Voluntary actions are shaped by desired goals and internal intentions. Multiple factors, includin... more Voluntary actions are shaped by desired goals and internal intentions. Multiple factors, including the planning of subsequent actions and the expectation of sensory outcome, were shown to modulate kinetics and neural activity patterns associated with similar goal-directed actions. Notably, in many real-world tasks, actions can also vary across the semantic meaning they convey, although little is known about how semantic meaning modulates associated neurobehavioral measures. Here, we examined how behavioral and functional magnetic resonance imaging measures are modulated when subjects execute similar actions (button presses) for two different semantic meanings—to answer “yes” or “no” to a binary question. Our findings reveal that, when subjects answer using their right hand, the two semantic meanings are differentiated based on voxel patterns in the frontoparietal cortex and lateral-occipital complex bilaterally. When using their left hand, similar regions were found, albeit only wit...
Summary The estimated accuracy of a classifier is a random quantity with variability. A common pr... more Summary The estimated accuracy of a classifier is a random quantity with variability. A common practice in supervised machine learning, is thus to test if the estimated accuracy is significantly better than chance level. This method of signal detection is particularly popular in neuroimaging and genetics. We provide evidence that using a classifier’s accuracy as a test statistic can be an underpowered strategy for finding differences between populations, compared to a bona fide statistical test. It is also computationally more demanding than a statistical test. Via simulation, we compare test statistics that are based on classification accuracy, to others based on multivariate test statistics. We find that the probability of detecting differences between two distributions is lower for accuracy-based statistics. We examine several candidate causes for the low power of accuracy-tests. These causes include: the discrete nature of the accuracy-test statistic, the type of signal accuracy...
Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain rema... more Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain remains elusive. We recorded the activity of 1019 neurons while twelve subjects performed self-initiated finger movement. We report progressive neuronal recruitment over $1500 ms before subjects report making the decision to move. We observed progressive increase or decrease in neuronal firing rate, particularly in the supplementary motor area (SMA), as the reported time of decision was approached. A population of 256 SMA neurons is sufficient to predict in single trials the impending decision to move with accuracy greater than 80% already 700 ms prior to subjects' awareness. Furthermore, we predict, with a precision of a few hundred ms, the actual time point of this voluntary decision to move. We implement a computational model whereby volition emerges once a change in internally generated firing rate of neuronal assemblies crosses a threshold. Neuron
The functional organization of human sensory cortex was studied by comparing intracranial EEG (iE... more The functional organization of human sensory cortex was studied by comparing intracranial EEG (iEEG) recordings of local field potentials in neurosurgical patients with functional magnetic resonance imaging (fMRI) obtained in healthy subjects. Using naturalistic movie stimuli, we found a tight correlation between these two measures throughout the human sensory cortex. Importantly, the correlation between the iEEG and fMRI signals was site-specific, exhibiting neuroanatomically specific coupling. In several cortical sites the iEEG activity was confined strictly to one object category. This site selectivity was not limited to faces but included other object categories such as houses and tools. The selectivity of the iEEG signals to images of different object categories was remarkably higher when compared with the selectivity of the corresponding fMRI signals. A plausible interpretation of the fMRI and iEEG results concerns cortical organization in which object categories are organized in a mosaic of narrowly tuned object-selective clusters.
Functional magnetic resonance imaging (fMRI) is an important tool for investigating human brain f... more Functional magnetic resonance imaging (fMRI) is an important tool for investigating human brain function, but the relationship between the hemodynamically based fMRI signals in the human brain and the underlying neuronal activity is unclear. We recorded single unit activity and local field potentials in auditory cortex of two neurosurgical patients and compared them with the fMRI signals of 11 healthy subjects during presentation of an identical movie segment. The predicted fMRI signals derived from single units and the measured fMRI signals from auditory cortex showed a highly significant correlation ( r = 0.75, P < 10 –47 ). Thus, fMRI signals can provide a reliable measure of the firing rate of human cortical neurons.
