Temporal multiplexing of perception and memory codes in IT cortex.

A central assumption of neuroscience is that long-term memories are represented by the same brain areas that encode sensory stimuli1. Neurons in inferotemporal (IT) cortex represent the sensory percept of visual objects using a distributed axis code2-4. Whether and how the same IT neural population represents the long-term memory of visual objects remains unclear. Here we examined how familiar faces are encoded in the IT anterior medial face patch (AM), perirhinal face patch (PR) and temporal pole face patch (TP). In AM and PR we observed that the encoding axis for familiar faces is rotated relative to that for unfamiliar faces at long latency; in TP this memory-related rotation was much weaker. Contrary to previous claims, the relative response magnitude to familiar versus unfamiliar faces was not a stable indicator of familiarity in any patch5-11. The mechanism underlying the memory-related axis change is likely intrinsic to IT cortex, because inactivation of PR did not affect axis change dynamics in AM. Overall, our results suggest that memories of familiar faces are represented in AM and perirhinal cortex by a distinct long-latency code, explaining how the same cell population can encode both the percept and memory of faces.

Unveiling the axonal connectivity between the precuneus and temporal pole: Structural evidence from the cingulum pathways.

Neuroimaging studies have consistently demonstrated concurrent activation of the human precuneus and temporal pole (TP), both during resting-state conditions and various higher-order cognitive functions. However, the precise underlying structural connectivity between these brain regions remains uncertain despite significant advancements in neuroscience research. In this study, we investigated the connectivity of the precuneus and TP by employing parcellation-based fiber micro-dissections in human brains and fiber tractography techniques in a sample of 1065 human subjects and a sample of 41 rhesus macaques. Our results demonstrate the connectivity between the posterior precuneus area POS2 and the areas 35, 36, and TG of the TP via the fifth subcomponent of the cingulum (CB-V) also known as parahippocampal cingulum. This finding contributes to our understanding of the connections within the posteromedial cortices, facilitating a more comprehensive integration of anatomy and function in both normal and pathological brain processes. PRACTITIONER POINTS: Our investigation delves into the intricate architecture and connectivity patterns of subregions within the precuneus and temporal pole, filling a crucial gap in our knowledge. We revealed a direct axonal connection between the posterior precuneus (POS2) and specific areas (35, 35, and TG) of the temporal pole. The direct connections are part of the CB-V pathway and exhibit a significant association with the cingulum, SRF, forceps major, and ILF. Population-based human tractography and rhesus macaque fiber tractography showed consistent results that support micro-dissection outcomes.

Defining the Temporal and Occipital Lobes: Cadaveric Study with Application to Neurosurgery of the Inferior Brain.

BACKGROUND: For surgical interventions, a precise understanding of the anatomical variations of the brain and defined anatomical landmarks to demarcate the regions of the temporal lobe is essential. Many anatomical studies have facilitated important surgical approaches to the temporobasal region. Because there is considerable sulcal variability, morphological analysis of the brain is imperative. The aim of this study was to define the boundaries of the temporal and occipital lobes and to define the variations in sulci and gyri in the inferior aspect. METHODS: In 110 cerebral hemispheres variations were identified and the major landmarks of the gyral-sulcal pattern at the inferior aspect of the brain were defined. RESULTS: The anatomy of the inferior aspect of the brain is defined in detail by morphological analysis of formalin-fixed hemispheres with a view to informing important surgical approaches. CONCLUSIONS: Since the literature defines no clear separation between the temporal and occipital lobes, certain landmarks such as the preoccipital notch and a basal temporo-occipital line were suggested as ways of making the distinction. The parahippocampal ramus is a constant structure that can be used as a reliable landmark for the posterior end of the hippocampus.

Considerations for implanting speech brain computer interfaces based on functional magnetic resonance imaging.

