Greater nucleic acids oxidation in the temporal lobe than the frontal lobe in SAMP8

Our previous studies have shown that substantial amounts of 8-oxoguanine are present in the DNA and RNA in the hippocampi of old senescence-accelerated mice (SAMP8); however, oxidative damage to DNA and RNA in the other regions of the brain from a month after birth to the onset of aging has not been examined completely. In this study, we analyzed the amount of 8-oxoguanine in DNA and RNA in the temporal and frontal lobes of SAMP8 during aging by the immunohistochemical method. Compared with age-matched control acceleration-resistant mice (SAMR1), 8- and 12-month-old SAMP8 had increased amounts of 8-oxoguanine in the DNA and RNA in the frontal lobe, whereas in the temporal lobe, this trend began to appear as early as 4 months. The levels of 8-oxoguanine in the temporal lobe were significantly higher than those in the frontal lobe. These results indicate that nucleic acid oxidative damage occurs as an age-associated phenomenon, and can occur more easily in the temporal lobe than in the frontal lobe of SAMP8.     

Ontogeny of proopiomelanocortin (POMC) gene expression in the intermediate lobe of the rat pituitary gland

The ontogeny of proopiomelanocortin (POMC) gene expression in the intermediate lobe of the pituitary was studied in rats of both sexes using quantitative in situ hybridization performed on fixed pituitary sections. Electron microscopic studies revealed in the adult animal the hybridization signal was found in all the secretory cells of the intermediate lobe and only in the POMC cells in the anterior lobe, thus indicating the specificity of the technique used. Hybridization signal was first detected on day 15 of gestation and progressively increased during foetal life. After birth, POMC and mRNA levels markedly increased so that, in one-day old animals, they were 4.5-fold higher than at the end of gestation. Thereafter, mRNA concentrations steadily increased to reach a plateau at 60 days of age in both sexes. No sexual dimorphism was observed at any ages. The results indicate that the development of intermediate lobe cells occurs mostly after birth. They are consistent with previous results indicating a 200-fold increase in the levels of POMC-derived peptides from birth to adulthood.     

The effect of a unilateral ablation of the occipital lobe on pattern discrimination in the rabbit

Binocular brightness and striated pattern discrimination were studied in Dutch-belted rabbits. A comparison was made between normal animals and animals in which a unilateral lesion of the occipital lobe had been made three months after birth. No difference between the two groups was found in brightness discrimination learning. However, normal animals were found to do better both in acquisition and accuracy of striated pattern discrimination.     

Increased temporal lobe gyrification in preterm children

Preterm birth often results in significant learning disability, and previous magnetic resonance imaging (MRI) studies of preterm children have demonstrated reduction in overall cortical tissue with particular vulnerability in the temporal lobe. We measured cortical gyrification in 73 preterm and 33 term control children at 8 years of age and correlated these findings with tests of language ability to determine the associations among preterm birth, neurodevelopment and functional outcome. Preterm children demonstrated significantly increased bilateral temporal lobe gyrification index compared to term controls. Left temporal gyrification index was significantly negatively correlated with left temporal lobe gray matter volume as well as reading recognition scores in the preterm group. Cortical development in the temporal lobe appears to be differentially vulnerable to preterm birth.     

A CHANGE IN SUSCEPTIBILITY OF RAT CEREBELLAR PURKINJE CELLS TO DAMAGE BY ALCOHOL DURING FETAL, NEONATAL AND ADULT LIFE

Phillips S.C. & Cragg B.G.1982 Neuropathology and Applied Neurobiology 8, 441–454
A change in susceptibility of rat cerebellar Purkinje cells to damage by alcohol during fetal, neonatal and adult life
The sensitivity of rat cerebellar Purkinje cells to ethanol exposure during fetal, neonatal or adult life was assessed by histological techniques. Pregnant female rats were exposed to ethanol vapour during the last 2 weeks of gestation. Purkinje cells were counted 5 days after the pups were born. The number of Purkinje cells in lobe VIII was reduced by 45%, and the linear density of Purkinje cells in lobe I was 47% less than in controls not exposed to ethanol. Smaller reductions were found in other lobes. The weight of the cerebellum was reduced by 34%. Neonatal rats were exposed to ethanol vapour briefly during daylight hours on the third and fourth days after birth. Purkinje cells were counted on the fifth day after birth, and losses similar to those described above were found, with additional significant reductions of cell numbers in lobe I and of Purkinje cell density in lobe VIII. The weight of the cerebellum was reduced by only 4%. Adult male rats were exposed to ethanol vapour for 3 weeks and no Purkinje cell losses were subsequently found. The dura overlying the cerebellum of separate adult male rats was superfused with 100% ethanol for 1 h and no abnormalities were detected with electron microscopy in the exposed cortex 6 days later. It is remarkable that the brief neonatal treatment caused a more widespread loss of Purkinje cells than the 10 days of exposure to ethanol in utero , whereas the Purkinje cells present in adult animals show a great resistance to ethanol. The neonatal period seems to be a time of high susceptibility of Purkinje cells to ethanol.     

