Barlow's 1961 chapter never invokes center-surround receptive fields (or any retinal circuitry) as the redundancy-removing mechanism — it works entirely in abstract information theory

Barlow's "Redundancy-Reducing Hypothesis" section is worked out entirely in the abstract language of information theory — noiseless binary channels, fibers A/B and X/Y, impulse frequencies, channel capacity — illustrated by one toy two-binary-input recoder and one photographic-negative analogy for expectation-based coding. No mention of "center," "surround," "receptive field," "ganglion cell," or any specific retinal anatomy occurs anywhere in the 14-page text as the implementation of redundancy reduction. Barlow states the scope limit himself: "This paper is not a discussion of the physiological mechanisms of sensory pathways, but an attempt to formulate ideas about the operations these mechanisms perform" (Summary, p. 233).

This corrects the second over-attribution in claim-barlow-1961-efficient-coding-removes-sensory-redundancy, which read center-surround receptive fields — few spikes for uniform patches, strong response to local contrast — as the 1961 hypothesis's implementation. That mechanism is not in this chapter. The confirmed 1961 content is the redundancy-reduction principle at the level of abstract operations (claim-barlow-1961-primary-states-redundancy-reduction-in-his-own-words); the center-surround reading is a later synthesis grafted onto Barlow's name, most likely tracing to the retinal-physiology lineage (Kuffler 1953; Barlow, FitzHugh & Kuffler 1957) rather than to this text. It is the companion correction to claim-barlow-1961-does-not-name-factorial-code: the 1961 chapter is more modest and more purely information-theoretic than the textbook "Barlow 1961" that circulates.