that the NPH, beyond its traditional oculomotor function, plays a critical role in conveying vestibular-related information to the HD circuit.

13. Neuromuscular transmission disorders in miller fisher syndrome

Introduction Miller Fisher syndrome (MFS) is a variant of Guillain–Barre syndrome (GBS). MFS is clinically defined by trias – ophthalmoplegia, ataxia, areflexia. Antibodies against ganglioside GQ1b are bound on the nodal and paranodal sections of oculomotor nerves, sensory nerves (including spinal ganglia) and cerebellum. Ophthalmoparesis is usually severe with prominent fatiguability. In these patients neuromuscular transmission disorders are suspected. Case report A 52-year man was admitted to neurological department for progressive external ophthalmoparesis with generalized ataxia. The neurological signs and symptoms developer during 5 days with preceding upper respiratory tract infection. The first diagnosis was MFS. There was very prominent especially oculomotor fatiguability with worsening during the day and after rehabilitation, that neuromuscular transmission was suspected too. Neurophysiological investigation Motor conduction studies (including F-waves) were normal, sensory conduction studies with very low amplitude of sensory nerve action potentials. H-reflex was not elicitable. Needle EMG of biceps brachii was normal (14 days after disease onset). Repetitive stimulation (3 Hz) with recording from trapezius with 7% decrement (4th response) and from nasalis 5.8%. Axonal stimulated SF EMG with recording by concentric needle electrode from frontalis muscle presented an increased jitter −32.91 μs and 9% blocking - with the stimulation rate 3 Hz. With stimulation rate 10 Hz the jitter decreased to 26.26 μs and without blocking, with 20 Hz stimulation rate was the jitter normal (21.83 μs) and without blocking. Other investigations GQ1b antibody level was prominent – 315.7% (norm – up to 9%), antibodies against acetylcholine receptors were not found. MR of brain and thorax were normal. The patient was treated with a series of plasma exchange. After 14 days he began to walk with crutches and ptosis and diplopia significantly decreased. 6 weeks later he was able to walk without support and oculomotor function normalized. Neurophysiological findings in MFS are discussed. Conclusion In our patient with MFS we diagnosed presynaptic type (axonal) disorder of neuromuscular transmission.

Predicting oculomotor behaviour from correlated populations of posterior parietal neurons.

Oculomotor function critically depends on how signals representing saccade direction and eye position are combined across neurons in the lateral intraparietal area (LIP) of the posterior parietal cortex. Here we show that populations of parietal neurons exhibit correlated variability, and that using these interneuronal correlations yields oculomotor predictions that are more accurate and also less uncertain. The structure of LIP population responses is therefore essential for reliable read-out of oculomotor behaviour.

Eye movements in Alzheimer's disease.

A growing body of literature has investigated changes in eye movements as a result of Alzheimer's disease (AD). When compared to healthy, age-matched controls, patients display a number of remarkable alterations to oculomotor function and viewing behavior. In this article, we review AD-related changes to fundamental eye movements, such as saccades and smooth pursuit motion, in addition to changes to eye movement patterns during more complex tasks like visual search and scene exploration. We discuss the cognitive mechanisms that underlie these changes and consider the clinical significance of eye movement behavior, with a focus on eye movements in mild cognitive impairment. We conclude with directions for future research.

Effects of repetitive low-level blast exposure on visual system and ocular structures.

The purpose of this study was to determine whether repetitive exposure to low-level blasts during military breacher training produces acute and cumulative damage to the ocular tissues or visual system. The effects of low-level blast exposure on high-contrast visual acuity, contrast sensitivity, oculomotor function, color vision, visual field (VF), pupillary light reflex, corneal endothelial cell density (ECD), macular thickness, retinal nerve fiber layer thickness, and cup-to-disc ratio were assessed using a battery of standard clinical ophthalmic tests administered 10 times over a 2-year period. Data from nine breacher instructors (Cadre) were compared with data from four breacher engineers (CONTROL). The Cadre group showed higher vertical deviation at near than the CONTROL group over time. The VF mean deviation on the left eye that tended to be worse in the Cadre group was worse throughout the study, suggesting a decrease in VF sensitivity (Cadre: -0.20 +/- 0.15 dB; 1.05 +/- 0.15 dB; p = 0.03). The Cadre group had a reduced ECD (right eye: Cadre 2,502 cells/mm(2) vs CONTROL 2,808 cells/mm(2), p = 0.05; left eye: Cadre 2,558 cells/mm(2) vs CONTROL 2,892 cells/mm(2), p = 0.04). These results suggest that even low-level primary blast has the potential to produce occult eye injury.

