Do grandmother cells fly?


How do we hold ideas in our brains? One model is that for every concept, word or object we can think about there is a cell (or more likely a small group of cells) that ‘are’ that idea. Such cells have been called grandmother cells, gnostic cells, cardinal cells, as well as other names.

 

Most people have difficulty taking in this notion because it seems to require too large a number of cells. So let’s do some arithmetic.

  1. A good English dictionary contains about 500,000 words. A person’s vocabulary of understood words is unlikely to be greater than this.
  2. For every word there is likely to be a visual representation are well as a semantic one. Add another 500,000.
  3. If we assume that a person adds about 1000 new people to the people that they recognize each year of their life, than in a 100 year lifetime they would store 100,000 people. And let us assume that they get to know a similar number of places and another 200,000 for proper names and their equivalents.
  4. Let us assume that words, images, people and places only cover the majority of ideas. So double the count to cover a minority of other types of idea. That is a total so far of 2.4 million.
  5. We would have to assume that each idea has a number of forms. Take Sally: there is Sally when she was a child, Sally as an adult, Sally when she bleached her hair, Sally as one person out of fourteen in her choir group, Sally as a professional at work, and so on. Let us assume that each idea has a subgroup of 100 simpler or even duplicated ideas. That gives us 240 million.
  6. Further, we can say that there would be more than one cell for each idea. Let us leave room for each sense mode to have a couple of separate idea maps. And let us leave room for a couple maps each for planning, consciousness, and memory to use. That would be 16 copies – make it 20. Now we have just under 5000 million.  

 

So how do 5 billion cells dedicated to a gnostic function compare with the number of cells available? It is 5% of the 100 billion neurons estimated to be in the brain. But all the brain is not used for cognition, consciousness and memory. Suppose that three-quarters of the neurons are concerned with homeostasis, with motor coordination, and with early sensory input – activities that would not use gnostic cells. We are still using only 20% of the neurons directly concerned with cognition, consciousness and memory. The other 80% could be available to make, break or modify the connections between ideas. I do not see any impossibility in this model.

 

From a computer point of view (not that conventional computer science is necessarily applicable to understanding how the brain works) there is an analogy with storage structures. If grandmother cells are equivalent to extremely sparse matrix storage, then the extreme other end of spectrum would be a very dense matrix storage. 5 billion outcomes can be stored in 33 devices (2 to the power of 32 is just under 5 billion). Maintaining sparse and dense matrices require very different types of algorithms though. The nice thing about grandmother cells is how natural they seem to feel. They seem to feel more like the concepts we know than does the outcome of a dense matrix.

Living in the Present 2


Brain Blogger (here) had a post on predicting the near future based on a paper (paper) by Changizi, Hsieh, Nijhawan, Kenai, and Shimojo called ‘Percieving the Present and a Systematization of Illusions’. The Abstract:

“Over the history of the study of visual perception there has been great success at discovering countless visual illusions. There has been less success in organizing the overwhelming variety of illusions into empirical generalizations (much less explaining them all via a unifying theory). Here, this article shows that it is possible to systematically organize more than 50 kinds of illusion into a 7 x 4 matrix of 28 classes. In particular, this article demonstrates that (1) smaller size, (2) slower speeds, (3) greater luminance contrast, (4) farther distance, (5) lower eccentricity, (6) greater proximity to the vanishing point, and (7) greater proximity to the focus of expansion all tend to have similar perceptual effects, namely, to (A) increase perceived size, (B) increase perceived speed, (C) decrease perceived luminance contrast, and (D) decrease perceived distance. The detection of these empirical regularities was motivated by a hypothesis, called ‘perceiving the present’, that the visual system possesses mechanisms for compensating neural delay during forward motion. This articles shows how this hypothesis predicts the empirical regularity.”