Objective.Brain-computer interfaces (BCIs) have the potential to reinstate lost communication faculties. Results from speech decoding studies indicate that a usable speech BCI based on activity in the sensorimotor cortex (SMC) can be achieved using subdurally implanted electrodes. However, the optimal characteristics for a successful speech implant are largely unknown. We address this topic in a high field blood oxygenation level dependent functional magnetic resonance imaging (fMRI) study, by assessing the decodability of spoken words as a function of hemisphere, gyrus, sulcal depth, and position along the ventral/dorsal-axis.Approach.Twelve subjects conducted a 7T fMRI experiment in which they pronounced 6 different pseudo-words over 6 runs. We divided the SMC by hemisphere, gyrus, sulcal depth, and position along the ventral/dorsal axis. Classification was performed on in these SMC areas using multiclass support vector machine (SVM).Main results.Significant classification was possible from the SMC, but no preference for the left or right hemisphere, nor for the precentral or postcentral gyrus for optimal word classification was detected. Classification while using information from the cortical surface was slightly better than when using information from deep in the central sulcus and was highest within the ventral 50% of SMC. Confusion matrices where highly similar across the entire SMC. An SVM-searchlight analysis revealed significant classification in the superior temporal gyrus and left planum temporale in addition to the SMC.Significance.The current results support a unilateral implant using surface electrodes, covering the ventral 50% of the SMC. The added value of depth electrodes is unclear. We did not observe evidence for variations in the qualitative nature of information across SMC. The current results need to be confirmed in paralyzed patients performing attempted speech.

Working memory and left medial temporal cortical thickness / Memória de trabalho e espessura cortical temporal medial esquerda

ABSTRACT Objective To perform a pilot study to investigate the association between working memory and cortical thickness in a sample of attention deficit/hyperactivity disorder (ADHD) children. Methods Seventeen children aged 7-10 years diagnosed with ADHD and 16 healthy children underwent a magnetic resonance scan for cortical thickness measurements. Data was correlated with working memory performance using the Backwards Digit Span subtest of the Wechsler Intelligence Scale for Children. Results Working memory impairment, evidenced by lower scores on the Backwards Digit Span, was observed in patients with ADHD compared to healthy controls. There was a direct correlation between working memory and cortical thickness of the left medial temporal lobe (Spearman’s correlation coefficient: 0.499; p < 0.005). Conclusions Our data suggests, for the first time, a correlation between working memory, evaluated by the Backwards Digit Span, and left medial temporal cortical thickness.

RESUMO Objetivo Realizar estudo piloto para investigar a associação entre memória de trabalho e espessura cortical em crianças com transtorno de défict de atenção e hiperatividade (TDAH). Métodos Dezessete crianças com TDAH, entre 7 e 10 anos, e dezesseis crianças saudáveis foram submetidas a ressonância magnética para aferição de espessura cortical. Os dados foram correlacionados com desempenho da memória de trabalho usando a ordem inversa do subteste Dígitos da Escala de Inteligência Wechsler para Crianças. Resultados Prejuízos na memória de trabalho, evidenciado pela menor pontuação na ordem inversa do subteste Dígitos, foram observados em pacientes com TDAH, em comparação com crianças saudáveis. Observou-se correlação direta entre memória de trabalho e espessura do lobo temporal médio à esquerda (coeficiente de correlação de Spearman: 0,499; p < 0,005). Conclusões Nossos dados sugerem, pela primeira vez, uma correlação entre memória de trabalho, avaliada através da pontuação na ordem inversa do subteste Dígitos, e espessura do córtex temporal medial à esquerda.

Cortical projection of the inferior choroidal point as a reliable landmark to place the corticectomy and reach the temporal horn through a middle temporal gyrus approach / Projeção cortical do ponto coroideo inferior como uma referência anatômica confiável para a realização da corticectomia e abordagem do corno temporal através do giro temporal médio.

Objective To establish preoperatively the localization of the cortical projection of the inferior choroidal point (ICP) and use it as a reliable landmark when approaching the temporal horn through a middle temporal gyrus access. To review relevant anatomical features regarding selective amigdalohippocampectomy (AH) for treatment of mesial temporal lobe epilepsy (MTLE). Method The cortical projection of the inferior choroidal point was used in more than 300 surgeries by one authors as a reliable landmark to reach the temporal horn. In the laboratory, forty cerebral hemispheres were examined. Conclusion The cortical projection of the ICP is a reliable landmark for reaching the temporal horn. .

