Rosario Montoya-García, Valeria Fernández-Vargas, Karla Nalini Albor-Martínez , [...]
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Abstract
Background:
The hippocampus is highly vulnerable to damage in the brain ischemia-reperfusion injury model. Leuprolide acetate has been shown to promote neurological recovery after injury in various regions of the central nervous system.
Objective:
The objective of this study was to assess the histology of the hippocampus and the expression of neuronal recovery markers, specifically the 200 kDa neurofilaments and the myelin basic protein, in rats with brain ischemia-reperfusion injury treated with leuprolide acetate.
Methods:
The rats were divided into three groups: Sham, ischemia-reperfusion with saline solution, and ischemia-reperfusion treated with leuprolide acetate. Coronal brain slices were obtained and stained with hematoxylin-eosin. The histological analysis involved quantifying the number of neurons in the hippocampal regions CA1, CA3 and DG. The myelin basic protein and neurofilaments were quantified using western blot.
Results:
The number of neurons in CA1 and DG was significantly higher in the leuprolide acetate group compared to the untreated group. Additionally, the expression of neurofilament and myelin basic protein markers was significantly increased in rats treated with leuprolide acetate compared to the untreated rats.
Conclusions:
Leuprolide acetate promotes the recovery of hippocampal neurons in an acute brain ischemia-reperfusion injury model. These findings suggest that leuprolide acetate could be a potential therapeutic intervention for reversing damage in hippocampal ischemic lesions.
Research article
Open accessResearch articleFirst published December 8, 2023pp. 91-101
Lina Bunketorp Käll, Malin Björnsdotter, Johanna Wangdell , [...]
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Abstract
Background:
While functional near-infrared spectroscopy (fNIRS) can provide insight into cortical brain activity during motor tasks in healthy and diseased populations, the feasibility of using fNIRS to assess haemoglobin-evoked responses to reanimated upper limb motor function in patients with tetraplegia remains unknown.
Objective:
The primary objective of this pilot study is to determine the feasibility of using fNIRS to assess cortical signal intensity changes during upper limb motor tasks in individuals with surgically restored grip functions. The secondary objectives are: 1) to collect pilot data on individuals with tetraplegia to determine any trends in the cortical signal intensity changes as measured by fNIRS and 2) to compare cortical signal intensity changes in affected individuals versus age-appropriate healthy volunteers. Specifically, patients presented with tetraplegia, a type of paralysis resulting from a cervical spinal cord injury causing loss of movement and sensation in both lower and upper limbs. All patients have their grip functions restored by surgical tendon transfer, a procedure which constitutes a unique, focused stimulus for brain plasticity.
Method:
fNIRS is used to assess changes in cortical signal intensity during the performance of two motor tasks (isometric elbow and thumb flexion). Six individuals with tetraplegia and six healthy controls participate in the study. A block paradigm is utilized to assess contralateral and ipsilateral haemodynamic responses in the premotor cortex (PMC) and primary motor cortex (M1). We assess the amplitude of the optical signal and spatial features during the paradigms. The accuracy of channel locations is maximized through 3D digitizations of channel locations and co-registering these locations to template atlas brains. A general linear model approach, with short-separation regression, is used to extract haemodynamic response functions at the individual and group levels.
Results:
Peak oxyhaemoglobin (oxy-Hb) changes in PMC appear to be particularly bilateral in nature in the tetraplegia group during both pinch and elbow trials whereas for controls, a bilateral PMC response is not especially evident. In M1 / primary sensory cortex (S1), the oxy-Hb responses to the pinch task are mainly contralateral in both groups, while for the elbow flexion task, lateralization is not particularly clear.
Conclusions:
This pilot study shows that the experimental setup is feasible for assessing brain activation using fNIRS during volitional upper limb motor tasks in individuals with surgically restored grip functions. Cortical signal changes in brain regions associated with upper extremity sensorimotor processing appear to be larger and more bilateral in nature in the tetraplegia group than in the control group. The bilateral hemispheric response in the tetraplegia group may reflect a signature of adaptive brain plasticity mechanisms. Larger studies than this one are needed to confirm these findings and draw reliable conclusions.