 

It takes about a tenth of a second for light on the retina to be processed to a conscious perception. A significant distance can be traveled in that time by a person or an object that a person wants to avoid or wants to catch. It is unlikely that we could walk down a crowded street without accident if we had a tenth of a second delay between our ‘now’ and the real ‘now’. By looking at the optic flow regularities of a moving observer going in the same direction as they are looking, it is possible to predict the scene changes in a tenth of a second. This appears to be what the brain does (whether or not we are moving forward). The logic would be that it everything is a little wrong because we are not moving forward, that is a safe mistake. But it would not be safe to have everything a little wrong if we are moving forward. One can do no harm and the other just might be lethal.

 

This adds more weight to the notion that we do live our lives in a projection into the near future. Also pointing in this direction are investigations of the flash-lag illusion (as described below by Chappell and Hine).

“The flash-lag effect occurs when an object is flashed adjacent to the path of a smoothly moving object, and abreast of the moving object. The flashed object appears to spatially lag the moving object in the direction of motion…”

 

In other words, the moving object is seen to be ahead of its position at the time of the flash. It has been projected into the future in our consciousness. This trick of foreseeing the probably future about a tenth of a second ahead is either a sophisticated calculation of the trajectories of objects depending on their bearing and speed or it is a collection of little ‘rule of thumb’ corrections that are ‘good enough’ for the purpose most of the time.

A bird’s eye view


Until recently the conventional wisdom was that birds were not very intelligent. But this view is changing. Especially the crow, parrot, owl and woodpecker families contain some very intelligent species. Some of these birds show traits that imply brains as powerful as the smarter mammals. The list is amazing: using tools, making tools, powerful spatial memory, logical reasoning, communication, social behaviour in family and larger groups, cooperation, consoling behaviour, counter-espionage showing a theory of mind, passing the mirror test for self awareness, an artistic talent. Relative to body weight, a crow has as big a brain as a chimp. Not only are they comparable to mammals in their intelligence, they also seem to have a similar sort of intelligence. So it is probably that they have a similar sort of consciousness as primates, dolphins, dogs, elephants and the like.

 

But there is a rub. A bird’s brain is very different from a mammal’s. Here is the intro to Gunturkun’s 2005 paper (please supply umlauts on all u’s in the name) The avian ‘prefrontal cortex’ and cognition.

“Mammals such as humans, macaques or rats can adjust their behaviour to changing demands. They are capable of reversing learned behavioral choices, selecting appropriate responses according to contextual information, and withholding actions until a suitable situation occurs. In short, they optimally organize their behaviour over time. The set of cognitive skills required for this behavioural optimization is called ‘executive functions’ and is associated with the operations of the prefrontal cortex. The phylogenetic success of the order of mammals is probably related to the extraordinary cognitive flexibility that is generated by prefrontal circuits. Birds represent a broadly equally successful vertebrate order and a vast literature on avian cognitive skills testifies that birds are able to generate the same set of executive functions as mammals. However, birds and mammals differ substantially with regard to the organization of their forebrains, with birds lacking a laminated cortex. So, which neutal mechanisms do birds use to generate cognitive functions for which the prefrontal cortex is required in mammals?”

 

He goes on to examine the structure of the two brain types (mammal and bird). Of course, they share the basic vertebrate pattern of a three part brain (forebrain, midbrain and hindbrain). The hindbrain, midbrain and the basal nuclei of the forebrain are highly conserved through evolution. It is in the rest of the forebrain that birds and mammals differ. Rather than our neocortex, birds have the neostriatum. Interestingly the connections, neurotransmitters, and functions of these two structures are similar. In particular the executive functions have been compared in the prefrontal cortex (PFC) and the nidopallium caudolaterale (NCL) part of the neostriatum.

“The mammalian PFC and the avian NCL show an astonishing degree of resemblance in terms of anatomical, neurochemical, electrophysiological and cognitive characteristics. Based on topographical and genetic arguments, however, they do not seem to be homologous as a telencephalic entity within the pallium but probably represent a case of evolutionary convergence in terms of neuronal circuits as paralleled by recent studies that clearly reveal that, in particular, corvids (crows) and parrots are able to generate cognitive abilities identical to apes. Emery and Clayton argue that these common cognitive operations derive from a shared cognitive tool kit consisting of causal reasoning, flexibility, imagination and perspective. Most of these shared cognitions thus depend on the PFC and the NCL…This makes it likely that there exist only very limited neural solutions for the realization of higher cognitive functions.”