ABSTRACTAccurate control over everyday goal-directed actions is mediated by sensory-motor predict... more ABSTRACTAccurate control over everyday goal-directed actions is mediated by sensory-motor predictions of intended consequences and their comparison with actual outcomes. Such online comparisons of the expected and re-afferent, immediate, sensory feedback are conceptualized as internal forward models. Current predictive coding theories describing such models typically address the processing of immediate sensory-motor goals, yet voluntary actions are also oriented towards long-term conceptual goals and intentions, for which the sensory consequence is sometimes absent or cannot be fully predicted. Thus, the neural mechanisms underlying actions with distal conceptual goals is far from being clear. Specifically, it is still unknown whether sensory-motor circuits also encode information regarding the global meaning of the action, detached from the immediate, movement-related goal. Therefore, using fMRI and behavioral measures, we examined identical actions (either right or left-hand butto...
A fundamental computation underlying visual word recognition is the ability to transform a set of... more A fundamental computation underlying visual word recognition is the ability to transform a set of letters into a visual word form. Neuropsychological data suggest that letter position within a word may be independently affected by brain damage, resulting in a dissociable subtype of peripheral dyslexia. Here we used functional magnetic resonance imaging and supervised machine learning techniques to classify letter position based on activation patterns evoked during reading Hebrew words. Across the entire brain, activity patterns in the left intraparietal sulcus provided the best classification accuracy (80%) with respect to letter position. Importantly, the same set of voxels that showed highest classification performance of letter position using one letter-of-interest also showed highest classification performance using a different letter-of-interest. A functional connectivity analysis revealed that activity in these voxels co-varied with activity in the Visual Word Form Area, confirming cross-talk between these regions during covert reading. The results converge with reports of patients with acquired letter position dyslexia, who suffer from left occipito-parietal lesions. These findings provide direct and novel evidence for the role of left IPS within the reading network in processing relative letter positions.
The ultimate goal of neuroscience research is to understand the operating mechanism of the human ... more The ultimate goal of neuroscience research is to understand the operating mechanism of the human brain and to exploit this understanding to devise methods for repair when it malfunctions. A key feature of this operating mechanism is electrical activity of single brain cells and cell assemblies. For obvious ethical reasons, scientists rely mostly on animal research in the study of such signals. Research in humans is often limited to electrical signals that can be recorded at the scalp or to surrogates of electrical activity, namely magnetic source imaging and measures of regional blood flow and metabolism. Invasive brain recordings performed in patients during various clinical procedures provide a unique opportunity to record high-resolution signals in vivo from the human brain—data that are otherwise unavailable. Of special value are the rare opportunities to record in awake humans the activity of single brain cells and small cellular assemblies. These recordings provide a unique vi...
Observation is a powerful way to learn efficient actions from others. However, the role of observ... more Observation is a powerful way to learn efficient actions from others. However, the role of observers’ motor skill in assessing efficiency of others is unknown. Preschoolers are notoriously poor at performing multi-step actions like grasping the handle of a tool. Preschoolers (N = 22) and adults (N = 22) watched video-recorded actors perform efficient and inefficient tool use. Eye tracking showed that preschoolers and adults looked equally long at the videos, but adults looked longer than children at how actors grasped the tool. Deep learning analyses of participants’ eye gaze distinguished efficient from inefficient grasps for adults, but not for children. Moreover, only adults showed differential action-related pupil dilation and neural activity (suppressed oscillation power in the mu frequency) while observing efficient vs. inefficient grasps. Thus, children observe multi-step actions without “seeing” whether the initial step is efficient. Findings suggest that observer’s own moto...
Sensory perception is a product of interactions between the internal state of an organism and the... more Sensory perception is a product of interactions between the internal state of an organism and the physical attributes of a stimulus. It has been shown across the animal kingdom that perception and sensory-evoked physiological responses are modulated depending on whether or not the stimulus is the consequence of voluntary actions. These phenomena are often attributed to motor signals sent to relevant sensory regions that convey information about upcoming sensory consequences. However, the neurophysiological signature of action-locked modulations in sensory cortex, and their relationship with perception, is still unclear. In the current study, we recorded neurophysiological (using Magnetoencephalography) and behavioral responses from 16 healthy subjects performing an auditory detection task of faint tones. Tones were either generated by subjects’ voluntary button presses or occurred predictably following a visual cue. By introducing a constant temporal delay between button press/cue a...