Social behavior impairment in offspring exposed to maternal seizures in utero

Human and animal models have demonstrated that maternal seizures in utero could be deleterious to the development of the offspring. This study focused on the social behavior of offspring exposed to seizures in utero. A pilocarpine model of temporal lobe epilepsy was induced in female Wistar rats that were mated after the first spontaneous seizure. Early after birth, pups from an epileptic mother were reared by a control mother. To evaluate the influence of the adoption process, two other groups were added: rat pups from control mothers cross-fostered with other control mothers, and rat pups reared by their birth mother. Animals exposed to seizures in utero showed impaired social behavior with no signs of anxiety-like behavior. This study demonstrated that epileptic seizures during pregnancy could be harmful to brain development and may increase the risk of developing neurodevelopmental disorders. The mechanisms underlying the abnormalities of social behavior are not well understood, and further studies in this field are warranted.     

Alexander's disease: a case report of a biopsy proven case

A case of infantile onset Alexander's disease in a two and a half year old male child is presented, who had progressively increasing macrencephaly since birth. A frontal lobe biopsy revealed collections of Rosenthal fibres in the subpial and perivascular areas with diffuse dysmyelination and presence of reactive astrocytes. The Rosenthal fibres were immunoreactive for glial fibrillary acidic protein and ubiquitin. Electron microscopic examination showed the Rosenthal fibres as intra-astrocytic and extracellular granular osmiphilic collections.     

Development of a corticotropin-releasing factor-mediated effect on the firing rate of Purkinje cells in the postnatal mouse cerebellum

Corticotropin-releasing factor (CRF), present in climbing and mossy fiber afferents to the adult mouse cerebellum, acts as a neuromodulator to enhance the spontaneous and amino-acid-induced firing rate of Purkinje cells. CRF also is present during development of the mouse cerebellum, at ages that precede synaptogenesis, which suggests that it may have a different function during development compared to its modulatory role in the adult. The intent of this study was to determine when CRF begins to affect the firing rate of Purkinje cells as well as the time course over which this effect matures. The earliest effect of CRF was elicited at postnatal day (P) 9 at which time a weak enhancement in the amplitude of the firing rate was recorded. However, the amplitude, time to peak, sustainability, and duration of the response were significantly different from that recorded in the older animals or adults. The excitatory effect of CRF became stronger and the duration of the response increased progressively from P9 until it was adult-like by P20. Purkinje cells in the posterior lobe vermis developed a mature response before those in the anterior lobe or hemispheres. Data from previous studies have shown that CRF and its type 1 receptor are present in the cerebellum before birth and that both undergo major reorganization around P10. Taken together, these immunohistochemical observations and the present physiologic data indicate that CRF does not modulate the activity of Purkinje cells until the peptide begins to assume an adult-like distribution in cerebellar afferents.     

Season of birth and electrodermal activity in functional psychoses.

The present study examined the association between electrodermal activity (EDA) and season of birth in a sample of first-episode patients with schizophrenia, schizophreniform disorder, and affective disorder with psychotic features, and in a normal control group. Patients with schizophrenia who were born during the season of excess risk (January-April) were less responsive than those born during other times of the year. They had lower skin-conductance levels and fewer skin-conductance responses. No such effects were found in patients with schizophreniform or affective disorder, or in the normal subjects. When compared with the control group, winter-born schizophrenics showed significantly more evidence of hyporesponsivity. In contrast, nonwinter-born patients did not differ from normal subjects in skin-conductance level or number of skin-conductance responses. Schizophreniform patients born during the other seasons of the year were more likely to be hyporesponsive. The above results provide supporting evidence for the validity of the season of birth phenomenon. We hypothesize that a viral infection, or some other perinatal complication associated with winter and early spring births, leads to temporal lobe damage and consequent dysregulation of electrodermal activity in patients with schizophrenia.     

Motor and behavioral responses obtained by stimulation with chronic electrodes of the optic lobe of Sepia officinalis.

