| 1. |
- Al Moubayed, Samer, et al.
(författare)
-
Human-robot Collaborative Tutoring Using Multiparty Multimodal Spoken Dialogue
- 2014
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we describe a project that explores a novel experi-mental setup towards building a spoken, multi-modally rich, and human-like multiparty tutoring robot. A human-robotinteraction setup is designed, and a human-human dialogue corpus is collect-ed. The corpus targets the development of a dialogue system platform to study verbal and nonverbaltutoring strategies in mul-tiparty spoken interactions with robots which are capable of spo-ken dialogue. The dialogue task is centered on two participants involved in a dialogueaiming to solve a card-ordering game. Along with the participants sits a tutor (robot) that helps the par-ticipants perform the task, and organizes and balances their inter-action. Differentmultimodal signals captured and auto-synchronized by different audio-visual capture technologies, such as a microphone array, Kinects, and video cameras, were coupled with manual annotations. These are used build a situated model of the interaction based on the participants personalities, their state of attention, their conversational engagement and verbal domi-nance, and how that is correlated with the verbal and visual feed-back, turn-management, and conversation regulatory actions gen-erated by the tutor. Driven by the analysis of the corpus, we will show also the detailed design methodologies for an affective, and multimodally rich dialogue system that allows the robot to meas-ure incrementally the attention states, and the dominance for each participant, allowing the robot head Furhat to maintain a well-coordinated, balanced, and engaging conversation, that attempts to maximize the agreement and the contribution to solve the task. This project sets the first steps to explore the potential of us-ing multimodal dialogue systems to build interactive robots that can serve in educational, team building, and collaborative task solving applications.
|
|
| 2. |
- Al Moubayed, Samer, et al.
(författare)
-
Tutoring Robots: Multiparty Multimodal Social Dialogue With an Embodied Tutor
- 2014
-
Konferensbidrag (refereegranskat)abstract
- This project explores a novel experimental setup towards building spoken, multi-modally rich, and human-like multiparty tutoring agent. A setup is developed and a corpus is collected that targets the development of a dialogue system platform to explore verbal and nonverbal tutoring strategies in multiparty spoken interactions with embodied agents. The dialogue task is centered on two participants involved in a dialogue aiming to solve a card-ordering game. With the participants sits a tutor that helps the participants perform the task and organizes and balances their interaction. Different multimodal signals captured and auto-synchronized by different audio-visual capture technologies were coupled with manual annotations to build a situated model of the interaction based on the participants personalities, their temporally-changing state of attention, their conversational engagement and verbal dominance, and the way these are correlated with the verbal and visual feedback, turn-management, and conversation regulatory actions generated by the tutor. At the end of this chapter we discuss the potential areas of research and developments this work opens and some of the challenges that lie in the road ahead.
|
|
| 3. |
- Jonsson, Samuel, et al.
(författare)
-
Effect of delayed peripheral nerve repair on nerve regeneration, Schwann cell function and target muscle recovery
- 2013
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:2
-
Tidskriftsartikel (refereegranskat)abstract
- Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2-3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months.
|
|
| 4. |
- Karalija, Amar, et al.
(författare)
-
Neuroprotective Effects of N-Acetyl-Cysteine and Acetyl-L-Carnitine after Spinal Cord Injury in Adult Rats
- 2012
-
Ingår i: PLOS ONE. - San Fransisco : Public library of Science. - 1932-6203. ; 7:7, s. e41086-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the initial acute stage of spinal cord injury, a cascade of cellular and inflammatory responses will lead to progressive secondary damage of the nerve tissue surrounding the primary injury site. The degeneration is manifested by loss of neurons and glial cells, demyelination and cyst formation. Injury to the mammalian spinal cord results in nearly complete failure of the severed axons to regenerate. We have previously demonstrated that the antioxidants N-acetyl-cysteine (NAC) and acetyl-L-carnitine (ALC) can attenuate retrograde neuronal degeneration after peripheral nerve and ventral root injury. The present study evaluates the effects of NAC and ALC on neuronal survival, axonal sprouting and glial cell reactions after spinal cord injury in adult rats. Tibial motoneurons in the spinal cord were pre-labeled with fluorescent tracer Fast Blue one week before lumbar L5 hemisection. Continuous intrathecal infusion of NAC (2.4 mg/day) or ALC (0.9 mg/day) was initiated immediately after spinal injury using Alzet 2002 osmotic minipumps. Neuroprotective effects of treatment were assessed by counting surviving motoneurons and by using quantitative immunohistochemistry and Western blotting for neuronal and glial cell markers 4 weeks after hemisection. Spinal cord injury induced significant loss of tibial motoneurons in L4-L6 segments. Neuronal degeneration was associated with decreased immunostaining for microtubular-associated protein-2 (MAP2) in dendritic branches, synaptophysin in presynaptic boutons and neurofilaments in nerve fibers. Immunostaining for the astroglial marker GFAP and microglial marker OX42 was increased. Treatment with NAC and ALC rescued approximately half of the motoneurons destined to die. In addition, antioxidants restored MAP2 and synaptophysin immunoreactivity. However, the perineuronal synaptophysin labeling was not recovered. Although both treatments promoted axonal sprouting, there was no effect on reactive astrocytes. In contrast, the microglial reaction was significantly attenuated. The results indicate a therapeutic potential for NAC and ALC in the early treatment of traumatic spinal cord injury.