Background: Parcellating the human brain into areas based on their neural connectivity is essenti... more Background: Parcellating the human brain into areas based on their neural connectivity is essential for understanding the functional organization of neural networks. New Method: We adapted density-peak clustering to identify functional neural networks in individuals without the need to select seed regions. We first assess the similarity between each pair of voxels based on their activation time-courses and then aggregate the voxels based on the assumption that cluster centers are dense (have high similarity with many voxels) and are at large distance from other high-density voxels. This data-driven approach allows intuitive selection of cluster centroids in individual subjects.Results: We applied our approach on resting-state data of individual subjects. Although similar networks across subjects were identified, there was large variability in the number of networks and their anatomical distribution between subjects. Manipulating the main free parameter of the model (density level th...
Problem solving is integral to goal-directed action—how to navigate an obstacle, open a latch, or... more Problem solving is integral to goal-directed action—how to navigate an obstacle, open a latch, or grasp the handle of a tool. Traditionally, researchers focus on when in development children succeed at solving particular problems, but this outcome-oriented approach does not inform on underlying mechanisms. The current study focuses on how children solve problems by examining the real-time interplay among planning components. We encouraged 3- to 5-year olds (N = 32) and adults (N = 22) to grasp a hammer to pound a peg when the hammer handle pointed in different directions. We simultaneously recorded participants’ movements, gaze, and neural activity using video microcoding, motion-tracking, head-mounted eye tracking, and EEG. When the handle pointed toward their non-dominant hand, participants had to use an adaptive underhand initial grip to implement the tool efficiently. Younger children (“non-adaptive child solvers”) used a habitual overhand grip that interfered with wielding the ...
Evoked neural activity in sensory regions and perception of sensory stimuli are modulated when th... more Evoked neural activity in sensory regions and perception of sensory stimuli are modulated when the stimuli are the consequence of voluntary movement, as opposed to an external source. It has been suggested that such modulations are due to motor commands that are sent to relevant sensory regions during voluntary movement. However, given the anatomical-functional laterality bias of the motor system, it is plausible that the pattern of such behavioral and neural modulations will also exhibit a similar bias, depending on the effector triggering the stimulus (e.g., right/left hand). Here, we examined this issue in the visual domain using behavioral and neural measures (fMRI). Healthy participants judged the relative brightness of identical visual stimuli that were either self-triggered (using right/left hand button presses), or triggered by the computer. Stimuli were presented either in the right or left visual field. Despite identical physical properties of the visual consequences, we f...
Sensory perception is a product of complex interactions between the internal state of an organism... more Sensory perception is a product of complex interactions between the internal state of an organism and the physical attributes of a stimulus. One factor that modulates the internal state of the perceiving agent is voluntary movement. It has been shown across the animal kingdom that perception and sensory-evoked physiological responses are modulated depending on whether or not the stimulus is the consequence of voluntary actions. These phenomena are often attributed to motor signals sent to relevant sensory regions (efference copies), that convey information about expected upcoming sensory consequences. However, to date, there is no direct evidence in humans for efferent signals underlying these motor-sensory interactions. In the current study we recorded neurophysiological (using Magnetoencephalography) and behavioral responses from 16 healthy subjects performing an auditory detection task of faint tones. Tones were either generated by subjects’ voluntary button presses or occurred p...
Undisclosed exploitation of flexibility in data acquisition and analysis blurs the important dist... more Undisclosed exploitation of flexibility in data acquisition and analysis blurs the important distinction between exploratory and hypothesis-driven findings and inflates false-positive rates1–4. Indeed, recent replication attempts have revealed low levels of replicability, pointing to high rates of false-positives in the literature5–10. A contemporary solution to this problem is pre-registration: commitment to aspects of methods and analysis before data acquisition11. This solution is valid only to the extent that the commitment stage is time-locked to precede data collection. To date, time-locking can only be guaranteed by introducing a third party such as peer reviewers at an early stage, making this solution less appealing for many12. Here we adapt a cryptographic method13 to encode information of study protocol within random aspects of the data acquisition process. This way, the structure of variability in the data time-locks the commitment stage with respect to data acquisition....
