INDIANA UNIVERSITY
BLOOMINGTON

SCRAMBLED SALAMANDER BRAINS:
A TEST OF HOLOGRAPHIC THEORIES OF NEURAL PROGRAM STORAGE.

by

Paul Pietsch, PhD

Indiana University,
Bloomington, Indiana, USA

internet contact: pietsch@indiana.edu

Originally published in the Anatomical Record 172:383-384, 1972 and presented from the platform before the 85th Annual Session of the American Association of Anatomists, Dallas, Texas, April 3-6, 1972.
Lashley's famous but futile attempts to dig out the engram in ablated chunks of cerebral cortex led him to conclude that memory must be an equipotential, reiterated, mass-action property of the brain. Indeed, physical precedence for such a mode of information came along in the late 1940's with Gabor's discovery of the hologram. And, in more recent years, holographic principles have been used by workers from diverse fields to account for storage of programs in the brain.

Meaning in ordinary, bit-messages exists in relationships of sets and subsets -- between or among. In a hologram, it abides within them. Repeated whole, again and again, holographic messages or patterns persist like the memory of Lashley's animals, if only a tiny fragment of the system survives. And holographic theory ably accounts for many seemingly bizarre results of ablations. But ablation is not an epistemologically complete test of the theory.

[A model such as the following can explain results like Lashley's.]

image
The test must exert non-zero changes between or among sets --reshuffle!
image
If the brain houses holograms, behavior should survive scrambling and reassembling, providing input and readout mechanisms remain viable.

This turned out to be the case in some 700 Amblystoma larvae.

Using as an endpoint the voracious attack of these animals on tubifex worms, and referring to this simple map of the salamander brain,
image

I rotated, added, subtracted, lengthened, shortened and rearranged their brain anterior to the medulla. The most important experiments are summarized in the following table:

BRAIN TRANSPLANTATIONS
HOST /DONOR
[part(s) removed/ part(s) transplanted]
N = map region
I-III/BLANK or LEGIII/III (orthotopic)
I-III/I/III(orthotopic)III/III (rotated) 180 deg.)
I-III/I-III(rotated)III/II
I-III/I-IV (autoplastic)I (left)/I (left)
I-III/I-IV (heteroplastic)*I (right)/I (left)
I-III/I-IV (xenoplastic)**I(bilateral)/cord (bilateral)
*A. tigrinum/A. opacum or A. punctatum
**A. punctatum/R. pipiens (Shumway-25)

Operations induced stupor, and controls, blank anterior to the medulla, thus remained.

image
"Brainless" salamander: section through the head of an animal some 2 months after its brain was amputated anterior to the medulla; the cells packing the neurocranium are fibroblasts and other connective tissue elements. With force-feeding (2-3 times a week on muscle tissue), and because they lack the endocrine mechanisms for metamorphosis (the pars media hypophysis lost to brain amputation), specimens can be kept alive and in this behaviorally inert condition for many months.
Otherwise, subjects regained consciousness and soon thereafter resumed feeding, in spite of drastic, permanent alterations in the anatomy of the brain.

image

image
This is a dissection as seen and photographed under the stereoscopic microscope of a I-III/I-IV (heteroplastic) specimen: the host was an A. tigrinum and the donor a much smaller A. opacumlarva, fixed in 10 % formalin and cleared in glycerin at the conclusion of a 2-month post-operative observation period. The delicate, almost transparent optic and olfactory nerves of the host, unfortunately not resolved in the photograph, were dissected from the host's eyes and nasal sacs, respectively, into the transplanted brain. Note that the specimen has 2 connected hindbrains. The specimen hunted and fed, reacted to visual cues and behaved in a manner indistinguishable from unoperated, normal control animals.
Xenoplastic brain transplants, presumably delivering new holograms, did modify salamander behavior -- and in accordance with the donor's habits.

Results support a critical premise of holographic theories and point to simple reproducible methods of further inquiry.

For popular science works on this subject (shufflebrain), go here.

pietsch@indiana.edu