 

I see another possibility. Maybe the root of the ‘tool kit’ is in the older parts of the forebrain (not the PFC or NCL but the basal nuclei and thalamus) that communicate with either the PFC or the NCL. It would be like the ‘tool kit’ has a computer to use in both mammals and birds but the computer was created from enlargement of different parts of the basal nuclei in the two types of vertebrate.

 

Also I presume that the ‘tool kit’ also includes consciousness.

The 3D World


There is something very basic in our construction of space.

  1. During the 20th century we came to realize that space might have more than three dimensions. But try and try as hard as we can to perceive a fourth (or more) dimension, we fail. Even if we firmly believe in more dimensions and can actually imagine how projection of 4D can give 3D, we cannot live in anything but the three dimensions that our brain supplies.
  2. It may be that the three dimensions stem from the semi-circular canals which give us our orientation relative to gravity and the direction of any acceleration. They are after all three measuring devices at mutual right angles.
  3. Where in space something is (or in what direction) is something that joins together various senses. The eye follows the ear and the ear follows the eye. Our consciousness does not give us the world according to sight, and another world according to hearing and a third world according to touch. Instead we experience one single consistent world.
  4. If consciousness is a construct that anticipates the very near future then it would have to have a space framework in which movements could be mapped and extrapolated and this framework would have to be central to the mechanism of predicting a fraction of a second into the future. There was a previous post on this subject – Living in the Present.
  5. We do not experience time in the same direct way. Instead we use various metaphors based on space. We move through time like we would move through a scene, with the past behind us and the future ahead. Or we can be still and time can move past us. Time is not the only idea that is experienced as a space metaphor. Change is often thought of as movement through space. Nearness and distance are powerful metaphors. There is our internal number-line. And so on and on.
  6. There are two ways to view space. We can be the permanent centre and we can think of directions as ahead-behind, left-right and up-down. Or we can either not be the centre. Then the space does not have a real center and we think of it as east-west-north-south and above-below. Or put another any – we can drag the space around with us or we can leave it still and move through it. In the one case I may look to my left and down. In the other case something is east and below something else. We very easily translate between the two views.
  7. Feeling lost is a very particular feeling. It seems to have its roots in losing our place in some aspect of space. We either do not know where we are in space or don’t know how to navigate it. Metaphorically we feel it whenever we are confused by a complex situation.
  8. The notion of place is connected to the notion of space. Place is probably also very basic but not identical to space. We seem to have an easy translation between place and a part of space.
  9. Our structure of space appears to hold the objects etc. that are in our consciousness but not in its immediate focus. It has something of the nature of a ‘filing system’ for the context of the conscious focus.
  10. Some part of the cortex (and probably other parts of the brain) must hold the space scaffolding. It is perhaps the planum temporale. This area does appear to integrate spatial information from sight and hearing unconsciously. The hippocampus and medial temporal lobe appear to cooperate in giving us an identification of place and perhaps also gives us a sense of space.

 

The origin of a nervous system with a brain (even a tiny primitive one like a worm’s) must be to facilitate movement. Movement has many components such motor control. One of the important components would be the aim, direction, speed of the movement and that takes an ability to track movement through a representation of space. So it should not be surprising that space is so basic to our consciousness.

Who is watching?


The point of this blog is to prepare for the revolution in brain sciences that is happening now. One of the greatest wrenches will be how we will have to look at ourselves. What about our conscious sense of self – the little homunculus, the ghost in the machine? This sense of self comes from many sources.

 

Most of the time, we are not aware of our consciousness – or of our sense of self. Only when we engage in introspection do we seem to be able to look at our consciousness and our ‘selves’. When we introspect, we set up the internal movie screen, so to speak, or the ‘Cartesian theatre’. We withdraw from consciousness in order to examine it. We now watch our consciousness as a spectator. Some little voice tells us that we are now watching us watching our consciousness and that this is a slippery slope of endless watchers of watchers. There is no reason to believe that the introspective self is anything but an illusion. That particular sense of self is a creation of introspection, for introspection, by introspection (to steal a bit of the Gettysburg Address). How can something be examined except to make it the object of something that does the examination?

