Microsurgical anatomy of the amygdaloid body and its connections.

The amygdaloid body is a limbic nuclear complex characterized by connections with the thalamus, the brainstem and the neocortex. The recent advances in functional neurosurgery regarding the treatment of refractory epilepsy and several neuropsychiatric disorders renewed the interest in the study of its functional Neuroanatomy. In this scenario, we felt that a morphological study focused on the amygdaloid body and its connections could improve the understanding of the possible  implications in functional neurosurgery. With this purpose we performed a morfological study using nine formalin-fixed human hemispheres dissected under microscopic magnification by using the fiber dissection technique originally described by Klingler. In our results the  amygdaloid body presents two divergent projection systems named dorsal and ventral amygdalofugal pathways connecting the nuclear complex with the septum and the hypothalamus. Furthermore, the amygdaloid body is connected with the hippocampus through the amygdalo-hippocampal bundle, with the anterolateral temporal cortex through the amygdalo-temporalis fascicle, the anterior commissure and the temporo-pulvinar bundle of Arnold, with the insular cortex through the lateral olfactory stria, with the ambiens gyrus, the para-hippocampal gyrus and the basal forebrain through the cingulum, and with the frontal cortex through the uncinate fascicle. Finally, the amygdaloid body is connected with the brainstem through the medial forebrain bundle. Our description of the topographic anatomy of the amygdaloid body and its connections, hopefully represents a useful tool for clinicians and scientists, both in the scope of application and speculation.

Surgical Approaches to the Thalamus in Relation to the White Matter Tracts of the Cerebrum.

BACKGROUND: Approaching the thalamus from any angle remains a challenge because of its deep-seated location and intimate relations with adjacent important neurovascular structures and functions such as relaying sensory and motor signals and cognition. Our aim was to explore the relationship of the white matter tracts of the cerebrum to the thalamus using a fiber dissection technique, to delineate anatomic principles of approaches to the thalamus, and to discuss the tracts at risk in relation to each approach. METHODS: The thalamus was subdivided into 6 different regions and 13 approaches were examined in an attempt to describe a surgical road map. RESULTS: To reach the anteroinferior, medial, and lateral parts of the thalamus, the anterior and middle group approaches were used, and to reach the posterosuperior and posteroinferior thalamus, posterior and middle group approaches were used. The anteroinferior zone was the most difficult site to be accessed and the posterosuperior thalamus had the maximum number of alternative approaches. The distal transsylvian approach to the posterosuperior thalamus and the supracarotid infrafrontal approach to the anteroinferior thalamus had the highest number of neural structures severed within the surgical corridor. The infratentorial approaches and the suboccipital transtentorial approach preserve most of the white matter tracts en route to the posterosuperior and medial posteroinferior parts of the thalamus. CONCLUSIONS: When the surgical approaches for thalamic lesions are defined, white matter tracts along the surgical route should be taken into consideration.

Physical fitness and shapes of subcortical brain structures in children.

A few studies have recently reported that higher cardiorespiratory fitness is associated with higher volumes of subcortical brain structures in children. It is, however, unknown how different fitness measures relate to shapes of subcortical brain nuclei. We aimed to examine the association of the main health-related physical fitness components with shapes of subcortical brain structures in a sample of forty-four Spanish children aged 9·7 (sd 0·2) years from the NUtraceuticals for a HEALthier life project. Cardiorespiratory fitness, muscular strength and speed agility were assessed using valid and reliable tests (ALPHA-fitness test battery). Shape of the subcortical brain structures was assessed by MRI, and its relationship with fitness was examined after controlling for a set of potential confounders using a partial correlation permutation approach. Our results showed that all physical fitness components studied were significantly related to the shapes of subcortical brain nuclei. These associations were both positive and negative, indicating that a higher level of fitness in childhood is related to both expansions and contractions in certain regions of the accumbens, amygdala, caudate, hippocampus, pallidum, putamen and thalamus. Cardiorespiratory fitness was mainly associated with expansions, whereas handgrip was mostly associated with contractions in the structures studied. Future randomised-controlled trials will confirm or contrast our findings, demonstrating whether changes in fitness modify the shapes of brain structures and the extent to which those changes influence cognitive function.

Microsurgical anatomy of the central core of the brain.

OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels. METHODS The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci. RESULTS The insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the "anterior perforated substance region." The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core. CONCLUSIONS As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

Diferencias en el volumen cerebral regional entre pacientes de fibromialgia y meditadores de larga duración / Difference in Regional Brain Volume between Fibromyalgia Patients and Long-Term Meditators

Contextualización teórica/antecedentes. La práctica de la meditación ha demostrado mejorar la calidad de vida en relación con el dolor padecido, así como alterar la actividad cerebral. Se evalúa la volumetría cerebral en pacientes de fibromialgia (FM), con grupos de control de meditadores y no-meditadores sanos, para dilucidar la posible asociación entre los cambios cerebrales en meditadores y los años de práctica de la meditación. Metodología. La muestra se compone de doce pacientes diagnosticados con FM, once meditadores Zen consolidados y diez sujetos control sanos clasificados por edad y sexo. Los sujetos se exploraron con una secuencia de Resonancia Magnética T1-3D de alta resolución y las imágenes se analizaron mediante una estrategia de normalización DARTEL (Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra) de alta dimensionalidad. Se administraron cuestionarios sobre ansiedad, depresión y deterioro cognitivo. Resultados. Se observó un incremento estadísticamente significativo en el volumen de la sustancia gris en el área 20 de Brodmann (giro inferior temporal derecho e izquierdo) en los pacientes con fibromialgia y una disminución significativa en el grupo de meditadores en comparación con el grupo control. Por otra parte, se observó un incremento significativo del volumen de sustancia gris en pacientes con fibromialgia en comparación con el grupo control y el grupo de meditadores en los giros temporales derechos (p=0.03, t=6.85) e izquierdos (p=0.04, t=6.31). El número de meses de práctica de la meditación no correlacionó con cambios significativos en el volumen de sustancia gris en el grupo de meditadores. Conclusiones. La fibromialgia y la meditación parecen estar asociadas de manera fiable con alteraciones anatómicas localizadas en el área 20 de Brodmann (giro inferior y temporal), estando a su vez estos cambios asociados con los niveles de ansiedad y depresión. Además, los análisis morfológicos exploratorios en los pacientes con fibromialgia y los meditadores, pueden revelar disminuciones estructurales relevantes en regiones cerebrales en los practicantes de meditación. Los cambios morfológicos podrían suponer una mayor predisposición al desarrollo de un estado de dolor crónico, mientras que tales disminuciones estructurales podrían indicar potenciales beneficios funcionales (AU)

Background. The practice of meditation has been shown to improve pain-related quality of life and also to alter brain activity. To assess brain volumetry in fibromyalgia (FM) patients, healthy meditators and healthy non-meditator control groups, and to elucidate the possible association between brain changes in meditators and years of meditation practice. Methods. Twelve patients diagnosed with FM, eleven long-term Zen meditators and ten healthy control subjects closely matched for sex and age were recruited. A high resolution T1-3D sequence was acquired and a high-dimensional DARTEL normalization strategy was applied. Questionnaires on anxiety, depression and cognitive impairment were administered. Results. There was a statistically significant increase in grey matter volume in the Brodmann area 20 (right and left inferior temporal gyri) in patients with fibromyalgia and a significant decrease in the meditator group as compared to controls. On the other hand, there was a significant increase in grey matter volume in fibromyalgia patients as compared to controls and meditators, to the right temporal gyrus (p=0.03, t=6.85) and left temporal gyrus (p=0.04, t=6.31). The number of months of meditation did not correlate with significant grey matter volume changes in the meditator group. Conclusions. FM and meditation appears to be reliably associated with altered anatomical structure in the Brodmann area 20 (in both inferior temporal gyri), and these changes are associated with anxiety and depression levels. In addition, exploratory morphometric analyses for fibromyalgia patients and meditators may reveal relevant brain regions showing structural diminution in meditation practitioners. Morphologic changes might predispose toward vulnerability to develop a chronic pain state. Such structural diminutions could potentially indicate functional benefits (AU)

¿Por qué llamamos cerebro al cerebro? / Why do we call the brain ‘brain’?

