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Sandeep Gautam is a psychology and cognitive neuroscience enthusiast, whose basic grounding is in computer science.
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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)
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!
Today I plan to touch upon the topic of consciousness (from which many bloggers shy) and more broadly try to delineate what I believe are the important different conscious and unconscious processes in the brain. I will be heavily using my evolutionary stages model for this.
To clarify myself at the very start , I do not believe in a purely reactive nature of organisms; I believe that apart from reacting to stimuli/world; they also act , on their own, and are thus agents. To elaborate, I believe that neuronal groups and circuits may fire on their own and thus lead to behavior/ action. I do not claim that this firing is under voluntary/ volitional control- it may be random- the important point to note is that there is spontaneous motion.
- Sensory system: So to start with I propose that the first function/process the brain needs to develop is to sense its surroundings. This is to avoid predators/ harm in general. this sensory function of brain/sense organs may be unconscious and need not become conscious- as long as an animal can sense danger, even though it may not be aware of the danger, it can take appropriate action – a simple ‘action’ being changing its color to merge with background.
- Motor system:The second function/ process that the brain needs to develop is to have a system that enables motion/movement. This is primarily to explore its environment for food /nutrients. Preys are not going to walk in to your mouth; you have to move around and locate them. Again , this movement need not be volitional/conscious – as long as the animal moves randomly and sporadically to explore new environments, it can ‘see’ new things and eat a few. Again this ‘seeing’ may be as simple as sensing the chemical gradient in a new environmental.
- Learning system: The third function/process that the brain needs to develop is to have a system that enables learning. It is not enough to sense the environmental here-and-now. One needs to learn the contingencies in the world and remember that both in space and time. I am inclined to believe that this is primarily pavlovaion conditioning and associative learning, though I don’t rule out operant learning. Again this learning need not be conscious- one need not explicitly refer to a memory to utilize it- unconscious learning and memory of events can suffice and can drive interactions. I also believe that need for this function is primarily driven by the fact that one interacts with similar environments/con specifics/ predators/ preys and it helps to remember which environmental conditions/operant actions lead to what outcomes. This learning could be as simple as stimuli A predict stimuli B and/or that action C predicts reward D .
- Affective/ Action tendencies system .The fourth function I propose that the brain needs to develop is a system to control its motor system/ behavior by making it more in sync with its internal state. This I propose is done by a group of neurons monitoring the activity of other neurons/visceral organs and thus becoming aware (in a non-conscious sense)of the global state of the organism and of the probability that a particular neuronal group will fire in future and by thus becoming aware of the global state of the organism , by their outputs they may be able to enable one group to fire while inhibiting other groups from firing. To clarify by way of example, some neuronal groups may be responsible for movement. Another neuronal group may be receiving inputs from these as well as say input from gut that says that no movement has happened for a time and that the organism has also not eaten for a time and thus is in a ‘hungry’ state. This may prompt these neurons to fire in such a way that they send excitatory outputs to the movement related neurons and thus biasing them towards firing and thus increasing the probability that a motion will take place and perhaps the organism by indulging in exploratory behavior may be able to satisfy hunger. Of course they will inhibit other neuronal groups from firing and will themselves stop firing when appropriate motion takes place/ a prey is eaten. Again nothing of this has to be conscious- the state of the organism (like hunger) can be discerned unconsciously and the action-tendencies biasing foraging behavior also activated unconsciously- as long as the organism prefers certain behaviors over others depending on its internal state , everything works perfectly. I propose that (unconscious) affective (emotional) state and systems have emerged to fulfill exactly this need of being able to differentially activate different action-tendencies suited to the needs of the organism. I also stick my neck out and claim that the activation of a particular emotion/affective system biases our sensing also. If the organism is hungry, the food tastes (is unconsciously more vivid) better and vice versa. thus affects not only are action-tendencies , but are also, to an extent, sensing-tendencies.
