The Thalamic Nuclei Classification in Relation to Their Engagement in the Correction of Initial Movements

The mamillothalamic pathways: my first encounter with the thalamus

10.1093/oso/9780198806738.003.0006 ◽

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.

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High-fidelity transmission of high-frequency burst stimuli from peripheral nerve to thalamic nuclei in children with dystonia

Scientific Reports ◽

10.1038/s41598-021-88114-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Estefanía Hernandez-Martin ◽

Enrique Arguelles ◽

Yifei Zheng ◽

Ruta Deshpande ◽

Terence D. Sanger

Keyword(s):

Deep Brain Stimulation ◽

Peripheral Nerve ◽

Brain Stimulation ◽

High Frequency ◽

Sensory Information ◽

Brain Structures ◽

High Fidelity ◽

Thalamic Nuclei ◽

Frequency Burst ◽

Deep Brain

AbstractHigh-frequency peripheral nerve stimulation has emerged as a noninvasive alternative to thalamic deep brain stimulation for some patients with essential tremor. It is not known whether such techniques might be effective for movement disorders in children, nor is the mechanism and transmission of the peripheral stimuli to central brain structures understood. This study was designed to investigate the fidelity of transmission from peripheral nerves to thalamic nuclei in children with dystonia undergoing deep brain stimulation surgery. The ventralis intermediate (VIM) thalamus nuclei showed a robust evoked response to peripheral high-frequency burst stimulation, with a greatest response magnitude to intra-burst frequencies between 50 and 100 Hz, and reliable but smaller responses up to 170 Hz. The earliest response occurred at 12–15 ms following stimulation onset, suggesting rapid high-fidelity transmission between peripheral nerve and thalamic nuclei. A high-bandwidth, low-latency transmission path from peripheral nerve to VIM thalamus is consistent with the importance of rapid and accurate sensory information for the control of coordination and movement via the cerebello-thalamo-cortical pathway. Our results suggest the possibility of non-invasive modulation of thalamic activity in children with dystonia, and therefore the possibility that a subset of children could have beneficial clinical response without the need for invasive deep brain stimulation.

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Distinct Burst Properties Contribute to the Functional Diversity of Thalamic Nuclei

The Journal of Comparative Neurology ◽

10.1002/cne.25141 ◽

2021 ◽

Author(s):

Nidhi Vasant Desai ◽

Carmen Varela

Keyword(s):

Functional Diversity ◽

Thalamic Nuclei

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Subcortical circuits mediate communication between primary sensory cortical areas in mice

Nature Communications ◽

10.1038/s41467-021-24200-x ◽

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.

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Astrocytes and neurons share region-specific transcriptional signatures that confer regional identity to neuronal reprogramming

Science Advances ◽

10.1126/sciadv.abe8978 ◽

2021 ◽

Vol 7 (15) ◽

pp. eabe8978

Author(s):

Álvaro Herrero-Navarro ◽

Lorenzo Puche-Aroca ◽

Verónica Moreno-Juan ◽

Alejandro Sempere-Ferràndez ◽

Ana Espinosa ◽

...

Keyword(s):

Molecular Diversity ◽

Regional Identity ◽

Brain Regions ◽

Molecular Signature ◽

Specific Gene ◽

Thalamic Nuclei ◽

Brain Repair ◽

Cell Diversity ◽

Regional Specificity ◽

Epigenetic Signatures

Neural cell diversity is essential to endow distinct brain regions with specific functions. During development, progenitors within these regions are characterized by specific gene expression programs, contributing to the generation of diversity in postmitotic neurons and astrocytes. While the region-specific molecular diversity of neurons and astrocytes is increasingly understood, whether these cells share region-specific programs remains unknown. Here, we show that in the neocortex and thalamus, neurons and astrocytes express shared region-specific transcriptional and epigenetic signatures. These signatures not only distinguish cells across these two brain regions but are also detected across substructures within regions, such as distinct thalamic nuclei, where clonal analysis reveals the existence of common nucleus-specific progenitors for neurons and astrocytes. Consistent with their shared molecular signature, regional specificity is maintained following astrocyte-to-neuron reprogramming. A detailed understanding of these regional-specific signatures may thus inform strategies for future cell-based brain repair.

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Structural Changes in Thalamic Nuclei Across Prodromal and Clinical Alzheimer’s Disease

Journal of Alzheimer s Disease ◽

10.3233/jad-201583 ◽

2021 ◽

pp. 1-11

Author(s):

Adam S. Bernstein ◽

Steven Z. Rapcsak ◽

Michael Hornberger ◽

Manojkumar Saranathan ◽

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Large Scale ◽

Structural Changes ◽

Thalamic Nuclei ◽

Medial Temporal Lobes ◽

Cognitive Changes ◽

Temporal Lobes ◽

Medial Geniculate ◽

Healthy Control

Background: Increasing evidence suggests that thalamic nuclei may atrophy in Alzheimer’s disease (AD). We hypothesized that there will be significant atrophy of limbic thalamic nuclei associated with declining memory and cognition across the AD continuum. Objective: The objective of this work was to characterize volume differences in thalamic nuclei in subjects with early and late mild cognitive impairment (MCI) as well as AD when compared to healthy control (HC) subjects using a novel MRI-based thalamic segmentation technique (THOMAS). Methods: MPRAGE data from the ADNI database were used in this study (n = 540). Healthy control (n = 125), early MCI (n = 212), late MCI (n = 114), and AD subjects (n = 89) were selected, and their MRI data were parcellated to determine the volumes of 11 thalamic nuclei for each subject. Volumes across the different clinical subgroups were compared using ANCOVA. Results: There were significant differences in thalamic nuclei volumes between HC, late MCI, and AD subjects. The anteroventral, mediodorsal, pulvinar, medial geniculate, and centromedian nuclei were significantly smaller in subjects with late MCI and AD when compared to HC subjects. Furthermore, the mediodorsal, pulvinar, and medial geniculate nuclei were significantly smaller in early MCI when compared to HC subjects. Conclusion: This work highlights nucleus specific atrophy within the thalamus in subjects with early and late MCI and AD. This is consistent with the hypothesis that memory and cognitive changes in AD are mediated by damage to a large-scale integrated neural network that extends beyond the medial temporal lobes.

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