A new technique using a stimulating chronically-implanted electrode has allowed us to study the motor responses induced by electrical stimulation of the optic lobe in a freely swimming Sepia. Electrical stimulation of the cortex of the optic lobe produces no motor response; this is in agreement with the results of preceding authors. The stimulation of the neuropil of the optic lobe by monopolar electrode produces many different motor responses, in support of Boycott's results obtained by the same type of excitation in acute experiments. However, the field of stimulation of these electrodes could not always have been the same and it is possible that we were sometimes stimulating nervous structures close to the optic lobe. Stimulation by a bipolar electrode, however, which does not have this advantage, induces only two very different motor responses: an ipsilateral rotation and an 'alarm reaction", so called because of its similarities to the 'attentive immobilization" of higher vertebrates. These two reactions are very complex and their different components are linked together as in a behavioural response from an intact animal. These reactions present very different characteristics of excitability. They are obtained from many areas in the neuropil of the optic lobe, within which there does not seem to be any preferential localization. These results emphasize the importance of the optic lobe in motor control.     

Development of the diencephalon in the rat. II. Correlation of the embryonic development of the hypothalamus with the time of origin of its neurons

The development of the nuclei of the hypothalamus was examined in normal and X-irradiated embryos from day 13 (E13) to the day before birth (E22). The diencephalic neuroepithelium was subdivided into three lobes (dorsal, medial, and ventral) and two lobules (superior and inferior). The hypothalamus is derived from the ventral lobe and the inferior lobule. The ventral neuropithelial lobe generates the neurons of most of the early arising hypothalamic structures, including those of the lateral tier nuclei associated with the medial forebrain bundle, and the heterogeneous intermediate tier nuclei. A specialized neuroepithelial region lining the diamond shaped ventricle produces the early neurohypophysial magnocellular neurons; the neurons of the paraventricular nucleus remain at the site, whereas the neurons of the supraoptic nucleus could be traced migrating laterally. The neurons of the late arising hypophysiotropic area of the posterior hypothalamus are derived from components of the inferior neuroepithelial lobule: the dorsomedial and ventromedial nuclei apparently from a shared matrix in the main portion of the inferior lobule; the tuberomammillary-arcuate complex from its posteroventral recess. The triple-decked and sequentially produced components of the mammillary system may arise from separate neuroepithelial sites. The autoradiographic results of the previous study (Altman and Bayer, '78a) showed that the structural and functional heterogeneity of the mature hypothalamus is paralleled by cytogenetic heterochronicity; the present embryonic observations indicate that many of the distinguishable components of the hypothalamus arise from a mosaic of heterogeneous neuroepithelial sites.     

Subcortical metabolic alterations in partial epilepsy

The function of subcortical nuclei in partial epilepsy was investigated using positron emission tomography (PET) to measure metabolism in the basal ganglia and thalamus. Sixteen patients undergoing surgical evaluation were studied with 18F-fluorodeoxyglucose (FDG) interictally and had intensive extracranial and intracranial electrophysiologic evaluations. Eight patients had left temporal lobe seizure foci, six had right temporal lobe foci, and two had right posterotemporal or parietal foci. The PET data were analyzed visually and quantitatively, using a multivariate analysis of variance on the quantitative data. Hypometabolism of subcortical nuclei was present ipsilateral to the cortical seizure focus. Cortical hypometabolism was noted focally in the temporal lobe in patients with left temporal lobe seizure foci, whereas patients with right temporal lobe seizure foci had diffuse hemispheric hypometabolism. We postulate that the subcortical hypometabolism is secondary to decreased efferent activity from temporal lobe structures, in particular amygdala and hippocampus, to subcortical nuclei. Diminished subcortical activity may then lead to defective regulation of cortical excitability in the temporal lobe, increasing the likelihood of seizure development and spread.     

Development of the diencephalon in the rat. VI. Re-evaluation of the embryonic development of the thalamus on the basis of thymidine-radiographic datings.