Objetivo Estabelecer a projeção cortical do ponto coiroideo inferior e usá-la como referência para realizar a corticectomia e a abordagem do corno temporal do ventrículo lateral em cirurgias para o tratamento da epilepsia temporal mesial. Método A projeção cortical do ponto coroideo inferior foi utilizada por um dos autores seniors em mais de 300 casos de epilepsia temporal mesial para atingir o corno temporal do ventrículo lateral. Conclusão A projeção cortical do ponto coroideo inferior foi útil e confiável na abordagem do corno temporal do ventrículo lateral e ela está geralmente localizada na margem inferior do giro temporal médio, em média, a 4,52 cm posterior ao polo temporal. .

Anatomic study of the optical radiation and its relationship in the temporal lobe: definition of a secure approach for amigdalohipocampectomy in epilepsy surgery / Estudio anatómico de la radiación óptica y su relación en el lóbulo temporal: definición de un abordaje seguro para amigdalohipocampectomía en cirugía de la epilepsia

Introducción/Objetivos: El lóbulo temporal anterior tiene importantes estructuras subcorticales, especialmente fibras blancas que llevan la información visual. La comprensión de esta región anatómica, importantes para la práctica microquirúrgica, se basa en técnicas de disección de fibras. Ellos proporcionan perspectiva tridimensional de esta región y añaden un enfoque quirúrgico exitoso para el tratamiento de las lesiones temporales mesiales. El propósito de este trabajo es el estudio de la anatomía de la pared lateral del ventrículo lateral con el fin de determinar una zona libre de la radiación óptica. Métodos: Se diseccionaron diez hemisferios cerebrales, preparados de acuerdo con técnicas de Klingler. Se utilizan espátulas de madera con puntas de diferentes tamaños. La radiación óptica fue delimitada y las medidas se tomaron a partir de esta estructura para el polo temporal, que se utiliza como punto de referencia. Resultados: Abordajes para el cuerno temporal superior a 27 mm más allá del polo temporal pueden cruzar asa de Meyer y determinar un perjuicio a la radiación óptica con los consiguientes déficits en los campos visuales. Conclusión: La determinación de la zona de libre de fibras de radiación óptica es factible. En este trabajo se podría inferir que el área libre de la radiación óptica se encuentra en la región anterioinferior del lóbulo temporal a una distancia de hasta 2,7 centímetros desde el polo temporal y permite el acceso a el hipocampo y la amígdala durante la cirugía de la epilepsia. Resecciones más grandes que estas medidas permiten aclarar de una lesión a la radiación óptica con los consiguientes déficits en los campos visuales.

Introduction/Objective: The anterior temporal lobe has important subcortical structures, especially white fibers that lead visual information. Understanding this anatomical region, important for microsurgical practice, is based on fibers dissection techniques. They provide three-dimensional perspective for this region and add a successful surgical approach for the treatment of mesial temporal lesions. The purpose of this paper is to study the anatomy of the lateral wall of the lateral ventricle in order to determine a free area of the optical radiation. Methods: Ten cerebral hemispheres were dissected, prepared according to Klingler´s techniques. Wooden spatulas with tips of various sizes were used. The optical radiation was delimited and measures were taken from this structure to the temporal pole, used as a reference point. Results: Approaches to the temporal horn larger than 27 mm beyond the temporal pole can cross Meyer´s loop and determine injury to the optical radiation with consequent postoperatively deficits in visual fields. Conclusion: The determination of free area of optical radiation fibers is feasible. In this work we could infer that free area of optical radiation is located in the anterioinferior region of the temporal lobe at a distance of up to 2.7 centimeters from the temporal pole and allows access to the hippocampus and amygdala during epilepsy surgery. Larger resections than these measures can possibly determine injury to the optical radiation with consequent deficits in visual fields.

