What's in the brain that ink may character?1 What’s in the brain that ink may character? (Net-based models in neurology, cognition, and social processes)

What's in the brain that ink may character? 1

What’s in the brain that ink may character?(Net-based models in neurology, cognition, and social processes)

National Reading Conference, December 7, 2002.John E. McEneaney, Oakland [email protected]

mailto:[email protected]


Purpose of the presentation

Historical/Conceptual Overview Logical Neurological Neuropsychological (from neurology to psychology) Psychoneurological (from psychology to neurology) Philosophical Issues

What’s in the brain that ink may character?(Net-based models in neurology, cognition, and social processes)


Logical FoundationsEstablished a systematic theoretical

language for modeling complex systems

Liebnitz & Boole: Algebraic LogicFrege & Russell: Propositional logicvon Neumann: Computational logic


Ramon y Cajal (1889): independence of nerve cells Lloyd (1941): inhibitory synapses demonstratedMcCulloch & Pitts (1943): A logical calculus …Penfield & Rasmussen (1957): motor & sensory mapLettvin, Maturana, M & P (1959): What the frog’s eye …

Neurological FoundationsEstablished fundamental principles

governing neural systems


Pitts, W. & McCulloch, W. (1947). How we know universals, The perception of auditory and visual forms. In Warren S. McCulloch (Ed.), Embodiments of Mind, p. 53. Cambridge: MIT Press.






The Motor HomunculusCortical regions and the motor functions they support.

But localization is not limited to motor functions.Cognitive functions and even specific memories may be local.


Lettvin, Maturana, McCulloch, & Pitts (1959). What the frog’s eye tells the frog’s brain. In Warren S. McCulloch (Ed.), Embodiments of Mind, pp. 230-255. Cambridge: MIT Press.

What the frog’s eyetells the frog’s brain

“There are four types of fibers, each type concerned with a different sort of pattern. Each type is uniformly distributed over the whole retina of the frog. Thus, there are four distinct parallel distributed channels …” (my emphasis)

1. Local edges & contrast2. Curved edges of dark objects3. Edge movement4. Dimming due to movement or rapid general darkening


Minsky, M. L. & Papert, S. A. (1988). Perceptrons, p. 144. Cambridge: MIT Press.

From Neurology to PsychologyGeneralizations from neurology are applied indeveloping psychological theory and models

Rosenblatt (1962): Principles of neurodynamics. Minsky & Papert (1969): PerceptronsMcClelland and Rumelhart (1981): IA modelMcClelland and Rumelhart (1986): PDP VolumesSeidenberg (1992): Simulating phonological dyslexiaPlaut & Shallice (1993): Simulating deep dyslexia McEneaney (1994): Simulating developmental dyslexia


Minsky, M. L. & Papert, S. A. (1988). Perceptrons, p. 5. Cambridge: MIT Press.Rosenblatt, F. (1958). The perceptron-a theory of statistical separability in cognitive systems. Cornell Aeronautical Laboratory Inc., Report No. VG-1196-G-1.Rosenblatt, F. (1962). Principles of neurodynamics. New York: Spartan.

Perceptrons as pattern recognition devices


Minsky, M. L. & Papert, S. A. (1988). Perceptrons, p. 206. Cambridge: MIT Press.

Introduction of multi-layer systems


McClelland, J. L. & Rumelhart, D. E. (1981). An interactive activation model of context effects in letter perception: Part 1. An account of basic findings. Psychological Review, 88, 375-407.

The Interactive Activation Model of Word RecognitionMulti-layer perceptrons re-emerge as PDP models


Architecture of the IA model


The problem of levels in PDP modelsMicrostructure versus Macrostructure


Hinton, G. E. & Shallice, T. (1991). Lesioning an attractor network: Investigations of acquired dyslexia. Psychologiucal Review, 98, 74-95.

Plaut, D. C. & Shallice, T. (1993). Deep dyslexia: A case study of connectionist neuropsychology. Cognitive Neuropsychology, 10(5), 377-500.

Architecture of the Hinton & Shallice Model


From Psychology to Neurology (by way of medical imaging technology)

Generalizations from psychology are applied indeveloping neurological theory and models

Angiography: dye injection reveals blood vesselsElectro-encephalography (EEG): reveals natural electrical activityComputerized Tomography (CT/CAT): X-rays, reveals structure Positron Emission Tomography (PET): radioactive decay, reveals activityMagnetic Resonance Imaging (MRI): induced emissions, shows structure

CT/CAT PET MRI PET + MRI


Distinguishing Dylexic and Normal Brains


Some Closing Questions

Are there fundamental epistemological limits on a brain’s knowledge of itself?

Are levels of description appropriate in biological and cognitive phenomena fundamentally incompatible?

How should and/or could knowledge about brain function inform teaching?

“I expect that the future art of brain design will have to be more like sculpturing than like our present craft of programming.” Marvin Minsky (1991)

What's in the brain that ink may character?1 What’s in the brain that ink may character? (Net-based models in neurology, cognition, and social processes)

Documents

mit press

embodiments of mind

motor functions

frogs brainthere

perception of auditory

visual forms

psychology psychoneurological

psychology generalizations