 

There are other ‘selves’. There are our bodies with their vague feelings and their aches and pains. We are usually aware of very little, if any, of the body’s processes. Consciousness is more about our environment then our own bodies. We are aware of our emotions and there is a sense in which that contributes to a sense of self. We are aware of our intentions, at least some of them, and this seems definitely to give us a sense of self through a sense of will. We have a memory of personal history and continuity that is a sense of self. Some of these aspects of these other selves may be illusionary and but not entirely so.

 

It may even be that we need something to attach our vague fringe feelings to so that they can enter the theatre of consciousness. What is it that is familiar with this place when we have a feeling of deja vu?

 

When awareness of all these aspects of self are put together with the introspective watcher, we have the perception of a self or an inferred conception of a self that is more elaborate then just the watcher. It is also stronger because of its diverse sources. The nature of this perception of self has been affected for many years by dualistic philosophy. If we are going to understand consciousness we have to lose the notion that there are two realms, the physical and the mental. We have to lose the idea that introspection has some absolute truth about it. ‘I think therefore I am’, has to be seen as a circular argument for a fictional type of self, the introspective self. The statement actually says nothing and proves nothing.

 

I am not suggesting that any of us do not exist. Of course we exist. I suggest only that we start to consider that our particular experience of ‘self’ may, and probably is, an illusion of consciousness.

Scientific Shocks


The world is in for another great scientific shock.

 

There was the Copernican revolution that gave us a new meaning for the word ‘revolution’. It took a while but people started feeling that they really were on the surface of a sphere, spinning around and orbiting a star. At first, the very thought made people dizzy and fearful. They might believe that the earth was round but they did not feel it. Now it is just how we think.

 

Then there was Darwin. Not everyone has digested that theory yet, but many people can now be comfortable with the feeling that we are one of the animals, not the opposite of animals, and feel a long, shared history with them. Darwinism along with plate tectonics has made us accustomed to the idea that the earth, and its life, has been slowly changing for an extremely long time rather than created as we see it now, in a short time. Now it is just how many of us think.

 

Next Newton’s universe of simple matter and energy, action and reaction, unfolding in a rigid, continuous space and time, was shattered by Einstein’s relativity and Quantum Mechanics. Most of us have not only failed to internalize these theories, we have not even managed to understand or really ‘believe’ them. There is an understanding gap between physicists and broadly well educated members of the public who cannot feel ‘they are living in’ the universe that the physicists describe.

 

It is time to get ready for the next shock. Science is shortly going to illuminate how the brain works and it is not going to be easy to assimilate. We will have to learn to see ourselves in a different way.

I hope this blog will help you prepare for the shock. That is why I am doing the blog.

Inner Voice


What is the connection between consciousness and language? Some would say that they are two aspects of the same thing. Not me. I have conscious thoughts that I cannot express in language. I have had conscious thoughts that were difficult to put into words and when I did, I was disappointed that the words seemed to change the thought and somehow degraded the feel of it.

 

The whole sight and sound world is modeled in my consciousness without any need for language. My awareness of my emotions is not verbal. Of course I very often think a category or proper name word for something I recognize, but I don’t exactly need the word to do the recognition.

 

Fairly often in conversation (interesting, heated or complicated conversation), I say something and it is not in my consciousness until I hear it. So it seems that there is a lot of consciousness without language and some language without consciousness. They cannot be two aspects of the same thing.

 

On the other hand, I do have an inner voice that seems to narrate my life. And this narration seems very important to the nature of my conscious experience. Language seems to supply a majority of concepts and symbols to the thoughts I am conscious of. It seems to help tie together the stream of consciousness.