The development of the thalamus was examined in normal and X-irradiated embryos from day 13 (E13) to the day before birth (E22). The differentiating, radioresistant neurons of the lateral habenular nucleus, derived from a portion of the superior neuroepithelial lobule (SL1), were settling by day E15 and by this time the habenulopeduncular tract was forming. The neurons of the reticular nucleus, derived from the middle neuroepithelial lobe, began to settle on day E15 but a massive migration was still evident on day E16. Adjacent to the reticular nucleus the internal capsule appeared on day E16; this fiber bundle seemed to be continuous with fibers embedded in the first transitory zone of cells issuing from the dorsal neuroepithelial lobe. Because of the immaturity of the neocortex at this time, it was postulated that thalamocortical fibers of the dorsal thalamus are the earliest components of the internal capsule. By day E17 all the sensory relay nuclei of the thalamus were recognizable and it was assumed that the second transitory zone issuing from the receding dorsal neuroepithelial lobe contained the neurons of the later forming intralaminar nuclei. Suggestive evidence was obtained that the late arising neurons of the medial thalamus (the anterior nuclei, the mediodorsal nucleus, and some or all of the midline nuclei) originate in a portion of the superior neuroepithelial lobule designated as SL2. Our present and previous studies showed that the major divisions of the hypothalamus and thalamus are derived embryonically from distinguishable parts of the third ventricle neuroepithelium. This implies the te third ventricle neuroepithelium has a "mosaic" organization and suggests that the fate of hypothalamic and thalamic neurons may be determined to some extent while their precursors are still proliferating.     

Afferent and efferent connections of cerebellar lobe C3 of the mormyrid fish Gnathonemus petersi: an HRP study

The present paper is devoted to the extrinsic connections of lobe C3 of the highly differentiated corpus cerebelli of the electric fish Gnathonemus petersi. For this purpose, HRP injections or gels were placed in distinct parts of lobe C3 or its peduncle, in the pretectal region, and in the eye. Moreover, the presence of serotonin and tyrosine-hydroxylase was studied with immunohistochemical methods. The afferent connections of the rostral and caudal part of lobe C3 appear to differ considerably. Although both parts receive comparable projections from two pretectal nuclei (termed nucleus geniculatus and dorsal anterior pretectal nucleus) and the inferior olive, they receive projections from different parts of the nucleus lateralis valvulae, a large cell mass in the midbrain tegmentum, composed of small, tightly packed neurons. The caudal part of lobe C3 receives a projection from the most rostromedial cap of cells of this nucleus, whereas the rostral cap of lobe C3 receives efferents from the neighboring, more caudolateral, zone of cells of the nucleus lateralis valvulae. The caudal part of lobe C3, but not its rostral part, receives an additional projection from a nucleus in the isthmus region, termed nucleus Q. This nucleus sends a collateral projection to the torus longitudinalis. The efferents of both parts of lobe C3 project to slightly different parts of the midbrain tegmentum and the nucleus reticularis superior, and originate at least partly from eurydendroid cells. None of the nuclei and fiber tracts labeled could be shown to contain serotonin or catecholamines. The connections of lobe C3, as revealed by the present study, are compared with those of other parts of the mormyrid cerebellum and with those of the corpus cerebelli of other teleosts, with emphasis on the homology and functional significance of pretectocerebellar connections, the topical order in the cerebellar projections of the nucleus lateralis valvulae, and the relations between the cerebellum and torus longitudinalis. Comparison of the cerebellar connections in different teleostean species suggests that the strong development and the considerable differentiation of the cerebellum of mormyrids are related to at least two types of changes in the extrinsic connections, i.e.: a redistribution or parcelling of connections and the development of connections specific for mormyrids.     

Visual functional magnetic resonance imaging of preterm infants

Aim The aim of this study was to determine the feasibility of undertaking visual functional magnetic resonance imaging (fMRI) in very preterm children. Method Forty‐seven infants born at less than 32 weeks gestational age (25 males, 22 females; mean (SD) age at birth 28.8wks [1.9]) were scanned using 1.5T MRI as part of a longitudinal neuroimaging study. These infants were scanned at preterm age (within 2wks of birth) and at term‐equivalent age. Quantitative T2* data and fMRI in response to visual stimuli (flashing strobe) were acquired in this population. T2* values were compared at preterm age and at term‐equivalent age using a two‐tailed t‐test. A general linear model was used to evaluate occipital lobe response to visual stimuli. Results T2* values were significantly higher at preterm age than at term‐equivalent age in both the medial and lateral occipital lobes (preterm infants: 187.2ms and 198.4ms respectively; term infants: 110.9ms and 133.2ms respectively; p<0.002). Significant positive occipital lobe activation (q<0.01) was found in 3 out of 65 (5%) fMRIs carried out at preterm age and in 19 out of 26 (73%) scans carried out at term‐equivalent age. Interpretation Visual stimuli do not elicit a reliable blood oxygen level‐dependent (BOLD) response in very preterm infants during the preterm period. This suggests that BOLD fMRI may not be the appropriate modality for investigating occipital lobe function in very preterm infants.     