- Decisional/evaluative system: the last function (for now- remember I adhere to eight stage theories- and we have just seen five brain processes in increasing hierarchy) that the brain needs to have is a system to decide / evaluate. Learning lets us predict our world as well as the consequences of our actions. Affective systems provide us some control over our behavior and over our environment- but are automatically activated by the state we are in. Something needs to make these come together such that the competition between actions triggered due to the state we are in (affective action-tendencies) and the actions that may be beneficial given the learning associated with the current stimuli/ state of the world are resolved satisfactorily. One has to balance the action and reaction ratio and the subjective versus objective interpretation/ sensation of environment. The decisional/evaluative system , I propose, does this by associating values with different external event outcomes and different internal state outcomes and by resolving the trade off between the two. This again need not be conscious- given a stimuli predicting a predator in vicinity, and the internal state of the organism as hungry, the organism may have attached more value to ‘avoid being eaten’ than to ‘finding prey’ and thus may not move, but camouflage. On the other hand , if the organisms value system is such that it prefers a hero’s death on battlefield , rather than starvation, it may move (in search of food) – again this could exist in the simplest of unicellular organisms.
Of course all of these brain processes could (and in humans indeed do) have their conscious counterparts like Perception, Volition,episodic Memory, Feelings and Deliberation/thought. That is a different story for a new blog post!
And of course one can also conceive the above in pure reductionist form as a chain below:
sense–>recognize & learn–>evaluate options and decide–>emote and activate action tendencies->execute and move.
and then one can also say that movement leads to new sensation and the above is not a chain , but a part of cycle; all that is valid, but I would sincerely request my readers to consider the possibility of spontaneous and self-driven behavior as separate from reactive motor behavior.
I am starting an experimental new feature today called Best of Tweets. Many other bloggers do weekly link fests and I had somehow refrained form doing one myself. Using twitter, I am able to share many more links that I find interesting instantly , but I know that many of you are not on twitter; so perhaps a weekly best of tweets post that aggregates the best of my tweets for the past week may be useful to the mouse trap blog readers. Do tell me via comments whether you find this useful.Remember that this is a manually compiled by me list of best of tweets and is not auto generated, so I am putting some additional efforts here.
Without further ado, here is the best of tweets for week ending 20-05-09:
- RT @Wildcat2030: In defense of distraction–it’s not a bug, it’s a feature of a new techno-nomadic culture. (via @LynJ) http://bit.ly/sYwcl
- Debates on free will / perchance or predetermined / now silence reigns, courtesy free won’t #haiku #scaiku (ver 2) #philosophy (for the background of this tweet go read the 4 way convesration I had on twitter on free-will yesterday)
- I believe in a libertarian free will concept and thus found the recent Nature article based on randomness in… re: http://ff.im/1Zo2A
- a 5 part npr series on brain/spirituality RT @kdwashburn: Great interactive graphic on the brain and spirituality: http://tr.im/lI7F
- RT @kdwashburn: “reading someone else’s attention involves the same brain circuits that control one’s own attention” http://tr.im/lIoZ
- Yes! 50 Scientifically Proven Ways to Be Persuasive http://ff.im/-30dO4
- Narrative gravity /go spin a yarn/define yourself .http://bit.ly/14h8sX via @LeadonYoung: http://bit.ly/aTo0e & http://bit.ly/13Qqto #scaiku
- Creativity ,esp. musical / ‘a seething cauldron of ideas’/ Jonah peeps in your brain : http://bit.ly/leSwf : #scaiku #haiku #science
- Triune Ethics: On Neurobiology and Multiple Moralities « Neuroanthropology http://ff.im/-2Vui8
- Your will is free / not everything is a reaction/ behold the fly acting random! http://bit.ly/hzBGh #scaiku #science #haiku #cognitive
- Depression and Mania / which one comes first / a serpent eating its tail ? : http://bit.ly/18ycU0 #scaiku #science #haiku
- psychosis or a dream/ hard to tell/an overactive default network : http://ff.im/-2QNny #scaiku #haiku #science
- “We can’t control the world, but we can control how we think about it”: Mischel . Sounds a lot like Viktor Frankl. http://bit.ly/118zfl
- via @anibalmastobiza : cool genomic imprinting paper that predates Badcock/Crespi’s work on Autism/Psychosis http://bit.ly/o8ppS
The title of my above post is a scaiku (scientific haiku in 140 chars on twitter) that I posted last night on twitter.I am using this title as the inspiration for this post is twitter itself.
