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Dutta A, Lahiri U, Das A, Nitsche MA, Guiraud D. Post-stroke balance rehabilitation under multi-level electrotherapy: a conceptual review. Front Neurosci 2015; 8:403. [PMID: 25565937 PMCID: PMC4266025 DOI: 10.3389/fnins.2014.00403] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 11/19/2014] [Indexed: 11/23/2022] Open
Abstract
Stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow thereby preventing delivery of oxygen and nutrients. About half of the stroke survivors are left with some degree of disability. Innovative methodologies for restorative neurorehabilitation are urgently required to reduce long-term disability. The ability of the nervous system to respond to intrinsic or extrinsic stimuli by reorganizing its structure, function, and connections is called neuroplasticity. Neuroplasticity is involved in post-stroke functional disturbances, but also in rehabilitation. It has been shown that active cortical participation in a closed-loop brain machine interface (BMI) can induce neuroplasticity in cortical networks where the brain acts as a controller, e.g., during a visuomotor task. Here, the motor task can be assisted with neuromuscular electrical stimulation (NMES) where the BMI will act as a real-time decoder. However, the cortical control and induction of neuroplasticity in a closed-loop BMI is also dependent on the state of brain, e.g., visuospatial attention during visuomotor task performance. In fact, spatial neglect is a hidden disability that is a common complication of stroke and is associated with prolonged hospital stays, accidents, falls, safety problems, and chronic functional disability. This hypothesis and theory article presents a multi-level electrotherapy paradigm toward motor rehabilitation in virtual reality that postulates that while the brain acts as a controller in a closed-loop BMI to drive NMES, the state of brain can be can be altered toward improvement of visuomotor task performance with non-invasive brain stimulation (NIBS). This leads to a multi-level electrotherapy paradigm where a virtual reality-based adaptive response technology is proposed for post-stroke balance rehabilitation. In this article, we present a conceptual review of the related experimental findings.
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Affiliation(s)
- Anirban Dutta
- DEMAR (INRIA Sophia Antipolis), INRIA, CNRS: UMR5506, Université Montpellier II - Sciences et Techniques, Université Montpellier I Montpellier, France ; Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier, CNRS: UMR5506, Université Montpellier II - Sciences et Techniques Montpellier, France
| | - Uttama Lahiri
- Electrical Engineering, Indian Institute of Technology Gandhinagar, India
| | - Abhijit Das
- Department of Neurorehabilitation, Institute of Neurosciences Kolkata, India
| | - Michael A Nitsche
- Department of Clinical Neurophysiology, Göttingen University Medical School Göttingen, Germany
| | - David Guiraud
- DEMAR (INRIA Sophia Antipolis), INRIA, CNRS: UMR5506, Université Montpellier II - Sciences et Techniques, Université Montpellier I Montpellier, France ; Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier, CNRS: UMR5506, Université Montpellier II - Sciences et Techniques Montpellier, France
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Abstract
In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.
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Affiliation(s)
- Wim Vanduffel
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium; Department of Radiology, Harvard Medical School, Boston, MA 02129, USA; A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.
