Changes in SWB following injury to different brain lobes

A neurological substrate for subjective wellbeing (SWB) has received little research attention.
Purpose This study was designed to conduct exploratory investigation into the neuroanatomical correlates of SWB, by monitoring the SWB of a head-injured population over a six-month period.
Method Seventy people with head injury (HI), aged 10–65, were studied. The SWB of each participant was measured, and computed tomography (CT) scans were analysed to obtain regional brain injury location (BIL).
Results SWB was associated with BIL. However, the hypothesis that individuals with left frontal injury would report lower SWB was not supported. Instead, it was observed that participants with injury to their right frontal lobe reported higher SWB than individuals with injury to other regions of the brain.
Conclusions This study provides initial exploration into the neuroanatomical correlates of SWB.

Inhibition and Phineas Gage : repression and Sigmund Freud

The similarities between the theories of thinking as inhibited action developed by David Ferrier and Sigmund Freud are examined in the context of the changes in the behavior of Phineas Gage, which Ferrier tried to explain with his inhibitory-motor theory. Johannes Müller's concept of will, its development by Alexander Bain, and Bain's influence on Ferrier's conceptualization of inhibitory centers localized in the frontal lobes are traced. Elements of the Bain-Ferrier theory found in Freud's theory of thinking, which do not derive from Brücke, Meynert, or Jackson, are itemized, and the implications of Freud's opting for a mechanism of inhibition that was basically excitatory is examined. Possible reasons for Ferrier's abandoning his concept of inhibitory centers are discussed and are contrasted with the reasons that Freud had for keeping to an excitatory conceptualization. The sensory-motor physiology of the day and its application to willing and thinking as inhibited action provide reasonably certain connections between Phineas Gage, David Ferrier, and Sigmund Freud.

Plastid division in mallomonas (Synurophyceae, Heterokonta)

Laser scanning confocal microscopy and TEM were used to study the morphology of secondary plastids in algae of the genus Mallomonas (Synurophyceae). At interphase, Mallomonas splendens (G. S. West) Playfair, M. rasilis Dürrschm., M. striata Asmund, and M. adamas K. Harris et W. H. Bradley contained a single H-shaped plastid consisting of two large lobes connected by a narrow isthmus. Labeling of DNA revealed a necklace-like arrangement of plastid nucleoids at the periphery of the M. splendens plastid and a less-patterned array in M. rasilis. The TEM of M. splendens and M. rasilis showed an electron-dense belt surrounding the plastid isthmus in interphase cells; this putative plastid-dividing ring (PD ring) was adpressed to the inner pair of the four plastid membranes, suggesting that it is homologous to the PD ring of green and red plastids. The PD ring did not contain actin (indicated by lack of staining with phalloidin) and displayed filaments or tubules of 5–10 nm in diameter that may be homologous to the tubules described in red algal PD rings. Confocal microscopy of chl autofluorescence from M. splendens showed that the plastid isthmus was severed as mitosis began, giving rise to two single-lobed daughter plastids, which, as mitosis and cell division progressed, separated from one another and then each constricted to form the H-shaped plastids of daughter cells. Similar plastid division cycles were observed in M. rasilis and M. adamas; however, the plastid isthmus of M. striata was retained throughout most of cell division and was eventually severed by the cell cleavage furrow.

MRI-negative PET-positive temporal lobe epilepsy (TLE) and mesial TLE differ with quantitative MRI and PET: a case control study

Background: 'MRI negative PET positive temporal lobe epilepsy' represents a substantial minority of temporal lobe epilepsy (TLE). Clinicopathological and qualitative imaging differences from mesial temporal lobe epilepsy are reported. We aimed to compare TLE with hippocampal sclerosis (HS+ve) and non lesional TLE without HS (HS-ve) on MRI, with respect to quantitative FDG-PET and MRI measures.

Methods: 30 consecutive HS-ve patients with well-lateralised EEG were compared with 30 age- and sex-matched HS+ve patients with well-lateralised EEG. Cerebral, cortical lobar and hippocampal volumetric and co-registered FDG-PET metabolic analyses were performed.

