Avoidance conditioning in bamboo sharks (Chiloscyllium griseum and C. punctatum): behavioral and neuroanatomical aspects.

Animals face different threats; to survive, they have to anticipate how to react or how to avoid these. It has already been shown in teleosts that selected regions in the telencephalon, i.e., the medial pallium, are involved in avoidance learning strategies. No such study exists for any chondrichthyan. In nature, an avoidance reaction may vary, ranging from a 'freeze' reaction to a startling response and quick escape. This study investigated whether elasmobranchs (Chiloscylliumgriseum and C. punctatum) can be conditioned in an aversive classical conditioning paradigm. Upon successful conditioning, the dorsal, medial and lateral pallium were removed (group 1) and performance tested again. In a second group, the same operation was performed prior to training. While conditioning was successful in individuals of both groups, no escape responses were observed. Post-operative performance was assessed and compared between individual and groups to reveal if the neural substrates governing avoidance behavior or tasks learned in a classical conditioning paradigm are located within the telencephalon, as has been shown for teleosts such as goldfish.

Embryological development of the human insula and its implications for the spread and resection of insular gliomas.

The human insular cortex, or the lobus insularis, is considered the developmentally most primitive lobe of the telencephalon. Covered by an overlying cortical lid, the insula has functions that are distinct from yet related to those of the adjacent temporal lobe and deep limbic structures. In the first part of this paper the authors outline the development of the human insula, including the cellular heterogeneity comprising the various parts of the insular lobe. Using the understanding gained from the development of the insula they then address implications of insular development for cortical development and connection as well as for tumorigenesis and tumor spread from the insula to other cortical structures, most notably the temporal lobe. An understanding of cortico-insular development and interconnection allows for both a better understanding of insular pathology and also facilitates planning of resection of cortico-insular gliomas to avoid damage to eloquent structures.

Chlorpheniramine impairs spatial choice learning in telencephalon-ablated fish.

This work investigated the effect of the H1 receptor blockade in the forebrain of ablated Carassius auratus in a simple stimulus-response learning task using a T-maze test with positive reinforcement. The goldfish were submitted to surgery for removal of both telencephalic lobes five days before beginning the experiment. A T-shaped glass aquarium was employed, with two feeders located at the extremities of the long arm. One of the two feeders was blocked. The experimental trials were performed in nine consecutive days. Each fish was individually placed in the short arm and confined there for thirty seconds, then it was allowed to swim through the aquarium to search for food for ten minutes (maximum period). Time to find food was analysed in seconds. Animals were injected intraperitoneally with chlorpheniramine (CPA) at 16 mg/kg of body weight or saline after every trial, ten minutes after being placed back in the home aquarium. The results show that all the training latencies of the A-SAL group were higher than the latencies of the S-SAL group. The S-SAL group had decreased latencies from the second trial on, while the S-CPA group showed decreased latencies after the fourth trial. The A-SAL group showed reduced latencies after the fifth trial, but the A-CPA group maintained the latencies throughout the experiment. This suggests that CPA impairs the consolidation of learning both on telencephalon ablated animals and in sham-operated ones through its action on mesencephalic structures of the brain and/or on the cerebellum in teleost fish.

Atypical growth pattern of a meningioma in an adult.

A 49-year-old woman presented with a rare atypical growth pattern of meningioma without evidence of dural attachment manifesting as chronic headache associated with transient paresthesia and left motor disorders. On admission, neurological examination showed no abnormalities. Magnetic resonance (MR) imaging revealed a right temporo-parieto-occipital lesion, which appeared to involve the subdural space and filling the cortical sulci. The lesion caused peritumoral white matter edema. The tumor appeared hypointense on T(1)-weighted and hyperintense on T(2)-weighted MR images, with homogeneous enhancement after contrast administration. A biopsy of the lesion was performed. Histological examination indicated that the lesion was a meningioma. Intraparenchymal meningiomas should be considered in the differential diagnosis of intraaxial lesions in patients of any age.

Nervous function after right hemispherectomy.

A hemispherectomy was performed on a girl of 20 because of progressively uncontrollable seizures and behavioral changes resulting from major head trauma at the age of five. Psychomotor development up to this age had been normal. Today she shows little impairment in higher nervous function depending on the ablated hemisphere. Left-sided motor performance has improved and sensory deficit is scant. There is no hemianopia and the right eye visual field is enlarged. Dichotic listening shows left ear preference and no lesion effect. These findings suggest that significant and positive adaptation may occur in mature brain.

Neural bases of song preferences in female zebra finches (Taeniopygia guttata).