| | - Qi Zhu
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium
| | - Guy A Orban
- Laboratory for Neuro- and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, Leuven, 3000, Belgium; Department of Neuroscience, University of Parma, Parma, 43125, Italy
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Probabilistic and single-subject retinotopic maps reveal the topographic organization of face patches in the macaque cortex. J Neurosci 2014; 34:10156-67. [PMID: 25080579 DOI: 10.1523/jneurosci.2914-13.2013] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Face perception is crucial to survival among social primates. It has been suggested that a group of extrastriate cortical regions responding more strongly to faces than to nonface objects is critical for face processing in primates. It is generally assumed that these regions are not retinotopically organized, as with human face-processing areas, showing foveal bias but lacking any organization with respect to polar angle. Despite many electrophysiological studies targeting monkey face patches, the retinotopic organization of these patches remains largely unclear. We have examined the relationship between cortical face patches and the topographic organization of extrastriate cortex using biologically relevant, phase-encoded retinotopic mapping stimuli in macaques. Single-subject fMRI results indicated a gradual shift from highly retinotopic to no topographic organization from posterior to anterior face patches in inferotemporal cortex. We also constructed a probabilistic retinotopic atlas of occipital and ventral extrastriate visual cortex. By comparing this probabilistic map to the locations of face patches at the group level, we showed that a previously identified posterior lateral temporal face patch (PL) is located within the posterior inferotemporal dorsal (PITd) retinotopic area. Furthermore, we identified a novel face patch posterior PL, which is located in retinotopically organized transitional area V4 (V4t). Previously published coordinates of human PITd coincide with the group-level occipital face area (OFA), according to a probabilistic map derived from a large population, implying a potential correspondence between monkey PL/PITd and human OFA/PITd. Furthermore, the monkey middle lateral temporal face patch (ML) shows consistent foveal biases but no obvious polar-angle structure. In contrast, middle fundus temporal (MF), anterior temporal and prefrontal monkey face patches lacked topographic organization.
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Andersen RA, Andersen KN, Hwang EJ, Hauschild M. Optic ataxia: from Balint's syndrome to the parietal reach region. Neuron 2014; 81:967-983. [PMID: 24607223 DOI: 10.1016/j.neuron.2014.02.025] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2014] [Indexed: 01/10/2023]
Abstract
Optic ataxia is a high-order deficit in reaching to visual goals that occurs with posterior parietal cortex (PPC) lesions. It is a component of Balint's syndrome that also includes attentional and gaze disorders. Aspects of optic ataxia are misreaching in the contralesional visual field, difficulty preshaping the hand for grasping, and an inability to correct reaches online. Recent research in nonhuman primates (NHPs) suggests that many aspects of Balint's syndrome and optic ataxia are a result of damage to specific functional modules for reaching, saccades, grasp, attention, and state estimation. The deficits from large lesions in humans are probably composite effects from damage to combinations of these functional modules. Interactions between these modules, either within posterior parietal cortex or downstream within frontal cortex, may account for more complex behaviors such as hand-eye coordination and reach-to-grasp.
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Affiliation(s)
- Richard A Andersen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Kristen N Andersen
- Departments of Neurology and Pediatrics, University of California, Los Angeles Medical Center, Los Angeles, CA 90095, USA
| | - Eun Jung Hwang
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Markus Hauschild
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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Ahveninen J, Huang S, Nummenmaa A, Belliveau JW, Hung AY, Jääskeläinen IP, Rauschecker JP, Rossi S, Tiitinen H, Raij T. Evidence for distinct human auditory cortex regions for sound location versus identity processing. Nat Commun 2014; 4:2585. [PMID: 24121634 PMCID: PMC3932554 DOI: 10.1038/ncomms3585] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 09/10/2013] [Indexed: 11/16/2022] Open
Abstract
Neurophysiological animal models suggest that anterior auditory cortex (AC) areas process sound-identity information, whereas posterior ACs specialize in sound location processing. In humans, inconsistent neuroimaging results and insufficient causal evidence have challenged the existence of such parallel AC organization. Here we transiently inhibit bilateral anterior or posterior AC areas using MRI-guided paired-pulse transcranial magnetic stimulation (TMS) while subjects listen to Reference/Probe sound pairs and perform either sound location or identity discrimination tasks. The targeting of TMS pulses, delivered 55–145 ms after Probes, is confirmed with individual-level cortical electric-field estimates. Our data show that TMS to posterior AC regions delays reaction times (RT) significantly more during sound location than identity discrimination, whereas TMS to anterior AC regions delays RTs significantly more during sound identity than location discrimination. This double dissociation provides direct causal support for parallel processing of sound identity features in anterior AC and sound location in posterior AC.
