mirror neurons
Major conscious and unconcoscious processes in the brain: part 2
3 years ago
This is the second in the series about major conscious and unconscious processes in the brain. The first part can be found here. This post tries to document a few more processes / functions in the brain and their neural substrates.
To recap, the major processes in brain (along with sample broad brain regions (grossly simplified) associated) are :
- Sensory (occipital)
- Motor (parietal)
- Learning (hippocampal formation in medial temporal)
- Affective (amygdalar and limbic system)
- Evaluative/decisional (frontal)
These are supplanted by the following processes and mechanisms.
6. Modeling system/ Hemispheric laterlaization: Another system/ mechanism that the brain may find useful and develop is the ability to model the world and model the self and others . This presents the following problem. The world consist of objects that follow deterministic casual laws thus lending order to it as well as seeming agents that act by their own volition and thus leading to chaos. The modeling required to model causal, deterministic world may suffer from different design constraints than that required to model a chaotic, agentic world. The brain, I propose, solves this, by having two hemispheres, one specialized for interacting with the world based on the model of the world as orderly, deterministic , statistically regular world; while the other hemisphere specialized for interacting with the world assuming it as a chaotic , agentic, probabilistically undetermined world. The two hemispheres co-operate with each other and respond using the advantages offered by the different strategies of both hemispheres. To recap, left hemisphere is specialized for causal patterns, sequences, analysis and interpretation, classifying objects (categorical spatial represnetation) , verbal abilities depending on analysis of sequences, uses prototypes (statistical mean) and uses Match strategy of responding in a statistical pattern, Music lyrics, and works on local stimuli (components) and parses high spatial frequency and values relativity. The right brain on the other hand is specialized for random/unperdicatble associations, scenes, synthesis and documentation, acting on objects (co-ordinate spatial representation), Spatial abilities depending on synthesis of objects making the scene, uses exemplars (actual events) and uses Maximizing strategy of responding as per probability at the moment, Music melody, and works on global stimuli (wholes) and parses low spatial frequency and values absoluteness. To summarize, left hemisphere is best suited to model temporal dimensions in an analytical and causal manner, while right hemisphere is best suited to model the spatial dimensions in an holistic and agentic manner. This modeling, it needs to be emphasized, need not be conscious, but could be entirely unconscious and have unconscious effects.
7. Communciation system/ perisylvian area/ mirror neurons?: Once an organism has discovered/ realized unconsciously that there are other agents/ con specifics in the world , a brain system that communicates (on an unconscious level) with the others can evolve. A system can evolve that signals the emotional/internal state to others and can also sense the emotional/ internal state of others. This can be used as an aid to predict how the agent will act – as the agent is similar to oneself, one can predict how the other will act based on its internal state by simulating how one would act himself , given the same internal state. Sensing the internal state of others is one side of the coin, the other part is signalling your own internal state honestly to others to aid communication and enhance fitness by group selection. Remember that none of these consdireations need to be conscious. Even unicellular bacteria that live in colonies/ cultures evolve communication systems based on sensing and emitting chemicals etc. In humans the mirror neuron system activated by others actions, the emotional expression and contagious unconscious empathy may all be the unconscious communciation system driven by non-verbal communication based on mirroring and mirror neurons.
8. Attention system : The last (for now!) system to evolve might be related to directing attention or selectivity processing relevant inputs, actions, affects, evaluations, associations, models and communciations while suppressing irrelevant ones. At any time , one is bombarded by many (all unconscious ) different stimuli, urges, activated associations, body states, values, models and communications from con specifics- these may or may not be relevant to current situation/ goal. Not everything can be processed equally as the brain has limited computational resources. This leads to a mechanism/system to gauze relevance and thus bias the other systems by selectively processing some aspects in detail while ignoring others. This attentional/orientational mechanism may be covert, may be unconscious and might be triggered by external events/ voluntarily directed; important thing to realize is that attention seems to integrate the output and inputs of other brain systems/ mechanisms by selectivity highlighting a few features that are relevant and coherent. This also ultimately leads to opening the doors to the next higher level of processing by brain – the conscious processing, which is computationally more demanding and thus requires attention to restrict the inputs that it can process. The attentional system opens the floodgates of heaven (consciousness) for the humans/ animals that are able to use it appropriately.
The spotlight of attention once created leads to conscious experiences of perception, agency, memory, feelings, thoughts, self-awareness, inner speech and identity. That of course is material for another post!
Mirror Neurons in news again!
5 years ago
A recent research by Rizzolatti et al, has once again come up with exciting new evidence that may be construed as evidence for the linkage between mirror neuron system in humans and the evolution of language.
This study has been able to establish that the same pre-motor cortical areas are engaged when one is performing an action like kicking as well as when one is just listening to the word ‘kicking’. This effect is found only for literal action words and not the same word ‘kicking’ when used metaphorically as in “kicking off”.
It is just a little stretch of imagination from here to making case for the link between language and mirror neurons.
Specifically, it is plausible, that when the mirror neurons gave an ability to humans to represent an action (irrespective of whether it was performed by self or by others) in the brain, then this capacity to abstract an action from its performer may have been the beginning of the symbolic representation capacity whereby a symbol that is remote from the original object can represent that object. This symbolic capacity to represent activation in brain region with both an action performed by self as well as others may have later lead to the first linguistic semantic words that would have been associated with such representations. The data that the action words activate the same pre motor regions as actual actions makes this hypothesis more attractive.
I know that mirror neurons are not exactly that popular in blogosphere, but still some food for thought.
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Mirror, mirror on the wall, who’s the most blogged of them all!
5 years ago
Mirror Neurons seems to be the answer as per the Neurotopia’s post encouraging all bloggers to come together and raise a toast for the mirror neurons (though Neurotopia’s article is more of a critical tone lamenting the fact that mirror neurons get so much attention in the blogosphere) !
Small Grey Matters too has taken the gauntlet and responded to some of the concerns raised by Mixing Memory regarding Mirror neuron research and attention. The defense is mostly on procedural concerns and does not tackle the defense of the more ‘speculative’ research in the filed for eg. related to language evolution.
Frontal Cortex speculates on the importance of mirror neurons in areas as diverse as sports, autism and movies.
It is interesting to observe that the debate on how much focus mirror neurons are getting has come full circle. My first, and I believe the most authoritative , encounter with the reason for focusing on Mirror Neurons was due to this Edge lecture by V S Ramachandran in which he laments the fact that mirror neurons is one of the most underrated discovery of our times (it was 1995 then). This Edge discussion is a must read for anyone interested in the topic.
I will discuss the mirror neurons in some detail in a later post, but what I encourage is that some edition of an online carnival like Encephalon or Synapse be focused on Mirror Neuron related contributions, so that one can clear the aura surrounding the matter for once and for all.
Before I part a few observations.
Neurotopia has a figure of a Brain Scan that shows that pars opercularis is activated differently in controls and autistic people indulging in imitation behavior. It is instructive to note that pars opercularis (along with ACC) has elsewhere been implicated in executive tasks like set-shifting tasks . This set shifting may be involved in going from concrete to abstract sets for a problem or from human to non-human set shift -this set-shifting would occur in normals and would not occur in autistics as autistics treat humans and non-humans alike.
Also, it is instructive to note, that by their very nature, mirror neurons have a strong role to play in empathy and social evolution as well as the observational learning that Albert Bandura proposed.
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