Results: There was no difference in whole brain, cerebral or cerebral cortical volumes. Both groups showed marginally smaller cerebral volumes ipsilateral to epileptogenic side (HS-ve 0.99, p = 0.02, HS+ve 0.98, p < 0.001). In HS+ve, the ratio of epileptogenic cerebrum to whole brain volume was less (p = 0.02); the ratio of epileptogenic cerebral cortex to whole brain in the HS+ve group approached significance (p = 0.06). Relative volume deficits were seen in HS+ve in insular and temporal lobes. Both groups showed marked ipsilateral hypometabolism (p < 0.001), most marked in temporal cortex. Mean hypointensity was more marked in epileptogenic-to-contralateral hippocampus in HS+ve (ratio: 0.86 vs 0.95, p < 0.001). The mean FDG-PET ratio of ipsilateral to contralateral cerebral cortex however was low in both groups (ratio: HS-ve 0.97, p < 0.0001; HS+ve 0.98, p = 0.003), and more marked in HS-ve across all lobes except insula.

Conclusion: Overall, HS+ve patients showed more hippocampal, but also marginally more ipsilateral cerebral and cerebrocortical atrophy, greater ipsilateral hippocampal hypometabolism but similar ipsilateral cerebral cortical hypometabolism, confirming structural and functional differences between these groups.

Sequential 123-I-iododexetimide scans in temporal lobe epilepsy: comparison with neuroimaging scans (MR imaging and 18-F-FDG-PET imaging)

Purpose Muscarinic acetylcholine receptors (mAChRs) play an important role in the generation of seizures. Single-photon emission computed tomography (SPECT) with ¹²³I-iododexetimide (IDEX) depicts tracer uptake by mAChRs. Our aims were to: (a) determine the optimum time for interictal IDEX SPECT imaging; (b) determine the accuracy of IDEX scans in the localisation of seizure foci when compared with video EEG and MR imaging in patients with temporal lobe epilepsy (TLE); (c) characterise the distribution of IDEX binding in the temporal lobes and (d) compare IDEX SPECT and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in identifying seizure foci.
Methods We performed sequential scans using IDEX SPECT imaging at 0, 3, 6 and 24 h in 12 consecutive patients with refractory TLE undergoing assessment for epilepsy surgery. Visual and region of interest analyses of the mesial, lateral and polar regions of the temporal lobes were used to compare IDEX SPECT, FDG PET and MR imaging in seizure onset localisation.
Results The 6-h IDEX scan (92%; κappa=0.83, p=0.003) was superior to the 0-h (36%; kappa=0.01, p>0.05), 3-h (55%;κappa=0.13, p>0.05) and 24-h IDEX scans in identifying the temporal lobe of seizure origin. The 6-h IDEX scan correctly predicted the temporal lobe of seizure origin in two patients who required intracranial EEG recordings to define the seizure onset. Reduced ligand binding was most marked at the temporal pole and mesial temporal structures. IDEX SPECT was superior to interictal FDG PET (75%; κappa=0.66, p=0.023) in seizure onset localisation. MR imaging was non-localising in two patients in whom it was normal and in another patient in whom there was bilateral symmetrical hippocampal atrophy.
Conclusion The 6-h IDEX SPECT scan is a viable alternative to FDG PET imaging in seizure onset localisation in TLE.