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Affiliation(s)
- Jyrki Ahveninen
- Harvard Medical School-Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA
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Guipponi O, Odouard S, Pinède S, Wardak C, Ben Hamed S. fMRI Cortical Correlates of Spontaneous Eye Blinks in the Nonhuman Primate. Cereb Cortex 2014; 25:2333-45. [PMID: 24654257 DOI: 10.1093/cercor/bhu038] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Eyeblinks are defined as a rapid closing and opening of the eyelid. Three types of blinks are defined: spontaneous, reflexive, and voluntary. Here, we focus on the cortical correlates of spontaneous blinks, using functional magnetic resonance imaging (fMRI) in the nonhuman primate. Our observations reveal an ensemble of cortical regions processing the somatosensory, proprioceptive, peripheral visual, and possibly nociceptive consequences of blinks. These observations indicate that spontaneous blinks have consequences on the brain beyond the visual cortex, possibly contaminating fMRI protocols that generate in the participants heterogeneous blink behaviors. This is especially the case when these protocols induce (nonunusual) eye fatigue and corneal dryness due to demanding fixation requirements, as is the case here. Importantly, no blink related activations were observed in the prefrontal and parietal blinks motor command areas nor in the prefrontal, parietal, and medial temporal blink suppression areas. This indicates that the absence of activation in these areas is not a signature of the absence of blink contamination in the data. While these observations increase our understanding of the neural bases of spontaneous blinks, they also strongly call for new criteria to identify whether fMRI recordings are contaminated by a heterogeneous blink behavior or not.
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Affiliation(s)
- Olivier Guipponi
- Centre de Neuroscience Cognitive, CNRS UMR 5229-Université Claude Bernard Lyon I, 69675 Bron Cedex, France
| | - Soline Odouard
- Centre de Neuroscience Cognitive, CNRS UMR 5229-Université Claude Bernard Lyon I, 69675 Bron Cedex, France
| | - Serge Pinède
- Centre de Neuroscience Cognitive, CNRS UMR 5229-Université Claude Bernard Lyon I, 69675 Bron Cedex, France
| | - Claire Wardak
- Centre de Neuroscience Cognitive, CNRS UMR 5229-Université Claude Bernard Lyon I, 69675 Bron Cedex, France
| | - Suliann Ben Hamed
- Centre de Neuroscience Cognitive, CNRS UMR 5229-Université Claude Bernard Lyon I, 69675 Bron Cedex, France
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de Haan B, Bither M, Brauer A, Karnath HO. Neural Correlates of Spatial Attention and Target Detection in a Multi-Target Environment. Cereb Cortex 2014; 25:2321-31. [PMID: 24642422 DOI: 10.1093/cercor/bhu046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Our ability to attend and respond in a multi-target environment is an essential and distinct human skill, as is dramatically demonstrated in stroke patients suffering from extinction. We performed a functional magnetic resonance imaging study to determine the neural anatomy associated with attending and responding to simultaneously presented targets. In healthy subjects, we tested the hypothesis that the right intraparietal sulcus (IPS) is associated both with the top-down direction of attention to multiple target locations and the bottom-up detection of multiple targets, whereas the temporo-parietal junction (TPJ) is predominantly associated with the bottom-up detection of multiple targets. We used a cued target detection task with a high proportion of catch trials to separately estimate top-down cue-related and bottom-up target-related neural activity. Both cues and targets could be presented unilaterally or bilaterally. We found no evidence of target-related neural activation specific to bilateral situations in the TPJ, but observed both cue-related and target-related neural activation specific to bilateral situations in the right IPS and target-related neural activity specific to bilateral situations in the right inferior frontal gyrus (IFG). We conclude that the IPS and the IFG of the right hemisphere underlie our ability to attend and respond in a multi-target environment.
