Exploring the brain through posterior hypothalamus surgery for aggressive behavior.

Neurological surgery offers an opportunity to study brain functions, through either resection or implanted neuromodulation devices. Pathological aggressive behavior in patients with intellectual disability is a frequent condition that is difficult to treat using either supportive care or pharmacological therapy. The bulk of the laboratory studies performed throughout the 19th century enabled the formulation of hypotheses on brain circuits involved in the generation of emotions. Aggressive behavior was also studied extensively. Lesional radiofrequency surgery of the posterior hypothalamus, which peaked in the 1970s, was shown to be an effective therapy in many reported series. As with other surgical procedures for the treatment of psychiatric disorders, however, this therapy was abandoned for many reasons, including the risk of its misuse. Deep brain stimulation (DBS) offers the possibility of treating neurological and psychoaffective disorders through relatively reversible and adaptable therapy. Deep brain stimulation of the posterior hypothalamus was proposed and performed successfully in 2005 as a treatment for aggressive behavior. Other groups reported positive outcomes using target and parameter settings similar to those of the original study. Both the lesional and DBS approaches enabled researchers to explore the role of the posterior hypothalamus (or posterior hypothalamic area) in the autonomic and emotional systems.

Dorsal premammillary projection to periaqueductal gray controls escape vigor from innate and conditioned threats.

Escape from threats has paramount importance for survival. However, it is unknown if a single circuit controls escape vigor from innate and conditioned threats. Cholecystokinin (cck)-expressing cells in the hypothalamic dorsal premammillary nucleus (PMd) are necessary for initiating escape from innate threats via a projection to the dorsolateral periaqueductal gray (dlPAG). We now show that in mice PMd-cck cells are activated during escape, but not other defensive behaviors. PMd-cck ensemble activity can also predict future escape. Furthermore, PMd inhibition decreases escape speed from both innate and conditioned threats. Inhibition of the PMd-cck projection to the dlPAG also decreased escape speed. Intriguingly, PMd-cck and dlPAG activity in mice showed higher mutual information during exposure to innate and conditioned threats. In parallel, human functional magnetic resonance imaging data show that a posterior hypothalamic-to-dlPAG pathway increased activity during exposure to aversive images, indicating that a similar pathway may possibly have a related role in humans. Our data identify the PMd-dlPAG circuit as a central node, controlling escape vigor elicited by both innate and conditioned threats.

Connectivity of an effective hypothalamic surgical target for cluster headache.

The purpose of this study was to look at the connectivity of the posterior inferior hypothalamus in a patient implanted with a deep brain stimulating electrode using probabilistic tractography in conjunction with postoperative MRI scans. In a patient with chronic cluster headache we implanted a deep brain stimulating electrode into the ipsilateral postero-medial hypothalamus to successfully control his pain. To explore the connectivity, we used the surgical target from the postoperative MRI scan as a seed for probabilistic tractography, which was then linked to diffusion weighted imaging data acquired in a group of healthy control subjects. We found highly consistent connections with the reticular nucleus and cerebellum. In some subjects, connections were also seen with the parietal cortices, and the inferior medial frontal gyrus. Our results illustrate important anatomical connections that may explain the functional changes associated with cluster headaches and elucidate possible mechanisms responsible for triggering attacks.

GLP-1 and estrogen conjugate acts in the supramammillary nucleus to reduce food-reward and body weight.

The obesity epidemic continues unabated and currently available pharmacological treatments are not sufficiently effective. Combining gut/brain peptide, GLP-1, with estrogen into a conjugate may represent a novel, safe and potent, strategy to treat diabesity. Here we demonstrate that the central administration of GLP-1-estrogen conjugate reduced food reward, food intake, and body weight in rats. In order to determine the brain location of the interaction of GLP-1 with estrogen, we avail of single-photon emission computed tomography imaging of regional cerebral blood flow and pinpoint a brain site unexplored for its role in feeding and reward, the supramammillary nucleus (SUM) as a potential target of the conjugated GLP-1-estrogen. We confirm that conjugated GLP-1 and estrogen directly target the SUM with site-specific microinjections. Additional microinjections of GLP-1-estrogen into classic energy balance controlling nuclei, the lateral hypothalamus (LH) and the nucleus of the solitary tract (NTS) revealed that the metabolic benefits resulting from GLP-1-estrogen injections are mediated through the LH and to some extent by the NTS. In contrast, no additional benefit of the conjugate was noted on food reward when the compound was microinjected into the LH or the NTS, identifying the SUM as the only neural substrate identified here to underlie the reward reducing benefits of GLP-1 and estrogen conjugate. Collectively we discover a surprising neural substrate underlying food intake and reward effects of GLP-1 and estrogen and uncover a new brain area capable of regulating energy balance and reward.

[Hypothalamic hamartoma with precocious puberty--a case report].

