The thalamus as a putative biomarker in neurodegenerative disorders

Abstract

Objective: This review provides a brief account of the clinically relevant functional neuroanatomy of the thalamus, before considering the utility of various modalities utilized to image the thalamus and technical challenges therein, and going on to provide an overview of studies utilizing structural imaging techniques to map thalamic morphology in the spectrum of neurodegenerative disorders. Methods:A systematic search was conducted for peer-reviewed studies involving structural neuroimaging modalities investigating the morphology (shape and/or size) of the thalamus in the spectrum of neurodegenerative disorders.Results: While the precise role of the thalamus in the healthy brain remains unclear, there is a large body of knowledge accumulating which defines more precisely its functional connectivity within the connectome, and a burgeoning literature implicating its involvement in neurodegenerative disorders. It is proposed that correlation of clinical features with thalamic morphology (as a component of a quantifiable subcortical connectome) will provide a better understanding of neuropsychiatric dysfunction in various neurodegenerative disorders, potentially yielding clinically useful endophenotypes and disease biomarkers. Conclusion:Thalamic biomarkers in the neurodegenerative disorders have great potential to provide clinically meaningful knowledge regarding not only disease onset and progression but may yield targets of and perhaps a way of gauging response to future disease-modifying modalities.

Disentangling the neural correlates of corticobasal syndrome and corticobasal degeneration with systematic and quantitative ALE meta-analyses

“…Other neurodegenerative diseases, such as Alzheimer’s disease, progressive supranuclear palsy, behavioral variant frontotemporal dementia, or Huntington’s disease are also characterized by thalamic atrophy. 14 Atrophy in the thalamus was also confirmed in recent ALE meta-analyses in Alzheimer’s disease, progressive supranuclear palsy, and multiple system atrophy. 9, 12, 15, 16 Furthermore, thalamic volume also shrinks in healthy people throughout life independent from and prior to total volume loss.…”

Structural connectome differences in HIV infection: brain network segregation associated with nadir CD4 cell count

“…As our results showed a lower number of connections between the left thalamus and all other nodes, it may be that HIV infection is linked with a reduced ability for the thalamus to serve as a relay center. Hypothesized mechanisms of thalamic compromise in neurodegenerative disease processes include trans-synaptic neurodegeneration and propagation of proteopathies (Power and Looi, 2015). These mechanisms are in line with our findings of group differences in MD, but not FA, as MD is theorized to best reflect WM microstructural density (Alexander et al, 2007; Lentz et al, 2014).…”

Thalamic functional connectivity and its association with behavioral performance in older age

“…Understanding the connectivity between brain regions is imperative to understanding brain function. A systematic review of the functional neuroanatomy of the thalamus by Power and Looi (2015) highlighted that, although the precise role of the thalamus remains unclear, its importance in the functional connectome is beyond doubt. Some have argued that a significant factor in determining the functions that any cortical region is capable of is its connectivity to the thalamus (Sherman & Guillery, 2013).…”