We examined the neural bases of song preferences in female zebra finches (Taeniopygia guttata). Females performed more courtship displays in response to conspecific songs than to heterospecific songs. Following electrolytic lesion to the HVc (sometimes referred to as high vocal center), females maintained normal song preferences. However, following lesion to cHV (caudal hyperstriatum ventrale, an auditory area) females performed courtship displays at high rates in response to both conspecific and heterospecific song. Thus cHV, but not HVc, must be intact for female zebra finches to exhibit normal song preferences. Differences between this study and those showing HVc lesions disrupting song preferences in female canaries (Serinus canaria) indicate interspecific variation in the function of HVc in female songbirds.

Feasibility of using early mesencephalic neural plate for intracerebral grafting.

The purpose of this study was to elucidate the biological significance and the possibility of intracerebral grafting of neuroepithelial stem cells derived from the mesencephalic neural plate. Immunohistological studies of embryonic day 10.5 (E10.5) Wister rats revealed strong nestin expression in the mesencephalic part of the neural plate. Mesencephalic neural plates removed from E10.5 rats were processed to either tissue or cell dissociation culture. They were cultured in vitro under various conditions and were analyzed 7 days after the primary culture. When they were cultured as a tissue, cell proliferation and differentiation into neurons extending long neurites were obvious in a serum-free medium, in a medium containing 3% serum, and in a medium containing 20 ng/ml epidermal growth factor. On the other hand, in a medium containing 10 ng/ml basic fibroblast growth factor (bFGF), both vigorous cell proliferation and sphere formation were recognized. Furthermore, marked neurite growth was rarely seen in this culture. When they were plated in a dissociation culture, cell proliferation and neurosphere generation were also recognized only in a medium containing bFGF, depending on the initial cell concentration. The spheres, generated 7 days after the primary cell culture, were positively stained by nestin. These data suggested that bFGF was able to amplify the stem cell population present in the mesencephalic neural plate derived from early embryos. This might make it possible to obtain a large number of stem cells as donor material for neural transplantation on demand.

Recovery of function after neonatal or adult hemispherectomy in cats. II. Limb bias and development, paw usage, locomotion and rehabilitative effects of exercise.

To investigate the relationship of age-related processes in the recovery of complex motor functions of the limbs, a variety of neurobehavioral assessments were applied to cats with either neonatal (n = 9) or adult (n = 11) removal of the entire left hemitelencephalon (hemispherectomy). Neonatal-lesioned kittens showed no paw preference in reaching for a manipulandum between 5 and 8 weeks of age; thereafter they developed a preference (5.6%) for the unimpaired left limb which persisted throughout adulthood. Adult-lesioned cats showed a significantly greater left bias (13.9%) than neonatal-lesioned cats and they exhibited more abnormal movements and postures when reaching with the impaired limb. Exercising the impaired limb, was effective in reversing the paw preference bias in all lesioned cats. To master a food retrieval task with the impaired limb, adult-lesioned cats required more trials than the neonatal-lesioned group, extensive food deprivation and at least 1 month of postsurgical recovery. However, after mastering this task all cats could continue to perform it indefinitely in their home cages. In a paw print analysis of locomotion, only adult-lesioned cats showed abnormalities including splayed paws, decreased stride length, and adduction of the right hind limb. The results support the 'Kennard Principle' of enhanced recovery following neonatal vs late brain lesions for the present complex motor patterns and are interpreted in the context of neural plasticity and anatomical reorganization during development.

Effects of telencephalic ablation on shoaling behavior in goldfish.

The role of the telencephalon in the shoaling behavior of the goldfish, Carassius auratus, was investigated. Experiments were carried out in a tank divided into three compartments. Subjects were introduced into the center compartment of the tank. In the activity phase, subjects swam alone, and swimming distance was used as an index of activity. In the shoaling behavior phase, a stimulus fish was introduced into one of the side compartments, and the time spent near the side compartment by the subject was used as index of shoaling behavior. After these measurements were made, visual and motor abilities were examined using the optomotor response. Subjects then received surgery and the same procedure was repeated. In Experiment 1, the effects of total ablation of the telencephalon and a section of the olfactory tract (OlT) were examined. The ablation group exhibited reduced activity and shoaling behavior compared with the sham and OlT group. In Experiment 2, the role of the dorsal part of the telencephalon was examined after damaging the dorsomedial and dorsolateral telencephalon. Lesions in either portion had no effect and no simple visual or motor deficits were seen. These results suggest that the ventral part of the telencephalon mediates shoaling behavior.

Surgical options for uncontrolled epilepsy.

