motor acts that were first executed and then observed. they concluded that there was a significant asymmetry between the two processes that indicated that mirror neurons do not exist in humans. they stated "crucially, we found no signs of adaptation for motor acts that were first executed and then observed. failure to find cross-modal adaptation for executed and observed motor acts is not compatible with the core assumption of mirror neuron theory, which holds that action recognition and understanding are based on motor simulation." however, in the same year, kilner et al. showed that if goal directed actions are used as stimuli, both ipl and premotor regions show the repetition suppression between observation and execution that is predicted by mirror neurons. in 2009, greg hickok published an extensive argument against the claim that mirror neurons are involved in action-understanding: "eight problems for the mirror neuron theory of action understanding in monkeys and humans." he concluded that "the early hypothesis that these cells underlie action understanding is likewise an interesting and prima facie reasonable idea. however, despite its widespread acceptance, the proposal has never been adequately tested in monkeys, and in humans there is strong empirical evidence, in the form of physiological and neuropsychological (double-) dissociations, against the claim." the mirror neurons can be activated only after the goal of the observed action has been attributed by other brain structures. vladimir kosonogov sees another contradiction. the proponents of mirror neuron theory of action understanding postulate that the mirror neurons code the goals of others' actions because they are activated if the observed action is goal-directed. however, the mirror neurons are activated only when the observed action is goal-directed (object-directed action or a communicative gesture, which certainly has a goal too). how do they "know" that the definite action is goal-directed? at what stage of their activation do they detect a goal of the movement or its absence? in his opinion, the mirror neuron system can be activated only after the goal of the observed action is attributed by some other brain structures. neurophilosophers such as patricia churchland have expressed both scientific and philosophical objections to the theory that mirror neurons are responsible for understanding the intentions of others. in chapter 5 of her 2011 book, braintrust, churchland points out that the claim that mirror neurons are involved in understanding intentions (through simulating observed actions) is based on assumptions that are clouded by unresolved philosophical issues. she makes the argument that intentions are understood (coded) at a more complex level of neural activity than that of individual neurons. churchland states that "a neuron, though computationally complex, is just a neuron. it is not an intelligent homunculus. if a neural network represents something complex, such as an intention , it must have the right input and be in the right place in the neural circuitry to do that." recently, cecilia heyes (professor of experimental psychology, oxford) has advanced the theory that mirror neurons are the byproduct of associative learning as opposed to evolutionary adaptation. she argues that mirror neurons in humans are the product of social interaction and not an evolutionary adaptation for action-understanding. in particular, heyes rejects the theory advanced by v.s. ramachandran that mirror neurons have been "the driving force behind the great leap forward in human evolution." development human infant data using eye-tracking measures suggest that the mirror neuron system develops before 12 months of age and that this system may help human infants understand other people's actions. a critical question concerns how mirror neurons acquire mirror properties. two closely related models postulate that mirror neurons are trained through hebbian or associative learning (see associative sequence learning). however, if premotor neurons need to be trained by action in order to acquire mirror properties, it is unclear how newborn babies are able to mimic the facial gestures of another person (imitation of unseen actions), as suggested by the work of meltzoff and moore. one possibility is that the sight of tongue protrusion recruits an innate releasing mechanism in neonates. careful analysis suggests that 'imitation' of this single gesture may account for almost all reports of facial mimicry by new-born infants. possible functions understanding intentions many studies link mirror neurons to understanding goals and intentions. fogassi et al. (2005) recorded the activity of 41 mirror neurons in the inferior parietal lobe (ipl) of two rhesus macaques. the ipl has long been recognized as an association cortex that integrates sensory information. the monkeys watched an experimenter either grasp an apple and bring it to his mouth or grasp an object and place it in a cup. in total, 15 mirror neurons fired vigorously when the monkey observed the "grasp-to-eat" motion, but registered no activity while exposed to the "grasp-to-place" condition. for 4 other mirror neurons, the reverse held true: they activated in response to the experimenter eventually placing the apple in the cup but not to eating it. only the type of action, and not the kinematic force with which models manipulated objects, determined neuron activity. it was also significant that neurons fired before the monkey observed the human model starting the second motor act (bringing the object to the mouth or placing it in a cup). therefore, ipl neurons "code the same act (grasping) in a different way according to the final goal of the action in which the act is embedded." they may furnish a neural basis for predicting another individual's subsequent actions and inferring intention. learning facilitation another possible function of mirror neurons would be facilitation of learning. the mirror neurons code the concrete representation of the action, i.e., the representation that would be activated if the observer acted. this would allow us to simulate (to repeat internally) the observed action implicitly (in the brain) to collect our own motor programs of observed actions and to get ready to reproduce the actions later. it is implicit training. due to this, the observer will produce the action explicitly (in his/her behavior) with agility and finesse. this happens due to associative learning processes. the more frequently a synaptic connection is activated, the stronger it becomes. empathy stephanie preston and frans