A long-standing controversy persists in psycholinguistic research regarding the way phonemes are ... more A long-standing controversy persists in psycholinguistic research regarding the way phonemes are coded in human auditory cortex during speech perception. The motor theory of speech perception [1, 2] describes phoneme perception in terms of the articulatory gestures that generate it. According to this theory, the objects of speech perception are the intended phonetic gestures of the speaker, such as, 'lip rounding', or 'jaw raising'. Alternatively, auditory theories argue that phonetic processing depends directly on properties of the auditory system [3-6]. According to this view, listeners identify spectro-temporal patterns in phoneme waveforms and match them with stored abstract acoustic representations. Here we recorded spiking activity in the auditory cortex (superior temporal gyrus; STG) from six neurosurgical patients who performed a listening task with phoneme stimuli. Using a Naive-Bayes model, we show that single-cell responses to phonemes are governed by arti...
Cross education is a phenomenon in which motor training of one hand induces motor learning in the... more Cross education is a phenomenon in which motor training of one hand induces motor learning in the other hand. We have recently shown in healthy subjects that the effect of cross-education is significantly augmented by provision of real-time manipulated bi-modal (visual and kinesthetic) sensory feedback, creating an illusory sensation of voluntary training with the other hand. Here we tested whether this training method may be applicable also in pathological conditions affecting one side of the body. We present here data showing behavioral gain accompanied by functional magnetic resonance imaging dynamics following training with this setup in the case of patient LA, a young man with significant unilateral upper-limb dysfunction stemming from hemi-Parkinson’s disease. Following two weeks of daily sessions in which he intensively trained the non-affected upper limb, he showed improvement in motor capacity of the affected limb, accompanied by enhanced activation in the pre-frontal corte...
Voluntary actions are shaped by desired goals and internal intentions. Multiple factors, includin... more Voluntary actions are shaped by desired goals and internal intentions. Multiple factors, including the planning of subsequent actions and the expectation of sensory outcome, were shown to modulate kinetics and neural activity patterns associated with similar goal-directed actions. Notably, in many real-world tasks, actions can also vary across the semantic meaning they convey, although little is known about how semantic meaning modulates associated neurobehavioral measures. Here, we examined how behavioral and functional magnetic resonance imaging measures are modulated when subjects execute similar actions (button presses) for two different semantic meanings—to answer “yes” or “no” to a binary question. Our findings reveal that, when subjects answer using their right hand, the two semantic meanings are differentiated based on voxel patterns in the frontoparietal cortex and lateral-occipital complex bilaterally. When using their left hand, similar regions were found, albeit only wit...
Summary The estimated accuracy of a classifier is a random quantity with variability. A common pr... more Summary The estimated accuracy of a classifier is a random quantity with variability. A common practice in supervised machine learning, is thus to test if the estimated accuracy is significantly better than chance level. This method of signal detection is particularly popular in neuroimaging and genetics. We provide evidence that using a classifier’s accuracy as a test statistic can be an underpowered strategy for finding differences between populations, compared to a bona fide statistical test. It is also computationally more demanding than a statistical test. Via simulation, we compare test statistics that are based on classification accuracy, to others based on multivariate test statistics. We find that the probability of detecting differences between two distributions is lower for accuracy-based statistics. We examine several candidate causes for the low power of accuracy-tests. These causes include: the discrete nature of the accuracy-test statistic, the type of signal accuracy...
Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain rema... more Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain remains elusive. We recorded the activity of 1019 neurons while twelve subjects performed self-initiated finger movement. We report progressive neuronal recruitment over $1500 ms before subjects report making the decision to move. We observed progressive increase or decrease in neuronal firing rate, particularly in the supplementary motor area (SMA), as the reported time of decision was approached. A population of 256 SMA neurons is sufficient to predict in single trials the impending decision to move with accuracy greater than 80% already 700 ms prior to subjects' awareness. Furthermore, we predict, with a precision of a few hundred ms, the actual time point of this voluntary decision to move. We implement a computational model whereby volition emerges once a change in internally generated firing rate of neuronal assemblies crosses a threshold. Neuron
The functional organization of human sensory cortex was studied by comparing intracranial EEG (iE... more The functional organization of human sensory cortex was studied by comparing intracranial EEG (iEEG) recordings of local field potentials in neurosurgical patients with functional magnetic resonance imaging (fMRI) obtained in healthy subjects. Using naturalistic movie stimuli, we found a tight correlation between these two measures throughout the human sensory cortex. Importantly, the correlation between the iEEG and fMRI signals was site-specific, exhibiting neuroanatomically specific coupling. In several cortical sites the iEEG activity was confined strictly to one object category. This site selectivity was not limited to faces but included other object categories such as houses and tools. The selectivity of the iEEG signals to images of different object categories was remarkably higher when compared with the selectivity of the corresponding fMRI signals. A plausible interpretation of the fMRI and iEEG results concerns cortical organization in which object categories are organized in a mosaic of narrowly tuned object-selective clusters.
Functional magnetic resonance imaging (fMRI) is an important tool for investigating human brain f... more Functional magnetic resonance imaging (fMRI) is an important tool for investigating human brain function, but the relationship between the hemodynamically based fMRI signals in the human brain and the underlying neuronal activity is unclear. We recorded single unit activity and local field potentials in auditory cortex of two neurosurgical patients and compared them with the fMRI signals of 11 healthy subjects during presentation of an identical movie segment. The predicted fMRI signals derived from single units and the measured fMRI signals from auditory cortex showed a highly significant correlation ( r = 0.75, P < 10 –47 ). Thus, fMRI signals can provide a reliable measure of the firing rate of human cortical neurons.
ABSTRACTAccurate control over everyday goal-directed actions is mediated by sensory-motor predict... more ABSTRACTAccurate control over everyday goal-directed actions is mediated by sensory-motor predictions of intended consequences and their comparison with actual outcomes. Such online comparisons of the expected and re-afferent, immediate, sensory feedback are conceptualized as internal forward models. Current predictive coding theories describing such models typically address the processing of immediate sensory-motor goals, yet voluntary actions are also oriented towards long-term conceptual goals and intentions, for which the sensory consequence is sometimes absent or cannot be fully predicted. Thus, the neural mechanisms underlying actions with distal conceptual goals is far from being clear. Specifically, it is still unknown whether sensory-motor circuits also encode information regarding the global meaning of the action, detached from the immediate, movement-related goal. Therefore, using fMRI and behavioral measures, we examined identical actions (either right or left-hand butto...
A fundamental computation underlying visual word recognition is the ability to transform a set of... more A fundamental computation underlying visual word recognition is the ability to transform a set of letters into a visual word form. Neuropsychological data suggest that letter position within a word may be independently affected by brain damage, resulting in a dissociable subtype of peripheral dyslexia. Here we used functional magnetic resonance imaging and supervised machine learning techniques to classify letter position based on activation patterns evoked during reading Hebrew words. Across the entire brain, activity patterns in the left intraparietal sulcus provided the best classification accuracy (80%) with respect to letter position. Importantly, the same set of voxels that showed highest classification performance of letter position using one letter-of-interest also showed highest classification performance using a different letter-of-interest. A functional connectivity analysis revealed that activity in these voxels co-varied with activity in the Visual Word Form Area, confirming cross-talk between these regions during covert reading. The results converge with reports of patients with acquired letter position dyslexia, who suffer from left occipito-parietal lesions. These findings provide direct and novel evidence for the role of left IPS within the reading network in processing relative letter positions.