An analysis of the time of origin of neurons in the entorhinal and subicular cortices of the cat

The [³H]thymidine autoradiographic method was used to determine the birth dates of neurons in the cat parahippocampal gyrus. Cat fetuses were exposed to a single pulse of the radioactive marker between the 20th and 55th embryonic days. All animals were delivered normally and allowed to survive for 2–6 months postnatal. The resulting autoradiographs demonstrate three spatiotemporal gradients of cell birth in the entorhinal and subicular cortices. First, an inside-out gradient is apparent; i.e., neurons in the deeper layers are born earlier than those in the more superficial layers. Second, a rhino to dentate gradient exists. Accordingly, cells closer to the lateral entorhinal region tend to be generated earlier than those further away. Third, a temporal to septal gradient is present. Neurons close to the anterior pole of the temporal lobe are born earlier than those more caudally located. Whereas the first two gradients have been observed in other species, the latter gradient has not been reported consistently. Three exceptions to these overall gradients exist. First, neurons near the layer I/II border are born earlier than the majority of the layer II neurons. Second, neurons near the transition zone between two adjacent regions are born earlier than neurons located in the middle of each region. Third, the prosubiculum and subiculum do not exhibit a clear inside-out or temporal to septal gradient.     

Seizure-induced miosis and ptosis: association with temporal lobe magnetic resonance imaging abnormalities

Two patients with seizure-associated miosis and ptosis are described. In both there are magnetic resonance imaging abnormalities of the temporal lobe. In one patient, increased magnetic resonance imaging signal intensity is present in the temporal lobe contralateral to ptosis and miosis. In the other, there is temporal lobe asymmetry with the smaller temporal lobe ipsilateral to the miotic pupil and ptotic lid. The relevant human and experimental literature related to cortical control of pupil size and lid movement is reviewed. Based on the available literature and the findings in these two patients, it is proposed that the increased signal intensity in the temporal lobe of one patient represents an irritative stimulus causing contralateral miosis and ptosis, whereas the temporal lobe hypoplasia in the second patient permitted impulses from the contralateral normal temporal lobe to predominate, resulting in miosis and ptosis homolateral to the hypoplastic temporal lobe.     

Postnatal ontogeny of POMC gene expression in the rat pituitary: an analysis by in situ hybridization histochemistry

Postnatal development of proopiomelanocortin gene expression in the rat pituitary was examined using in situ hybridization histochemistry. In adult rats, a very high density of hybridization signals was seen in the intermediate lobe of the pituitary, while only a moderate density occurred in the anterior lobe. No evidence of hybridization was detected in the posterior lobe. At birth, both the intermediate and anterior lobes had low to moderate frequencies of hybridization signals but a rapid rise to moderate density was noted by the 8th postnatal day. Radioactive labelling in the intermediate lobe continued to increase sharply with age to reach a plateau at postnatal day 28, while hybridization signals in the anterior lobe levelled off at postnatal day 8 with no subsequent rise in density.     

Limbic P3 potentials, seizure localization, and surgical pathology in temporal lobe epilepsy

Limbic P3 event-related potentials were recorded from mesial temporal electrodes implanted for presurgical investigation in 70 patients with intractable focal seizures. In 46 (81%) of 57 patients with unilateral temporal lobe epilepsy, the limbic P3 potential was absent or rudimentary ipsilateral to the seizure focus and a robust P3 potential was always elicited from the nonepileptogenic temporal lobe. Bilateral P3 potentials were recorded in 6 patients (10%) with unilateral temporal lobe epilepsy. In the remaining 5 patients in the group with unilateral temporal lobe epilepsy, results showed P3 bilaterally absent (2 patients), P3 present in a unilateral investigation (1 patient), P3 absent contralateral to the seizure focus (1 patient), and technically unsatisfactory recordings (1 patient). Bilaterally absent P3 potentials were noted in 2 patients with bilateral temporal lobe epilepsy. In 6 patients with technically adequate P3 studies and extratemporal seizures, bilaterally present P3 potentials were noted. Sensitivity and specificity of P3 absence as a predictor of an epileptogenic temporal lobe were 87% and 95%, respectively. Tissue specimens of the hippocampus were available in 22 patients (43%). Thirteen hippocampi showed sclerosis, all of which were associated with unilaterally absent P3 potentials. Nine hippocampi were normal (5 patients with the P3 absent, 4 with P3 present). Sensitivity and specificity of an absent limbic P3 as a function of hippocampal pathological findings were 100% and 44%, respectively. Absent limbic P3 potentials in temporal lobe epilepsy thus indicate structural or functional hippocampal abnormality and may add important information in presurgical evaluation with depth electrodes of patients who have temporal lobe epilepsy.