Ladders

This being prompted by a piece in ScienceDaily at reference 1 about work involving noradrenaline (a chemical which is important in signalling in and around the brain), pain (in the form of mild electric shocks), fear, brain waves and attention (a quantity related to but not identical to consciousness). This was followed up at reference 2, but not at the real prompt, reference 3, as that one has not yet leaked into the public domain and is presently too expensive.

I was reminded of the layers and ladders of processing in the brain which have previously resulted in references 4, 5, 6 and 7. Against the background of LWS-R, introduced at reference 8. Which resulted in the present post.

The important feature of LWS-R for present purposes is that the conscious percept is something (here called a frame) which has to be built. The building takes time, perhaps of the order of a second or so, and the finished building is then held, more or less static, for a bit. To be replaced in due course by a new building, a new frame. While a second can be rather a long time when it comes to dealing with danger, perhaps dealing with a predator ready to pounce. Think of the speed of the reactions of a cat when playing with a mouse. So there needs to be more than the conscious percept.

Let us suppose we have something like the world of LWS-R at the right in the figure above. Our subject is a young mother, on a sunny afternoon, gazing intently at the prize rose bush in her back garden, perhaps wondering about the pruning schedule for the season to come. Gazing intently mean that the conscious alert level meter right is taking a fairly high value.

Somewhere nearby, her baby is peacefully sleeping in its perambulator.

In other words, frame 1 of consciousness at time A: a rich and fulfilling experience of prize rose.

So the box on the right is the conscious world, that in the middle is the unconsciousness world and that on the left is the battery, the supply of energy needed to keep the whole show on the road. The conscious and unconscious worlds have alert levels and the battery has a level. The system is deemed to be dead in the case that both alert levels are zero. The system will soon be dead if the battery level is and remains zero.

B, a non-negative number, is the battery level. In the case that the battery is not nearly fully charged, we have: ∂B/∂t = α  – β × UAL – γ × CAL. Where UAL is the unconscious alert level and CAL is the conscious alert level. And α, β and γ  are positive constants – perhaps slowly moving functions of time in a more complicated model. Otherwise we have: ∂B/∂t = – β × UAL – γ × CAL. ∂B/∂t may be positive or negative, depending on circumstances. Being alert is not free, partly because being alert means that the neurons are more active and consume more energy.

If the system as a whole starts to break down, battery charging may fail, but for present purposes we suppose it to work in this sort of way, chugging along in the background. Perhaps charging the battery up for the day to come is one of the things that is supposed to happen when we are asleep and CAL is or is close to zero.

Battery charging happens in slow time, alert levels change in mid time and attention happens in fast time. The former being essentially chemical and the latter essentially electrical. With the mid time changes to alert levels being the result of changes in the chemical milieu in which the neurons live?

Frame 1 has been constructed with a cunning blend of sensory data coming in from outside and inside and stored data from the inside. Quite a lot of the sensory data coming in has been omitted in this conscious percept, omitted from frame 1, having been deemed irrelevant to the matter in hand, in this example a prize rose bush. And then there is the consideration that there is only so much that one can only pay attention to at any one time. All this being suggested by only a fraction of the bottom bar, standing for the sensory world, inside and out, being connected to consciousness, to the box on the right.

Note also that quite a lot of sensory information reaching the (vicinity of the) brain from the body never makes it to consciousness at all, although people do vary a bit in how much they consciously know about the inner workings of their bodies. Doctors with their tests and scans apart.

A frame is not completely static and some predicted change may have been included in its construction, but it is not, nevertheless, taking in anything like all of the changes coming in from the outside. Partly because the conscious percept is an integrated whole, it is an edifice which would need to be rebuilt to take in all those changes. And even then, only the changes up to the new cut-off point, up to the new copy deadline, to use a newspaper publishing analogy.

With another analogy of sorts being given by the film rolling across the gate of a projector. It would not work at all if it just rolled smoothly, rolled continuously across the gate. Rather, it proceeds by a sequence of jumps and stops, as it jumps to the next frame, stops for a bit and then jumps again. The jumping occupying in aggregate a lot less time than the stopping.

So instead of more or less continuous conscious update, our young mother relies on unconscious processing to tell her if there is anything going on which justifies disturbing her contemplation of her prize rose: a judgement call for the unconscious.

 Suppose that after a bit, a giant hornet arrives on the scene, buzzing loudly. The unconscious registers the hornet. It knows enough about hornets to know that this does justify disturbing the contemplation, alerting consciousness. That is to say, hornet stings can be very unpleasant, dangerous even and the unconscious alert level meter left jumps to a high value (66), higher than the conscious alert level (40), this last having fallen a bit in response to the rise of the first. Which means that the processing needed to transfer this information to consciousness is triggered. 

After getting on for a second, our young mother has a new frame of consciousness, one in which the noise if not the sight of the hornet takes centre stage and she is now wondering what to do about it, if anything. In any event, it is likely that the conscious scene has gone beyond the purely visual, with sounds and emotions now getting in too. This being suggested bottom left in the figure above.

Alert level right is now high (60), but with the baton having been passed to consciousness, alert level middle is dropping back down again.

But her baby is not interacting with the hornet, is probably safe and alert level right will probably drop down a bit after a few seconds, depending on how our young mother is with hornets.