Introducción. Todos los días, millones de profesionales utilizan un sinfín de palabras técnicas para referirse a las distintas estructuras que se hallan dentro del cráneo, pero pocos sabrían explicar su procedencia. En este trabajo se indaga sobre el origen etimológico de algunos de estos términos neuroanatómicos. Desarrollo. Se realiza un recorrido etimológico por el sistema nervioso central; recorrido que no pretende ser una revisión exhaustiva y pormenorizada de los términos actualmente en uso, sino familiarizar al lector con el pasado lingüístico de palabras como cerebro, hipocampo, tálamo, claustro, fórnix, cuerpo calloso o sistema límbico. Todas ellas provienen del griego o del latín, durante siglos las lenguas francas de la ciencia. También se analiza la evolución de la palabra meninges, originalmente de procedencia grecolatina, si bien los usos actuales derivan del árabe. Conclusiones. Los términos neuroanatómicos que se utilizan hoy en día no proceden de palabras que asocien una determinada estructura encefálica con su función, sino de palabras que reflejan la similitud formal o conceptual entre una estructura y una entidad familiar o cotidiana (por ejemplo, un objeto o una parte del cuerpo humano). En otros casos, estas palabras indican la ubicación espacial de la estructura neuroanatómica respecto a un tercero, o bien son términos derivados de personajes de la mitología grecolatina (AU)

Introduction. Every day millions of professionals use a countless number of technical words to refer to the different structures inside the skull. But few of them would know how to explain their origin. In this study we take an in-depth look into the etymological origins of some of these neuroanatomical terms. Development. The study takes an etymological tour of the central nervous system. It is in no way meant to be an exhaustive, detailed review of the terms currently in use, but instead a means to familiarise the reader with the linguistic past of words like brain, hippocampus, thalamus, claustrum, fornix, corpus callosum or limbic system. All of them come from either Greek or Latin, which were used for centuries as the lingua francas of science. The study also analyses the evolution of the word meninges, originally of Greco-Latin origin, although its current usages derive from Arabic. Conclusions. The neuroanatomical terms that are in use today do not come from words that associate a particular brain structure with its function, but instead from words that reflect the formal or conceptual similarity between a structure and a familiar or everyday entity (for example, an object or a part of the human body). In other cases, these words indicate the spatial location of the neuroanatomical structure with respect to a third, or they may be terms derived from characters in Greco-Latin mythology (AU)

[Motion-Onset Responses During Active and Passive Listening to the Moving Sound Stimuli].

This study investigated the energy-onset and motion-onset responses (N1, P2, cN 1 and cP2 components of the auditory evoked potential) elicited by moving sound stimuli in the passive and active listening conditions. In the passive conditions the subjects were distracted from auditory information; in active conditions they lo- calized the starting and final points of the stimulus trajectory. The sound movement to the left/right from the head midline was produced by linear-changes of the interaural time delay (ITD). The onset of motion was preceded by stationary sound located near the head midline. In the active conditions, the NI component was higher and the P2 component was higher and peaked later as compared to the passive listening. The early and later parts of the motion-onset response (cN 1 and cP2) also were larger in magnitude and peaked later during active listening. Both in active and passive conditions, cNI and cP2 amplitude exhibited increase and latency showed decrease when the stimulus velocity increased. Contralateral asymmetry was found only in the mo- tion-onset responses recorded from the left hemisphere.

Organización de redes neuronales en el cerebro del síndrome de Down / No disponible

Todas las funciones cerebrales -sensoriales, motoras, cognitivas, conductuales- son el resultado de la actividad de las neuronas. Pero éstas no funcionan de manera aislada sino que conforman intrincadas redes y circuitos perfectamente establecidos, gracias a los cuales se van originando los elementos que sustancian la percepción, la conciencia, el conocimiento, etc. Cuanto más compleja sea la función a desarrollar, más complicada y extensa será la red neuronal responsable de poner en marcha y mantener dicha función. El número de unidades neuronales y de sus conexiones está reducido en ciertas zonas del cerebro del síndrome de Down, por lo que las redes y circuitos que conforman tendrán una menor extensión y una menor capacidad organizativa, lo que constituye la base del decremento en la expresión de determinadas habilidades. Pero ¿es posible que en el síndrome de Down la reducción de la actividad de una zona cerebral afectada pueda ser sustituida o compensada por la actividad de otra, menos o nada afectada?

No disponible

Sound-sensitive neurons innervate the ventro-lateral protocerebrum of the heliothine moth brain.

Many noctuid moth species perceive ultrasound via tympanic ears that are located at the metathorax. Whereas the neural processing of auditory information is well studied at the peripheral and first synaptic level, little is known about the features characterizing higher order sound-sensitive neurons in the moth brain. During intracellular recordings from the lateral protocerebrum in the brain of three noctuid moth species, Heliothis virescens, Helicoverpa armigera and Helicoverpa assulta, we found an assembly of neurons responding to transient sound pulses of broad bandwidth. The majority of the auditory neurons ascended from the ventral cord and ramified densely within the anterior region of the ventro-lateral protocerebrum. The physiological and morphological characteristics of these auditory neurons were similar. We detected one additional sound-sensitive neuron, a brain interneuron with its soma positioned near the calyces of mushroom bodies and with numerous neuronal processes in the ventro-lateral protocerebrum. Mass-staining of ventral-cord neurons supported the assumption that the ventro-lateral region of the moth brain was the main target for the auditory projections ascending from the ventral cord.

