On cognition

A while ago now, Andy at Figural Effect posted a concise summary (by way of quotations) of four definitions of 'Cognition' from researchers in different disciplines: Williamson, LeDoux, Clark & Grush, and Neisser. Because I see the Clark & Grush definition as more clearly defining a computationally implementable framework (as I've discussed previously), I find this one the more appealing, however, as noted by Andy, the views from different disciplines is interesting to note.

Related to this, and as mentioned in the comments of the Figural Effect post, is an interesting compilation of definitions of intelligence as viewed from psychology, AI, and others. Personally though, the view of intelligence given by H.G. Wells in 'The Time Machine' is possibly the most elegant I have seen.

I'm afraid I can't post properly at the moment, as am having problems with blogger...

Encephalon #52

The 52nd issue of Encephalon has now been put up at Ouroboros. With a nice Q&A layout, it covers the usual wide range of subjects, from neurogenesis to grannies, and from perception to culture. A couple of, in my view, the most interesting:

- From Neurophilosophy, a review of a paper on brain plasticity, particularly the visual cortex: visual experience can modulate the production of proteins which can influence plasticity along the visual pathway.

- From Neuroscientifically Challenged comes a look at the reason for sleep, and how the humble fruit fly has helped to shed some light on the problem.

- Finally, from Neuroanthropology is a lengthy review of a paper which lays the foundation of "cultural neuroscience": the influence of cultural and social factors on neural mechanisms, and how this may be taken into account in neuroimaging studies. My first thought though when reading this was that it would then be of more immediate concern to somehow account for individual differences in bodily morphology and individual personal histories - these, I would suggest, would have a more direct influence on development, and hence present neural mechanisms, than cultural influences - even though these are, as evidenced by this paper, obviously present. But then again, I'm not a neuroscientist, and have not studied the paper in great detail yet, so may have missed something.

The Inseparability of Emotion and Cognition

A paper on how emotion and cognition should not really be considered as separate entities, but as integrated - a move away from functional specialisations in the brain, and towards widespread interaction and integration for the production of behaviour. Abstract:

The current view of brain organisation supports the notion that there is a considerable degree of functional specialisation and that many regions can be conceptualised as either 'affective' or 'cognitive'. Popular examples are the amygdala in the domain of emotion and the lateral prefrontal cortex in the case of cognition. This prevalent view is problematic for a number of reasons. Here, I will argue that complex cognitive-emotional behaviours have their basis in dynamic coalitions of networks of brain areas, none of which should be conceptualised as specifically affective or cognitive. Central to cognitive-emotional interactions are brain areas with a high degree of connectivity, called hubs, which are critical for regulating the flow and integration of information between regions.

Reference: Pessoa L (2008) On the relationship between emotion and cognition. Nat Rev Neurosci 9:148-158 - full text (may require subscription)

The Animat project at Reading University

As reported on the BBC news website (and now many other news channels), and as subsequently nicely summarised by Mo at Neurophilosophy, the Animat project at the University of Reading aims to use a biological neuron culture to not just control a mobile robot, but also to receive sensory signals (in this case from 4 sonar sensors) from the robot - thus a closed loop system. The work is being done by CIRG (of which I am a part), in collaboration with the Pharmacy department, and hopes to allow the the biological neuronal culture to learn control of the mobile robot through the feedback mechanism in order to produce meaningful real-world behaviours - such as obstacle avoidance for example.

The official press release is here, and further information can be found here.

The Loebner Prize and Turing Test Symposium

On Sunday October the 12th, this year's Loebner Prize will be held here at the University of Reading. The Loebner Prize is essentially an implementation of the Turing Test which started in 1991, and which uses a text-based interface between the tester and the subjects (a human and a 'chat-bot'). This year, there are six finalists who will take part in proceedings on the day.

