Fixing Brains With Engineered Neural Tissue

Micro Tissue Engineered Neural Networks (micro-TENNs) are preformed neural network structures which can serve as a foundation for reconstruction of damaged brain pathways. These engineered tissues are being injected into the brains of lab rats for testing. If the neural network tissue is “trained” with a specific knowledge set before being injected, it might become possible to inject new knowledge sets into a brain in addition to repairing damage.

“We Can Remember It For You Wholesale” is the name of a science fiction short story by Philip K. Dick that was used as the basis for both “Total Recall” movies. The technology in the movies involved implanting realistic experience memories that never actually occurred.

Using Neural Tissue Engineering to Restore Brain Function and Form Bionic Connections – [pennmedicine.org]

The brain is unique among organs. The function of nerve cells (neurons) gives rise to consciousness — who we are — yet these cells have very limited capacity to regenerate. Nerve cells work by growing long fibrous projections known as axons which connect neurons within the brain and form the body’s signal transmission and communication structure.

Although new neurons are born in select regions of the brain, the long axon cables crisscrossing the brain do not regenerate, yet they are necessary for normal function. Researchers have been working for decades to coax damaged axons to regenerate, with little success in getting enough axons to grow to the right places.

But, it turns out that groups of nerve cells, or tissue, can be organized outside the body and engineered to restore and repair axon pathways in the nervous system that may be damaged by injury or disease. Dr. Cullen is a national leader in the emerging area of research known as neural tissue engineering. He works at the intersection of neuroscience and engineering to come up with unique ways to aid those with brain function-related issues.

“Replacing individual cells does not work, but if we reform the tissue structure, complete with long axons, we are seeing signs that this engineered tissue will link into the existing tissue in the brain to mimic the function of the missing structures,” says Cullen.

Rebuilding Brain Circuitry with Living Micro-Tissue Engineered Neural Networks. – [nih.gov]

Abstract

Prominent neuropathology following trauma, stroke, and various neurodegenerative diseases includes neuronal degeneration as well as loss of long-distance axonal connections. While cell replacement and axonal pathfinding strategies are often explored independently, there is no strategy capable of simultaneously replacing lost neurons and re-establishing long-distance axonal connections in the central nervous system. Accordingly, we have created micro-tissue engineered neural networks (micro-TENNs), which are preformed constructs consisting of long integrated axonal tracts spanning discrete neuronal populations. These living micro-TENNs reconstitute the architecture of long-distance axonal tracts, and thus may serve as an effective substrate for targeted neurosurgical reconstruction of damaged pathways in the brain. Cerebral cortical neurons or dorsal root ganglia neurons were precisely delivered into the tubular constructs, and properties of the hydrogel exterior and extracellular matrix internal column (180-500 μm diameter) were optimized for robust neuronal survival and to promote axonal extensions across the 2.0 cm tube length. The very small diameter permits minimally invasive delivery into the brain. In this study, preformed micro-TENNs were stereotaxically injected into naive rats to bridge deep thalamic structures with the cerebral cortex to assess construct survival and integration. We found that micro-TENN neurons survived at least 1 month and maintained their long axonal architecture along the cortical-thalamic axis. Notably, we also found neurite penetration from micro-TENN neurons into the host cortex, with evidence of synapse formation. These micro-TENNs represent a new strategy to facilitate nervous system repair by recapitulating features of neural pathways to restore or modulate damaged brain circuitry.

SEE ALSO:
Mind Control Interface
Neural Networks
Rebuilding Our Bodies

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