Spontaneous improvement in oculomotor function of children with cerebral palsy.

Eye movements are essential to get a clear vision of moving objects. In the present study, we assessed quantitatively the oculomotor deficits of children with cerebral palsy (CP). We recorded eye movements of 51 children with cerebral palsy (aged 5-16 years) with relatively mild motor impairment and compared their performance with age-matched control and premature children. Overall eye movements of children with CP are unexpectedly close to those of controls even though some oculomotor parameters are biased by the side of hemiplegia. Importantly, the difference in performance between children with CP and controls decreases with age, demonstrating that the oculomotor function of children with CP develops as fast as or even faster than controls for some visual tracking parameters. That is, oculomotor function spontaneously improves over the course of childhood. This evolution highlights the ability of lesioned brain of children with CP to compensate for impaired motor function beyond what would be achieved by normal development on its own.

PO-0428 Visual Motion Perception In Very Preterm Infants At 4 Months And Relation To Cerebral Imaging: Abstract PO-0428 Table 1

<h3>Background and aims</h3> Children born very preterm are at increased risk for visual motor impairment. Our aim was to investigate whether ifmpaired oculomotor function is associated with morphological and ADC (Apparent Diffusion Coefficient) changes on brain MRI. <h3>Method</h3> Visual tracking ability (eye and head movements) was measured at 4 months corrected age in 32 very preterm infants (mean GA 27 w). The following variables were assessed; Gain of gaze, Smooth pursuit (SP) eye movements, the number of saccades &gt;100 deg/s, and head movements. MRI examinations were performed at 2.5–5 years of age, including ADC measurements at multiple locations. <h3>Results</h3> There were significant univariate correlations between some gaze parameters, MR abnormalities and asymmetries in ADC values. Moreover, there was a correlation between the number of observed perivascular spaces and SP (r_s = -0.407 p = 0.025) <h3>Conclusion</h3> This is the first study to examine the relationship between young infants’ visual tracking abilities and later MRI. Poorer tracking for gaze and saccades correlated with white matter damage, while SP correlated with ADC values for the pons.

King of the field

Accumulating evidence on the long-term damage of repeated concussive injuries is strengthening the need for pitch-side recognition and immediate removal of players from the arena of play if a concussion is suspected. However, current guidelines fall short of providing any practical guidance for the withdrawal of a player to seek further clinical assessment, and the letter of these are not adhered to in many cases.1The Lancet NeurologyTime for a gamechanger in the management of concussion.Lancet Neurol. 2013; 12: 415Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar, 2The Lancet NeurologyTackling the sports-related concussion crisis.Lancet Neurol. 2014; 13: 747Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar As more than half of pathways in the brain are involved in visual processing, these systems are particularly susceptible to the effects of traumatic brain injury; therefore, tests that evaluate the integrity of the visual systems provide a potentially useful surrogate to screen for and monitor the effects of concussion.3Ventura RE Balcer LJ Galetta AL The neuro-ophthalmology of head trauma.Lancet Neurol. 2014; 13: 1006-1016Summary Full Text Full Text PDF Scopus (128) Google Scholar The King-Devick (K-D) test has been used in this context in several sports, including rugby, boxing, mixed martial arts, American football, soccer, basketball, and ice hockey.4King D Brughelli M Hume P Gissane C Assessment, management and knowledge of sport-related concussion: systematic review.Sports Med. 2014; 44: 449-471Crossref PubMed Scopus (83) Google Scholar It was first developed to investigate the relation between poor oculomotor function and learning disabilities.4King D Brughelli M Hume P Gissane C Assessment, management and knowledge of sport-related concussion: systematic review.Sports Med. 2014; 44: 449-471Crossref PubMed Scopus (83) Google Scholar The time taken to correctly read out numbers on cards, which progressively become more difficult to read in a flowing manner, measures alterations in saccades, attention, concentration, speech and language, and other correlates of brain function. In the sporting context, any increase in the time taken to complete the test from a predetermined baseline might indicate a concussive event requiring immediate withdrawal from play and referral for medical evaluation. The K-D test can be done in minutes and does not necessarily need to be administered by medically trained personnel;5Leong DF Balcer LJ Galetta SL Liu Z Master CL The King-Devick test as a concussion screening tool administered by sports parents.J Sports Med Phys Fit. 2014; 54: 70-77PubMed Google Scholar however, it is only one of several potential tests, and further validation—in longitudinal studies and in cohorts of different ages—is required before we know if it is generalisable in different populations and could form part of assessment strategies for a wider range of sports.