In conjunction with this event, AISB have decided to run a symposium on the Turing Test in parallel with the Loebner Prize. There are some fantastic speakers due to present, and I anticipate some lively discussions. I'm looking forward to it :-)

Sense about Science

Something I blogged about over a year ago, I've just noticed that the Sense about Science campaign (which is a charitable trust "promoting good science and evidence in public debates") has a leaflet "...to help people to query the status of science and research reported in the media". As well as this, they've produced a button which links to it:

Hopefully, it will help prevent this sort of thing (from Jan 2007)...

Hemispherical 'electronic eye' - and some implications...

The BBC News website yesterday reported on the development of a camera with a hemispheric detection surface, rather than the traditional 2D array. The paper on which this article is based (in Nature - link) proposes that this new technology will enable devices with "...a wide field of view and low aberrations with simple, few-component imaging optics", including bio-inspired devices for prosthetics purposes, and biological systems monitoring. This figure from the paper gives a very nice overview of the construction and structural properties of the system. Note that the individual sensory detectors are the same shape throughout - it is the interconnections between them which are modified. Abstract:

The human eye is a remarkable imaging device, with many attractive design features. Prominent among these is a hemispherical detector geometry, similar to that found in many other biological systems, that enables a wide field of view and low aberrations with simple, few-component imaging optics. This type of configuration is extremely difficult to achieve using established optoelectronics technologies, owing to the intrinsically planar nature of the patterning, deposition, etching, materials growth and doping methods that exist for fabricating such systems. Here we report strategies that avoid these limitations, and implement them to yield high-performance, hemispherical electronic eye cameras based on single-crystalline silicon. The approach uses wafer-scale optoelectronics formed in unusual, two-dimensionally compressible configurations and elastomeric transfer elements capable of transforming the planar layouts in which the systems are initially fabricated into hemispherical geometries for their final implementation. In a general sense, these methods, taken together with our theoretical analyses of their associated mechanics, provide practical routes for integrating well-developed planar device technologies onto the surfaces of complex curvilinear objects, suitable for diverse applications that cannot be addressed by conventional means.

From the cognitive/developmental robotics point of view, this sort of sensory capability has (to my mind) some pretty useful implications. Given that the morphology of the robots concerned, and that would include the morphology of the sensory systems, take central importance in the development (or learning) that the robot may perform, then these more 'biologically plausible' shapes may allow better comparisons to be made between robotic agent models and animals. Furthermore, from the morphological computation point of view (e.g. here, and here), this sort of sensory morphology may remove the need for a layer of image pre-processing - motion parallax for example. As seen in flighted insects, the shape of the eye and arrangements of the individual visual detectors upon it remove the need for complex transformations when the insect is flying through an environment - an example of how morphology reduces 'computational load'. If effects similar to these can be taken advantage of in cognitive and developmental robotics research, then a greater understanding and functionality may be gained. The development of this type of camera may be an additional step in this direction.

The necessity for Intelligence

From "The Time Machine" - H.G. Wells, 1895:

"It is a law of nature we overlook, that intellectual versatility is the compensation for change, danger, and trouble. An animal perfectly in harmony with its environment is a perfect mechanism. Nature never appeals to intelligence until habit and instinct are useless. There is no intelligence where there is no change and no need of change. Only those animals partake of intelligence that have to meet a huge variety of needs and dangers."

In case you don't know the story, a synopsis is here. As far as I'm concerned though, well worth reading in full.

On Grandmother Cells

Grandmother cells were proposed as single neurons which encoded for a single concept - in this case one's Grandmother. The concept was used as a straw-man to criticise sensory hierarchy-based brain organisation theories, but the ideas underlying it are becoming increasingly accepted (not the single neuron per concept I hasten to add). In a paper by Charles Gross (2002 - full ref below), a history of the term is given, with origins and influences.

These cells were originally proposed at the opposite end of the spectrum to ensemble or population coding - where it is the pattern of activity across a group of neurons which codes for a sensory percept. Although the term was coined by Jerry Lettvin in the late 1960's, after which its use quickly proliferated, it was actually proposed as a scientific theory a number of years earlier by the Polish neurophysiologist Jerzy Konorski.