A case of hypothalamic hamartoma with precocious puberty is presented and the literature of reported cases is reviewed. An 8-year-old boy was admitted to our hospital because of precocious puberty and mental retardation. His genital development was Tanner's stage 4 and pubic hair was Tanner's stage 3. Bone age was 11 years. Plain CT showed an isodense mass in the suprasellar cistern which was not enhanced following contrast administration. Metrizamide CT cisternography showed a filling defect in the suprasellar cistern. Endocrinological evaluation revealed high levels of serum luteinizing hormone (LH) and testosterone with a marked response of LH to LH-RH injection. A left frontotemporal craniotomy was performed and the tumor was partially removed. The tumor was gray, firm and well-circumscribed with poor vascularity. Postoperatively, a right oculomotor palsy and transient diabetes insipidus developed. He was discharged ambulatory one month later. Serum LH and testosterone returned to normal and the response of LH to LH-RH injection became normal. Hamartoma was diagnosed on histological examination. Electron micrographic study showed numerous dense granules with approximately 0.1 mu in diameter, in which Judge proved LH-RH by immunofluorescent study in 1977. Our case supports the hypothesis that hypothalamic hamartoma may cause precocious puberty by autonomous secretion of LH-RH and we consider that neurosurgical treatment is recommended.

Tratamiento de la agresividad refractaria mediante amigdalotomía e hipotalamotomía posteromedial por radiofrecuencia / Treatment of refractory aggressiveness by amygdalotomy and posteromedial hypothalamotomy by radiofrequency

Introducción. Dado que, en algunas circunstancias, las conductas defensivas o de ataque muestran un patrón de dominancia motora, tal como se observa en los sujetos dedicados a los deportes de contacto o de lucha, se consideró que la conducta agresiva tiene un patrón motor dominante. Con el fin de evitar los problemas funcionales descritos con los procedimientos de lesión bilateral tanto del núcleo central de la amígdala como del hipotálamo posteromedial, se decidió combinarlos; es decir, realizar amigdalotomía del núcleo central de la amígdala e hipotalamotomía posteromedial de manera unilateral y simultánea, basándose en la dominancia motora del paciente mediante la prueba de Edimburgo. Pacientes y métodos. Este estudio muestra la experiencia quirúrgica en una serie de nueve pacientes con el diagnóstico de síndrome neuroagresivo resistente al tratamiento farmacológico. Dentro del protocolo de estudio, se les realizó resonancia magnética cerebral para descartar la presencia de neoplasias, enfermedades vasculares, infecciones y trastornos degenerativos. El grado de agresividad se cuantificó mediante la escala global de agresividad de Yudofsky. Adicionalmente, se determinó la dominancia manual a través de la prueba de Edimburgo. Resultados y conclusiones. El buen control de la agresividad se observó de modo inmediato. En algunos casos fue necesario reducir la medicación de antipsicóticos o benzodiacepinas, ya que aumentaban la agresividad. Sólo un caso requirió una segunda cirugía. Se logró seguimiento del 100% de los casos en 24 meses y del 78% en 36 meses

Introduction. Since, under certain circumstances, defensive or attacking behaviours display a pattern of motor dominance, as observed in subjects who participate in contact or fighting sports, aggressive behaviour was considered to have a dominant motor pattern. With the aim of preventing the functional problems reported with bilateral lesion procedures involving both the central nucleus of the amygdala and the posteromedial hypothalamus, the decision was made to combine them; thus, an amygdalotomy of the central nucleus of the amygdala and a posteromedial hypothalamotomy were to be performed simultaneously and unilaterally, on the basis of the motor dominance of the patient determined by means of the Edinburgh test. Patients and methods. This study describes the surgical experience in a series of nine patients diagnosed with refractory neuroaggressive syndrome. As part of the study protocol, a magnetic resonance brain scan was performed to rule out the presence of neoplasms, vascular diseases, infections and degenerative disorders. The degree of aggressiveness was quantified using Yudofsky's Overt Aggression Scale. Additionally, manual dominance was determined by means of the Edinburgh test. Results and conclusions. Good control of aggressiveness was seen immediately. In some cases it was necessary to reduce the antipsychotic or benzodiazepine medication, as it was seen to increase aggressiveness. Only one case required a second surgical intervention. Follow-up was achieved in 100% of the cases at 24 months and 78% at 36 months

Air-ventriculography provokes an anterior displacement of the third ventricle during functional stereotactic procedures.

The width of the third ventricle, the length of the anterior commissure-posterior commissure line (AC-PC line), the spatial position of the midplane of the third ventricle, and the co-ordinates of the AC, the PC, and of 17 brain targets in the thalamus, hypothalamus and pallidum, were assessed on a pre-operative stereotactic computed-tomography (CT) study and compared to measurements on intra-operative air-ventriculography, using a non-invasive relocatable stereotactic frame. There were no significant differences in the length of the AC-PC line, in the position of the midsagittal plane of the third ventricle, or in the vertical or lateral co-ordinates of the AC, the PC and the cerebral targets, between measurements on CT and on air-ventriculography. However, the width of the third ventricle was significantly larger, and the spatial positions of both AC and PC were significantly more anterior on air-ventriculography than on the CT study. This anterior dislocation of the commissures was presumably due to the insufflation of air into the ventricles of patients being in the supine position during surgery.