Last night, after a hard day full of tweeting (yes tweeting and keeping up with all the friends’ tweets is a lot of hard work- go check the 4-way conversation I had on cosnsciousness and free will), I was not able to relax myself, but found myself in a constant state of distraction and restlessness, and getting up in middle of night to update my status. Of course I have heard of twitter addiction and would rubbish that off; but I could not rubbish off the unique demands on attention and juggling that twittering makes on you. First off, you need to read a lot of tweets and find the needle in the haystack- the tweets that need to be retweeted/replied to and ignore/forget the rest of them as soon as possible. Secondly, I at least, juggle constantly between windows and tabs of tweetdeck and other application trying to do optimal scavenging (feeding off good content tweeted by others) and foraging (finding a good tweetable link myself).
So to sum up, I found that twitter had taxed, at least yesterday, my attentional system- leading to a habitual distractibility and also my motor system hat had constantly flitted between open windows and tabs leading to a habitual distractibility. I am sure that was a very short term and temporary phenomenon, but that set me thinking I have already devoted an entire post to how attention allocation and action selection may be similar and have drawn many parallels. The fundamental problem in both the cases is to choose an action/ stimuli to attend to, that can maximize the rewards from the world/ predictability of the world. At any given time, there are many more stimuli to attend to and acts to indulge in than are the attentional/intentional resources required for the same and thus one has to choose between alternatives. Mathematicaly, different acts have different probabilities associated with them that they would lead to a rewarding state- this wave function needs to be collapsed such that only one act is actually intended. One way to do is my maximizing Utility (ExV) associated with different acts and choosing the maximal one always; another solution is to randomly choose an act from the given set in accordance with the probability distribution that is a function of their utilities.I believe that instead of maximizers most of us are staisficers and especially in time-sensitive decisions go for an undeliberate choice that does’nt actually maximize the utility over all possible behavioral acts, but choses one of them randomly/probabilistically as per their prior known probabilities of rewards. Thus, we can be both maximizers as well as satisficers and which system we engage depends both on situational factors as well as our personality tendencies/ habits.
Anyway that was a lot of digression from the main line of argument. To continue with the digression for some more time, if one extends the analogy to attending to stimuli, on can either attend to stimuli that leads to greatest predictability (P= ExR) ; or one can attend to a stimuli from a given set in accordance with a probability distribution that is a function of their prior predictabilities. again I haven’t even got into Bayesian models where thing should get more complicated; suffice it to note for now that both attention-allocation and action-selection involve choosing an act / stimuli from a set.
A look at the Utility function of acts (U=ExV) and Predictability function of stimuli (P = ExR) , immediately outlines the importance of dopamine in the above choosing mechanism as it encodes both (reward) expectancy as well as incentive salience/Value for acts; on the attentional side of things, it should encode both the strength of conditioned association (E) as well as (stimuli) Relevance for minimizing surprise. As such it should detect novelty in stimuli that can indicate that things have changed and the internal model needs updating.
I also talked in my last post about a general energy level that leads to more propensity to indulge in operant acts and a general arousal level that leads to more propensity to attend to external stimuli. Today I want to elaborate on that concept using ADHD as a guide – ADHD has primarily two varieties (and in most general case both co-exist) – the inattentive type and the hyperactive-impulsive type. In the inattentive type, one is easily distracted or to put in my conceptualization – has a high baseline arousal leading to more frequent monitoring to the world/ external stimuli . The attention-reallocation happens faster than controls and may be triggered by irrelevant stimuli too. In the hyperactive-impulsive type, one is overly active and impulsive or to put in mu conceptualization- has a high baseline energy level leading to more frequent shifts in activities and possibly triggering unvalued acts (impulses that are not really rewarding) .
It is important to note that dopamine and dopamine mediated regions like smaller PFC, cerebellum and basal ganglia, dopamine related genes like DAT1 and DRD4 and Ritalin that works primarily on dopamine have been implicated in ADHD. All the above points to a dopamine signalling aberration in ADHD. Once one embraces the overarching framework of action-allocation and action-selection as similar in nature and possibly involving dopamine neurons, it is easy to see why ADHD children should have both hyperactive-impulsive and inattentive syndromes and subgroups.
