scholarly journals A newly identified trigeminal brain pathway in a night-migratory bird could be dedicated to transmitting magnetic map information

2020 ◽  
Vol 287 (1919) ◽  
pp. 20192788 ◽  
Author(s):  
Dmitry Kobylkov ◽  
Susanne Schwarze ◽  
Bianca Michalik ◽  
Michael Winklhofer ◽  
Henrik Mouritsen ◽  
...  
Keyword(s):  
Neuronal Population ◽  
Migratory Bird ◽  
Great Precision ◽  
Neuronal Tracing ◽  
Migratory Songbirds ◽  
Brain Circuit ◽  
Somatosensory Pathway ◽  
Trigeminal Nerves ◽  
Crucial Part ◽  
The Brain

Night-migratory songbirds can use geomagnetic information to navigate over thousands of kilometres with great precision. A crucial part of the magnetic ‘map’ information used by night-migratory songbirds is conveyed via the ophthalmic branches of the trigeminal nerves to the trigeminal brainstem complex, where magnetic-driven neuronal activation has been observed. However, it is not known how this information reaches the forebrain for further processing. Here, we show that the magnetically activated region in the trigeminal brainstem of migratory Eurasian blackcaps ( Sylvia atricapilla ) represents a morphologically distinctive neuronal population with an exclusive and previously undescribed projection to the telencephalic frontal nidopallium. This projection is clearly different from the known trigeminal somatosensory pathway that we also confirmed both by neuronal tracing and by a thorough morphometric analysis of projecting neurons. The new pathway we identified here represents part of a brain circuit that—based on the known nidopallial connectivities in birds—could potentially transmit magnetic ‘map’ information to key multisensory integration centres in the brain known to be critically involved in spatial memory formation, cognition and/or controlling executive behaviour, such as navigation, in birds.

scholarly journals Interpreting Neuronal Population Activity by Reconstruction: Unified Framework With Application to Hippocampal Place Cells

1998 ◽  
Vol 79 (2) ◽  
pp. 1017-1044 ◽  
Author(s):  
Kechen Zhang ◽  
Iris Ginzburg ◽  
Bruce L. McNaughton ◽  
Terrence J. Sejnowski
Keyword(s):  
Bayesian Methods ◽  
Neuronal Population ◽  
Place Cells ◽  
The Body ◽  
Unified Framework ◽  
Population Activity ◽  
Reconstruction Methods ◽  
Special Cases ◽  
Physical Variables ◽  
The Brain

Zhang, Kechen, Iris Ginzburg, Bruce L. McNaughton, and Terrence J. Sejnowski. Interpreting neuronal population activity by reconstruction: unified framework with application to hippocampal place cells. J. Neurophysiol. 79: 1017–1044, 1998. Physical variables such as the orientation of a line in the visual field or the location of the body in space are coded as activity levels in populations of neurons. Reconstruction or decoding is an inverse problem in which the physical variables are estimated from observed neural activity. Reconstruction is useful first in quantifying how much information about the physical variables is present in the population and, second, in providing insight into how the brain might use distributed representations in solving related computational problems such as visual object recognition and spatial navigation. Two classes of reconstruction methods, namely, probabilistic or Bayesian methods and basis function methods, are discussed. They include important existing methods as special cases, such as population vector coding, optimal linear estimation, and template matching. As a representative example for the reconstruction problem, different methods were applied to multi-electrode spike train data from hippocampal place cells in freely moving rats. The reconstruction accuracy of the trajectories of the rats was compared for the different methods. Bayesian methods were especially accurate when a continuity constraint was enforced, and the best errors were within a factor of two of the information-theoretic limit on how accurate any reconstruction can be and were comparable with the intrinsic experimental errors in position tracking. In addition, the reconstruction analysis uncovered some interesting aspects of place cell activity, such as the tendency for erratic jumps of the reconstructed trajectory when the animal stopped running. In general, the theoretical values of the minimal achievable reconstruction errors quantify how accurately a physical variable is encoded in the neuronal population in the sense of mean square error, regardless of the method used for reading out the information. One related result is that the theoretical accuracy is independent of the width of the Gaussian tuning function only in two dimensions. Finally, all the reconstruction methods considered in this paper can be implemented by a unified neural network architecture, which the brain feasibly could use to solve related problems.