Longitudinal brain volumetric changes during one year in non-elderly healthy adults: a voxel-based morphometry study

Previous cross-sectional magnetic resonance imaging (MRI) studies of healthy aging in young adults have indicated the presence of significant inverse correlations between age and gray matter volumes, although not homogeneously across all brain regions. However, such cross-sectional studies have important limitations and there is a scarcity of detailed longitudinal MRI studies with repeated measures obtained in the same individuals in order to investigate regional gray matter changes during short periods of time in non-elderly healthy adults. In the present study, 52 healthy young adults aged 18 to 50 years (27 males and 25 females) were followed with repeated MRI acquisitions over approximately 15 months. Gray matter volumes were compared between the two times using voxel-based morphometry, with the prediction that volume changes would be detectable in the frontal lobe, temporal neocortex and hippocampus. Voxel-wise analyses showed significant (P < 0.05, family-wise error corrected) relative volume reductions of gray matter in two small foci located in the right orbitofrontal cortex and left hippocampus. Separate comparisons for males and females showed bilateral gray matter relative reductions in the orbitofrontal cortex over time only in males. We conclude that, in non-elderly healthy adults, subtle gray matter volume alterations are detectable after short periods of time. This underscores the dynamic nature of gray matter changes in the brain during adult life, with regional volume reductions being detectable in brain regions that are relevant to cognitive and emotional processes.

Esclerosis temporal mesial: paradigma de la epilepsia de resolución quirúrgica / Mesial temporal sclerosis: paradigm of surgically treatable epilepsy

Objetivo. Describir la esclerosis temporal mesial (ETM) es sus aspectos anatómicos, fisiopatológico, clínico, imagenológico, neurofisiológico, neuropsicológico y quirúrgico; y su relación con la epilepsia de resolución quirúrgica. Luego analizar estadísticamente nuestra casuística y resultados. Materiales y métodos. De los 469 (115 adultos y 354 niños) pacientes intervenidos quirúrgicamente por presentar epilepsia entre los años 1989-2007 en el Hospital Dr. Juan P. Garraham, FLENI, Hospital Dr. Cosme Argerich y Hospital Prof. Dr. Rodolfo Rossi, se analizar 91 pacientes (19.4%) con el diagnóstico de ETM; 38 de los cuales (41.75%) son niños y 53 (58.25%) adultos. Resultados. Los resultados son evaluados mediante el score de Engel. Aplicando esta clasificación, nuestra población tiene la siguiente distribución; 69 pacientes (75.8%) se encuentran en clase IA de Engel, de ellos 36 son niños (52.2%) y 33 adultos (47.8%); 4 pacientes adultos se encuentran en Engel IB (4.4%), 3 en Engel IC (3.3%), 1 adulto en Engel ID (1.1%), 4 adultos en Engel IIA (4.4%), 5 adultos en Engel IIB (5.5%) y 3 pacientes en Engel IVA (3.3%) de ellos 1 niño a quien posteriormente se le implantó un estimulador del nervio vago y los 2 restantes adultos. Un paciente adulto se suicidó luego de un año de la cirugía (en clase IA de Engel). Un paciente se encuentra durante su primer año postoperatorio por lo cual no puede ser incluido aún en la estadística de resultados. Conclusión. La ETM es el paradigma de la epilepsia refractaria en al población adulta y la causa de un porcentaje significativo de pacientes pediátricos sometidos a cirugía. La evolución prequirúrgica debe ser exhaustiva para lograr la selección del paciente. La resección quirúrgica debe ser realizada con la mayor selectividad posible. El diagnóstico y tratamiento precoz permite lograr un alto índice de curación.

Asymmetries of the Left and Right Temporal Lobes / Asimetría de los Lóbulos Temporales Izquierdo y Derecho

Anatomical brain asymmetries are subtle and still little studied in humans. Among all the animals, humans have the most asymmetric brains Crow (2004). The language faculty and handedness are localized on the left side. The objective this paper is to verify whether the temporal lobes are anatomically different. Our sample was composed of 40 post mortem adult brains of both sexes, which were investigated at the Human Anatomy Laboratory of the Nove de Julho University Center in Sao Paulo, Brazil. The brains were fixed in a solution of 5% paraformaldehyde. Three different measurements were taken using a pachimeter (Mitutoyo) and a goniometer (Card) on both hemispheres: Ml - the length of the lateral sulcus; M2 - the distance from the lateral sulcus to the inferior margin of the inferior temporal gyrus, and M3 - the angle formed between the lines of the collateral sulcus and the inferior margin of the inferior temporal gyrus. Results were submitted to a statistical analysis (ANOVA) and demonstrated that Ml was larger in the left hemisphere, by contrast with the data obtained for M2 and M3, which were larger in the right hemisphere. The measurements taken showed differences between the right and left temporal lobes.

