Simulating mirror-neuron responses using a neural model for visual action recognition

The finding of mirror neurons (MNs) has provided a biological substrate to a new concept of cognition, relating data on actions and perceptions not only to integrate perception in action planning and execution but also as a neural mechanism supporting a wide range of cognitive functions. Here we first summarize data on MN localization and role in primates, then we report findings in normal human subjects: functional magnetic resonance imaging and neurophysiological studies sustain that MNs have a role in motor learning and recognizing actions and intentions of others, and they also support an embodied view of language, empathy, and memory. Then, we detail the results of literature searching on MNs and embodied cognition in Parkinson's disease (PD), frontotemporal dementia (FTD)/amyotrophic lateral sclerosis (ALS), and in mild cognitive impairment (MCI)/Alzheimer's disease (AD). In PD the network of MN could be altered, but its hyperactivation might support motor and cognitive performances at least in early stages. In the ALS/FTD continuum, preliminary evidence points out to an involvement of the MN network, which could explain language and inter-subjectivity deficits shown in patients affected by these clinical entities. In the MCI/AD spectrum, a few recent studies suggest a possible progressive involvement from posterior to anterior areas of the MN network, with the brain putting in place compensatory mechanisms in early stages. Reinterpreting neurodegenerative diseases at the light of the new views about brain organization stemming from the discovery of MN could help to better comprehend clinical manifestations and open new pathways to rehabilitation.

Ever since the discovery of mirror neurons in the ventral premotor cortex (area F5) of the macaque brain, in the late 1980s, by Rizzolatti and his University of Parma colleagues, the question was put forward whether the same type of neurons could be found in the human brain. Could it be possible that these same neurons that activate not only when the monkey reaches for or takes a bite out of some sort of food -like a nut or a raisin- but also when someone picks it up to hand it to the monkey, be found in our brains? This essay does not have the scope to consider all concepts of empathy nor to include all relevant studies on mirror neurons concerning its relation to empathy. That being so, I shall take the following path: 1) introduce mirror neurons, what they are, where they are and their implications; 2) consider some aspects of empathy from different areas of research and present Edith Stein and Theodor Lipps's ideas; 3) relate the philosophers' ideas with the discussion put forward by Iacoboni, Gallese, Rizzolatti and Ramachandran concerning mirror neurons and empathy.

In recent years, human motion recognition in computer vision has become a hot research direction in this field. Based on 2D human motion recognition technology, real-time extraction of motion features from 2D planes is used to recognize human movements. This method can only learn the position contour and color information of the image. It cannot directly reflect the motion situation, which results in low recognition accuracy and efficiency. In response to this issue, this study proposes a combination method of motion recognition and 3D pose estimation to recognize and classify basketball movements. First, the 2D skeleton model is obtained by extracting the feature information in the video action, which is converted into a 3D model, and the model is replaced by the time-space convolutional network to establish a human action recognition model. The experiment showed that when the number of iterations reached 6, the accuracy of the spatio-temporal graph convolutional network algorithm model reached 92%. Comparing the accuracy rates of different algorithm models, the average accuracy rates of convolutional neural network, long short memory network, graph convolution, long short model of action recognition and graph convolution model of action recognition were 61.6%, 65.4%, 72.5%, 76.8% and 90.3% respectively. The results show that the proposed 3D recognition algorithm can accurately recognize different basketball movements. This study can provide reference for basketball coaches and athletes in basketball training.

To probe the presence of mirror neurons in the human brain, cross-modal fMRI adaptation has been suggested as a suitable technique. The rationale behind this suggestion is that this technique allows making more accurate inferences about neural response properties underlying fMRI voxel activations, beyond merely showing shared voxels that are active during both action observation and execution. However, the validity of using cross-modal fMRI adaptation to demonstrate the presence of mirror neurons in parietal and premotor brain regions has been questioned given the inconsistent and weak results obtained in human studies. A better understanding of cross-modal fMRI adaptation effects in the macaque brain is required as the rationale for using this approach is based on several assumptions related to macaque mirror neuron response properties that still need validation. Here, we conducted a cross-modal fMRI adaptation study in macaque monkeys, using the same action execution and action observation tasks that successfully yielded mirror neuron region cross-modal action decoding in a previous monkey MVPA study. We scanned two male rhesus monkeys while they first executed a sequence of either reach-and-grasp or reach-and-touch hand actions and then observed a video of a human actor performing these motor acts. Both whole-brain and region-of-interest analyses failed to demonstrate cross-modal fMRI adaptation effects in parietal and premotor mirror neuron regions. Our results, in line with previous findings in non-human primates, show that cross-modal motor-to-visual fMRI adaptation is not easily detected in monkey brain regions known to house mirror neurons. Thus, our results advocate caution in using cross-modal fMRI adaptation as a method to infer whether mirror neurons can be found in the primate brain.

Single-Neuron Responses in Humans during Execution and Observation of Actions

In this chapter, I critically assess the thesis that the discovery of mirror neurons (MNs) provides empirical support for the simulation theory (ST) of social cognition. This thesis can be analyzed into two claims: (i) MNs are involved in understanding others’ intentions or emotions. (ii) The way in which they do so supports a simulationist viewpoint. I will be giving qualified support to both (i) and (ii). Starting with (i), I will present theoretical and empirical points in support of the view that MNs play a substantial role and are perhaps necessary although not sufficient for understanding at least some intentions or emotions.

