development

Major conscious and unconcoscious processes in the brain

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.

  1. 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. 
  2. 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.
  3. 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 .
  4. 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.
  5. 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. 

GD Star Rating
loading...
GD Star Rating
loading...

Effecient Related Posts:

  • No Related Posts

Child Psychology: The Mouse Trap turns 3

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:

  1. 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.
  2. 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.
  3. 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!
  4. 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!
  5. 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!!
  6. 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!!
  7. 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!

GD Star Rating
loading...
GD Star Rating
loading...

Effecient Related Posts:

  • No Related Posts

Children not mini-adults, at least in cognitive control

A predominant, but unstated, thinking that biases many research paradigms is the assumption that children are just mini-adults with less well developed mechanisms than adults, but fundamentally using and relying on the same unitary cognitive mechanisms as the adults use. this has proven time and again wrong, and better psychologists now agree that children view the world in a fundamentally different manner from adults. I have covered some research in the past that showed for example that while differentiating between two color hues (categorical color perception), children show a more right hemisphere domination (non-verbal); while adults rely on Left hemisphere (verbal knowledge). Over development the RH processes are shadowed by the maturing LH verbal process, as far as it relates to Categorical Perception.

This recent PNAS article , by none other than the famed Chris Catham of the Developing Intelligence fame, is an effort in the same direction, showing that children use a different mechanism than adults when it comes to using cognitive control. while Adults use a more proactive cognitive control, the children rely on a reactive cognitive control. The authors do a good job of describing the proactive and reactive cognitive control so over to them:

Although sometimes derided as ‘‘creatures of habit,’’ humans develop an unparalleled ability to adaptively control thought and behavior in accordance with current goals and plans. Dominant theories of cognitive control suggest that this flexibility is enabled by the proactive regulation of behavior through sustained inhibition of inappropriate thoughts and actions , the active biasing of task-relevant thoughts, or construction of rule-like representations. Theories of the developmental origins of cognitive control converge in positing that children engage these same proactive processes, but in a weaker form, with less strength or stability , less resistance toward habitual responses, or degraded complexity.

However, children can be notoriously constrained to the present, raising the possibility that the temporal dynamics of immature cognitive control are fundamentally different from that of adults. Specifically, we hypothesized that young children may show ‘‘reactive’’ as opposed to ‘‘proactive’’ context processing , characterized by a failure to proactively prepare for even the predictable future and a tendency to react to events only as they occur, retrieving information from memory as needed in the moment. For lack of age-appropriate methods, the possibility of this qualitative developmental shift has not been directly tested.

They also describe the paradigm used beautifully so again quoting from the article:

In the AX-CPT, subjects provide a target response to a particular probe (‘‘X’’) if it follows a specific contextual cue (‘‘A’’). Nontarget responses are provided to other cue–probe sequences (‘‘A’’ then ‘‘Y,’’ ‘‘B’’ then ‘‘X,’’ or ‘‘B’’ then ‘‘Y’’), each occurring with lower probability than the target pair. This asymmetry in trial type frequency is critical for revealing distinct behavioral profiles for proactive versus reactive control. Proactive control supports good BX trial performance at the expense of AY trials. Maintenance of the ‘‘B’’ cue supports a nontarget response to the subsequent ‘‘X’’ probe; however, maintenance of the ‘‘A’’ cue leads to anticipation of an X and thus a target response (due to the expectancy effect cultivated by the asymmetry in trial type frequencies), which can lead to false alarms in AY trials . Reactive control leads to the opposite pattern. The preceding cue is retrieved when needed, that is, in response to ‘‘X’’ probes but not to ‘‘Y’’ probes. Such retrieval renders BX trials vulnerable to retrieval-based interference; the lack of such retrieval on AY trials means that false alarms are less likely in this case. Similarly, proactive control should lead to increased delay-period effort, whereas reactive control should lead to increased effort to probes.

What they found was consistent with their hypothesis. The reaction time data, the effort data gauged from puppilometry, the speed-accuracy trade off data all pointed to the fact that children used a reactive cognitive control mechanism while adults used a proactive cognitive control mechanism. This what they conclude:

By dissociating proactive and reactive control mechanisms in children, our findings call into question a previously untested assumption of developmental theories of cognitive control, that is, relative to young adults, weaker but qualitatively similar control processes guide the task performance of children. Of course, children and even infants may be capable of sustaining context representations over shorter delays than the 1.2 s used here, but such limited proactive mechanisms would seem unlikely to strongly influence most behaviors.

Further research is needed to determine the processes that drive the developmental transition from reactive to proactive control. This qualitative shift could reflect genuinely qualitative changes, for example, in metacognitive strategies that allow children to engage proactive control. Alternatively (or additionally), the underlying mechanisms for this qualitative shift could be continuous. For example, the gradual strengthening of task-relevant representations could allow proactive control to become effective, thus supporting a shift in the temporal dynamics of control. In any case, the developmental progression to be addressed is a shift from reactive to proactive control rather than merely positing incremental improvements with development.

I think these are steps in the right direction; I lean towards a stage theory account of development so am supportive of a dramatic developmental stage whereby reactive cognitive control mechanisms are replaced by proactive ones, although both strategies may be available to the critical age children equally. However, it may be the case that the neural architecture for proactive CC develops late (just like linguistic CP) and overrides the default reactive CC circuit. that dominance of Proactive CC over reactive CC to me should mark an important developmental stage.

Thanks Chris, for your wonderful blog posts and this paper!

ResearchBlogging.org

Chatham, C., Frank, M., & Munakata, Y. (2009). Pupillometric and behavioral markers of a developmental shift in the temporal dynamics of cognitive control Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0810002106

GD Star Rating
loading...
GD Star Rating
loading...

Effecient Related Posts:

  • No Related Posts
Get Adobe Flash playerPlugin by wpburn.com wordpress themes