|
|
| 5. |
- Karalija, Amar, et al.
(författare)
-
The effects of N-acetyl-cysteine and acetyl-l-carnitine on neural survival, neuroinflammation and regeneration following spinal cord injury
- 2014
-
Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 269, s. 143-151
-
Tidskriftsartikel (refereegranskat)abstract
- Traumatic spinal cord injury induces a long-standing inflammatory response in the spinal cord tissue, leading to a progressive apoptotic death of spinal cord neurons and glial cells. We have recently demonstrated that immediate treatment with the antioxidants N-acetyl-cysteine (NAC) and acetyl-l-carnitine (ALC) attenuates neuroinflammation, induces axonal sprouting, and reduces the death of motoneurons in the vicinity of the trauma zone 4weeks after initial trauma. The objective of the current study was to investigate the effects of long-term antioxidant treatment on the survival of descending rubrospinal neurons after spinal cord injury in rats. It also examines the short- and long-term effects of treatment on apoptosis, inflammation, and regeneration in the spinal cord trauma zone. Spinal cord hemisection performed at the level C3 induced a significant loss of rubrospinal neurons 8weeks after injury. At 2weeks, an increase in the expression of the apoptosis-associated markers BCL-2-associated X protein (BAX) and caspase 3, as well as the microglial cell markers OX42 and ectodermal dysplasia 1 (ED1), was seen in the trauma zone. After 8weeks, an increase in immunostaining for OX42 and the serotonin marker 5HT was detected in the same area. Antioxidant therapy reduced the loss of rubrospinal neurons by approximately 50%. Treatment also decreased the expression of BAX, caspase 3, OX42 and ED1 after 2weeks. After 8weeks, treatment decreased immunoreactivity for OX42, whereas it was increased for 5HT. In conclusion, this study provides further insight in the effects of treatment with NAC and ALC on descending pathways, as well as short- and long-term effects on the spinal cord trauma zone.
|
|
| 6. |
- Kingham, Paul J, et al.
(författare)
-
Stimulating the neurotrophic and angiogenic properties of human adipose-derived stem cells enhances nerve repair
- 2014
-
Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 23:7, s. 741-754
-
Tidskriftsartikel (refereegranskat)abstract
- In future, adipose-derived stem cells (ASC) might be used to treat neurological disorders. In this study, the neurotrophic and angiogenic properties of human ASC were evaluated, and their effects in a peripheral nerve injury model were determined. In vitro growth factor stimulation of the cells resulted in increased secretion of brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), vascular endothelial growth factor-A (VEGF-A), and angiopoietin-1 proteins. Conditioned medium from stimulated cells increased neurite outgrowth of dorsal root ganglia (DRG) neurons. Similarly, stimulated cells showed an enhanced ability to induce capillary-like tube formation in an in vitro angiogenesis assay. ASC were seeded into a fibrin conduit that was used to bridge a 10 mm rat nerve gap. After 2 weeks, the animals treated with control or stimulated ASC showed an enhanced axon regeneration distance. Stimulated cells evoked more total axon growth. Analysis of regeneration and apoptosis-related gene expression showed that both ASC and stimulated ASC enhanced GAP-43 and activating transcription factor 3 (ATF-3) expression in the spinal cord and reduced c-jun expression in the DRG. Caspase-3 expression in the DRG was reduced by stimulated ASC. Both ASC and stimulated ASC also increased the vascularity of the fibrin nerve conduits. Thus, ASC produce functional neurotrophic and angiogenic factors, creating a more desirable microenvironment for nerve regeneration.
|
|
| 7. |
- Kolar, Mallappa K, et al.