Prevalence of visual problems among stroke survivors in Hong Kong Chinese

BackgroundStroke, a common cerebrovascular accident, usually results in various extents of functional disability. Extensive studies have shown that ocular and visual problems are common in patients with stroke. Unfortunately, current stroke rehabilitation programs rarely address stroke‐related ocular and visual problems in Hong Kong.MethodsTo examine how visual impairment (for example, deterioration in visual acuity and restriction in visual field) affects the stroke population in Hong Kong, vision screening was conducted for post‐stroke patients attending in‐patient and out‐patient stroke clinics at two hospitals.ResultsOne hundred and thirteen stroke patients were recruited. The percentage of various aspects of visual problems in Hong Kong post‐stroke patients was generally lower than that reported in Western countries; however, a high percentage of patients had deficits in oculomotor (53.1 per cent) and vergence functions (11.5 per cent), restrictions in binocular visual field (11.5 per cent) and impairment in visual acuity (worse than 0.30-logMAR, 29.8 per cent). Conversely, only a small proportion of patients noticed problems with their vision (for example, diplopia and blurry vision) through subjective reports. This revealed that many post‐stroke patients had undetected or undiagnosed ocular and visual problems. Appropriate referral was given to patients with visual problems for further evaluation and treatment.ConclusionNeglecting visual problems may impose deteriorating effect on patients' stroke rehabilitation and functional independence and lead to increased incidents of injury. To address this potential hindrance in rehabilitation, formal screening for visual problems in stroke patients in a rehabilitation setting is essential.

J27 System For Assessment Of The Visual Smooth Pursuit Impairment In Huntington Disease

<h3>Background</h3> During the development of Huntington disease smooth pursuit may become impaired, decreasing the gain of the pursuit and releasing the saccadic intrusions. Although UHDRS includes the pursuit evaluation, it estimates the performance of this oculomotor function only qualitatively. Meanwhile its quantitative evaluation without eye movement recording equipment is practically impossible. It barely allows to notice large saccadic intrusions and it cannot detect reduction of the gain. Furthermore UHDRS motor score uses four point scale to assess the pursuit, rating it from “normal”, through “jerky”, “incomplete range” and “cannot pursue”. Such a subjective method strongly depends on examiner’s skill and experience. <h3>Technique</h3> We designed the system that allows objective measurement of smooth pursuit parameters and its quantification. Additionally, the immobilisation of the head usually required in studying smooth pursuit is unnecessary. The sensor is placed on the subject’s head along with the laser servo projector mounted on forehead plate allowing for viewing the moving target on the wall. Eye movement measuring system uses infrared reflectometry, providing high temporal and spatial resolution (1kHz, 5 angular minutes). Such a device, along with accompanying custom-designed software, allows automatic detection of saccadic intrusions as small as 1 degree. <h3>Conclusions</h3> The developed instrumentation demonstrated the capability for immediate and quantitative assessment of the smooth pursuit quality. Furthermore, it is characterised by easy application and minimal intrusiveness.

