scholarly journals Primary Graviceptive System and Astasia: Case Report and Literature Review

2021 ◽  
Author(s):  
Ko-Ting Chen ◽  
Sheng-Yao Huang ◽  
Yi-Jye Chen
Keyword(s):  
English Literature ◽  
Vestibular Nuclei ◽  
Subcortical White Matter ◽  
Upright Posture ◽  
Neural Pathways ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Cortical Projections ◽  
Contralateral Projection ◽  
Motor Strength

Abstract Purpose of ReviewAstasia refers to the inability to maintain upright posture during standing, despite having full motor strength. However, the pathophysiology and neural pathways of astasia remains unclear.Recent FindingsWe analyzed 26, including ours, non-psychogenic astasia patients in English literature. Seventy-three percent of them were man, 73% were associated with other neurologic symptoms and 62% of reported lesions were at right side. Contralateral lateropulsion was very common followed by retropulsion while describing astasia. Infarction (54%) was the most commonly reported cause. Thalamus (65%) was the most commonly reported location. Infarction being the mostly likely to recover (mean:10.6 days), while lesions at brainstem had longer time to recover (mean: 61.6 days).SummaryThe underlying interrupted pathway may be the primary graviceptive system, which composed of at least five unilateral and contralateral projection fibers from vestibular nuclei to thalamic nuclei, and thalamo-cortical projections including subcortical white matter tracts and cortical areas.

The mamillothalamic pathways: my first encounter with the thalamus

2017 ◽  
Author(s):  
Ray Guillery
Keyword(s):  
Sensory Input ◽  
Great Success ◽  
Cortical Lesions ◽  
Head Direction ◽  
Thalamic Nuclei ◽  
Sensory Pathways ◽  
Cortical Areas ◽  
Thalamic Relay ◽  
The Many

My thesis studies had stimulated an interest in the mamillothalamic pathways but also some puzzlement because we knew nothing about the nature of the messages passing along these pathways. Several laboratories were studying the thalamic relay of sensory pathways with great success during my post-doctoral years. Each sensory relay could be understood in terms of the appropriate sensory input, but we had no way of knowing the meaning of the mamillothalamic messages. I introduce these nuclei as an example of the many thalamic nuclei about whose input functions we still know little or nothing. Early clinical studies of mamillary lesions had suggested a role in memory formation, whereas evidence from cortical lesions suggested a role in emotional experiences. Studies of the smallest of the three nuclei forming these pathways then showed it to be concerned with sensing head direction, relevant but not sufficient for defining an animal’s position in space. More recent studies based on studies of cortical activity or cortical damage have provided a plethora of suggestions: as so often, the answers reported depend on the questions asked. That simple conclusion is relevant for all transthalamic pathways. The evidence introduced in Chapter 1, that thalamocortical messages have dual meanings, suggests that we need to rethink our questions. It may prove useful to look at the motor outputs of relevant cortical areas to get clues about some appropriate questions.

scholarly journals Subcortical circuits mediate communication between primary sensory cortical areas in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Lohse ◽  
Johannes C. Dahmen ◽  
Victoria M. Bajo ◽  
Andrew J. King
Keyword(s):  
Cortical Neurons ◽  
Common Property ◽  
Primary Auditory Cortex ◽  
Facilitatory Effect ◽  
Thalamic Nuclei ◽  
Auditory Midbrain ◽  
Cortical Areas ◽  
Auditory Responses ◽  
Evoked Activity

AbstractIntegration of information across the senses is critical for perception and is a common property of neurons in the cerebral cortex, where it is thought to arise primarily from corticocortical connections. Much less is known about the role of subcortical circuits in shaping the multisensory properties of cortical neurons. We show that stimulation of the whiskers causes widespread suppression of sound-evoked activity in mouse primary auditory cortex (A1). This suppression depends on the primary somatosensory cortex (S1), and is implemented through a descending circuit that links S1, via the auditory midbrain, with thalamic neurons that project to A1. Furthermore, a direct pathway from S1 has a facilitatory effect on auditory responses in higher-order thalamic nuclei that project to other brain areas. Crossmodal corticofugal projections to the auditory midbrain and thalamus therefore play a pivotal role in integrating multisensory signals and in enabling communication between different sensory cortical areas.

