Editorial

Brain size is widely used as a measure of behavioural complexity and sensory-locomotive capacity in avians but has largely relied upon laborious dissections, endoneurocranial tissue displacement, and physical measurement to derive comparative volumes. As an alternative, we present a new precise calculation method based upon coupled magnetic resonance (MR) imaging and computed tomography (CT). Our approach utilizes a novel interactive Fakir probe cross-referenced with an automated CT protocol to efficiently generate total volumes and surface areas of the brain tissue and endoneurocranial space, as well as the discrete cephalic compartments. We also complemented our procedures by using sodium polytungstate (SPT) as a contrast agent. This greatly enhanced CT applications but did not degrade MR quality and is therefore practical for virtual brain tissue reconstructions employing multiple imaging modalities. To demonstrate our technique, we visualized sex-based brain size differentiation in a sample set of Ring-necked pheasants (Phasianus colchicus). This revealed no significant variance in relative volume or surface areas of the primary brain regions. Rather, a trend towards isometric enlargement of the total brain and endoneurocranial space was evidenced in males versus females, thus advocating a non-differential sexually dimorphic pattern of brain size increase amongst these facultatively flying birds

Multiphase progenetic development shaped the brain of flying archosaurs

The growing availability of virtual cranial endocasts of extinct and extant vertebrates has fueled the quest for endocranial characters that discriminate between phylogenetic groups and resolve their neural significances. We used geometric morphometrics to compare a phylogenetically and ecologically comprehensive data set of archosaurian endocasts along the deep evolutionary history of modern birds and found that this lineage experienced progressive elevation of encephalisation through several chapters of increased endocranial doming that we demonstrate to result from progenetic developments. Elevated encephalisation associated with progressive size reduction within Maniraptoriformes was secondarily exapted for flight by stem avialans. Within Mesozoic Avialae, endocranial doming increased in at least some Ornithurae, yet remained relatively modest in early Neornithes. During the Paleogene, volant non-neoavian birds retained ancestral levels of endocast doming where a broad neoavian niche diversification experienced heterochronic brain shape radiation, as did non-volant Palaeognathae. We infer comparable developments underlying the establishment of pterosaurian brain shapes

Volume of the crocodilian brain and endocast during ontogeny

<div><p>Understanding complex situations and planning difficult actions require a brain of appropriate size. Animal encephalisation provides an indirect information about these abilities. The brain is entirely composed of soft tissue and, as such, rarely fossilises. As a consequence, the brain proportions and morphology of some extinct vertebrates are usually only inferred from their neurocranial endocasts. However, because the morphological configuration of the brain is not fully reflected in the endocast, knowledge of the brain/endocast relationship is essential (especially the ratio of brain volume to endocast volume or the equivalent proportion of interstitial tissue) for studying the endocasts of extinct animals. Here we assess the encephalic volume and structure of modern crocodilians. The results we obtained using ex vivo magnetic resonance imaging reveal how the endoneurocranial cavity and brain compartments of crocodilians change configuration during ontogeny. We conclude that the endocasts of adult crocodilians are elongated and expanded while their brains are more linearly organised. The highest proportion of brain tissue to endocast volume is in the prosencephalon at over 50% in all but the largest animals, whereas the proportion in other brain segments is under 50% in all but the smallest animals and embryos. Our results may enrich the field of palaeontological study by offering more precise phylogenetic interpretations of the neuroanatomic characteristics of extinct vertebrates at various ontogenetic stages.</p></div

pBV-BV at various ontogenetic stages.

<p>pBV-BV at various ontogenetic stages.</p

MR images of crocodilian brains.

<p>T2w coronal image of an embryo—scan time 3 h 21m (A), T1w coronal image of an early juvenile—scan time 9 h 6 m (B), T1w sagittal image of a late juvenile—scan time 2 h 36 m (C), T2w sagittal image of an adult—scan time 7 m (D), T1w sagittal image of an adult—scan time 40 m (E). Scale bar– 5 mm (A, B, C) and 10 mm (D, E). Double-headed arrows in (E) show the typical area of the interstitium.</p

Total surface and volume of the brain, interstitium and endocast with EV-BV at various ontogenetic stages.