Research article
Available accessResearch articleFirst published December 8, 2023pp. 103-113
Cognitive dysfunctions after a brain stroke have a huge impact on patients’ disability and activities of daily living. Prism adaptation (PA) is currently used in patients with right brain damage to improve lateralized spatial attentional deficits. Recent findings suggest that PA could also be useful for rehabilitation of other cognitive functions.
Objective:
In the present study, we tested for the efficacy on cognitive rehabilitation of a novel device in which the procedure of prism adaptation is digitized and followed by cognitive training of attention and executive functions using serious games.
Methods:
Thirty stroke patients were randomly assigned to two groups: an experimental group of 15 patients, which performed the experimental rehabilitation training using the novel device in 10 consecutive daily sessions; a control group of 15 patients, which performed the routine cognitive training in 10 consecutive daily sessions. Both groups were tested before and after the rehabilitation program on neuropsychological tests (digit and spatial span forward and backward, attentional matrices, Stroop task) and on functional scales (Barthel index and Beck Anxiety Index).
Results:
The main results showed that only patients who received the experimental rehabilitation training improved their scores on tests of digit span forward, spatial span backward, attentional matrices and Stroop. Moreover, patients of the experimental but not of the control group showed a significant correlation between improvement on some tasks (mainly spatial span backward) and improvement on activities of daily living as well as with reduction of anxiety levels.
Conclusions:
These results suggest that combining digital PA with cognitive training using serious games may be added in clinical settings for cognitive rehabilitation of stroke patients, with beneficial effects extending in promoting independency in activities of daily living and reduction of psychiatric symptoms.
Research article
Open accessResearch articleFirst published December 8, 2023pp. 115-127
The default mode network (DMN) is a large-scale brain network tightly correlated with self and self-referential processing, activated by intrinsic tasks and deactivated by externally-directed tasks.
Objective:
In this study, we aim to investigate the novel approach of default mode activation during progressive muscle relaxation and examine whether differential activation patterns result from the movement of different body parts.
Methods:
We employed neuroimaging to investigate DMN activity during simple body movements, while performing progressive muscle relaxation. We focused on differentiating the neural response between facial movements and movements of other body parts.
Results:
Our results show that the movement of different body parts led to deactivation in several DMN nodes, namely the temporal poles, hippocampus, medial prefrontal cortex (mPFC), and posterior cingulate cortex. However, facial movement induced an inverted and selective positive BOLD pattern in some of these areas precisely. Moreover, areas in the temporal poles selective for face movement showed functional connectivity not only with the hippocampus and mPFC but also with the nucleus accumbens.
Conclusions:
Our findings suggest that both conceptual and embodied self-related processes, including body movements during progressive muscle relaxation, may be mapped onto shared brain networks. This could enhance our understanding of how practices like PMR influence DMN activity and potentially offer insights to inform therapeutic strategies that rely on mindful body movements.
Research article
Open accessResearch articleFirst published December 8, 2023pp. 129-191
Priyanka Shah-Basak, Olga Boukrina, Xin Ran Li , [...]
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Abstract
Background:
Aphasia is a debilitating language impairment, affecting millions of people worldwide. About 40% of stroke survivors develop chronic aphasia, resulting in life-long disability.
Objective:
This review examines extrinsic and intrinsic neuromodulation techniques, aimed at enhancing the effects of speech and language therapies in stroke survivors with aphasia.
Methods:
We discuss the available evidence supporting the use of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation, and functional MRI (fMRI) real-time neurofeedback in aphasia rehabilitation.
Results:
This review systematically evaluates studies focusing on efficacy and implementation of specialized methods for post-treatment outcome optimization and transfer to functional skills. It considers stimulation target determination and various targeting approaches. The translation of neuromodulation interventions to clinical practice is explored, emphasizing generalization and functional communication. The review also covers real-time fMRI neurofeedback, discussing current evidence for efficacy and essential implementation parameters. Finally, we address future directions for neuromodulation research in aphasia.
Conclusions:
This comprehensive review aims to serve as a resource for a broad audience of researchers and clinicians interested in incorporating neuromodulation for advancing aphasia care.