An autoradiographic study of cortical projections from motor thalamic nuclei in the macaque monkey

1992 ◽  
Vol 13 (2) ◽  
pp. 119-137 ◽  
Author(s):  
Katsuma Nakano ◽  
Akinori Tokushige ◽  
Masako Kohno ◽  
Yasuo Hasegawa ◽  
Tetsuro Kayahara ◽  
...  
Keyword(s):  
Macaque Monkey ◽  
Autoradiographic Study ◽  
Thalamic Nuclei ◽  
Cortical Projections

Electrophysiological Properties and Input-Output Organization of Callosal Neurons in Cat Association Cortex

2003 ◽  
Vol 89 (3) ◽  
pp. 1402-1413 ◽  
Author(s):  
Youssouf Cissé ◽  
François Grenier ◽  
Igor Timofeev ◽  
Mircea Steriade
Keyword(s):  
Cortical Cell ◽  
Association Cortex ◽  
Thalamic Nuclei ◽  
Postsynaptic Potentials ◽  
Electrophysiological Properties ◽  
Cortical Areas ◽  
Pathway Data ◽  
Antidromic Responses ◽  
Contralateral Cortex ◽  
Current Steps

Intracellular recordings from association cortical areas 5 and 7 were performed in cats under barbiturate or ketamine-xylazine anesthesia to investigate the activities of different classes of neurons involved in callosal pathways, which were electrophysiologically characterized by depolarizing current steps. Excitatory postsynaptic potentials (EPSPs), inhibitory postsynaptic potentials (IPSPs), and/or antidromic responses were elicited by stimulating homotopic sites in the contralateral cortical areas. Differential features of EPSPs related to latencies, amplitudes, and slopes were detected in closely located (50 μm or less) neurons recorded in succession along the same electrode track. In contrast to synchronous thalamocortical volleys that excited most neurons within a cortical column, stimuli applied to homotopic sites in the contralateral cortex activated neurons at restricted cortical depths. Median latencies of callosally evoked EPSPs were 1.5 to 4 ms in various cortical cell-classes. Fast-rhythmic-bursting neurons displayed EPSPs whose amplitudes were threefold larger, and latencies two- or threefold shorter, than those found in the three other cellular classes. Converging callosal and thalamic inputs were recorded in the same cortical neuron. EPSPs or IPSPs were elicited by stimulating foci spaced by <1 mm in the contralateral cortex. In the overwhelming majority of neurons, latencies of antidromic responses were between 1.2 and 3.1 ms; however, some callosal neurons had much longer latencies, ≤18.5 ms. Some neurons were excited monosynaptically through the callosal pathway and identified antidromically from appropriate thalamic nuclei, thus revealing a callosal-corticothalamic pathway. Data are discussed in relation to the commissural spread of fast and slow normal oscillations as well as paroxysmal activities.

scholarly journals Neural circuits controlling diaphragm function in the cat revealed by transneuronal tracing

2009 ◽  
Vol 106 (1) ◽  
pp. 138-152 ◽  
Author(s):  
James H. Lois ◽  
Cory D. Rice ◽  
Bill J. Yates
Keyword(s):  
Rabies Virus ◽  
Red Nucleus ◽  
Respiratory Muscles ◽  
Vestibular Nuclei ◽  
Neural Pathways ◽  
Survival Times ◽  
Medullary Reticular Formation ◽  
Thoracic Spinal Cord ◽  
Diaphragm Function ◽  
Thoracic Spinal

Although a number of studies have considered the neural circuitry that regulates diaphragm activity, these pathways have not been adequately discerned, particularly in animals such as cats that utilize the respiratory muscles during a variety of different behaviors and movements. The present study employed the retrograde transneuronal transport of rabies virus to identify the extended neural pathways that control diaphragm function in felines. In all animals deemed to have successful rabies virus injections into the diaphragm, large, presumed motoneurons were infected in the C4–C6spinal segments. In addition, smaller presumed interneurons were labeled bilaterally throughout the cervical and upper thoracic spinal cord. While in short and intermediate survival cases, infected interneurons were concentrated in the vicinity of phrenic motoneurons, in late survival cases, the distribution of labeling was more expansive. Within the brain stem, the earliest infected neurons included those located in the classically defined pontine and medullary respiratory groups, the medial and lateral medullary reticular formation, the region immediately ventral to the spinal trigeminal nucleus, raphe pallidus and obscurus, and the vestibular nuclei. At longer survival times, infection appeared in the midbrain, which was concentrated in the lateral portion of the periaqueductal gray, the region of the tegmentum that contains the locomotion center, and the red nucleus. Considerable labeling was also present in the fastigial nucleus of the cerebellum, portions of the posterior and lateral hypothalamus and the adjacent fields of Forel known to contain hypocretin-containing neurons and the precruciate gyrus of cerebral cortex. These data raise the possibility that several parallel pathways participate in regulating the activity of the feline diaphragm, which underscores the multifunctional nature of the respiratory muscles in this species.