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Affiliation(s)
- Bianca de Haan
- Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Maria Bither
- Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Anne Brauer
- Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Hans-Otto Karnath
- Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany Department of Psychology, University of South Carolina, Columbia, SC, USA
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Yttri EA, Wang C, Liu Y, Snyder LH. The parietal reach region is limb specific and not involved in eye-hand coordination. J Neurophysiol 2013; 111:520-32. [PMID: 24198328 DOI: 10.1152/jn.00058.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Primates frequently reach toward visual targets. Neurons in early visual areas respond to stimuli in the contralateral visual hemifield and without regard to which limb will be used to reach toward that target. In contrast, neurons in motor areas typically respond when reaches are performed using the contralateral limb and with minimal regard to the visuospatial location of the target. The parietal reach region (PRR) is located early in the visuomotor processing hierarchy. PRR neurons are significantly modulated when targets for either limb or eye movement appear, similar to early sensory areas; however, they respond to targets in either visual field, similar to motor areas. The activity could reflect the subject's attentional locus, movement of a specific effector, or a related function, such as coordinating eye-arm movements. To examine the role of PRR in the visuomotor pathway, we reversibly inactivated PRR. Inactivation effects were specific to contralateral limb movements, leaving ipsilateral limb and saccadic movements intact. Neither visual hemifield bias nor visual attention deficits were observed. Thus our results are consistent with a motoric rather than visual organization in PRR, despite its early location in the visuomotor pathway. We found no effects on the temporal coupling of coordinated saccades and reaches, suggesting that this mechanism lies downstream of PRR. In sum, this study clarifies the role of PRR in the visuomotor hierarchy: despite its early position, it is a limb-specific area influencing reach planning and is positioned upstream from an active eye-hand coordination-coupling mechanism.
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Affiliation(s)
- Eric A Yttri
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
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Boly M, Seth AK, Wilke M, Ingmundson P, Baars B, Laureys S, Edelman DB, Tsuchiya N. Consciousness in humans and non-human animals: recent advances and future directions. Front Psychol 2013; 4:625. [PMID: 24198791 PMCID: PMC3814086 DOI: 10.3389/fpsyg.2013.00625] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 08/24/2013] [Indexed: 12/30/2022] Open
Abstract
This joint article reflects the authors' personal views regarding noteworthy advances in the neuroscience of consciousness in the last 10 years, and suggests what we feel may be promising future directions. It is based on a small conference at the Samoset Resort in Rockport, Maine, USA, in July of 2012, organized by the Mind Science Foundation of San Antonio, Texas. Here, we summarize recent advances in our understanding of subjectivity in humans and other animals, including empirical, applied, technical, and conceptual insights. These include the evidence for the importance of fronto-parietal connectivity and of “top-down” processes, both of which enable information to travel across distant cortical areas effectively, as well as numerous dissociations between consciousness and cognitive functions, such as attention, in humans. In addition, we describe the development of mental imagery paradigms, which made it possible to identify covert awareness in non-responsive subjects. Non-human animal consciousness research has also witnessed substantial advances on the specific role of cortical areas and higher order thalamus for consciousness, thanks to important technological enhancements. In addition, much progress has been made in the understanding of non-vertebrate cognition relevant to possible conscious states. Finally, major advances have been made in theories of consciousness, and also in their comparison with the available evidence. Along with reviewing these findings, each author suggests future avenues for research in their field of investigation.
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Affiliation(s)
- Melanie Boly
- Department of Neurology, University of Wisconsin Madison, WI, USA ; Department of Psychiatry, Center for Sleep and Consciousness, University of Wisconsin Madison, WI, USA ; Coma Science Group, Cyclotron Research Centre and Neurology Department, University of Liege and CHU Sart Tilman Hospital Liege, Belgium
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Aksenov DP, Li L, Iordanescu G, Miller MJ, Wyrwicz AM. Volume effect of localized injection in functional MRI and electrophysiology. Magn Reson Med 2013; 72:1170-5. [PMID: 24273205 DOI: 10.1002/mrm.24996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/19/2013] [Accepted: 09/21/2013] [Indexed: 11/09/2022]
Abstract
PURPOSE The local injection of neurotransmitter agonists and antagonists to modulate recorded neurons in awake animals has long been an important and widely used technique in neuroscience. Combined with functional magnetic resonance imaging (fMRI) and simultaneous electrophysiology, local injection enables the study of specific brain regions under precise modulations of their neuronal activity. However, localized injections are often accompanied by mechanical displacement of the tissue, known as volume effect (VE), which can induce changes in electrophysiological recordings as well as artifacts that are particular to fMRI studies. METHODS We characterize the changes produced by VE in an agarose phantom as well as during stimulus-evoked and resting-state fMRI and simultaneously acquired electrophysiology in awake rabbits. RESULTS Our results demonstrate that localized injection can produce significant intensity changes in fMRI data, even while effects on electrophysiological recordings are minimized. These changes are localized to the vicinity of the injection needle and diminish over time due to diffusion of the injected volume. CONCLUSION Sufficient time should be allowed for drug diffusion to ensure stable results, particularly for resting-state fMRI experiments.