Las asimetrías anatómicas del cerebro humano son sutiles y aún poco estudiadas. Entre todos los animales, el Hombre es el que presenta el cerebro más asimétrico (Crow, 2004). En el lado izquierdo del cerebro se localiza la facultad del lenguaje, como también de la lateralidad manual. El objetivo del trabajo fue verificar si los lóbulos temporales son anatómicamente diferentes. La muestra estuvo compuesta de 40 encéfalos adultos, post mortem, de ambos sexos, del Laboratorio de Anatomía del Centro Universitario Nove de Julho, en Sao Paulo, SP, Brasil. Los encéfalos fueron fijados en solución de formalina al 5%. Fueron realizadas 3 medidas diferentes utilizando un pié de metro Mitutoyo y goniómetro (Carci), en ambos hemisferios: medida MI, largo del surco lateral; medida M2 distancia del surco lateral hasta el margen inferior del giro temporal inferior y la medida M3 el ángulo formado entre las líneas del surco colateral y margen inferior del giro temporal inferior. Los resultados se sometieron a análisis estadístico y mostraron que MI era mayor en el hemisferio izquierdo, en contraposición a los datos obtenidos en M2 y M3, que fueron mayores en el hemisferio derecho. Las medidas realizadas presentaron diferencias entre los lóbulos temporales derecho e izquierdo.

Anatomía de las fibras blancas del lóbulo temporal en 3D / Three dimensional anatomy of the white fibers of the temporal lobe

Objetivo: aplicar la técnica de disección de fibras blancas para la comprensión tridimensional de las diferentes estructuras localizadas en el lóbulo temporal. Material y métodos: se utilizaron cinco cerebros humanos normales los que fueron sometidos a la técnica de preparación de Klinger para disección de fibras blancas. Se utilizó microscopio de luz con aumentos de cinco y veinte X.Resultados: las fibras del lóbulo temporal pueden dividirse dependiendo de la cara que examinemos. En la cara lateral y superior se destacan el fascículo longitudinal superior, el stratum sagital, el fascículo uncinado, el fascículo occipito - frontal, fascículo amígdalo - insular, la comisura anterior y el tapetum. En la cara inferior observamos el fascículo longitudinal inferior, banda diagonal de Brocca, ansa pendularis y estrías olfatorias y en la cara mesial las estructuras del lóbulo límbico, el fascículo del cingulum, el giro dentado, el giro fasciolar, la fimbria del fornix, y la estría terminalis. Conclusiones: la técnica de disección de fibras blancas es una herramienta útil para la comprensión tridimensional de las estructuras neuronales localizadas dentro del lóbulo temporal. El entendimiento de la disposición de estas estructuras ayuda al neurocirujano a lidiar con las patologías localizadas en la cara mesial como los tumores y la esclerosis mesial temporal, entidades que requieren claros conocimientos anatómicos para su adecuada resolución.

Frontopolar and anterior temporal cortex activation in a moral judgment task: preliminary functional MRI results in normal subjects

OBJECTIVE: To study the brain areas which are activated when normal subjects make moral judgments. METHOD: Ten normal adults underwent BOLD functional magnetic resonance imaging (fMRI) during the auditory presentation of sentences that they were instructed to silently judge as either "right" or "wrong". Half of the sentences had an explicit moral content ("We break the law when necessary"), the other half comprised factual statements devoid of moral connotation ("Stones are made of water"). After scanning, each subject rated the moral content, emotional valence, and judgment difficulty of each sentence on Likert-like scales. To exclude the effect of emotion on the activation results, individual responses were hemodynamically modeled for event-related fMRI analysis. The general linear model was used to evaluate the brain areas activated by moral judgment. RESULTS: Regions activated during moral judgment included the frontopolar cortex (FPC), medial frontal gyrus, right anterior temporal cortex, lenticular nucleus, and cerebellum. Activation of FPC and medial frontal gyrus (BA 10/46 and 9) were largely independent of emotional experience and represented the largest areas of activation. CONCLUSIONS: These results concur with clinical observations assigning a critical role for the frontal poles and right anterior temporal cortex in the mediation of complex judgment processes according to moral constraints. The FPC may work in concert with the orbitofrontal and dorsolateral cortex in the regulation of human social conduct