Cerebral cortex : an MRI-based study of volume and variance with age and sex

The aim of the present study was to examine quantitative differences in lobar cerebral cortical volumes in a healthy adult population. Quantitative volumetric MRI of whole brain, cerebral and cerebellar volumes was performed in a cross-sectional analysis of 97 normal volunteers, with segmented frontal, temporal, parietal and occipital cortical volumes measured in a subgroup of 60 subjects, 30 male and 30 female, matched for age and sex. The right cerebral hemisphere was larger than the left across the study group with a small (<1%) but significant difference in symmetry (P < 0.001). No difference was found between volumes of right and left cerebellar hemispheres. Rightward cerebral cortical asymmetry (right larger than left) was found to be significant across all lobes except parietal. Males had greater cerebral, cerebellar and cerebral cortical lobar volumes than females. Larger male cerebral cortical volumes were seen in all lobes except for left parietal. Females had greater left parietal to left cerebral hemisphere and smaller left temporal to left cerebral hemisphere ratios. There was a mild reduction in cerebral volumes with age, more marked in males. This study confirms and augments past work indicating underlying structural asymmetries in the human brain, and provides further evidence that brain structures in humans are differentially sensitive to the effects of both age and sex.

Spermatogenesis in the blue swimming crab, Portunus pelagicus, and evidence for histones in mature sperm nuclei

Spermatogenesis in the blue swimming crab, Portunus pelagicus, is described by light and electron microscopy. The testis is composed of anterior (AT) and posterior (PT) lobes, that are partitioned into lobules by connective tissue trabecula, and further divided into zones (germinal, transformation and evacuation), each with various stages of cellular differentiation. The vas deferens is classified into three distinct regions: anterior (AVD), median (MVD), and posterior (PVD), on the presence of spermatophores and two secretions, termed substance I and II. Based on the degree and patterns of heterochromatin, spermatogenesis is classified into 13 stages: two spermatogonia (SgA and SgB), six primary spermatocytes (leptotene, zygotene, pachytene, diplotene, diakinesis, and metaphase), a secondary spermatocyte (SSc), three spermatids (St 1–3), and a mature spermatozoon. Spermatid stages are differentiated by chromatin decondensation and the formation of an acrosomal complex, which is unique to brachyurans. Mature spermatozoa are aflagellated, and have a nuclear projection and a spherical acrosome. AUT-PAGE and Western blots show that, during chromatin decondensation, there is a reduction of most histones, with only small amounts of H2B and H3 remaining in mature spermatozoa.

Histological and global gene expression analysis of the ‘lactating’ pigeon crop

Background: Both male and female pigeons have the ability to produce a nutrient solution in their crop for the nourishment of their young. The production of the nutrient solution has been likened to lactation in mammals, and hence the product has been called pigeon ‘milk’. It has been shown that pigeon ‘milk’ is essential for growth and development of the pigeon squab, and without it they fail to thrive. Studies have investigated the nutritional value of pigeon ‘milk’ but very little else is known about what it is or how it is produced. This study aimed to gain insight into the process by studying gene expression in the ‘lactating’ crop.
Results: Macroscopic comparison of ‘lactating’ and non-’lactating’ crop reveals that the ‘lactating’ crop is enlarged and thickened with two very obvious lateral lobes that contain discrete rice-shaped pellets of pigeon ‘milk’. This was characterised histologically by an increase in the number and depth of rete pegs extending from the basal layer of the epithelium to the lamina propria, and extensive proliferation and folding of the germinal layer into the superficial epithelium. A global gene expression profile comparison between ‘lactating’ crop and non-’lactating’ crop showed that 542 genes are up-regulated in the ‘lactating’ crop, and 639 genes are down-regulated. Pathway analysis revealed that genes up-regulated in ‘lactating’ crop were involved in the proliferation of melanocytes, extracellular matrix-receptor interaction, the adherens junction and the wingless (wnt) signalling pathway. Gene ontology analysis showed that antioxidant response and microtubule transport were enriched in ‘lactating’ crop.
Conclusions: There is a hyperplastic response in the pigeon crop epithelium during ‘lactation’ that leads to localised cellular stress and expression of antioxidant protein-encoding genes. The differentiated, cornified cells that form the pigeon ‘milk’ are of keratinocyte lineage and contain triglycerides that are likely endocytosed as very low density lipoprotein (VLDL) and repackaged as triglyceride in vesicles that are transported intracellularly by microtubules. This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon ‘milk’ fulfils a similar function to mammalian milk, but is produced by a different mechanism.