Spatial Resolution of an Eye Containing a Grouped Retina: Ganglion Cell Morphology and Tectal Physiology in the Weakly Electric Fish Gnathonemus petersii

The retina of the weakly electric fish Gnathonemus petersii is a so‐called grouped retina where photoreceptors are bundled. These bundles are regarded as functional units and this type of retinal specialization is uniquely found in teleosts. To understand how this anatomical organization influences visual information processing we investigated the morphology and distribution of retinal ganglion cells (GCs) and the response properties of retinal afferents terminating in the major retinorecipient area, the optic tectum. GCs were classified based on their dendritic morphology (dendritic field diameters <90–100 μm: narrow‐field GCs; 110–280 μm: widefield GCs; >280 μm: giant GCs). Within these classes subtypes were distinguished based on the ramification patterns of the dendrites in the sublaminae of the inner plexiform layer. Properties of presumed optic nerve terminals were investigated in the optic tectum using extracellular recordings. Physiological classes could be observed based on their response to visual stimuli (on; off; on‐off, and fast units). Receptive field sizes and spatiotemporal properties were classified and the topographical representation of the visual space was mapped in the tectum. Gratings of low spatial frequencies were best responded to and followed up to high temporal frequencies (>30 Hz). Most of the recorded units were directionally selective. No evidence of distorted topographies in the tectum was found, i.e., no overrepresentation of the retina was seen in the tectum opticum. The grouped retina of G. petersii seems to be optimized for the detection of large, fast objects in an environment of low optical quality. J. Comp. Neurol. 521:4075–4093, 2013. © 2013 Wiley Periodicals, Inc.     

The process of cognitive behaviour therapy for chronic fatigue syndrome: Which changes in perpetuating cognitions and behaviour are related to a reduction in fatigue?

Objective

Cognitive behaviour therapy (CBT) can significantly reduce fatigue in chronic fatigue syndrome (CFS), but little is known about the process of change taking place during CBT. Based on a recent treatment model (Wiborg et al. J Psych Res 2012), we examined how (changes in) cognitions and behaviour are related to the decrease in fatigue.

Methods

We included 183 patients meeting the US Centers for Disease Control criteria for CFS, aged 18 to 65 years, starting CBT. We measured fatigue and possible process variables before treatment; after 6, 12 and 18 weeks; and after treatment. Possible process variables were sense of control over fatigue, focusing on symptoms, self-reported physical functioning, perceived physical activity and objective (actigraphic) physical activity. We built multiple regression models, explaining levels of fatigue during therapy by (changes in) proposed process variables.

Results

We observed large individual variation in the patterns of change in fatigue and process variables during CBT for CFS. Increases in the sense of control over fatigue, perceived activity and self-reported physical functioning, and decreases in focusing on symptoms explained 20 to 46% of the variance in fatigue. An increase in objective activity was not a process variable.

Conclusion

A change in cognitive factors seems to be related to the decrease in fatigue during CBT for CFS. The pattern of change varies considerably between patients, but changes in process variables and fatigue occur mostly in the same period.     

Aneurysm of the superficial temporal artery following parotid gland surgery-Case report and review of the literature

Possible complications of parotid gland surgery are numerous, just as the reasons for aneurysms of the superficial temporal artery. The occurrence of such an aneurysm as a consequence of parotidectomy, however, has so far only been published once. Here, we report of an aneurysm of the superficial temporal artery following parotid gland surgery. It presented as a pulsating mass in the preauricular region. Combining clinical examination, duplex ultrasound, and CT scan, the diagnosis was readily established and treated with a circumscribed revision at low risk and without complications.     

Presence of six different lesion types suggests diverse mechanisms of tissue injury in neuromyelitis optica