The ultimate goal of neuroscience research is to understand the operating mechanism of the human ... more The ultimate goal of neuroscience research is to understand the operating mechanism of the human brain and to exploit this understanding to devise methods for repair when it malfunctions. A key feature of this operating mechanism is electrical activity of single brain cells and cell assemblies. For obvious ethical reasons, scientists rely mostly on animal research in the study of such signals. Research in humans is often limited to electrical signals that can be recorded at the scalp or to surrogates of electrical activity, namely magnetic source imaging and measures of regional blood flow and metabolism. Invasive brain recordings performed in patients during various clinical procedures provide a unique opportunity to record high-resolution signals in vivo from the human brain—data that are otherwise unavailable. Of special value are the rare opportunities to record in awake humans the activity of single brain cells and small cellular assemblies. These recordings provide a unique vi...
Observation is a powerful way to learn efficient actions from others. However, the role of observ... more Observation is a powerful way to learn efficient actions from others. However, the role of observers’ motor skill in assessing efficiency of others is unknown. Preschoolers are notoriously poor at performing multi-step actions like grasping the handle of a tool. Preschoolers (N = 22) and adults (N = 22) watched video-recorded actors perform efficient and inefficient tool use. Eye tracking showed that preschoolers and adults looked equally long at the videos, but adults looked longer than children at how actors grasped the tool. Deep learning analyses of participants’ eye gaze distinguished efficient from inefficient grasps for adults, but not for children. Moreover, only adults showed differential action-related pupil dilation and neural activity (suppressed oscillation power in the mu frequency) while observing efficient vs. inefficient grasps. Thus, children observe multi-step actions without “seeing” whether the initial step is efficient. Findings suggest that observer’s own moto...
Sensory perception is a product of interactions between the internal state of an organism and the... more Sensory perception is a product of interactions between the internal state of an organism and the physical attributes of a stimulus. It has been shown across the animal kingdom that perception and sensory-evoked physiological responses are modulated depending on whether or not the stimulus is the consequence of voluntary actions. These phenomena are often attributed to motor signals sent to relevant sensory regions that convey information about upcoming sensory consequences. However, the neurophysiological signature of action-locked modulations in sensory cortex, and their relationship with perception, is still unclear. In the current study, we recorded neurophysiological (using Magnetoencephalography) and behavioral responses from 16 healthy subjects performing an auditory detection task of faint tones. Tones were either generated by subjects’ voluntary button presses or occurred predictably following a visual cue. By introducing a constant temporal delay between button press/cue a...
Background: Parcellating the human brain into areas based on their neural connectivity is essenti... more Background: Parcellating the human brain into areas based on their neural connectivity is essential for understanding the functional organization of neural networks. New Method: We adapted density-peak clustering to identify functional neural networks in individuals without the need to select seed regions. We first assess the similarity between each pair of voxels based on their activation time-courses and then aggregate the voxels based on the assumption that cluster centers are dense (have high similarity with many voxels) and are at large distance from other high-density voxels. This data-driven approach allows intuitive selection of cluster centroids in individual subjects.Results: We applied our approach on resting-state data of individual subjects. Although similar networks across subjects were identified, there was large variability in the number of networks and their anatomical distribution between subjects. Manipulating the main free parameter of the model (density level th...
Problem solving is integral to goal-directed action—how to navigate an obstacle, open a latch, or... more Problem solving is integral to goal-directed action—how to navigate an obstacle, open a latch, or grasp the handle of a tool. Traditionally, researchers focus on when in development children succeed at solving particular problems, but this outcome-oriented approach does not inform on underlying mechanisms. The current study focuses on how children solve problems by examining the real-time interplay among planning components. We encouraged 3- to 5-year olds (N = 32) and adults (N = 22) to grasp a hammer to pound a peg when the hammer handle pointed in different directions. We simultaneously recorded participants’ movements, gaze, and neural activity using video microcoding, motion-tracking, head-mounted eye tracking, and EEG. When the handle pointed toward their non-dominant hand, participants had to use an adaptive underhand initial grip to implement the tool efficiently. Younger children (“non-adaptive child solvers”) used a habitual overhand grip that interfered with wielding the ...
