Horace Barlow
(1921-2020)
Horace Barlow was a British neuroscientist who specialized in research on vision.
He wrote two seminal articles on the neuroscience of vision.
The first was just a couple of years before the pioneering work on the frog's eye by
David Hubel,
Torsten Wiesel,
Jerome Lettvin,
Warren McCulloch,
Walter Pitts, and
Humberto Maturana, Barlow identified neurons in the frog's brain that fire in response to particular visual stimuli.
A Vision of the Brain, pp.118-119
Barlow's second seminal article was
Single Units and Sensation: A Neuron Doctrine for Perceptual Psychology? in 1972. In it, Barlow began with five dogmas
1. To understand nervous function one needs to look at interactions at a cellular level, rather than
either a more macroscopic or microscopic level, because behaviour depends upon the organized
pattern of these intercellular interactions.
2. The sensory system is organized to achieve as complete a representation of the sensory stimulus
as possible with the minimum number of active neurons.
3. Trigger features of sensory neurons are matched to redundant patterns of stimulation by
experience as well as by developmental processes.
4. Perception corresponds to the activity of a small selection from the very numerous high-level
neurons, each of which corresponds to a pattern of external events of the order of complexity of
the events symbolized by a word.
5. High impulse frequency in such neurons corresponds to high certainty that the trigger feature is
present.
The development of the concepts leading up to these speculative dogmas, their experimental
basis, and some of their limitations are discussed.
Single Units and Sensation, p.371
In
David Marr's "Epilogue" to his
Vision book, Marr wrote an imagined conversation between himself, his colleague Tomaso Poggio, and
Francis Crick. He began with the work of Horace Barlow.
CONVERSATION
Can we begin with the levels-of-explanation idea, since you attribute so much importance to it? How is it related to ideas about feature detectors and in particular to Horace Barlow’s first dogma (1972, p. 380), which states, “A description of the activity of a single nerve cell which is transmitted to and influences other nerve cells, and of a nerve cell’s response to such influences from other cells, is a complete enough description for functional understanding of the nervous system ”?
Here, of course, I must disagree with Barlow’s formulation, although I do agree with one of the thoughts behind this dogma, namely, that there is nothing else looking at what the cells are doing — they are the ultimate correlates of perception. However, the dogma fails to take level one analysis—the level of the computational theory—into account.
Vision, p.336
Barlow applied statistical methods to reduce the information redundancy in "pixels" of the visual field.
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