The selfish brain: Competition for energy resources.

Obesity and type 2 diabetes have become the major health problems in many industrialized countries. Here, I present the unconventional concept that a healthy organism maintains its systemic homeostasis by a "competent brain-pull", i.e., the brain's ability to properly demand glucose from the body, and that the underlying cause of obesity is "incompetent brain-pull." I describe the energy fluxes from the environment, through the body, toward the brain as the final consumer in a "supply chain" model. There is data-based support for the hypothesis, which states that under conditions of food abundance incompetent brain-pull will lead to build ups in the supply chain culminating in obesity and type 2 diabetes. There is also support for the related hypothesis, which states that under conditions of food deprivation, a competent brain-pull mechanism is indispensable for the continuation of the brain's high energy level. To experimentally determine how the competent brain-pull functions to demand for cerebral energy, healthy young men undergoing psychosocial stress were studied. It was found that the brain under stressful conditions demands for energy from the body by using a brain-pull mechanism, which is referred to as "cerebral insulin suppression" and in so doing it can satisfy its excessive needs during stress. This article gives an overview about the recent work on the "Selfish Brain" theory dealing with the maintenance of the cerebral and peripheral energy homeostasis.

Anterior interhemispheric approach for 100 tumors in and around the anterior third ventricle.

OBJECTIVE: We report our experience with anterior interhemispheric approach for tumors in and around the anterior third ventricle, including surgical technique, instrumentation, pre- and postoperative hormonal disturbances, and resection rate. METHODS: One hundred patients with 46 craniopharyngiomas, 12 hypothalamic gliomas, 12 meningiomas, 6 hypothalamic hamartomas, and 24 other lesions were operated on using an anterior interhemispheric approach with or without opening of the lamina terminalis. This surgical approach involves no frontal sinus opening; a narrow (approximately 15-20 mm in width) access between the bridging veins, which is sufficient to remove the tumor totally; and sparing of the anterior communicating artery. Specially designed long bipolar forceps and scissors are necessary for this approach, and concomitant use of angled instruments (endoscope, aspirator, and microforceps) is required frequently. The postsurgical follow-up period varied from 4 months to 18 years. RESULTS: Total removal of the neoplasm was accomplished in 37 of 46 patients with craniopharyngiomas (80.4%), whereas subtotal resection was performed in hypothalamic gliomas. No significant differences in pre- and postoperative hormonal disturbances were observed in 37 craniopharyngiomas and 10 hypothalamic gliomas. There was no operative mortality. Visual acuity was preserved or improved in 68 of 75 patients assessed. The Karnofsky Performance Scale score did not deteriorate in 72 of 75 patients tested. CONCLUSION: The minimally invasive anterior interhemispheric approach, with or without opening of the lamina terminalis, is useful for removal of tumors in and around the anterior third ventricle, such as craniopharyngiomas and hypothalamic gliomas.

Diet supplement CoQ10 delays brain atrophy in aged transgenic mice with mutations in the amyloid precursor protein: an in vivo volume MRI study.

We tested the hypotheses that supplemental intake of the diet supplement Coenzyme Q10 (CoQ10) could delay brain atrophy in double transgenic amyloid precursor protein (APP) / presenilin 1 (PS1), single transgenic APP and PS1 as well as wild type mice by volume MR image in vivo. One hundred and twelve mice (28 APP/PS1, 28 APP, 28 PS1 and 28 wild types) were studied. Half of each genotype group (n = 14 per group) was treated with CoQ10 2400 mg/kg/day, and the other half with placebo for 60 days. Magnetic resonance (MR) images were used to obtain the volumes of the hemispheres and hippocampi. APP / PS1, APP, PS1 and wild type mice treated with CoQ10 exhibited significantly less atrophy in hemisphere and hippocampus than those receiving placebo. The neuro-protective effect of the CoQ10 on hemispheric volume, and hippocampal volume was related to genotype; greater in APP/PS1 than APP and PS1 mice and less in wild type mice. Our result indicated that CoQ10 may have therapeutic potential in the prevention and treatment of MCI and AD.

The cerebrum. Anatomy.