scholarly journals Transformation of spatiotemporal dynamics in the macaque vestibular system from otolith afferents to cortex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jean Laurens ◽  
Sheng Liu ◽  
Xiong-Jie Yu ◽  
Raymond Chan ◽  
David Dickman ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Translational Motion ◽  
Three Dimensional ◽  
Cerebellar Nuclei ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Temporal Properties ◽  
Spatio Temporal ◽  
Translation Signals ◽  
Self Motion

Sensory signals undergo substantial recoding when neural activity is relayed from sensors through pre-thalamic and thalamic nuclei to cortex. To explore how temporal dynamics and directional tuning are sculpted in hierarchical vestibular circuits, we compared responses of macaque otolith afferents with neurons in the vestibular and cerebellar nuclei, as well as five cortical areas, to identical three-dimensional translational motion. We demonstrate a remarkable spatio-temporal transformation: otolith afferents carry spatially aligned cosine-tuned translational acceleration and jerk signals. In contrast, brainstem and cerebellar neurons exhibit non-linear, mixed selectivity for translational velocity, acceleration, jerk and position. Furthermore, these components often show dissimilar spatial tuning. Moderate further transformation of translation signals occurs in the cortex, such that similar spatio-temporal properties are found in multiple cortical areas. These results suggest that the first synapse represents a key processing element in vestibular pathways, robustly shaping how self-motion is represented in central vestibular circuits and cortical areas.

scholarly journals VII-The thalamic connections of the parietal and frontal lobes of the brain in the monkey

1935 ◽  
Vol 224 (515) ◽  
pp. 313-359 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Lateral Geniculate Body ◽  
Great Accuracy ◽  
Relay Station ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Cortical Connections ◽  
Sensory Nucleus ◽  
Proper Functions ◽  
The Brain

It is well known that a large proportion of the thalamus proper functions as a relay station through which sensory impulses are projected on to the cerebral cortex. With the exception of the lateral geniculate body (whose detailed relations to the area striata have recently been worked out with great accuracy by Poliak (1933)) the precise relation of the various thalamic nuclei and their subdivisions to the different cortical areas still remains to be established. The investigation of which this communication represents a report was undertaken in the first place in order to define precisely the manner in which the main sensory nucleus of the thalamus (nucleus ventralis) is projected on to the sensory areas of the cortex. We have, however, extended our original plans to include a survey of the thalamo-cortical connections of the greater part of the frontal and parietal regions of the cerebral cortex. The work of previous investigators which bears on this question we will leave for consideration in the discussion at the end of this paper.

scholarly journals Hierarchical Organization of Corticothalamic Projections to the Pulvinar

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Reza Abbas Farishta ◽  
Denis Boire ◽  
Christian Casanova
Keyword(s):  
Higher Order ◽  
Hierarchical Organization ◽  
Hierarchical Level ◽  
Thalamic Nuclei ◽  
Cortical Areas ◽  
Visual Areas ◽  
Cortical Hierarchy ◽  
Area 21A ◽  
Extrastriate Areas ◽  
Corticothalamic Projections

Abstract Signals from lower cortical visual areas travel to higher-order areas for further processing through cortico-cortical projections, organized in a hierarchical manner. These signals can also be transferred between cortical areas via alternative cortical transthalamic routes involving higher-order thalamic nuclei like the pulvinar. It is unknown whether the organization of transthalamic pathways may reflect the cortical hierarchy. Two axon terminal types have been identified in corticothalamic (CT) pathways: the types I (modulators) and II (drivers) characterized by thin axons with small terminals and by thick axons and large terminals, respectively. In cats, projections from V1 to the pulvinar complex comprise mainly type II terminals, whereas those from extrastriate areas include a combination of both terminals suggesting that the nature of CT terminals varies with the hierarchical order of visual areas. To test this hypothesis, distribution of CT terminals from area 21a was charted and compared with 3 other visual areas located at different hierarchical levels. Results demonstrate that the proportion of modulatory CT inputs increases along the hierarchical level of cortical areas. This organization of transthalamic pathways reflecting cortical hierarchy provides new and fundamental insights for the establishment of more accurate models of cortical signal processing along transthalamic cortical pathways.

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