<p>Total surface and volume of the brain, interstitium and endocast with EV-BV at various ontogenetic stages.</p

A combined MR and CT study for precise quantitative analysis of the avian brain

Brain size is widely used as a measure of behavioural complexity and sensory-locomotive capacity in avians but has largely relied upon laborious dissections, endoneurocranial tissue displacement, and physical measurement to derive comparative volumes. As an alternative, we present a new precise calculation method based upon coupled magnetic resonance (MR) imaging and computed tomography (CT). Our approach utilizes a novel interactive Fakir probe cross-referenced with an automated CT protocol to efficiently generate total volumes and surface areas of the brain tissue and endoneurocranial space, as well as the discrete cephalic compartments. We also complemented our procedures by using sodium polytungstate (SPT) as a contrast agent. This greatly enhanced CT applications but did not degrade MR quality and is therefore practical for virtual brain tissue reconstructions employing multiple imaging modalities. To demonstrate our technique, we visualized sex-based brain size differentiation in a sample set of Ring-necked pheasants (Phasianus colchicus). This revealed no significant variance in relative volume or surface areas of the primary brain regions. Rather, a trend towards isometric enlargement of the total brain and endoneurocranial space was evidenced in males versus females, thus advocating a non-differential sexually dimorphic pattern of brain size increase amongst these facultatively flying birds

3D reconstructions of the brains and endocasts of crocodilians at various ontogenetic stages divided into four major brain sectors.

<p>3D reconstructions of an embryo (A), early juvenile (B), late juvenile (C), adult (D) and larger adult (E) from ventral (bottom left), lateral (upper left), dorsal (upper right) and lateral (bottom right—major brain sectors coloured) perspectives for each specimen. Brain—dark blue; endocast—light blue. Major brain sectors: olfactory (Olf)—violet, prosencephalic (Pros)—green, mesencephalic (Mes)—yellow and rhombencephalic (Rhomb)—red. Scale bar— 10 mm.</p

Feasibility of Home-Use Animal-Assisted Activities in Patients With Implanted Cardiac Electronic Devices

Animal-assisted activities (AAAs) are mainly carried out in institutions. The aim of this prospective pilot study was to assess the willingness of patients with cardiac implanted electronic devices (IEDs) to participate in AAA. The sample included 75 ambulatory patients (18 females, M age = 69 years), who attended an outpatient clinic for control of antibradycardic pacemakers ( n = 15) or implanted cardioverter defibrillators ( n = 60). Twenty-three percent were current and 48% were previous pet-owners. Current pet-owners were younger than non-pet-owners (63.5 vs. 72.0 years, p = .0003). Twelve patients (16%) showed interest in AAA visits. However, only two patients agreed to an AAA visit. Both patients were visited once, but declined further visits. Hence, AAA sessions at home were poorly accepted, mainly because the patients considered themselves too busy or healthy, or due to a general disinterest in AAA. Potential health benefits associated with AAA may not be feasible to investigate during home visits of AAA-teams in patients with IEDs who are healthy enough to leave their homes. For further studies concerning AAA in patients with cardiovascular diseases, we suggest focusing on institutions like rehabilitation centers or day care centers and on more severely sick, homebound patients

Fluorinated water-soluble poly(2-oxazoline)s as highly sensitive F-19 MRI contrast agents

Recently, F-19 magnetic resonance imaging (MRI) emerged as a powerful noninvasive diagnostic tool in modern medicine. Fluorinated polymer materials represent an attractive class of MRI contrast agents (CAs) due to their structural variability and tunable properties. Herein, we describe for the first time the F-19 MRI of CAs based on fluorinated water-soluble poly(2-oxazoline)s (PAOx), a polymer class with increasing popularity in biomedical sciences. A series of fluorinated PAOx with increasing fluorine content were synthesized by controlled side-chain hydrolysis of poly(2- methyl-2-oxazoline) followed by reacylation of its ethylenimine units by difluoroacetic anhydride. As the increasing fluorine content leads to the copolymer hydrophobization, their composition was optimized for maximal F-19 MRI performance while retaining good solubility in water. The magnetic properties of the water-soluble polymers were studied in vitro by F-19 NMR and MRI, revealing their outstanding relaxation properties and imaging sensitivity. All CAs were found to be noncytotoxic for HeLa cells in vitro. Finally, the diagnostic potential of the new CAs was demonstrated by a successful in vivo F-19 MRI visualization of the selected fluorinated polymer in rats