Surgical management of refractory epilepsy has undergone many modifications since it was instituted for the treatment of post-traumatic seizures many decades ago. Localization of onset of all seizures to a single resectable area of brain by various noninvasive and invasive recording methods is a complicated and controversial area, but guidelines are available. Success is correlated with accurate location and complete resection of the focus. When this is accomplished, resective surgery for epilepsy can provide cure or over 95 per cent reduction in seizure frequency in 60 to 90 per cent of patients undergoing these procedures. Although most often applied to temporal lobe foci, resections may be done in any cerebral lobe in the dominant or nondominant hemisphere with appropriate modifications of the evaluation and surgical procedure. When patients have unlocalizable or unresectable foci, depending on their exact pattern of seizures, electrical abnormalities, and neurologic status, other procedures may be used for surgical control of seizures. These include hemispherectomy, corpus callosum section, or stereotaxic procedures. The risks of all evaluation and surgical approaches are well balanced by the benefits obtained in a large proportion of patients.

Habituation to sound stimulation in detelencephalated pigeons (Columba livia).

Habituation to sound stimulation was analyzed in terms of the functional role of the telencephalon in learning. Sixteen pigeons were exposed to 1000-Hz, 83-dB, 1-s sound (stimulus A) at 30-s intervals until there was habituation of the exploratory and pre-exploratory responses. The learning criterion was 10 trials without the occurrence of these responses. Twenty-four hours after habituation to stimulus A the birds were tested with a 500-Hz, 85-dB, 1-s sound (stimulus B). On the day following habituation to stimulus B, the birds of the experimental group (N = 8) suffered ablation of the telencephalon and the birds of the control group (N = 8) had sham surgery. Retesting with the same sequence of procedures was carried out 10 days after surgery. In the POST-lesion situation there was a decrease of the number of habituation trials to stimulus A (P less than 0.01) and to stimulus B (P less than 0.05) by experimental pigeons compared to the PRE-lesions situation. The data suggest an interaction of a facilitatory effect of the lesion and long-term learning effects.

Surgical treatment of coenurosis (gid) in sheep.

During the past six years 623 cases of coenurosis (gid) in sheep have been treated surgically. Cysts were removed successfully from 573 of them (92 per cent) and 517 (83 per cent) were able to return to their flocks, although 36 showed no clinical improvement In 37 cases, the cyst could not be localised, and postmortem examinations showed that in nine cases the cyst was in the brainstem, and in 28 cases it was in the cerebellum. Fifty-six cases deteriorated gradually after surgery and in these cases more than one cyst was found postmortem. Thirteen cases died during surgery.

Anatomic study of the central core of the cerebrum correlating 7-T magnetic resonance imaging and fiber dissection with the aid of a neuronavigation system.

BACKGROUND: Different strategies have been used to study the fiber tract anatomy of the human brain in vivo and ex vivo. Nevertheless, the ideal method to study white matter anatomy has yet to be determined because it should integrate information obtained from multiple sources. OBJECTIVE: We developed an anatomic method in cadaveric specimens to study the central core of the cerebrum combining traditional white matter dissection with high-resolution 7-T magnetic resonance imaging (MRI) of the same specimen coregistered using a neuronavigation system. METHODS: Ten cerebral hemispheres were prepared using the traditional Klingler technique. Before dissection, a structural ultrahigh magnetic field 7-T MRI study was performed on each hemisphere specifically prepared with surface fiducials for neuronavigation. The dissection was then performed from the medial hemispheric surface using the classic white fiber dissection technique. During each step of the dissection, the correlation between the anatomic findings and the 7-T MRI was evaluated with the neuronavigation system. RESULTS: The anatomic study was divided in 2 stages: diencephalic and limbic. The diencephalic stage included epithalamic, thalamic, hypothalamic, and subthalamic components. The limbic stage consisted of extending the dissection to complete the Papez circuit. The detailed information given by the combination of both methods allowed us to identify and validate the position of fibers that may be difficult to appreciate and dissect (ie, the medial forebrain bundle). CONCLUSION: The correlation of high-definition 7-T MRI and the white matter dissection technique with neuronavigation significantly improves the understanding of the structural connections in complex areas of the human cerebrum.

Successful anterior capsulotomy in comorbid anorexia nervosa and obsessive-compulsive disorder: case report.

BACKGROUND AND IMPORTANCE: State-of-the-art treatment of anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) often proves ineffective. Both disorders have common features, and anterior capsulotomy is a last-resort treatment for OCD. We document the effect of bilateral anterior capsulotomy in a patient with comorbid AN and OCD. CLINICAL PRESENTATION: A 38-year-old woman with life-threatening, chronic, treatment-refractory AN and OCD underwent anterior capsulotomy. Psychiatric and neuropsychological evaluations at baseline and at follow-up document the severity and progress of the case. Bilateral anterior capsulotomy resulted in normalization of eating pattern and weight and a significant decrease of food-related and overall obsessive-compulsive symptoms. Psychiatric evaluations and exposure to food cues confirmed the clinical improvement that was evident immediately after surgery and sustained at 3-month follow-up. CONCLUSION: This case report suggests that bilateral anterior capsulotomy can be a therapeutic option for patients with comorbid AN and OCD. However, a well-controlled study is warranted.