Biomedical subjects

K L Bellman

Publications and source records attributed to K L Bellman.

3 recordsLinked to original sources

PubMed1984

Biological processing.

The organization of brain processes leading to language and movement show important parallels with one another and also express important aspects of biological organization in general. Four major differences between biological processes and their commonly proposed analogues, machine processes, are as follows. 1) Reduction is not simplification in biological analysis; rather the subsystems that result from separation of parts of a biological system are themselves complex, often potentially viable, systems. 2) Machine processes are typically generalized, or, if specialized, they are specialized by connecting general-type subsystems in special ways. But biological systems are typically specialized at many levels, both in subsystems and their connections. 3) The history of a biological system is often an intimate and inseparable part of its structure. Furthermore biological systems never develop alone or de novo. Not only do they develop in clusters of contemporaries, they also develop in the presence of an older generation and a "culture." 4) Not only do formal logics have some constraints that biological minds may not have (e.g., internal consistency and universality), formal logics require descriptions of qualitative phenomena in a language that is inadequate and (as a deeper issue) may always require parsing a meaningful whole into approximate parts (e.g., as in writing this abstract). Instances of contrasts between biological systems and machine-type systems are seen in language and movement phenomena, such as embodying a distinction between purposes and causes and having flexibly reorganizable subassemblies, multiple goals, and motor equivalence.

Brain↗

PubMed1984

Common origin of linguistic and movement abilities.

We start with the view that the development of systems of symbols is rooted in the regulation of cellular processes and the behavior of unicellular animals. Animals would thereafter start to externalize these internal symbol systems, to coordinate movements with each other. We propose that the brains of multicellular animals can be understood as a continuing elaboration of the early chemical symbol systems of unicellular animals: the labile symbols of the unicellular animal are replaced by hormones, more stable chemical compounds, and nerves that are seen as more stable and more specific routes of activation; and brains developed layers of symbols such that the domain of a symbol is not a set of bodily processes but rather a set of brain processes. Human language is very much in the "style" of the rule-governed symbol manipulation required by all behaving animals, although unique in its complexity. We suggest that the essential question is not how humans have evolved symbolic and linguistic abilities from a primitive sensorimotor brain but rather how do symbols come to exist in biological systems and what is useful and necessary about a system of symbols for the coordination of action within animals and among animals.

Animals↗

PubMed1981

Different command neurons select different outputs from a shared premotor interneuron of crayfish tail-flip circuitry.

In the crayfish a bilateral pair of interneurons (the 13's) are involved in the generation of two types of tail-flip escape responses, one mediated by giant neurons and the other by nongiant circuitry. The 13's make a variety of output connections with the motoneurons and with other interneurons involved in tail flipping. The motoneuronal outputs include strong synapses on telson flexor motoneurons, whose activity during tail flips mediated by lateral giant fibers would be maladaptive. The lateral giants always drive the 13's, but also drive inhibitory neurons that prevent the undesirable outputs of the 13's while permitting their adaptive outputs to be expressed. It is often adaptive for tail flips initiated by nongiant circuitry to utilize the telson flexor muscles that 13 strongly excites. During such tail flips 13 is often fired, and this firing is important in driving the telson flexors.

Action Potentials↗