Year: 2014
Type: dissertation
Study design: Observational Study
Abstract: Cerebrovascular diseases (CD) are the third most common cause of death and the leading cause of disability in adults in developed countries (Carmichael, 2012; World Health Organization, 2004). Specifically, ischemic stroke and white matter lesions (WML) often result in multiple neurological, cognitive impairment and behavioral and emotional disorders (Gorelick et al., 2011; Troncoso et al., 2008). Strokes are responsible for damage in the core of the ischemic lesion but may also cause alterations in remote areas from the primary ischemic lesion. The thalamus is a key structure in the cortico-subcortical circuits (Alexander et al., 1986; Byne et al., 2009) and is involved in multiple cognitive functions (Herrero et al., 2002; Sherman, 2005) especially in functions executive, one of the most affected cognitive domains after suffering a stroke. Although it is known that the cortico- subcortical circuits are involved in cognitive functions, to date their neuroimage correlates are unknown. The overall objective of this thesis was to study the effects of a disruption in the cortico-subcortical circuits, due to a direct or remote damage, in executive functions. For the study of remote thalamic abnormalities we use the technique of diffusion tensor image (DTI) for both ischemic stroke and WML. Moreover, due to attention and cognitive inhibition are one of the most important functions of executive domain, we studied the relationship between a specific white matter (WM) tract -called Front aslant Tract (FAT)- and these functions. The study results showed that remote thalamic microstructural abnormalities secondary to a cerebrovascular lesion can occur in both ipsilateral and contralateral thalamus, in healthy subjects with WML and in patients with cerebral ischemic stroke. These thalamic abnormalities may be related to a disruption in the cortico-subcortical circuits associated with executive dysfunction. In addition, the right FAT is involved in attention and response inhibition functions in community-dwelling subjects and participants with ischemic stroke. In conclusion, the results obtained in this thesis suggest that stroke can affect the cortico-subcortical circuits through thalamic microstructural abnormalities and these could be related to cognitive dysfunction. Finally, the novel technique of DTI can play an important role in understanding the cognitive functioning in both ischemic stroke and WML.
Author: Marina Fernández‐Andújar
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W624984800