The cerebrum is the crown jewel of creation and evolution. It is a remarkably delicate, intricate, and beautiful structure. The goal of this chapter is to provide the information needed to permit the neurosurgeon to navigate accurately, gently, and safely around and through the cerebrum and intracranial space. The location of deep structures is frequently described in relation to cranial and superficial cerebral landmarks in order to develop the concept of see-through, x-ray type knowledge of the cerebrum. In numerous illustrations, stepwise dissections are used to clarify the relationship between structures in different layers. Important clinical and surgical concepts are intermixed with the description of the cerebrum and its arteries, veins, and ventricles.

Hallazgos angiotomográficos en pacientes con diagnóstico clínico de enfermedad vascular cerebral / Angiotomography in patients with cerebral vascular disease

Se describe, retrospectivamente los hallazgos angiotomográficos en 58 pacientes con diagnóstico de enfermedad vascular cerebral consistentes en isquemia cerebral transitoria, insuficiencia vértebrobasilar, ictus completo, alteraciones visuales y cefalea. Las ventajas de este procedimiento son su rapidez, alta sensibilidad para detectar placas de ateroma calcificadas y excelente demostración de la anatomía vascular intra y extracraneal. La aterosclerosis (31 por ciento) y los infartos lacunares (21 por ciento) fueron los hallazgos más comunes sobrre todo en pacientes mayores a los 50 años de edad. El 20 por ciento de los estudios no presentaron anormalidades, 8 por ciento correspondieron a aneurismas y el restante 20 por ciento correspondió a infartos crónicos, trombosis arterial, vasculitis, angiomas venosos, lesión selar y hemorragia subaracnoidea. Por último, considerando únicamente los estudios de cráneo (50 pacientes) los aneurismas saculares a nivel del polígono de Willis fueron el 12 por ciento

Valor semiológico de los signos clínicos en el diagnóstico topográfico de las epilepsias refractarias: Epilepsias parciales / Semiologic value of the clinical signs in topographic diagnosis of the refractory epilepsies: Partial epipsies

El análisis de los síntomas y signos clínicos obtenidos por medio de un interrogatorio detallado y por la observación secuencial de los fenómenos motores a través de técnicas de monitoreo continua TV-EEG constituye una herramienta poderosa para establecer el diagnóstico topográfico de los pacientes con crisis parciales de difícil control en los cuales se complementa un tratamiento quirúrgico ablativo. Las alteraciones de la conciencia. Las auras y síntomas somatosensoriales, visuales y auditivos localizan el origen y la propagación de las crisis dentro de las cortezas primarias SI, VI y AI en el hemisferio. Los fenómenos motores representan la expresión sintomática de las crisis que se originan en, o se propagan a distinto territorios corticales: Las contracciones musculares focales con marcha Kachsoniana y parálisis de Tood apuntan al área Rolándica. El arreste conductual y los automatismos oroalimentarios y exploratorios al área temporal mesial. Los movimientos tónicos posicionales abruptos al área motora suplementaria; los movimiento versivos a las áreas frontopolar y dorsolateral; y la supresión del habla al opercular y al área temporal lateral. La progresión y secuencia de los síntomas y fenómenos motores durante las crisis permite diferenciar el origen (lesión, foco y área epileptógena) de la propagación (área sintomática) lo cual es factible en aquellas que se propagan lentamente a sitios distantes

Undernutrition during suckling does not change the specific or total activity of hypothalamic proline endopeptidase in adult rats

Undernutrition during suckling causes a decrease in hypothalamic beta-endorphin-like immunoreactivity in rats. Since proline endopeptidase (E.C. 3.4.21.26) has been proposed to play a role in the processing of Beta-endorphin, we examined the effects of undernutrition during suckling on the enzyme activity. Rats were undernourished by feeding their dams an 8% casein diet from the day of birth until weaning (21 days). Dams of well-nourished rats were fed a 25% casein diet during the same period. After weaning, all rats received a 20% protein diet until 90 to 120 days of age when they were killed for the enzyme assay. The specific and total activity of hypothalamic proline endopeptidase was not altered by undernutrition followed by nutritional rehabilitation(2.37 + or - 0.24 nmol sulphamethoxazole min-1 mg-1 for well-nourished rats vs 2.68 + or - 0.24 nmol sulphamethoxazole min-1 mg-1 for undernourished rats). This lack of correlation suggests that proline endopeptidase is probably not responsible for the low levels of hypothalamic Beta-endorphin found in adult rats submitted to undernutrition during suckling