Localizaçäo dos sulcos e giros da face súpero-lateral do cérebro na tomografia computadorizada e na ressonância magnética / The sulci and gyri localization of the brain superolateral surface in computed tomography and magnetic resonance imaging

O conhecimento da anatomia da face súpero-lateral do cérebro é fundamental para localizar e abordar as lesões cerebrais. Faz-se a revisäo da literatura dos sinais e referências para identificar os sulcos e giros da face súpero-lateral do cérebro na tomografia computadorizada e na ressonância magnética. O uso conjunto dos vários sinais possibilita a identificaçäo dos sulcos e giros e a localizaçäo das lesões cerebrais na quase totalidade dos casos

Precisiones históricas sobre la vena de Labbé / Historical precisions about the veins to Labbé

La disposición anatómica de la vena de Labbé (V.L.) así como sus principales variaciones son conocidas por anatomistas, neurocirujanos, neurólogos y neuroimagenólogos. Su importancia clínica en las trombósis venosas así como la jerarquía de su conservación en abordaje quirúrgico centrado en la región temporal es ampliamente conocida. En las últimas decadas ha habido un mayor interés en conocer su variaciones anatómicas, fundamentalmente por el desarrollo de la cirugía de base de cráneo. Sin embargo, poco se conoce de quien describió la vena que lleva su nombre, Charles Labbé, médico y anatomista francés que vivió entre 1851 y 1889. En el presente artículo, se discuten algunos datos biográficos de Labbé y se compara su descripción inicial de la vena anastomótica inferior con la concepción del drenaje venoso del lóbulo temporal de autores clásicos y actuales.

Esquizofrenia: qual é a sua base biológica? / Schizophrenia: what is their biologiacal basis?

Recentes avanços nas áreas de neurociência têm possibilitado estudos que levaram a maiores evidências do papel dos fatores genéticos e da patologia cerebral na esquizofrenia. Neste artigo, revisamos vários desses estudos e suas contribuiçöes para as modernas ainda que controversas hipóteses sobre a etiopatologia dessa doença

Efectos de la extirpación del area piriforme sobre la ultraestructura de la corteza suprerrenal / Effects of resection of piriform area on suprarenal cortex ultrastructure

Hemos estudiado la ultraestructura de la corteza suprarrenal de 40 ratas macho Wistar, de pesos entre 200 y 259 gm. Los animales fueron divididos en 3 grupos: grupo control (animales intactos o animales de operación simulada); grupo experimental I (animales sacrificados al mes de la operación) y grupo experimental II (animales sacrificados a los dos meses de la operación). Los animales experimentales fueron sometidos a la extirpación bilateral del área piriforme. Hemos observado un progresivco decremento de las gotitas lipídicas ( y de la esteroidogénesis) y un incremento de las alteraciones mitocondriales en las células de la capa fasciculada y también en las células de la capa reticular; lo que indica la existencia de una disminución en la elaboración de las hormonas cortico-suprerrenales. Estos hallazgos nos sugieren que el área piriforme estimula la elaboración de hormonas por la corteza suprarrenal

The anatomy of language revisited

The language areas have been classically viewed as a posterior, perceptual Wernicke's region connected with an anterior, motor Broca's area via a tract of long fibers denominated the arcuate fasciculus. Recent connectional studies in the monkey indicate that there may be few direct connections between the regions strictly corresponding to Broca's or Wernicke's areas, and that inferior parietal areas may serve as a link between them. The proposed connectional pattern of the language regions fits the network of parietotemporal-prefrontal connections that participate in working memory, a type of memory used in immediate cognitive processing. Supporting this concept, brain activation studies in the human during linguistic working memory tasks have determined a close relation between the supramarginal gyrus (parietal area 40) and Broca's area. We suggest that language processing is closely related to working memory networks, and that the language regions in fact originated in evolution from a working memory network for linguistic utterances