Cortical regions contributing to the anterior commissure in man

1999 ◽  
Vol 124 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Gabrielle Di Virgilio ◽  
S. Clarke ◽  
Gianpaolo Pizzolato ◽  
Thomas Schaffner
Keyword(s):  
Anterior Commissure ◽  
Cortical Regions

scholarly journals Four-dimensional tractography animates neural propagations via distinct interhemispheric pathways

2020 ◽  
Author(s):  
Takumi Mitsuhashi ◽  
Masaki Sonoda ◽  
Jeong-won Jeong ◽  
Brian H. Silverstein ◽  
Hirotaka Iwaki ◽  
...  
Keyword(s):  
Time Window ◽  
Physiological Function ◽  
Focal Epilepsy ◽  
Anterior Commissure ◽  
Single Pulse ◽  
Peak Latency ◽  
Drug Resistant ◽  
Methodological Study ◽  
Cortical Regions ◽  
Spectral Responses

Objective: To visualize and validate the dynamics of interhemispheric neural propagations induced by single-pulse electrical stimulation (SPES). Methods: This methodological study included three patients with drug-resistant focal epilepsy who underwent measurement of cortico-cortical spectral responses (CCSRs) during bilateral stereo-electroencephalography recording. We delivered SPES to 83 electrode pairs and analyzed CCSRs recorded at 268 nonepileptic electrode sites. Diffusion-weighted imaging (DWI) tractography localized the interhemispheric white matter pathways as streamlines directly connecting two electrode sites. We localized and visualized the putative SPES-related fiber activation, at each 1-ms time window, based on the propagation velocity defined as the DWI-based streamline length divided by the early CCSR peak latency. Results: The resulting movie, herein referred to as four-dimensional tractography, delineated the spatiotemporal dynamics of fiber activation via the corpus callosum and anterior commissure. Longer streamline length was associated with delayed peak latency and smaller amplitude of CCSRs. The cortical regions adjacent to each fiber activation site indeed exhibited CCSRs at the same time window. Conclusions: Our four-dimensional tractography successfully animated neural propagations via distinct interhemispheric pathways. Significance: Our novel animation method has the potential to help investigators in addressing the mechanistic significance of the interhemispheric network dynamics supporting physiological function.

scholarly journals Redundancy Circuits of the Commissural Pathways in Human and Rhesus Macaque Brains

2020 ◽  
Author(s):  
Zulfar Ghulam-Jelani ◽  
Jessica Barrios-Martinez ◽  
Aldo Eguiluz-Melendez ◽  
Ricardo Gomez ◽  
Yury Anania ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Human Brain ◽  
Rhesus Macaque ◽  
Anterior Commissure ◽  
Brain Disorders ◽  
Commissural Pathways ◽  
Commissural Pathway ◽  
Cortical Regions ◽  
Temporal Redundancy ◽  
First Time

AbstractIt has been hypothesized that the human brain has traded redundancy for efficiency, but the structural existence has not been identified to examine this claim. Here, we report three redundancy circuits of the commissural pathways in primate brains, namely the orbitofrontal, temporal, and occipital redundancy circuits of the anterior commissure and corpus callosum. Each redundancy circuit has two distinctly separated routes connecting a common pair of cortical regions. We mapped their trajectories in human and rhesus macaque brains using individual and population-averaged tractography. The dissection results confirmed the existence of these redundancy circuits connecting the orbitofrontal lobe, amygdala, and visual cortex. The volume analysis showed a significant reduction in the orbitofrontal and occipital redundancy circuits of the human brain, whereas the temporal redundancy circuit had a substantial organizational difference between the human and rhesus macaque. Our overall findings suggest that the human brain is more efficient in the commissural pathway, as shown by the significantly reduced volume of the anterior commissure which serves as the backup connections for the corpus callosum. This reduction of the redundancy circuit may explain why humans are more vulnerable to psychiatric brain disorders stemming from the corpus callosum compared to non-human primates.SignificanceWe report and describe the connection routes of three redundancy circuits of the commissural pathways in human and rhesus macaque brains and compare their volumes. Our tractography and dissection studies confirmed that the human brain has smaller redundancy circuits. This is the first time such redundancy circuits of the commissural pathways have been identified, and their differences quantified in human and rhesus macaque to verify the redundancy-efficiency tradeoff hypothesis. The findings provide new insight into the topological organization of the human brain and may help understand the circuit mechanism of brain disorders involving these pathways.

Magnetic Resonance Imaging of the Brain of a Monotreme, the Short-Beaked Echidna (Tachyglossus aculeatus)

2017 ◽  
Vol 89 (4) ◽  
pp. 233-248 ◽  
Author(s):  
Sandilya Cherupalli ◽  
Craig D. Hardman ◽  
Andre Bongers ◽  
Ken W.S. Ashwell
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Thalamic Nucleus ◽  
Anterior Commissure ◽  
Association Cortex ◽  
Medial Lemniscus ◽  
Resonance Imaging ◽  
Cortical Regions ◽  
The Brain ◽  
Tachyglossus Aculeatus

