28/11/2009 by admin.

ScienceDaily reports on the work of L. Chittka (here) on the relationship between brain size and complexity.

“Research repeatedly shows how insects are capable of some intelligent behaviours scientists previously thought was unique to larger animals. Honeybees, for example, can count, categorise similar objects like dogs or human faces, understand ’same’ and ‘different’, and differentiate between shapes that are symmetrical and asymmetrical…. We know that body size is the single best way to predict an animal’s brain size….The size increase allows the brain to function in greater detail, finer resolution, higher sensitivity or greater precision: in other words, more of the same….In bigger brains we often don’t find more complexity, just an endless repetition of the same neural circuits over and over. This might add detail to remembered images or sounds, but not add any degree of complexity. …This must mean that much ‘advanced’ thinking can actually be done with very limited neuron numbers. Computer modelling shows that even consciousness can be generated with very small neural circuits, which could in theory easily fit into an insect brain. In fact, the models suggest that counting could be achieved with only a few hundred nerve cells and only a few thousand could be enough to generate consciousness.”

I believe that this may be a slight over simplification. For a particular kind of animal, after correction for body size, brain size predicts intelligence. It is just that intelligence does not relate to brain size across different types of animal. Also the body size correction must be made. Of course intelligence would have something to do with level of detail, resolution, precision etc. and that relationship would follow brain size within a particular brain architecture. But a particular capability (without reference to its resolution) would not be related to brain size. In that case all animals could have some degree of consciousness.

There is a quote mistakenly attributed to Stalin or Lenin but said by David Glantz about the WW2 Soviet army, “Sometimes, quantity has a quality all its own”. This is probably true of brains.

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27/09/2008 by admin.

In a recent ScienceDaily item was a summary of Joydeep Bhattacharya’s work on the ‘eureka’ moment.

“Real-world problems come in two broad flavors: those requiring sequential reasoning and those requiring transformative reasoning: a break from past thinking and restructuring followed by an insight (also known as Eureka or “Aha!”), which is a process by which a problem solver abruptly, through a quantum leap of understanding with no conscious forewarning, moves from a state of not knowing how to solve a problem to a state of knowing how to solve it.

Despite its widespread reports, the brain mechanism underlying eureka is poorly understood. What happens in the brain during that particular moment? Is that moment purely sudden as often reported by the solver or is there any (neural) precursor to it? Can we predict whether and when, if at all, the solver will hit upon the final eureka moment?

In a new study led by Joydeep Bhattacharya at Goldsmiths, University of London, these questions were addressed by measuring brainwaves of human participants as they attempted to solve puzzles or brainteasers that call for intuitive strategies and novel insight. They detected an array of specific patterns in characteristic brainwaves which occurred several (up to eight) seconds before the participant was consciously aware of an insight. Right hemisphere was further found to be critically involved in transformative reasoning.

These results indicate that insight is a distinct spectral, spatial, and temporal pattern of unconscious neural activity corresponding to pre-solution cognitive processes, and not to one’s self-assessment of their insight or the emotional “Aha!” that accompanies problem solution. Further, this study also postulates that consciousness is like an emergent tip of an iceberg of neuronal information processing, and remote brainwave patterns could reveal the underlying structure leading to that emergence.”

It is interesting that conscious concentration on a problem can postpone the eureka type solution. As Richard Highfield’s Telegraphy article puts it, “Scientists have discovered why Archimedes had to relax in a bath before discovering his famous principle.” One might also say we know why Newton was relaxing under an apple tree or Kekule was falling off to sleep.

The stages that can be traced in combined behaviour, verbal reporting and brain wave measurements are: mental impasse including attention overload, relaxation of attention allowing the restructuring the problem, deeper understanding or insight into the problem and its solution, sudden consciousness of the correct solution or the insightful path to it.

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23/08/2008 by admin.

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.

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