Bioelectric control of planarian morphogenesis

Findings (18)

• Bioelectric Head Patterning in PlanariaBioelectric gradients regionalize gene expression to determine head structure in planaria; system can be hijacked by microbes to control host head number and morphology.
• Bioelectric perturbation permanently alters planarian head number to two-headed or zero-headedManipulation of Vmem via gap junction or ion channel drugs rewrites pattern memory, causing planaria to regenerate with stable, heritable aberrant head numbers.
• Bioelectric signatures control morphogenetic target patterns; transient bioelectrical modulation in planaria produces persistent two-headed phenotype.
• In planaria, the most depolarized region becomes the head; altering bioelectric pattern changes head location and number (Beane et al. 2011, Durant et al. 2017)The collective interprets relative voltage differences, not absolute values, to decide anterior identity.
• Manipulation of resting potential pattern in planaria stably alters target morphology (head number) despite wild-type genetics.Transient bioelectric perturbation with ion channel drugs/RNAi permanently alters the number of heads regenerated even in subsequent rounds without further treatment, demonstrating bioelectric pattern memory.
• Memory retention in planarian tail fragment regeneration
• Modification of cell-cell communication during planarian regeneration causes genetically-normal fragments to produce heads appropriate to other species (Emmons-Bell et al. 2015, Sullivan et al. 2016)Shows that morphological attractors can be switched via physiological cues, revealing the navigation of morphospace by collectives.
• Permanent two-headed planarians created by manipulating bioelectric circuits.From Oviedo et al. (2010) and Durant et al. (2017), shows memory of anatomical set points beyond genomic default.
• Planaria exposed to barium regenerate heads insensitive to barium via limited transcriptional changesDespite no evolutionary exposure to barium, planaria solve the physiological stressor by regulating a small set of genes, demonstrating problem-solving in transcriptional space.
• Planaria retain conditioned responses after complete brain regenerationWorms trained before decapitation re-acquire the memory after regenerating a new brain, showing transfer of information across tissues.
• Planarian Brain Regeneration with Memory RetentionEmpirical finding that planaria tail fragments retain learned information and imprint memories onto newly regenerated brains.
• Planarian fragments regenerate with near 100% fidelity of anatomical structurePlanarians cut into pieces regenerate precisely what is missing and re-scale tissue to form complete worms.
• Planarian fragments regenerating from bioelectrically re-patterned tissue produce permanent two-headed phenotype, demonstrating transient bioelectric states can produce lasting morphological memory changes.Key evidence that morphogenetic memories are stored in bioelectric circuits and are rewritable via transient voltage state modifications; memory persists across multiple regeneration cycles.
• Planarian memory persistence across head regeneration
• Planarian Two-Headed Regeneration via Bioelectric Circuit Rewriting
• Planarians derived from tail fragments of trained worms retain original information after brain regenerationBehavioral memories in planaria persist through complete brain regeneration, indicating movement of memory across tissues.
• Planarians maintain high regenerative fidelity despite genetic heterogeneity and chromosomal variation
• Tail fragments of trained planarians retain original learned information, with memories reimprinted on newly-developing brains.Empirical evidence that memories persist through regeneration; challenges substrate-dependence of identity.