F02 Cognitive And Oculomotor Performance In Premanifest Huntington Disease: One-year Follow-up

Background Cognitive and oculomotor performance have been extensively studied in Huntington Disease (HD), but evidence for significant deficits in premanifest gene carriers is still controversial. Moreover, their role as markers of disease status and progression is not yet convincingly established. Aims This study aims to understand the evolution of neuropsychological and saccadic performance in premanifest HD (preHD) over a course of 3 years. The results of the baseline assessment and preliminary longitudinal data regarding the one-year follow-up visit of the preHD group are shown here. Methods 15 preHD participants and 22 controls completed the baseline assessment. 10 preHD participants have completed the second visit so far. A comprehensive neuropsychological test battery was used to evaluate the overall cognitive functioning of the participants. An experimental paradigm was designed to assess oculomotor function. Participants completed four different horizontal saccadic tasks with an increasing executive/memory load: prosaccade, antisaccade, 1-or-2 back memory prosaccade and antisaccade. Success rate (percentage of error free trials), latency, directional and timing errors were calculated. Results No significant differences were found between preHD and controls in any of the neuropsychological tests, suggesting a similar overt cognitive baseline at visit #1. The cognitive results of the preHD group at visits #1 and #2 showed that their performance improved in some of the tests used. Concerning saccadic parameters, the preHD group exhibited at baseline a significantly faster response time compared to controls, specifically in memory antisaccades. At visit #2, preHD participants showed a lower success rate and an increased latency, particularly in tasks involving inhibitory processes. Conclusions These data suggest that oculomotor performance of the preHD group may rely on more automatic responses when an executive/memory load is added to the task, deteriorates in time, and also that temporal saccade properties can mark the presence of early neurodegeneration in HD. Furthermore, despite an already evident decline in the saccadic performance of preHD individuals after one year, this is not paralleled by overt cognitive deficits as measured by conventional neuropsychological tests.

E06 Neuroimaging In Huntington's Disease: On Brain Function, And On Brain Structure From Classical Approaches To Application Of Multivoxel Pattern Analysis

<h3>Background</h3> In Huntington’s disease, structural and functional changes of the central nervous system affect primarily the basal ganglia and fronto-striatal circuitry, as demonstrated by large cohort studies. <h3>Aims</h3> This project aims at detecting earliest functional/structural alterations in premanifest gene carriers (preHD). Here, we present year1 assessments with neuroimaging, including brain function, structure, and application of support vector machines. <h3>Methods</h3> 18 controls, 14 preHD (far YEO), and 11 early-HD patients underwent MRI in a 3T Siemens Scanner. Acquisitions comprised two structural MRI scans, diffusion weighted imaging (60 directions, b = 1000), and fMRI study of oculomotor function. The latter included pro-saccades, anti-saccades, and 1-and-2 back memory-antisaccade. Additionally, oculomotor psychophysics were performed out-bore. <h3>Results</h3> Early-HD participants have significant decreased volumes of basal ganglia structures, which correlated significantly with saccade express errors, and cortical thinning throughout an extended area. To preHD, thinning is identified once using less conservative thresholds. PreHD participant had decreased volume of the left caudate, and express and direction errors correlated with striatal volumes. On the other hand, when applying support vector machines to grey matter or fractional anisotropy (whole-brain, basal-ganglia ROIs), classification of HD versus pre-HD/controls attained accuracies above 80%, whereas preHD vs. Controls results were not significant. Finally, fMRI results showed robust difference between preHD and control group (RFX, cluster thresholded) for oculomotor tasks involving inhibitory components, in areas comprising caudate, ACC and pre-frontal cortex. <h3>Conclusions</h3> HD patients had overall alterations whereas first HD-related detectable alterations might derive from neural dysfunction preceding and/or simultaneous to initial neural loss.

Ethanol consumption impairs vestibulo-ocular reflex function measured by the video head impulse test and dynamic visual acuity.