The Mouse Trap turns 3 today. It was exactly three years and 334 posts earlier that the Mouse Trap was born. The Mouse Trap has indeed learnt to walk on its own and has also developed adequate linguistic skills in the meantime. The toddler years are all but over, as it now becomes more playful and enters play age of early childhood. Already people are demanding that it not be developmentally delayed, but start indulging in rich imaginative pretend play with topics being requested like symbolic interactionsim and social epistemology.
Some stock taking and reality check is in store. The wiki page on toddler lists the following last milestones for 25-36 months and I hope the Mouse trap is doing fine. To recap:
- Speaking in sentences: Hopefully the strands of mouse trap blog posts now form more cohesive sentences (like the theme of autism-psychosis, stage theories etc) and are not disjointed phrases and one-off utterances.
- Ability to be independent to primary care giver: I hope that the reader partcipation has increased and with more reader participatory initiatives like Skribit suggestions, Google FriendConnect etc., the Mouse Trap is able to become more and more independent of its primary caregiver, that is me, and instead make deep attachments with other secondary caregivers like its prized readers and subscriber base.
- Easily learns new words, places and people’s names: Hopefully as the Mouse trap matures, it is learning to expand its horizons and foraying into topics left hitherto untouched; with better reader connect features , like twitter/Frinedfeed etc it is surely remembering peoples names and where they come form!
- Anticipates routines: The mouse trap hopefully has learnt to anticipate the routine articles and topics that its readership likes to read and is doing a decent job on that score. do suggest your topics if the mouse trap doesn’t anticipate them!
- Toilet learning continues : Once th emouse trap might have been suffering from blogorrehea, but now it knows that passing motion (posting articles) once a week is adequate enough an dthat one should write a article only when one is full of it! There does exist scope for more routinized daily motion passing though!!
- Plays with toys in imaginative ways: I am experimenting a lot with social media (my favorite web 2.0 toy) so as to engage more readers in a conversation. If you have any imaginative ideas of how to play with this toy, do let me know!!
- Attempts to sing in-time with songs: Hopefully, the mouse trap has learnt to sing in tune with the zeitgeist of the day; though here I believe Mouse trap more has an original, unsynchronised with others voice and singing profile. Hope to change that and be more in sync with what others in the science blogosphere are singing (but definitely not the atheism/evolution debate which just bores me)
So, the Mouse trap is just about doing fine. It has been consistently featured in wikio top 100 science blogs, is amongst the top 5 blogs in India as ranked by Indiblogger.in, has a google page rank of 6 and has a subscriber base of close to 450 dedicated RSS feed subscribers, besides those that visit it daily on web via search. Also , the twitter followers of @sandygautam are increasing steadily and have reached 450 and the rate at which they are growing it seems they’ll grow way beyond the Mouse trap feed subscribers. With micro-blogging and twitter/ FriendFeed, I have found a new way to share links and ideas and deepen conversations and connect with my readers, that was not possible with just the Mouse Trap.
I would also like to take this opportunity to encourage all feed subscribers to join me at twitter (@sandygautam) to keep up to date on links that I don’t find exciting enough to write a blog post about or do not have much to add to, but which still are related to theme of what I write about and would make for a good read and need to be shared. I would also encourage new as well as veteran readers and subscribers, just for today, to visit the mouse trap blog on the web and not in their feed readers (to celebrate its B’day, you are invited to the party at the web) so that they can become familiar with new social media tools I have put together on the Mouse Trap blog, like the ‘recommended by readers’ widget, the ‘top posts by PostRank’ widget or the ‘suggest topics to write’ widget.
Lastly as a primary caregiver, though my investment in the mouse trap has been more and my pride consequently in its progress has been immense; I must also thank all the other caregivers like you , the reader, or the peers like the other science blogs that have provided a safe and playful environment in which the Mouse Trap could flower or learn by peer play/ imitation learning. You all are a part and parcel of the Mouse Trap blog, so thanks everyone and take pride in your child’s development and maturation and now that it becomes more independent come forward and supplant the primary caregiver and let it achieve its full potential! Amen!