Neuromyelitis optica (NMO) is an autoimmune disease targeting aquaporin 4 (AQP4), localized mainly at the astrocytic foot processes. Loss of AQP4 and glial fibrillary acidic protein (GFAP) was reported, but the pathological significance of astrocytopathy is still controversial. Here we show that active lesions in NMO display a wide spectrum of pathology even within a single tissue block of an individual patient. We have distinguished six different lesion types. The first reflects complement deposition at the surface of astrocytes, associated with granulocyte infiltration and astrocyte necrosis and followed by demyelination, global tissue destruction and the formation of cystic, necrotic lesions (lesion type 2). Such destructive lesions lead to Wallerian degeneration in lesion-related tracts (lesion type 3). Around active NMO lesions AQP4 may selectively be lost in the absence of aquaporin 1 (AQP1) loss or other structural damage (lesion type 4). Another pattern is characterized by clasmatodendrosis of astrocytes, defined by cytoplasmic swelling and vacuolation, beading and dissolution of their processes and nuclear alterations resembling apoptosis, which was associated with internalization of AQP4 and AQP1 and astrocyte apoptosis in the absence of complement activation. Such lesions give rise to extensive astrocyte loss, which may occur in part in the absence of any other tissue injury, such as demyelination or axonal degeneration (lesion type 5). Finally, lesions with a variable degree of astrocyte clasmatodendrosis are found, which show plaque-like primary demyelination that is associated with oligodendrocyte apoptosis, but with preservation of axons (lesion type 6). In active multiple sclerosis (MS) lesions astrocytes reveal changes of reactive protoplasmatic or fibrillary gliosis. Only in a subset of lesions, in patients with aggressive disease, loss of AQP4 is observed in the initial stage of their formation, which is associated with retraction of astrocyte processes in the absence of complement deposition, granulocyte infiltration or loss of AQP1 or astrocytes. Our data underline the primary assault of astrocytes in NMO lesions, but also indicate that different mechanisms of tissue injury operate in parallel in the same patient and even within the same lesion.     

Clinical predictors of the psychosocial long term outcome after brain injury

Abstract

The correlation of clinical with psychological and social data is an attempt to find predictors of the definite long term outcome after brain injury. 34 patients were reexamined 3 to 8 years after the accident using a number of psychological tests. Additionally, life quality was defined and evaluated. Only patients with an initial Glasgow Coma Scale-Score of 3–12, an intracranial traumatic lesion on computertomography and age 16–65 years at the time of accident were included in this study. Patients exhibited a uniform pattern of disturbances in psychosocial long term outcome. These disturbances were compared with initial clinical data: memory, attention and learning were significantly correlated with the duration of coma and the presence of additional extracerebraI injuries. From the initial computerized tomography, the findings 'compression of basal cisterns' and lintracerebral contusion' showed to be predictors of the cerebral function. Late social status and behavior, defined as quality of life, were clearly related with initial clinical findings. In conclusionl there are early clinical predictors of the long term social and psychological outcome after brain injury. [Neural Res 1997; 19: 305–310]     

Parental Age and Risk of Autism Spectrum Disorders in a Finnish National Birth Cohort

Aim of the study was to examine the associations between parental age and autism spectrum disorders (ASD). Data were based on the FIPS-A (Finnish Prenatal Study of Autism and Autism Spectrum Disorders), a case-control study with a total of 4,713 cases with childhood autism (n = 1,132), Asperger’s syndrome (n = 1,785) or other pervasive developmental disorder (PDD) (n = 1,796), which were ascertained from the Finnish Hospital Discharge Register. Controls were selected from the Finnish Medical Birth Register. Conditional logistic regression models were used for statistical analyses. Advanced paternal age (35–49 years) was associated with childhood autism in offspring, whereas advanced maternal age was associated with both Asperger’s syndrome and PDD in offspring (35 years or more and 40 years or more, respectively). Teenage motherhood (19 years or less) was associated with PDD in offspring. The main finding was that maternal and paternal ages were differentially associated with ASD subtypes. In addition to advanced parental age, teenage pregnancy seems to incur a risk for PDD in offspring.     

Validation of cephalic index measurements in scaphocephaly

Introduction

The cephalic index (CI) of the head can be measured manually using a caliper, the original technique, but it is also possible to determine it using skull X-ray, 2DCT and 3DCT images, 3D photo and with help of plagiocephalometry (PCM).

Patients and methods

In this study, the manual caliper determination is statistically compared with other measuring methods for scaphocephaly patients (n?=?39).

Results

The CI mean differences for the most representative data are sequentially 3.74, 2.16, 1.09 and 0.97 for the 2DCT, PCM, 3D photo and 3DCT techniques. The CI 2DCT values show a significant difference (p?<?0.01) in reference to CI manually, while the other techniques show a p?>?0.05.

Conclusion

The conclusions are that significantly different results are achieved when using 2DCT relative to the manual caliper determination. No significant difference is observed between the 3D techniques and the manual method.