Ethanol affects many parts of the nervous system, from the periphery to higher cognitive functions. Due to the established effects of ethanol on vestibular and oculomotor function, we wished to examine its effect on two new tests of the vestibulo-ocular reflex (VOR): the video head impulse test (vHIT) and dynamic visual acuity (DVA). We tested eight healthy subjects with no history of vestibular disease after consumption of standardized drinks of 40% ethanol. We used a repeated measures design to track vestibular function over multiple rounds of ethanol consumption up to a maximum breath alcohol concentration (BrAC) of 1.38 per mil. All tests were normal at baseline. VOR gain measured by vHIT decreased by 25% at the highest BrAC level tested in each subject. Catch-up saccades were negligible at baseline and increased in number and size with increasing ethanol consumption (from 0.13° to 1.43° cumulative amplitude per trial). DVA scores increased by 86% indicating a deterioration of acuity, while static visual acuity (SVA) remained unchanged. Ethanol consumption systematically impaired the VOR evoked by high-acceleration head impulses and led to a functional loss of visual acuity during head movement.

Effects of 24 h working on-call on psychoneuroendocrine and oculomotor function: a randomized cross-over trial.

On-call duty (OCD) is frequently associated with health and safety risks for both physicians and patients. The lack of studies conducted in clinical care environments and the ongoing public dialogue concerning OCD led to a detailed investigation of a working schedule including sleep fragmentation and extended work hours. Within-person randomized cross-over trial. Comparison of a 24h on-call shift (OCD) compared to a routine working-day (non on call, NOC) in hospital. 30 residents and senior physicians of the Department of Internal Medicine, Neurology and Otorhinolaryngology at the University Hospital Innsbruck. Sleep variables, cognitive performance (Concentration-Endurance d2 test), emotional status (Eigenschaftswoerterliste 60S), serum-cortisol, urinary cortisol and noradrenaline, heart-rate variability, and saccadic eye movements were determined before and after OCD and NOC respectively. Concentration-endurance performance was significantly reduced after OCD as compared to NOC by 16.4% (p<0.001). Changes in emotional status consisted in a reduction of subjective concentration and performance related activation after OCD by 17.4% (p<0.001) and 16.0% (p<0.001) respectively together with a 21.8% increase of general deactivation (p<0.001) and a 29.2% rise of fatigue (p<0.001). On the contrary, subjective activation and raised mood showed an 18.3% and 21.7% increase after OCD (p<0.01). Urinary noradrenaline excretion (46 μg/24 h, 19-97) was greater during OCD when compared to NOC (36 μg/24 h, 10-54, p<0.01). Sympathetic activity measured by heart rate variability was significantly higher during OCD in contrast to NOC (p<0.05). Serum-cortisol was lower in the morning after (132 ng/l, 60-273) than the morning before OCD (p<0.01). Finally, the number of short saccadic latencies was reduced after OCD (p<0.05) compared to NOC. 24 h OCD alters both, the sympathetic-adrenomedullary system as well as the hypothalamic pituitary-adrenocortical axis. Moreover, physicians' emotional state, cognitive and oculomotor performance seems to be influenced independently from sleep interruptions. The discrepancy between subjective feeling and objective cognitive impairments pose a risk for performing complex manual and cognitive tasks. Hence, our findings argue against an oversimplified interpretation of alterations in the physicians' psychoneuroendocrine structure in terms of impaired mood and neurocognitive deterioration combined with up-/dysregulated stress axes associated with OCD as a consequence of sleep deprivation.

Perspectivas sobre o uso de modelos murinos da síndrome de down em pesquisas translacionais envolvendo função visual e motora

1 . Presently, Brazilian epidemiological data show that the incidence of live born infants with DS is 1:600, whereas in the USA this number is approximately 1:700 2,3 . The large repertoire of phenotypic features and comorbities generally listed in association with DS includes various congenital cardiac malformations, conductive and sensorineural hearing loss, increased risk of seizure disorder, atlantoaxial subluxation, and thyroid dysfunction (typically hypothyroidism; sometimes subsequent to transitory hyperthyroidism). Many features compatible with early aging are also common; including the universal presence of the characteristic Alzheimer-type pathology in the fourth decade of life and consequent increased frequency of dementia starting in the fifth decade 4,5 . Besides these important DS components, the occurrence of alterations in visual and motor functions are also extremely frequent. The visual system in persons with DS can be affected in several ways, including the increased incidence of refractive errors, accommodative imprecision, amblyopia, strabismus, spontaneous nystagmus, oculomotor and vestibular function abnormalities, decreased visual acuity, and reduced sensitivity for color and contrast 6-11

