Crawling C. elegans hermaphrodite worm (Photo credit: Wikipedia)
In one of my earlier posts I had lamented what the fate of psychology could have been had it had an Indian heritage.
In that post I had exposed readers to the Sankhya system of philosophy, which lays equal focus on 5 sense organs ( smell, taste, vision, touch and audition) as that on 5 motor organs (karmendriyan)—feet and movement, genitals and sexual activity, bowels and excretion, hands and grasping, mouth and feeding. They are also related to panch maha bhut and panch tanmatras viz. Smell with earth, taste with water; vision with fire (infra-red vision?) touch with air, and audition with ether.
The reason I am reiterating is because the simplest of nervous system, that of nematode worm (C elegans), whose connectome has been completely mapped (302 neurons only), corresponds to similar functional circuits, and again, call it coincidence, but I came to know of this research by reading an article by Indian psychologists/neuroscientists.
In this article [pdf] by Nivedita Chatterjee and Sitabhra Sinha, they focussed on eight functional networks of nematode worm viz.
In the present work we have chosen eight functional circuits, namely, (a) touch sensitivity, (b) egg laying, (c) thermotaxis, (d) chemosensory, (e) defecation, and, three types of locomotion: when (f) satiated (feeding), (g) hungry (exploration) and (h) during escape behaviour (tap withdrawal).
It is apt to note here that as per the greater or equal focus on motor aspects, they include the five karmendrey related functional circuits, viz. Escape behaviour (tap withdrawal)—the nematode ’running using its feet’; egg-laying related to sexual activity; defecation or related to bowels and excretion; hungry and exploring —‘grasping with its hands’; and finally satiated or feeding and involving ‘mouth.’
They only refer to 3 sensory networks, Chemosensory or smell related; thermotaxis or vision related and touch sensitivity or skin touch related; ample research literature exists about the remaining two sensory modalities—mechanosensory or audition related and osmotic or taste related.
It is not my contention that nematode worms see, smell, taste, feel touch or hear like us humans, but these basic functional networks of chemosensation etc are equivalent in worm space and are the building blocks on which human sense circuits build.
It’s also notable that there are 10 ganglions in the worm—5 in head and 5 in rest of the body. Also another group of researchers had found five clusters of neurons in the worm and thus this figure of five keeps repeating—who knows the five clusters may be the basis for the five personality traits of humans?
As always I look forward to reading more of this literature especially if there are ICN or rsfcMRI studies done on worms; I’m just waiting for those studies to be done and the basic structure of nervous system delineated.