(författare)
-
The therapeutic effects of human adipose derived stem cells in a rat cervical spinal cord injury model
- 2014
-
Ingår i: Stem Cells and Development. - : Mary Ann Liebert. - 1547-3287 .- 1557-8534. ; 23:14, s. 1659-1674
-
Tidskriftsartikel (refereegranskat)abstract
- Spinal cord injury triggers a cascade of degenerative changes leading to cell death and cavitation. Severed axons fail to regenerate across the scar tissue and are only capable of limited sprouting. In this study we investigated the effects of adult human adipose derived stem cells (ASC) on axonal regeneration following transplantation into the injured rat cervical spinal cord. ASC did not induce activation of astrocytes in culture and supported neurite outgrowth from adult rat sensory DRG neurons. After transplantation into the lateral funiculus 1mm rostral and caudal to the cervical C3-C4 hemisection, ASC continued to express BDNF, VEGF and FGF-2 for 3 weeks but only in animals treated with cyclosporine A. Transplanted ASC stimulated extensive ingrowth of 5HT-positive raphaespinal axons into the trauma zone with some terminal arborisations reaching the caudal spinal cord. In addition, ASC induced sprouting of raphaespinal terminals in C2 contralateral ventral horn and C6 ventral horn on both sides. Transplanted cells also changed the structure of the lesion scar with numerous astrocytic processes extended into the middle of the trauma zone in a chain-like pattern and in close association with regenerating axons. The density of the astrocytic network was also significantly decreased. Although the transplanted cells had no effect on the density of capillaries around the lesion site, the activity of OX42-positive microglial cells was markedly reduced. However, ASC did not support recovery of forelimb function. The results suggest that transplanted ASC can modify the structure of the glial scar and stimulate axonal sprouting.
|
|
| 8. |
- McGrath, Aleksandra M, et al.
(författare)
-
Fibrin conduit supplemented with human mesenchymal stem cells and immunosuppressive treatment enhances regeneration after peripheral nerve injury
- 2012
-
Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 516:2, s. 171-176
-
Tidskriftsartikel (refereegranskat)abstract
- To address the need for the development of bioengineered replacement of a nerve graft, a novel two component fibrin glue conduit was combined with human mesenchymal stem cells (MSC) and immunosupressive treatment with cyclosporine A. The effects of MSC on axonal regeneration in the conduit and reaction of activated macrophages were investigated using sciatic nerve injury model. A 10mm gap in the sciatic nerve of a rat was created and repaired either with fibrin glue conduit containing diluted fibrin matrix or fibrin glue conduit containing fibrin matrix with MSC at concentration of 80×10(6)cells/ml. Cells were labeled with PKH26 prior to transplantation. The animals received daily injections of cyclosporine A. After 3 weeks the distance of regeneration and area occupied by regenerating axons and ED1 positives macrophages was measured. MSC survived in the conduit and enhanced axonal regeneration only when transplantation was combined with cyclosporine A treatment. Moreover, addition of cyclosporine A to the conduits with transplanted MSC significantly reduced the ED1 macrophage reaction.
|
|
| 9. |
|
|
| 10. |
- Novikova, Liudmila N, et al.
(författare)
-
Neuroprotective and growth-promoting effects of bone marrow stromal cells after cervical spinal cord injury in adult rats
- 2011
-
Ingår i: Cytotherapy. - : Elsevier BV. - 1465-3249 .- 1477-2566. ; 13:7, s. 873-887
-
Tidskriftsartikel (refereegranskat)abstract
- Background aims. Bone marrow stromal cells (BMSC) have been shown to provide neuroprotection after transplantation into the injured central nervous system. The present study investigated whether adult rat BMSC differentiated along a Schwann cell lineage could increase production of trophic factors and support neuronal survival and axonal regeneration after transplantation into the injured spinal cord. Methods. After cervical C4 hemi-section, 5-bromo-2-deoxyuridine (BrdU)/green fluorescent protein (GFP)-labeled BMSC were injected into the lateral funiculus at 1 mm rostral and caudal to the lesion site. Spinal cords were analyzed 2-13 weeks after transplantation. Results and Conclusions. Treatment of native BMSC with Schwann cell-differentiating factors significantly increased production of brain-derived neurotrophic factor in vitro. Transplanted undifferentiated and differentiated BMSC remained at the injection sites, and in the trauma zone were often associated with neurofilament-positive fibers and increased levels of vascular endothelial growth factor. BMSC promoted extensive in-growth of serotonin-positive raphaespinal axons and calcitonin gene-related peptide (CGRP)-positive dorsal root sensory axons into the trauma zone, and significantly attenuated astroglial and microglial cell reactions, but induced aberrant sprouting of CGRP-immunoreactive axons in Rexed's lamina III. Differentiated BMSC provided neuroprotection for axotomized rubrospinal neurons and increased the density of rubrospinal axons in the dorsolateral funiculus rostral to the injury site. The present results suggest that BMSC induced along the Schwann cell lineage increase expression of trophic factors and have neuroprotective and growth-promoting effects after spinal cord injury.
|
|
