Lecturer's Précis - Charcot's (1883) "Bell" Diagram

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First published online 08:20 GMT 4th February 2003, Copyright Derek J. Smith (Chartered Engineer). This version [HT.1 - transfer of copyright] dated 12:00 13th January 2010

An earlier version of this material appeared in Smith (1996; Chapter 7). It is repeated here with minor amendments and supported with hyperlinks.

 

Charcot's "Bell" Diagram

In various papers during the early 1880s (eg. Charcot, 1883), and closely influenced by Kussmaul (1878), the French physician Jean-Martin Charcot (1825-1893) developed an explanatory schema for language processing based around a word meaning store linked to no less than four fundamentally different word image (ie. surface form) stores. Specifically, Charcot proposed separate memories (a) for a word's semantic referents and associations, (b) for its auditory word image (the spoken word, as recognised with our ears), (c) for its visual word image (the written word, as recognised with our eyes), (d) for its articulatory motor image (the skill unit which drives the muscles of our lips and palate when we speak the word), and (e) for its graphic motor image (the skill unit which drives the muscles of our hand and arm when we write the word). In all, this makes two input image stores, two output image stores, and one central semantic store, a psycholinguistic modelling tradition which was resurrected a century later by modern psycholinguistic modellers such as Ellis and Young (1988).

Like Wernicke (1874) and Kussmaul (1878) before him, and Lichtheim (1885) after him, Charcot saw these stores as being damageable individually or in various permutations, each with characteristic results. Indeed, he provided a detailed worked example of how he saw the various modules interacting. He took the example of a bell (French = "cloche"), and pointed out that this had a number of fundamentally different type of memory images, all separately stored as noted above, but all intricately interlinked. A supporting diagram was developed for use as a lecture aid, and this was subsequently published in Charcot and Bernard (1883). This combination of explanatory schema and supporting diagram is nowadays commonly known as "Charcot's bell" after this specific example. Here are the key points .....

Charcot's "Bell": Here are Charcot's original French names for the five processing modules already described, plus two others dealing with non-verbal (ie. general purpose) vision and hearing. We have included the equivalent or (nearest equivalent) Ellis and Young (1988) Module No., where possible.

Key to Charcot's Proposed Psycholinguistic Modules

IC = Ideation Commun = common conceptual (semantic) centre = Ellis and Young Module #4

CAC = Centre Auditif Commun = general purpose auditory centre = Ellis and Young Module (#1)

CAM = Centre Auditif des Mots = auditory centre for heard word forms = Ellis and Young Module #2

CVC = Centre Visuel Commun = general purpose visual centre = Ellis and Young Module (#5)

CVM = Centre Visuel des Mots = visual centre for seen word forms = Ellis and Young Module #6

CLA = Centre du Langage Articulé = motor centre for spoken word forms = Ellis and Young Module #8

CLE = Centre du Langage Écrit = motor centre for written word forms = Ellis and Young Module #16

This functional architecture closely follows the Kussmaul (1878) hierarchical model in locating the higher functions module (IC) at the apex. General purpose sensory inputs ascend to the left (CAC) and right (CVC). Inboard from these are the more specialised input word form stores (CAM and CVM), and inboard again are the two output word form stores (CLA and CVE). The ringing of the bell is heard via the CAC. If, on the other hand, the spoken word "cloche" is heard then pathway CAM is activated. The same basic argument holds true when comparing seeing the physical object itself (in CVC) with seeing the written letters "C-L-O-C-H-E" (in CVM). Note the complex of interconnecting pathways between IC and the various input and output stores. Note especially the "counterflow" arrows (which we have highlighted in red), which in modern parlance are "feedback" (knowledge of results) pathways. These run upwards in the motor pathways, and downwards in the sensory pathways, and are responsible for the rapid detection of motor errors in the former and matters of orientation and fine tuning in the latter.

PICcharcot1883.gif

Redrawn from Piéron (1927, p151), with additional colour coding. Apparently after Charcot and Bernard (1883), after Charcot. This graphic Copyright © 2003, Derek J. Smith.

 

Where To Next?

For a timeline showing the principle nineteenth century neuropsychological advances, click here. For more on the modern psycholinguistic models, click here.

 

References

Charcot, J.-M. (1883). Des différentes formes de l'aphasie. De la cécité verbale. Le Progrès Médicale, 11:441-444. [Contains neuropsychological casenotes relating to Patient HP, a 35-year old haberdasher, whom Charcot described as "un des plus beaux exemples que se puissent voir" of word blindness (the cécité verbale of his title).] 

Charcot, J.-M. and Bernard, D. (1883). Un cas de suppression brusque et isolée de la vision mentale des signes et des objets (formes ets coulours). Le Progrès Médicale, 11:568-571. [Contains neuropsychological casenotes relating to Patient X, who had lost the ability to generate visual mental imagery and had to run his life instead using auditory imagery and inner speech. Discussed in detail in Ellis and Van de Wal (1996).]

Ellis, A.W. and Van de Wal, C. (1996). Charcot's case of impaired imagery. In Code, C., Wallesch, C.-W., Joanette, Y., and Lecours, A.R. (Eds.), Classical Cases in Neuropsychology, Hove: Psychology Press. [ISBN: 0863773966]

Piéron, H. (1927). Thought and the Brain. London: Kegan Paul.

Smith, D.J. (1996). Memory, Amnesia, and Modern Cognitive Theory. Cardiff: UWIC. [ISBN: 1900666006]

Recommended Reading

"Classic Cases in Neuropsychology"

Code et al (Eds.) (1996)

To see an abstract, or to order this book, click here