scholarly journals A neuroscientific grasp of concepts: from control to representation

2003 ◽  
Vol 358 (1435) ◽  
pp. 1231-1240 ◽  
Author(s):  
Vittorio Gallese
Keyword(s):  
Conceptual Knowledge ◽  
Outer Space ◽  
Cognitive Activity ◽  
Semantic Content ◽  
Macaque Monkey ◽  
Conceptual Representations ◽  
Neurophysiological Data ◽  
Neural Underpinnings ◽  
Crucial Part ◽  
The Brain

Abstraction denotes the cognitive process by means of which general concepts are formed. The dominant view of abstraction considers it not only as a complex and sophisticated cognitive activity, but also as a distinctive hallmark of mankind. The distinctiveness of abstract thought has indeed been closely related to another feature peculiar to our species: language. Following this perspective, the possibility to entertain conceptual representations is thus precluded to animals devoid of full–blown language. I challenge this view and propose that the representational dynamic of the brain is conceivable as a type of self–organization, in which action plays a crucial part. My aim will be to investigate whether, and to what extent, conceptual knowledge can be attributed to non–linguistic animal species, with particular emphasis on nonhuman primates. I therefore introduce the notion of semantic content as a type of ‘relational specification’. A review of recent neurophysiological data on the neural underpinnings of action end–states in the macaque monkey brain is presented. On the basis of this evidence, I propose that conceptual representations can be conceived as the expression of a coherent internal world model. This model decomposes the ‘outer’ space inhabited by things in a meaningful way only to the extent that it accords to biologically constrained, embodied invariance. Finally, I discuss how the ‘comparative’ neuroscientific approach to abstraction proposed here may shed some light on its nature and its evolutionary origin.

Babies and bathwaters: attachment, neuroscience, evolution and the left

Soundings ◽  
2019 ◽  
Vol 73 (73) ◽  
pp. 111-128
Author(s):  
Graham Music
Keyword(s):  
Attachment Theory ◽  
Developmental Psychology ◽  
Huge Amount ◽  
Far Right ◽  
Interpersonal Neurobiology ◽  
Selfish Genes ◽  
The Social ◽  
Social Orders ◽  
Crucial Part ◽  
The Brain

This article challenges thinkers and activists on the left who are over-suspicious of ideas heralding from disciplines such as interpersonal neurobiology, attachment theory, developmental psychology, and perhaps especially, evolutionary theory. Although scepticism is frequently warranted, especially as such discourses are often co-opted for neoliberal or far right ends, there is much in all of them that melds well with critiques of hegemonic social orders, providing potential fuel for those working for social change. Much work, for example that of Amy Cuddy, can be interpreted both conservatively and progressively. Work from within an attachment theory paradigm can play a crucial part in the battle of ideas: it has a huge amount to teach about how to create a more humane and egalitarian world, and in countering neoliberal beliefs that humans are innately primarily aggressive, competitive or selfish, or have selfish genes. The days are now over when the biological, psychological and the social need to be pitted against each other. Rather, they now have to be seen as mutually constituted. The brain is a social organ, embedded, embodied, enactive and extended, in large part a reflection of the social conditions in which it grows.

Genesis of rhythmic respiratory activity in pons independent of medulla

1985 ◽  
Vol 59 (3) ◽  
pp. 684-690 ◽  
Author(s):  
W. M. St John ◽  
T. A. Bledsoe
Keyword(s):  
Brain Stem ◽  
Phrenic Nerve ◽  
Respiratory Activity ◽  
Respiratory Rhythm ◽  
Related Activity ◽  
Pharmacological Agents ◽  
Pneumotaxic Center ◽  
Trigeminal Nerves ◽  
The Brain ◽  
Pontomedullary Junction