 

I feel four levels of speaking. One level is saying something out loud. How this is done is not in my consciousness. All that is conscious is knowledge of the intent and knowledge that the intent is being carried out. Occasionally, as mentioned above, I do not even have knowledge of the intent to say something. It is also rare for me to completely form the verbal string before speaking. I do not have knowledge of the intent to say a particular sentence, but rather the intent is to say some semi-verbal idea. How it gets to be a fully verbal idea is a bit of a mystery as it does not enter my consciousness.

 

A second level is that I can speak to myself. This is just the same as speaking out loud including the knowledge that the intent is being carried out. Everything is the same as saying something out loud except that there is no sound and no outward movement of the mouth. This seems to be a motor act but with the ‘volume’ turned down to next to nothing. So a normal linguistic string can be included in my consciousness by speaking to myself. Reading is similar; it produces a sort of speaking to myself.

 

A third level is what I would call a semi-verbal inner voice. There is no feeling of intent or of the intent being carried out. It does not seem a motor act. It does not seem a linguistic string. It is more like a mixture of words and other symbols and relationships between them. It does seem to be an early part of speaking because when I do speak, it is a bit of this semi-verbal inner voice stream that is picked out to become the object of the intent to speak and so ends up as a normal linguistic string being spoken. The bulk of that inner voice is never spoken out loud or to myself but remains semi-verbal.

Are Animals Conscious?


First I must declare my interests here. I like dogs and I know how smart and how dumb they can be. I have had a dog that would look where you pointed and I have had dogs that looked at your finger. Whether an animal like a dog, or an ape, or dolphin, or parrot, or elephant is conscious is going to depend on how consciousness is defined. If you want the answer to be no, it can be. If you want it to be yes, it can be. But if your search is to understand consciousness, then you must be interested in its earliest beginnings, whether you consider them fully formed or not.

 

When we look for the earliest nervous system, we look at the earliest animals. It is very early animals that developed the neuron, although some important pieces existed earlier and are shared with fungus. Yeasts use something akin to synapses to sense their environment. Vertebrate synapses have about 600 proteins, invertebrate only about 300 of these and yeast share about 50. (see here) The neuron is a major feature of a nervous system and the synapse is a major feature of a neuron. We have to go back to the common ancestor with worms to find the start of brains, organized groups of neurons working together as opposed to wide nets. We share a nervous system architecture type with all other vertebrates. We share more specifics with other mammals, still more with other primates and most with other apes. It is going to be impossible to put a point along this history and say before this there was no trace of consciousness and after it there was full consciousness. So the question should probably not be ‘are animals conscious?’ but ‘how similar is the consciousness of this particular species to ours?’ Is it very similar, hardly similar at all or somewhere in between?

 

Here is the abstract of BJ Baars’ paper, There are no known differences in brain mechanisms of consciousness between humans and other mammals. (paper here)

‘Recent scientific findings indicate that consciousness is a fundamental biological adaptation. The known brain correlates of consciousness appear to be ancient phylogenetically, going back at least to early mammals. In all mammals alertness and sensory consciousness are required for the goal-directed behaviors that make species survival and reproduction possible. In all mammals the anatomy, physiology, neurochemistry and electrical activity of the brain in alert states shows striking similarities. After more than seven decades of cumulative discoveries about waking and sensory consciousness, we have not yet found fundamental differences between humans and other mammals. Species differences such as the size of neocortex seem to be irrelevant to the existence of alertness and sensory consciousness, though different mammals obviously specialize in different of kinds of sensory, cognitive and motor abilities. Skeptics sometimes claim that objective evidence for consciousness tells us little about subjective experience, such as the experience of conscious pain. Scientifically, however, plausible inferences are routinely based on reliable and consistent patterns of evidence. In other humans we invariably infer subjective experiences from objective behavioral and brain evidence — if someone yells Ouch! after striking a finger with a hammer, we infer that they feel pain. The brain and behavioral evidence for subjective consciousness is essentially identical in humans and other mammals. On the weight of the objective evidence, therefore, subjective experience would seem to be equally plausible in all species with humanlike brains and behavior. Either we deny it to other humans (which is rarely done), or, to be consistent, we must also attribute it to other species that meet the same objective standards. It seems that the burden of proof for the absence of subjectivity in mammals should be placed on the skeptics.’