Evoked neural activity in sensory regions and perception of sensory stimuli are modulated when th... more Evoked neural activity in sensory regions and perception of sensory stimuli are modulated when the stimuli are the consequence of voluntary movement, as opposed to an external source. It has been suggested that such modulations are due to motor commands that are sent to relevant sensory regions during voluntary movement. However, given the anatomical-functional laterality bias of the motor system, it is plausible that the pattern of such behavioral and neural modulations will also exhibit a similar bias, depending on the effector triggering the stimulus (e.g., right/left hand). Here, we examined this issue in the visual domain using behavioral and neural measures (fMRI). Healthy participants judged the relative brightness of identical visual stimuli that were either self-triggered (using right/left hand button presses), or triggered by the computer. Stimuli were presented either in the right or left visual field. Despite identical physical properties of the visual consequences, we f...
Sensory perception is a product of complex interactions between the internal state of an organism... more Sensory perception is a product of complex interactions between the internal state of an organism and the physical attributes of a stimulus. One factor that modulates the internal state of the perceiving agent is voluntary movement. It has been shown across the animal kingdom that perception and sensory-evoked physiological responses are modulated depending on whether or not the stimulus is the consequence of voluntary actions. These phenomena are often attributed to motor signals sent to relevant sensory regions (efference copies), that convey information about expected upcoming sensory consequences. However, to date, there is no direct evidence in humans for efferent signals underlying these motor-sensory interactions. In the current study we recorded neurophysiological (using Magnetoencephalography) and behavioral responses from 16 healthy subjects performing an auditory detection task of faint tones. Tones were either generated by subjects’ voluntary button presses or occurred p...
Undisclosed exploitation of flexibility in data acquisition and analysis blurs the important dist... more Undisclosed exploitation of flexibility in data acquisition and analysis blurs the important distinction between exploratory and hypothesis-driven findings and inflates false-positive rates1–4. Indeed, recent replication attempts have revealed low levels of replicability, pointing to high rates of false-positives in the literature5–10. A contemporary solution to this problem is pre-registration: commitment to aspects of methods and analysis before data acquisition11. This solution is valid only to the extent that the commitment stage is time-locked to precede data collection. To date, time-locking can only be guaranteed by introducing a third party such as peer reviewers at an early stage, making this solution less appealing for many12. Here we adapt a cryptographic method13 to encode information of study protocol within random aspects of the data acquisition process. This way, the structure of variability in the data time-locks the commitment stage with respect to data acquisition....
A long-standing controversy persists in psycholinguistic research regarding the way phonemes are ... more A long-standing controversy persists in psycholinguistic research regarding the way phonemes are coded in human auditory cortex during speech perception. The motor theory of speech perception [1, 2] describes phoneme perception in terms of the articulatory gestures that generate it. According to this theory, the objects of speech perception are the intended phonetic gestures of the speaker, such as, 'lip rounding', or 'jaw raising'. Alternatively, auditory theories argue that phonetic processing depends directly on properties of the auditory system [3-6]. According to this view, listeners identify spectro-temporal patterns in phoneme waveforms and match them with stored abstract acoustic representations. Here we recorded spiking activity in the auditory cortex (superior temporal gyrus; STG) from six neurosurgical patients who performed a listening task with phoneme stimuli. Using a Naive-Bayes model, we show that single-cell responses to phonemes are governed by arti...
Cross education is a phenomenon in which motor training of one hand induces motor learning in the... more Cross education is a phenomenon in which motor training of one hand induces motor learning in the other hand. We have recently shown in healthy subjects that the effect of cross-education is significantly augmented by provision of real-time manipulated bi-modal (visual and kinesthetic) sensory feedback, creating an illusory sensation of voluntary training with the other hand. Here we tested whether this training method may be applicable also in pathological conditions affecting one side of the body. We present here data showing behavioral gain accompanied by functional magnetic resonance imaging dynamics following training with this setup in the case of patient LA, a young man with significant unilateral upper-limb dysfunction stemming from hemi-Parkinson’s disease. Following two weeks of daily sessions in which he intensively trained the non-affected upper limb, he showed improvement in motor capacity of the affected limb, accompanied by enhanced activation in the pre-frontal corte...
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Papers by Roy Mukamel