We hypothesized that rhythmic respiratory-related activity could be generated in pons independent of medullary mechanisms. In decerebrate, cerebellectomized, vagotomized, paralyzed, and ventilated cats, we recorded efferent activities of the phrenic nerve and mylohyoid branch of the trigeminal nerve. Following transections of the brain stem at the pontomedullary junction, the phrenic and trigeminal nerves discharged with independent rhythms. Spontaneous trigeminal discharges eventually ceased but were reestablished after strychnine, doxapram, and/or protriptyline were administered. In some animals having no spontaneous trigeminal discharges after transection, these discharges appeared, with a rhythm different from the phrenic, following administration of these agents. In other cats having no transections between pons and medulla, these pharmacological agents induced trigeminal and phrenic discharges after kainic acid had been injected into the entire dorsal and ventral medullary respiratory nuclei. Phrenic and trigeminal discharges were linked, indicating survival of bulbospinal neurons or presence of pontospinal units. We conclude that rhythms, similar to respiratory rhythm, can occur by mechanisms in isolated pons. Such mechanisms are hypothesized to be within the pneumotaxic center and may underlie the neurogenesis of eupnea.

scholarly journals Functional divisions for visual processing in the central brain of flying Drosophila

2015 ◽  
Vol 112 (40) ◽  
pp. E5523-E5532 ◽  
Author(s):  
Peter T. Weir ◽  
Michael H. Dickinson
Keyword(s):  
Visual Processing ◽  
Visual Stimuli ◽  
Automated Analysis ◽  
Fruit Fly ◽  
Cell Types ◽  
Visual Responses ◽  
Behavioral Context ◽  
Central Brain ◽  
Brain Circuit ◽  
The Brain

Although anatomy is often the first step in assigning functions to neural structures, it is not always clear whether architecturally distinct regions of the brain correspond to operational units. Whereas neuroarchitecture remains relatively static, functional connectivity may change almost instantaneously according to behavioral context. We imaged panneuronal responses to visual stimuli in a highly conserved central brain region in the fruit fly, Drosophila, during flight. In one substructure, the fan-shaped body, automated analysis revealed three layers that were unresponsive in quiescent flies but became responsive to visual stimuli when the animal was flying. The responses of these regions to a broad suite of visual stimuli suggest that they are involved in the regulation of flight heading. To identify the cell types that underlie these responses, we imaged activity in sets of genetically defined neurons with arborizations in the targeted layers. The responses of this collection during flight also segregated into three sets, confirming the existence of three layers, and they collectively accounted for the panneuronal activity. Our results provide an atlas of flight-gated visual responses in a central brain circuit.

scholarly journals Minireview: Recent Progress in Gonadotropin-Releasing Hormone Neuronal Migration

Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1159-1165 ◽  
Author(s):  
Stuart A. Tobet ◽  
Gerald A. Schwarting
Keyword(s):  
Basal Forebrain ◽  
Direct Evidence ◽  
Neuronal Population ◽  
External Factors ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Molecular Phenotypes ◽  
The Brain

Neurons that synthesize GnRH are critical brain regulators of the reproductive axis, yet they originate outside the brain and must migrate over long distances and varied environments to get to their appropriate positions during development. Many studies, past and present, are providing clues for the types of molecules encountered and movements expected along the migratory route. Recent studies provide real-time views of the behavior of GnRH neurons in the context of in vitro preparations that model those in vivo. Live images provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more alterations in direction after they enter the brain. The heterogeneity of molecular phenotypes for GnRH neurons likely ensures that multiple external factors will be found that regulate the migration of different portions of the GnRH neuronal population at different steps along the route. Molecules distributed in gradients both in the peripheral olfactory system and basal forebrain may be particularly influential in directing the appropriate movement of GnRH neurons along their arduous migration. Molecules that mediate the adhesion of GnRH neurons to changing surfaces may also play critical roles. It is likely that the multiple external factors converge on selective signal transduction pathways to engage the mechanical mechanisms needed to modulate GnRH neuronal movement and ultimately migration.

scholarly journals Morphologic and Immunoperoxidase Study of Neurologic Lesions in Naturally Acquired Rabies of Raccoons