de waal, jean decety, and vittorio gallese and christian keysers have independently argued that the mirror neuron system is involved in empathy. a large number of experiments using fmri, electroencephalography (eeg) and magnetoencephalography (meg) have shown that certain brain regions (in particular the anterior insula, anterior cingulate cortex, and inferior frontal cortex) are active when people experience an emotion (disgust, happiness, pain, etc.) and when they see another person experiencing an emotion. david freedberg and vittorio gallese have also put forward the idea that this function of the mirror neuron system is crucial for aesthetic experiences. nevertheless, an experiment aimed at investigating the activity of mirror neurons in empathy conducted by soukayna bekkali and peter enticott at the university of deakin yielded a different result. after analyzing the report's data, they came up with two conclusions about motor empathy and emotional empathy. first, there is no relationship between motor empathy and the activity of mirror neurons. second, there is only weak evidence of these neurons' activity in the inferior frontal gyrus (ifg), and no evidence of emotional empathy associated with mirror neurons in key brain regions (inferior parietal lobule: ipl). in other words, there has not been an exact conclusion about the role of mirror neurons in empathy and if they are essential for human empathy. however, these brain regions are not quite the same as the ones which mirror hand actions, and mirror neurons for emotional states or empathy have not yet been described in monkeys. in a recent study, done in 2022, sixteen hand actions were given for each assignment. the assignment pictured both an activity word phase and the intended word phase. the hand actions were selected in "trails" each introduced twice. one of the times was with a matching phase and the other time was with a misleading word phase. the action words were depicted in two to three words with each beginning with the word "to". for instance, "to point" (action) or "to spin" (intention). participants were expected to answer whether the correct word phase matched the corresponding action or intention word. the word phase had to be answered within 3000 ms, with a 1000 ms black screen between each image. the black screens purpose was for an adequate amount of time in between responses. participants pressed on the keyboard "x" or "m" to indicate their responses in a yes/no format. christian keysers at the social brain lab and colleagues have shown that people who are more empathic according to self-report questionnaires have stronger activations both in the mirror system for hand actions and the mirror system for emotions, providing more direct support for the idea that the mirror system is linked to empathy. some researchers observed that the human mirror system does not passively respond to the observation of actions but is influenced by the mindset of the observer. researchers observed the link of the mirror neurons during empathetic engagement in patient care. studies in rats have shown that the anterior cingulate cortex contains mirror neurons for pain, i.e. neurons responding both during the first-hand experience of pain and while witnessing the pain of others, and inhibition of this region leads to reduced emotional contagion in rats and mice, and reduced aversion towards harming others. this provides causal evidence for a link between pain mirror neurons, and emotional contagion and prosocial behavior, two phenomena associated with empathy, in rodents. that brain activity in the homologous brain region is associated with individual variability in empathy in humans suggests that a similar mechanism may be at play across mammals. human self awareness v. s. ramachandran has speculated that mirror neurons may provide the neurological basis of human self-awareness. in an essay written for the edge foundation in 2009 ramachandran gave the following explanation of his theory: "... i also speculated that these neurons can not only help simulate other people's behavior but can be turned 'inward'—as it were—to create second-order representations or meta-representations of your own earlier brain processes. this could be the neural basis of introspection, and of the reciprocity of self awareness and other awareness. there is obviously a chicken-or-egg question here as to which evolved first, but... the main point is that the two co-evolved, mutually enriching each other to create the mature representation of self that characterizes modern humans." language in humans, functional mri studies have reported finding areas homologous to the monkey mirror neuron system in the inferior frontal cortex, close to broca's area, one of the hypothesized language regions of the brain. this has led to suggestions that human language evolved from a gesture performance/understanding system implemented in mirror neurons. mirror neurons have been said to have the potential to provide a mechanism for action-understanding, imitation-learning, and the simulation of other people's behaviour. this hypothesis is supported by some cytoarchitectonic homologies between monkey premotor area f5 and human broca's area. rates of vocabulary expansion link to the ability of children to vocally mirror non-words and so to acquire the new word pronunciations. such speech repetition occurs automatically, fast and separately in the brain to speech perception. moreover, such vocal imitation can occur without comprehension such as in speech shadowing and echolalia. further evidence for this link comes from a recent study in which the brain activity of two participants was measured using fmri while they were gesturing words to each other using hand gestures with a game of charades – a modality that some have suggested might represent the evolutionary precursor of human language. analysis of the data using granger causality revealed that the mirror-neuron system of the observer indeed reflects the pattern of activity in the motor system of the sender, supporting the idea that the motor concept associated with the words is indeed transmitted from one brain to another using the mirror system the mirror neuron system seems to be inherently inadequate to play any role in syntax, given that this definitory property of human languages which is implemented in hierarchical recursive structure is flattened into linear sequences of phonemes making the recursive structure not accessible to sensory detection automatic imitation the term is commonly used to refer to cases in which an individual, having observed a body