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Affiliation(s)
- Daniil P Aksenov
- Center for Basic MR Research, NorthShore University HealthSystem, Evanston, Illinois, USA
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61
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Wilke M, Kagan I, Andersen RA. Effects of Pulvinar Inactivation on Spatial Decision-making between Equal and Asymmetric Reward Options. J Cogn Neurosci 2013; 25:1270-83. [DOI: 10.1162/jocn_a_00399] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
The ability to selectively process visual inputs and to decide between multiple movement options in an adaptive manner is critical for survival. Such decisions are known to be influenced by factors such as reward expectation and visual saliency. The dorsal pulvinar connects to a multitude of cortical areas that are involved in visuospatial memory and integrate information about upcoming eye movements with expected reward values. However, it is unclear whether the dorsal pulvinar is critically involved in spatial memory and reward-based oculomotor decision behavior. To examine this, we reversibly inactivated the dorsal portion of the pulvinar while monkeys performed a delayed memory saccade task that included choices between equally or unequally rewarded options. Pulvinar inactivation resulted in a delay of saccade initiation toward memorized contralesional targets but did not affect spatial memory. Furthermore, pulvinar inactivation caused a pronounced choice bias toward the ipsilesional hemifield when the reward value in the two hemifields was equal. However, this choice bias could be alleviated by placing a high reward target into the contralesional hemifield. The bias was less affected by the manipulation of relative visual saliency between the two competing targets. These results suggest that the dorsal pulvinar is involved in determining the behavioral desirability of movement goals while being less critical for spatial memory and reward processing.
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Affiliation(s)
- Melanie Wilke
- 1California Institute of Technology
- 2University of Goettingen
- 3German Primate Center, Leibniz Institute for Primate Research, Goettingen, Germany
| | - Igor Kagan
- 1California Institute of Technology
- 3German Primate Center, Leibniz Institute for Primate Research, Goettingen, Germany
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Large-scale reorganization of the somatosensory cortex of adult macaque monkeys revealed by fMRI. Brain Struct Funct 2013; 219:1305-20. [PMID: 23652854 DOI: 10.1007/s00429-013-0569-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/23/2013] [Indexed: 12/29/2022]
Abstract
Somatosensory cortex of adult primates undergoes topographic reorganization following spinal cord or peripheral nerve injuries. Electrophysiological studies in monkeys show that after chronic lesions of dorsal columns of the spinal cord at cervical levels, there is an expansion of face representation into the deafferented hand region of area 3b of cortex. However, these techniques can sample only a limited portion of the brain. In order to help understand mechanisms of brain reorganization use of noninvasive tools in non-human primate experimental model is important. Use of blood oxygen level dependent-functional magnetic resonance imaging (BOLD-fMRI) to study brain reorganization in non-human primates has been extremely limited. Here, we show that in monkeys with long-term unilateral lesions of the dorsal columns at cervical levels, tactile stimulation of the chin showed BOLD activation in the deafferented hand region of contralesional area 3b in the post-central gyrus. In a monkey with a partial lesion of the dorsal columns, stimulations of both hand and chin activated the partially deafferented hand region. We also show that the somatotopic organization in the non-deafferented ipsilesional somatosensory cortex remained normal.
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