1992 ◽  
Vol 4 (4) ◽  
pp. 369-373 ◽  
Author(s):  
A. N. Hamir ◽  
G. Moser ◽  
C. E. Rupprecht
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Ganglion Cells ◽  
Cervical Spinal Cord ◽  
Fluorescent Antibody ◽  
Antibody Test ◽  
Immunoperoxidase Method ◽  
Spinal Cord Regions ◽  
Trigeminal Nerves ◽  
The Brain

Histopathologic (hematoxylin and eosin [HE]) and immunoperoxidase (streptavidin-biotin complex) methods were used for examination of formalin-fixed tissues of rabid raccoons from an enzootic area of Pennsylvania. Extensive morphologic lesions of rabies encephalitis were present in the cerebrum and the brain stem regions. Negri bodies were detected by both methods and were present in the brain (cerebral cortex, hippocampus, brain stem, cerebellum, and cervical spinal cord) and in the ganglia of the trigeminal nerves. The viral inclusions were also seen in ganglion cells in the tongue, parotid salivary glands, pancreas, intestines, and adrenal glands. These sites were not associated with any inflammatory cellular infiltrate. The immunoperoxidase method was superior to HE for the detection of Negri bodies. Because lesions of rabies encephalitis were consistently observed in the cerebrum, brain stem, and cervical spinal cord regions, these areas of the brain should be included when raccoons are examined by the fluorescent antibody test for rabies.

scholarly journals Brain Tumor Extraction Using Matlab

2021 ◽  
Vol 9 (VI) ◽  
pp. 4619-4625
Author(s):  
P. Chandra Sandeep
Keyword(s):  
Image Processing ◽  
Brain Tumor ◽  
Brain Mri ◽  
Continuous Growth ◽  
Infected People ◽  
Abnormal Cells ◽  
Tumor Extraction ◽  
Crucial Part ◽  
The Brain

The brain is the most crucial part of our human body which acts as central coordinating system for all the controlling and all regular functions of our body. The continuous growth of abnormal cells which creates certain mass of tissue is called as tumor. Tumor in the brain can be either formed inside the brain or gets into brain after formed at other part. But there is no clear information regarding the formation of brain tumor till date. Though the formation tumor in brain is not common or regular but the mortality rate of the infected people is very high because the brain is major part of body. So, it is very important get the treatment at the early stages of brain tumor but there is no direct procedure for detection and classification of tumor in the very first step of diagnosis. In actual medical diagnosis, mri images alone can’t be able to determine the detected tumor as either the cancerous or non-cancerous. But the tumor may be sometimes danger to life or may not be danger to life. Tumor inside the brain can be of either the benign(non- cancerous) or the malignant(cancerous). So, we need to detect the tumor from the MRI images through image processing and then to classify the detected tumor as it belongs to either the benign or malignant tumor. We are going to get the brain mri images as our dataset for our proposed method but the images we got may have the noise. So, we need to preprocess the image using the image preprocessing techniques. We are going to use several algorithms like thresholding, clustering to make the detection of tumor by using the image processing and image segmentation and after the detection of tumor we are going do feature extraction. This step involves the extraction of detected objects features using DWT. This extracted features are given as input to classifier algorithms like SVM’s and CNN after reduction of features using the PCA.

scholarly journals Morphometric analysis of dopaminergic neurons (substantia nigra) in the brain of MPTP-treated alpha-synuclein knockout mice

2021 ◽  
pp. 32-37
Author(s):  
В.В. Голоборщева ◽  
Н.А. Воронина ◽  
Р.К. Овчинников ◽  
В.Г. Кучеряну ◽  
С.Г. Морозов
Keyword(s):  
Substantia Nigra ◽  
Morphometric Analysis ◽  
Knockout Mice ◽  
Dopaminergic Neurons ◽  
Water Solution ◽  
Neuronal Population ◽  
Alpha Synuclein ◽  
Substantia Nigra Pars Compacta ◽  
Mptp Toxicity ◽  
The Brain