We used magnetic resonance imaging to study the anatomy of cortical regions, nuclear groups, and major tracts in the brain of a monotreme, i.e., the short-beaked echidna (Tachyglossus aculeatus). Our specimens were from a collection held at the Australian Museum in Sydney and had been stored in formaldehyde solution for at least 70 years. Despite this, we were able to detect fine detail in the nuclear divisions of structures as well as in fiber tracts. In particular, we could detect the medial lemniscus as it approached the ventral posterior thalamic nucleus, subdivisions within the ventral posterior thalamic nucleus, lamination and subdivisions within the hippocampal formation, components of the olfactory pathways, and nuclei within the temporal amygdala. We were able to map the topography of subcortical white matter and relate it to cortical regions determined on the basis of physiology, as well as chemical and cytoarchitecture. As expected, dense aggregations of fibers were noted in association with the primary sensory areas of the isocortex (somatosensory, visual, and auditory) and connecting primary olfactory regions (intrabulbar anterior commissure and associated fibers). We found longitudinal fibers in the basal forebrain (medial forebrain bundle) and brainstem (corticopontine and corticospinal tracts), as well as a dense array of fibers associated with the vermal and paravermal zones of the anterior lobe of the cerebellum. We also observed previously unrecognized fiber systems, i.e., commissural connections between the paired frontal isocortical fields (dorsal Fr1), dense fibers to the retrosplenial association cortex, and prominent, paired longitudinal fiber bundles in the dorsal forebrain (longitudinal fasciculus) that intersected the dorsal anterior commissure. The connectome results are consistent with the known neuroanatomy of this monotreme and they extend our knowledge of the fiber topography within this unusual brain. Our findings demonstrate the feasibility of using this sort of imaging of archived brains to analyze the neuroanatomy of rare, endangered, and evolutionarily significant species.

scholarly journals Corticostriatal Projections of Macaque Area 44

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Cole Korponay ◽  
Eun Young Choi ◽  
Suzanne N Haber
Keyword(s):  
Injection Site ◽  
Caudate Nucleus ◽  
Anterior Commissure ◽  
Cortical Input ◽  
Motor Circuits ◽  
Corticostriatal Projections ◽  
Prior Investigation ◽  
Cortical Regions ◽  
Anterograde And Retrograde Tracing ◽  
Caudal Area

Abstract Ventrolateral frontal area 44 is implicated in inhibitory motor functions and facilitating prefrontal control over vocalization. The contribution of corticostriatal circuits to area 44 functions is unclear, as prior investigation of area 44 projections to the striatum—a central structure in motor circuits—is limited. Here, we used anterograde and retrograde tracing in macaques to map the innervation zone of area 44 corticostriatal projections, quantify their strengths, and evaluate their convergence with corticostriatal projections from other frontal cortical regions. First, whereas terminal fields from a rostral area 44 injection site were found primarily in the central caudate nucleus, those from a caudal area 44 injection site were found primarily in the ventrolateral putamen. Second, amongst sampled injection sites, area 44 input as a percentage of total frontal cortical input was highest in the ventral putamen at the level of the anterior commissure. Third, area 44 projections converged with orofacial premotor area 6VR and other motor-related projections (in the putamen), and with nonmotor prefrontal projections (in the caudate nucleus). Findings support the role of area 44 as an interface between motor and nonmotor functional domains, possibly facilitated by rostral and caudal area 44 subregions with distinct corticostriatal connectivity profiles.

Central Nervous System Processing of Emotions in Children with Fecal Incontinence and Constipation

2019 ◽  
Vol 47 (1) ◽  
pp. 67-71
Author(s):  
Monika Equit ◽  
Justine Niemczyk ◽  
Anna Kluth ◽  
Carla Thomas ◽  
Mathias Rubly ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Fecal Incontinence ◽  
Event Related Potentials ◽  
Anterior Cingulate ◽  
Afferent Pathways ◽  
Study Results ◽  
Related Potentials ◽  
The Central Nervous System ◽  
Cortical Regions

Abstract. Objective: Fecal incontinence and constipation are common disorders in childhood. The enteric nervous system and the central nervous system are highly interactive along the brain-gut axis. The interaction is mainly afferent. These afferent pathways include centers that are involved in the central nervous processing of emotions as the mid/posterior insula and the anterior cingulate cortex. A previous study revealed altered processing of emotions in children with fecal incontinence. The present study replicates these results. Methods: In order to analyze the processing of emotions, we compared the event-related potentials of 25 children with fecal incontinence and constipation to those of 15 control children during the presentation of positive, negative, and neutral pictures. Results: Children with fecal incontinence and constipation showed altered processing of emotions, especially in the parietal and central cortical regions. Conclusions: The main study results of the previous study were replicated, increasing the certainty and validity of the findings.

HYPOTHALAMIC SEXUAL PRECOCITY IN FEMALE RATS OPERATED SHORTLY AFTER BIRTH

1962 ◽  
Vol 41 (2) ◽  
pp. 301-313 ◽  
Author(s):  
S. Horowitz ◽  
J. J. Van der Werff ten Bosch
Keyword(s):  
Anterior Commissure ◽  
Anterior Hypothalamus ◽  
Female Rats ◽  
Vaginal Opening ◽  
Sexual Precocity ◽  
Paraventricular Nuclei ◽  
Gonadotrophin Secretion ◽  
Electrolytic Lesions

ABSTRACT Electrolytic lesions were placed in the anterior hypothalamus of 3–4 day-old female rats; vaginal opening was hastened in comparison with blank-operated littermates in 12 of 17 rats bearing a lesion in the basal supra-and post-chiasmatic area. In the animals with the earliest vaginal opening, lesions reached upward towards the region of the anterior commissure and the paraventricular nuclei. The degree of advancement of puberty in rats operated at the age of 3 or 4 days was similar to that caused by lesions made at 10, 14 or 15 days. This finding suggests that the effect of a lesion upon gonadotrophin secretion does not begin to take place until after the age of at least two weeks.

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