Preface

Preface Brian J. McAllister (bio) The essays in this special issue of Narrative offer a small sample of a growing field of study within narrative theory: narrative in poetic form. More precisely, the essays here investigate the potential intersections between the concerns of narrative theory and the concerns of poetry studies, using one to inform the other in a mutually productive discourse. Brian McHale’s essay “Beginning to Think about Narrative in Poetry” offers perhaps the most explicit call for new work in this field. Though he acknowledges from the outset that this work stands on the shoulders of a “huge body of precedent” (11)—from Plato to Bakhtin to Genette—this earlier work avoids addressing poetic narratives’ differences from other kinds of narrative. As McHale makes plain, “We need to begin thinking about narrative in poetry … because we have not been doing so very much lately, and because, whenever we have done so, we have rarely thought about what differentiates narrative in poetry from narrative in other genres or media, namely its poetry component” (11; emphasis original). When considering narrative poetry through the lens of narrative theory, one cannot simply brush aside the poetic aspects of the text. That seemingly obvious consideration of [End Page 151] the poetic in concert and in communication with the narrative directs the critical work in the essays that follow. With this larger objective in mind, this collection includes critical approaches that attempt to answer these questions about poetry’s position in and as narrative, considering narrative theory and poetic studies through a variety of methodologies—from rhetorical narrative theory to reader response to deconstruction—and with a range of poetic texts—from modernist poetic sequence to Romantic verse narrative to visual poetry. Peter Hühn’s essay begins the collection by exploring lyric poetry in either fictional or factual modes. Hühn situates the genre within larger fields of literary form in order to recognize lyric poetry’s ambivalent position between the two categories, as exemplified in his argument by the sonnet. Jason M. Coats then turns to Chistopher Isherwood and W. H. Auden’s problematically structured travel book, Journey to a War, in order to refine rhetorical considerations of the lyric by expanding theories of progression in lyric poetry. This refinement allows Coats to reconcile lyric poetry’s inherently weak narrativity with rhetorical narrative theory’s attention to judgment and the ethical implications of narrative form. Further investigating the narrative potential of lyric poetry, Stefan Kjerkegaard explores the ways that poetic form influences and interacts with narrativity and lyricality, as well as fictionality and non-fictionality, within the autobiographical lyric poem. Kjerkegaard employs narratological approaches to voice and narrativity in an effort to illuminate this understudied poetic genre. Lasse Gammelgaard pays similar attention to the reader by situating poetic studies within the larger concerns of recent reader-oriented studies of narrative production. Building from early work in reader response theory, Gammelgaard investigates the characteristics of poetic and narrative tracks within narrative poetry and locates the reader at the point of interaction between these two tracks. Lewis S. Gleich considers the influence of sonic and visual elements on reader engagement with a textual narrative, refining discussions of the relationship between poeticity and narrativity by incorporating studies of phonetic and oculomotor functioning. While both Gammelgaard and Gleich employ works by John Keats in their essays and build from reader-response foundations, their poetic intersection at Keats reveals how these two approaches offer distinct methodologies that ultimately take narrative theory, reader response, and poetic studies in different directions. My contribution takes an intermedial approach, surveying narrative’s capacity within visual poetry. First teasing out the form’s visual and poetic affordances, I then explore the material on which poetry appears, considering the ways that textual layout and textual surface enrich an understanding of narrative intermediality. Steven Nardi’s deconstructivist approach sheds light on the disruptive tendencies of poetry. Nardi examines the ways that poetic disruptions enrich current narrative theory by troubling distinctions between fabula and sjuzhet. The collection concludes with a conversation between Bruce Heiden and Brian McHale that returns us to a foundational question of this collection: can narrative theory enrich and be enriched...