Assuming she is OK, she will probably go back to her rose with frame 3, similar but not the same as the frame 1 we started with. Battery starting to charge back up again.

Contrariwise, sometimes our young mother is so wrapped up in her prize rose that not even a threat to her baby can break in on her. The system is not fool-proof.

As noted above, it is a judgement call. The unconscious is processing a lot of information, with all the different parts of the unconscious working away with their own bits of information, some of them bearing on the object of attention, assuming there is one, some of them not. Information which might come from the outside world, from the inside world or from memory. And one of these bits of information might be a cause for concern, might warrant a closer look. We envisage some kind of integration process driving the unconscious alert level, and when the unconscious alert level exceeds the conscious alert level, there is action, with a new frame of consciousness and with attention shifting from one object to another, or from one place to another.

At the extreme, such action might be more muscular. Something has to be done immediately and there is no time for conscious consideration. Muscular action which the unconscious might get wrong – but better to be safe than sorry. Somewhere between a spinal reflex and a cerebral, conscious and considered response.

The battery getting flat would also generate an alert. But in civilised, urban life this is not going to happen very often. Everything is too well organised.

A second mechanism

A high conscious alert state has various other ramifications. Experience is heightened – something that free solo rock climbers know all about – something that can be a bit addictive – as some fighter pilots found after the second world war. Reactions are faster. Performance is improved – be that something like kicking a football into a distant waste paper bin or doing one of the less muscular tasks favoured by experimental psychologists.

It seems that it can happen that this alert state is high because of matter A, say a hornet, but that efficiency spills over into matter B, say a prize rose. Alert state persists for longer than attention, so while it is apt to fade in time, it can carry over from one object of attention, object of consciousness, to another.

But alert state is not a free good. It is energy expensive and it diverts resources from other bodily activities. So it requires trickery and training to maintain a high alert state, typically tightly focussed on just one thing.

I associated to the saying about pinching oneself to stay awake, not the quite same thing, but which does link to the work reported at reference 2, where an alert state is triggered by presentation of a visual cue which has been associated with mild electric shocks. And it may be that the alert state is better prompted by fear of shocks than by the shocks themselves.

Additional information

I am reminded of the way that one’s image of the sky above or the land around seems to be updated in a seemingly random way. You have a bit of blue sky, then all of a sudden there is a bird or an aeroplane in it, as large as life. As if it has been there for a while, but the brain has taken a while to get around to attending to the relevant bit of signal from the retinas.

While something slightly different must be going on when somebody says something like ‘look at that aeroplane over there’ and even though one knows it is there and is actively looking for it, it can often take a while to bring the aeroplane into focus, to bring it into view. 

The scheme above with meters is similar to the interrupt feature in a large computer: the computer is beavering away, doing all kinds of stuff – but some of the resources of the computer are given over to keeping an eye on things. And from time to time, activity may need to be suspended in order that the operator can deal with some new information or some new requirement, of something happening in the wider world. Or the break feature in Visual Basic, whereby if a program that is running under Visual Basic tries to break the rules, it is stopped and control is returned to the user so that the problem can be fixed before the program is resumed.

The figures in the foregoing come from the save slide feature of Powerpoint, discovered a few days ago. And at one point there was a clock dial rather than a digital dial and I wanted to be able to move the needle on the dial to reflect the words in the story – which prompted the digression noticed at reference 10 and eventually resulted in the digital dial here present.

Conclusions

The presentation above is binary, unconscious versus conscious, while that of references 4, 5, 6 and 7 is much more ladder like, with processing going through a number of stages, perhaps in a directed network rather than a sequence, rather than just the two stages. I dare say the present presentation could be generalised in the same way, with a network of meters rather than just the two. But I leave that for mañana.

Time is important. All this is a matter of dynamics not statics, and the fact that different parts of the system work at different speeds is an important ingredient of the system as a whole.

I find this way of looking at things helpful and I shall now go back to trying to make sense of what for me is the rather dense reference 2.

References

Reference 1: How the brain’s blue spot helps us focus our attention: The neurotransmitter noradrenaline regulates our brain’s sensitivity to relevant information – Max Planck Institute for Human Development, ScienceDaily – 2022.

Reference 2: Noradrenergic Responsiveness Supports Selective Attention across the Adult Lifespan - Martin J. Dahl, Mara Mather, Myriam C. Sander, Markus Werkle-Bergner – 2020. Open access.

Reference 3 : Noradrenergic modulation of rhythmic neural activity shapes selective attention – Martin J. Dahl, Mara Mather, Markus Werkle-Bergner – 2022. Paywalled.

Reference 4: http://psmv2.blogspot.com/2015/08/its-dogs-life.html. The original version.

Reference 5: http://psmv3.blogspot.com/2017/04/its-chips-life.html. 

Reference 6: https://psmv3.blogspot.com/2017/11/a-dogs-life-reprised.html. 

Reference 7: https://psmv3.blogspot.com/2018/04/on-saying-cat-again.html. Transformation to a ladder.

Reference 8: https://psmv4.blogspot.com/2020/09/an-updated-introduction-to-lws-r.html. 

Reference 9: https://en.wikipedia.org/wiki/Hornet. 

Reference 10: https://psmv5.blogspot.com/2022/03/teach-yourself-powerpoint.html. 

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