Целью данной работы являлась оценка выживаемости популяции зрелых дофаминергических (ДА-ергических) нейронов чёрной субстанции двух альфа-синуклеин нокаутных линий мышей Abel-KO и ΔFlox-KO, а также бессинуклеиновых животных abg-КО в условиях МФТП-токсического моделирования паркинсонического синдрома. Методы исследования: Водный раствор нейротоксина МФТП вводили 3-месячным мышам внутрибрюшинно в дозе 30 мг/кг ежедневно в течение 5 дней по субхроническому протоколу. Через 21 день после последней инъекции МФТП у животных извлекали головной мозг, фиксировали в холодном растворе Карнуа и парафинизировали для последующего приготовления гистологических препаратов на ротационном микротоме Leica RM2265 (Leica Biosystems, Германия). Иммуногистохимическое окрашивание проводили антителами против тирозингидроксилазы (моноклональные антитела мыши, Sigma, разведение 1:2000). Сравнительный морфометрический анализ популяции ДА-ергических нейронов чёрной субстанции выполнен с учётом поправки Аберкромби. Результаты: Установлено, что в условиях дефицита альфа-синуклеина мыши устойчивы к потере ДА-ергических нейронов в компактной части ЧС после введения МФТП. При генетической делеции всех трёх синуклеинов чувствительность ДА-ергических нейронов ЧС к токсическому действию МФТП не отличается от таковой у животных с немодифицированным геномом. Заключение. На основании проведённого морфометрического анализа предполагается, что особенности чувствительности к нейротоксину МФТП у альфа-синуклеин нокаутных линий мышей обусловлены повышением функциональной активности (замещением) бета-синуклеина, оптимизирующего захват ДА синаптическими везикулами. The aim of this study was to assess survival of mature dopaminergic (DAergic) neuronal population in the substantia nigra pars compacta (SNpc) of two alpha-synuclein knockout mice strains (Abel-KO and ΔFlox-KO) and of non-synuclein animals (abg-KO) in MPTP-induced parkinsonism. Material and methods: MPTP water solution was administered to 3-month-old mice intraperitoneally (30 mg/kg daily for 5 days) according to a subchronic protocol. On the 21st day after the last MPTP injection, the brain was excised, fixed in cold Carnoy’s solution and paraffined for the subsequent preparation of histological samples on a Leica RM2265 rotary microtome (Leica Biosystems, Germany). Immunohistochemical staining was performed with antibodies against tyrosine hydroxylase (mouse monoclonal antibodies, Sigma, dilution 1:2000). A comparative morphometric analysis of substantia nigra dopaminergic neurons was performed using the Abercrombie correction. Results: MPTP-treated alpha-synuclein deficient mice were resistant to the loss of DAergic neurons in the SNpc. Genetic deletion of all three synucleins restored the sensitivity of SNpc DAergic neurons to the MPTP toxicity, which did not differ from the sensitivity of wild type animals. Conclusion: Based on the morphometric analysis, it was assumed that the specific features of MPTP sensitivity in alpha-synuclein knockout mice are due to an increased functional activity (substitution) of beta-synuclein, which optimizes the capture of DA by synaptic vesicles.

scholarly journals Object vision to hand action in macaque parietal, premotor, and motor cortices

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Stefan Schaffelhofer ◽  
Hansjörg Scherberger
Keyword(s):  
Primary Motor Cortex ◽  
Microelectrode Arrays ◽  
Neuronal Population ◽  
Movement Planning ◽  
Visual Coding ◽  
Parietal Area ◽  
Shape Processing ◽  
Object Features ◽  
The Brain ◽  
Hand Action

Grasping requires translating object geometries into appropriate hand shapes. How the brain computes these transformations is currently unclear. We investigated three key areas of the macaque cortical grasping circuit with microelectrode arrays and found cooperative but anatomically separated visual and motor processes. The parietal area AIP operated primarily in a visual mode. Its neuronal population revealed a specialization for shape processing, even for abstract geometries, and processed object features ultimately important for grasping. Premotor area F5 acted as a hub that shared the visual coding of AIP only temporarily and switched to highly dominant motor signals towards movement planning and execution. We visualize these non-discrete premotor signals that drive the primary motor cortex M1 to reflect the movement of the grasping hand. Our results reveal visual and motor features encoded in the grasping circuit and their communication to achieve transformation for grasping.

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