Proposed in his work "Integrative Activity of the Brain" (1967), Konorski predicted the existence of individual neurons sensitive to sensory stimuli such as faces, hands, emotional expressions, etc - and named them "Gnostic" neurons. These were proposed to be located in specific areas of the cortex (in "gnostic fields"), such as the ventral temporal cortex (for the face field), and the posterior parietal cortex (for space fields). These predictions have proven reasonably similar to current proposals for the extra-striate visual cortex in monkeys.

Naturally however, Konorski's work was influenced by that of others. Firstly, in the early 1960's, Hubel and Wiesel demonstrated the hierarchical processing of sensory information in the geniculo-striate system: from simple receptive fields up to the ability to selectively generalise across the retina. Secondly was research on what was then known as the Association Cortex by Pribram and Mishkin: lesions of the inferior temporal cortex produced specific visual cognition impairments in monkeys.

These two bodies of evidence, along with his own familiarity with various agnosias which follow human cortical lesions, led to Konorski's proposal of gnostic cells as a means of accounting for these cognitive impairment effects. Despite the publication of these ideas, and the subsequent coining of the term 'grandmother cells', for at least a decade afterwards, gnostic cells were only taken up in the learning literature, not the perception literature. The term has now, however, had greater use in general textbooks and the pattern recognition literature.

Two features of the gnostic cells have long histories in neuroscience research. Firstly, they are examples of labeled line coding. Labeled line coding refers to a neuron property that allows it to code a particular stimulus property, such as line orientation in the visual field. Secondly, gnostic cells were held to be at the top of a 'hierarchy of increasing convergence'. This concept of convergence hierarchies had, for example, been proposed by William James (the pontifical cell), C.S. Sherrington (in "Man on His Nature", 1940), and Barlow (with the slightly modified concept of cardinal cells, 1972).

In conclusion, the paper notes that the idea of convergence of neural input onto one cell seems to have arisen independently a number of times - and that contemporary human brain imaging have revealed cortical regions (e.g. inferior temporal cortex) which resemble the gnostic fields proposed by Konorski.

As an example of more recent research efforts in exploring this converging hierarchy proposal, Quiroga et al ("Sparse but not 'grandmother-cell' coding in the medial temporal lobe", TICS, 12(3), 2008) - which also involved the somewhat infamous experiments which identified the 'Jennifer Aniston cells' - identified very sparse coding of visual percepts in the medial temporal lobe. In this paper though, a number of arguments were presented for why these cannot be considered to be grandmother cells - a view which I think may be widespread: sparse encoding but not convergence onto a single cell.

Gross, C. (2002). Genealogy of the "Grandmother Cell". The Neuroscientist, 8(5), 512-518.

Encephalon #51

The 51st issue of Encephalon is now up at The Mouse Trap - an ode to the brain, which nicely intertwines the submitted subjects. Two which I found particularly interesting:

- From Effortless Incitement, a summary of a paper on the encoding of concepts in the mouse brain.

- On the exaggerated claims surrounding mirror neurons, from Neuroscientifically Challenged, particularly concerning an essay by Damasio and Meyer in Nature on Convergence/Divergence Zones.

A new name and a new look...

After a 4-month blogging gap, I've decided to overhaul this blog's appearance, and change the name as 'Memoirs of a Postgrad' seemed far too long and clunky. So, the new name is simply 'Combining Cognits' - much shorter I think you'll agree. The term 'cognit' is taken from the Network Memory theory, where it is used to describe a basic memory/perception associative unit in the human cognitive system.

A couple of other cosmetic changes: the colour scheme (much lighter), text (I hope a bit clearer), a couple of extra widgets (post ratings, recent comments lists, and a basic search function - all from widgets for free), and a pretty basic banner (the result of a 10-min playaround in paint.net: I'm certainly no artist!). I don't expect much else to change, other than the occasional minor detail in the coming days. I do however expect to post some more useful/interesting posts on cognition-related issues and studies in the next few days.

Please let me know what you think!

EDIT 04/08/08: changed the blog name again - to "combining cognits"