Autism Spectrum Disorder: Seeing Is Not Understanding

Nonvisual Motor Training Influences Biological Motion Perception

  When the music moves you, you dance. The bodily movement that develops in response to music is what is here considered “dance.” Philosophers have long understood music as possessing the power to move us. This paper employs Heinrich Wolfflin’s theory of “sympathetic modeling”—a theory recently validated by neuroscientists’ discovery of mirror neurons in humans—and Antonio Damasio’s neurobiological model of emotion to establish the mediating links between music and the bodily movements made in response. The first “motion” elicited by hearing music is, as Wolfflin suggested, an unconscious “sympathetic modeling,” an internal vocalization of what is heard; this activity involves muscular expansions and contractions. Signals of muscle movement are relayed to the brain by receptor cells imbedded in the muscles. In complex responses, the brain receives patterns of movement from throughout the entire body. When these whole-body kinesthetic sensations are made conscious as perceptions of a unified self, they enter awareness as subjectively felt emotion: the felt response to music. Such patterns of muscular stretching can be abstracted from the sort of external experience that produces emotion in ordinary life experience and reproduced at will. Thus, a dancer, by deliberately reproducing a pattern of muscle stretching, can re-create a chosen specific emotion. This activity constitutes “expressing” emotion in bodily movement. Performed in response to the emotion elicited by music, it is the expressive gesture of dance. One viewing the dance “understands” the emotion expressed by, once again, employing sympathetic modeling to reconstruct the internal pattern of movement associated with that emotion. In popular, social, dancing, dancers model one another’s movements and, together, model the muscle tension patterns of particular rhythms and melodic lines; this situation is easily accounted for by what is now known about mirror neurons. Neuroscience thus explains what happens when the music moves you.   Key words: Emotion, movement, music, dance, aesthetics, neuroscience.

Functional imaging of face and hand imitation: towards a motor theory of empathy

When we see or hear another person execute an action, we tend to automatically simulate that action. Evidence for this has been found at the neural level, specifically in parietal and premotor brain regions referred to collectively as the mirror neuron system (MNS), and the behavioural level, through an observer's tendency to mimic observed movements. This simulation process may play a key role in emotional understanding. It is currently unclear the extent to which the MNS is driven by bottom-up automatic recruitment of movement simulation, or by top-down (task driven) mechanisms. The present dissertation examines the role of the MNS in the bottom-up and top-down processing of action in the auditory and visual modalities, in response to emotional and neutral movements performed by humans. Study 1 used EEG to demonstrate that the MNS is affected by bottom-up manipulations of modality, and shows that the MNS is activated to a greater extent towards multi-modal versus unimodal sensory input. Study 2 employed an EEG paradigm utilizing a top-down emotion judgment manipulation. It was found that the left STG, part of the extended MNS, is affected by top-down manipulations of emotionality, but there were no areas in classical MNS that met the statistical threshold to be affected by top-down forces. Study 3 employed an fMRi paradigm combining bottom-up and top-down manipulations. It was found that the classical MNS was strongly affected by bottom-up differences in emotionality and modality, and minimally affected by the top-down manipulation. Together, the three studies presented in this dissertation support the premise that the classical mirror neuron system is primarily automatic. More research is needed to determine whether top-down manipulations can uniquely engage the MNS.

Human action recognition is a fundamental research problem in computer vision. The accuracy of human action recognition has important applications. In this book chapter, the authors use a YOLOv7-based model for human action recognition. To evaluate the performance of the model, the action recognition results of YOLOv7 were compared with those using CNN+LSTM, YOLOv5, and YOLOv4. Furthermore, a small human action dataset suitable for YOLO model training is designed. This data set is composed of images extracted from KTH, Weizmann, MSR data sets. In this book chapter, the authors make use of this data set to verify the experimental results. The final experimental results show that using the YOLOv7 model for human action recognition is very convenient and effective, compared with the previous YOLO model.

Imitation: is cognitive neuroscience solving the correspondence problem?

Among Leibniz’s contributions to the philosophy of mind, two topics bear relevance to contemporary discussions in cognitive sciences: the mind-body problem, and the universal language. Leibniz’s deterministic view rejects inter-substance causality between mental and bodily states, as well as between mental or bodily states of different individuals. In addition, Leibniz believed in the need to enhance communication through a universal language based on symbolic representations. Here I reconsider Leibniz’s ideas in the light of experimental evidence coming from mirror neurons. These recently discovered brain cells, responsive to both action execution and observation, are thought to enable the interpretation of the action performer’s intentions through their representation in the observer’s own brain, thus storing embodied shared representations. I propose that mirror neurons’ cross-modal responsiveness, whereby seeing an action being performed by somebody else triggers similar neural response to that of performing that action oneself, can be interpreted as an instantiation of intersubstance causality. I suggest that mirror neurons’ properties speak not only to the non-dualistic equation, supported by brain science in general, whereby in a given individual, mental states arise from bodily states but also introduce the possibility that bodily states may arise from someone else’s bodily states. In addition, I propose that this automatic embodied flow of information between individuals (from performer to observer) bears relevance to Leibniz’s intuitions on symbols. Specifically, I suggest that the shared representations stored in mirror neurons, thought to enable the interpretation of the action performer’s intentions, may be seen as a biological instantiation of Leibniz’s planned, but never realized, universal characteristic.

Since their discovery, mirror neurons--units in the macaque brain that discharge both during action observation and execution--have attracted considerable interest. Whether mirror neurons are an innate endowment or acquire their sensorimotor matching properties ontogenetically has been the subject of intense debate. It is widely believed that these units are an innate trait; that we are born with a set of mature mirror neurons because their matching properties conveyed upon our ancestors an evolutionary advantage. However, an alternative view is that mirror neurons acquire their matching properties during ontogeny, through correlated experience of observing and performing actions. The present article re-examines frequently overlooked neurophysiological reports of 'tool-use' and 'audiovisual' mirror neurons within the context of this debate. It is argued that these findings represent compelling evidence that mirror neurons are a product of sensorimotor experience, and not an innate endowment.