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Magnetic resonance–guided focused ultrasound for ablation of mesial temporal epilepsy circuits: modeling and theoretical feasibility of a novel noninvasive approach

Whitney E. Parker, Elizabeth K. Weidman, J. Levi Chazen, Sumit N. Niogi, Rafael Uribe-Cardenas, Michael G. Kaplitt, and Caitlin E. Hoffman

visualization of the tissue area being heated to various temperatures in order to determine, in real time, whether the desired tissue volume has been ablated. Instead of targeting the mesial temporal structures, this modality would target the posterior outflow tract of the hippocampus and potentially disrupt posterior escape and spread of electrical activity from a mesial temporal onset zone. The fornix-fimbria posterior outflow target represents a white matter pathway found to have diffusion abnormalities and corresponding axonal pathology in MTS. 8 , 9 The anterior nucleus

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Endoscopic transventricular resection of a colloid cyst

Sebastian Lehmann and Henry W. S. Schroeder

placed and the navigation-guided sheath for the endoscope is carefully inserted, following the preplanned trajectory, reaching the lateral ventricle with direct view to the interventricular septum and the head of the caudate nucleus. Once the caudate nucleus head is covered by the endoscope sheath, the sheath is used as a retractor to dislocate the head of the caudate nucleus a little bit laterally to get the ideal approach to the colloid cyst’s attachment at the roof of the third ventricle. The anatomical landmarks for orientation are the fornix, the choroid plexus

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Minimally invasive endoscopic transventricular hemispherotomy for medically intractable epilepsy: a new approach and cadaveric demonstration

Laboratory investigation

Biji Bahuleyan, Sunil Manjila, Shenandoah Robinson, and Alan R. Cohen

-forward rod lens was inserted. The image was transmitted to a high-definition video monitor using a microchip camera, and photographs were taken. White matter disconnections were created using a blunt probe or microscissors, which were inserted through a working channel in the endoscope sheath. The surgical steps followed in our technique were similar to those in the vertical parasagittal hemispherotomy popularized by Delalande et al. 2 , 3 These steps consisted of corpus callosotomy, temporal horn unroofing, frontobasal disconnection, and fornix disconnection. The

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Tractography of the amygdala and hippocampus: anatomical study and application to selective amygdalohippocampectomy

Laboratory investigation

Sophie Colnat-Coulbois, Kelvin Mok, Denise Klein, Sidonie Pénicaud, Taner Tanriverdi, and André Olivier

Tractography of Hippocampus We observed a common pattern of fibers crossing the hippocampus in which the shape was constant in every participant ( Fig. 2 ). Those fibers followed the hippocampus itself toward the crus fornicis and the body of the fornix in the internal part of the lateral ventricle ( Fig. 3 ). The connections between the 2 hippocampi appear to follow 2 main pathways: the splenium of the corpus callosum ( Fig. 4 ) and the dorsal hippocampal commissure located inferiorly to the callosal fibers ( Fig. 5 ). In some individuals, callosal fibers coming from the

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Neuromodulation for restoring memory

Sarah K. B. Bick and Emad N. Eskandar

integral to memory function ( Fig. 1 ). 80 It involves circular projections from hippocampus to fornix, to mammillary bodies, to anterior nucleus of the thalamus, to cingulum, to the entorhinal cortex, and back to the hippocampus. Much of the work on neuromodulation for memory has focused on altering activity in the Papez circuit. FIG. 1. Structures involved in memory circuitry and their interconnections. Dark gray structures indicate components of the circuit of Papez, and light gray structures indicate other components of memory circuitry discussed in the

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Central core of the cerebrum

Laboratory investigation

Chan-Young Choi, Seong-Rok Han, Gi-Taek Yee, and Chae-Heuck Lee

) into the thalamus above and the hypothalamus below and lies between the foramen of Monro and the aqueduct; it is surrounded by the stria medullaris, anterior commissure, lamina terminalis, habenular commissure, pineal body, posterior commissure, aqueduct, midbrain tegmentum, and mammillary body. B: The corpus callosum, tela and choroid plexus, and the hippocampal commissure have been removed to expose the medial view of the central core, including the caudate nucleus, fornix, and diencephalon. C: Superior view of the central core showing the dorsal diencephalic

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Comparative analysis of endoscopic third ventriculostomy trajectories in pediatric cases

Zsolt Zador, David J. Coope, and Ian D. Kamaly-Asl

(the floor of the third ventricle just anterior to the mammillary bodies) ( Fig. 2B and C ). The depth of the intersection with the anatomical structures was used to simulate the extent of tissue displacement caused by the rigid neuroendoscope. Displacement was categorized as 1) “anterior displacement,” which included displacement to the fornix, or 2) “lateral displacement,” which included displacement to the caudate nucleus, genu of the internal capsule, or thalamus. The diameter of the rigid neuroendoscope was incorporated into our simulations by assigning the

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Deep brain stimulation for dementias

David S. Xu and Francisco A. Ponce

severity of illness at the time of diagnosis, influence life expectancy. 20 Interestingly, an older age of AD onset has been associated with a slower rate of cognitive decline rather than a younger age, suggesting that AD onset in the young may represent a different disease phenotype. 4 , 37 Fornix Stimulation Rationale and Targeting Table 1 presents a summary of DBS targeting data reported on the rationale for, and targeting of, fornix stimulation. The cognitive effects of fornix stimulation were first encountered incidentally during bilateral DBS treatment of the

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Intracerebral drug delivery in rats with lesion-induced memory deficits

Matthew A. Howard III, Alan Gross, M. Sean Grady, Robert S. Langer, Edith Mathiowitz, H. Richard Winn, and Marc R. Mayberg

denervation reliably produced profound spatial memory deficits in rats. The cholinomimetic agent bethanechol was impregnated into polyanhydride microspheres and implanted in denervated hippocampus in rats to provide selective local administration of the drug. Materials and Methods Fimbria-Fornix Lesions Twenty-two adult Sprague-Dawley rats, each weighing 250 to 300 gm, were anesthetized with 1.6 ml/kg of intraperitoneal Chloropent (chloral hydrate, magnesium sulfate, pentobarbital, ethyl alchohol, and propylene glycol) and placed in a small-animal stereotactic

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Microsurgical anatomy of the choroidal arteries: Lateral and third ventricles

Kiyotaka Fujii, Carla Lenkey, and Albert L. Rhoton Jr.

and pass above the fimbria of the fornix to enter the choroid plexus. The medial posterior choroidal artery (M.P.Ch.A.) arises from the PCA and enters the choroid plexus of the third ventricle (Ch.Pl.-3V). The columns of the fornix have been divided to expose the choroid plexus in the foramen of Monro. The removal of the left thalamus exposes the anterior commissure (Ant. Com.) and the massa intermedia (Massa Int.) in the third ventricle. The proximal segment of the left (A-1) and distal (A-2) segments of both anterior cerebral arteries (ACA's) and the anterior