Alternative neurotechnology: from glial cells to artificial intelligence.

Recently, electroencephalography (EEG) celebrated its 100th anniversary, marking one of the leading approaches in neuroimaging. A survey of several hundred experts worldwide revealed high expectations for the routine application of this method in sleep monitoring, real-time prediction of epileptic seizures, and neurofeedback. In the next 20–40 years, EEG is anticipated to be widely utilized for the early detection of neurodegenerative diseases, the personalization of mental disorder treatments, and for everyday use alongside smartwatches and other devices.

However, certain applications are still viewed by experts as somewhat illusory. This includes the use of EEG for "reading thoughts," such as the content of dreams or long-term memory, as well as for lie detection. This elusiveness is related to the fact that, at present, there is no universal and scalable solution even for seemingly simple tasks like decoding emotions or stress levels from EEG data.

Undoubtedly, EEG provides us with much information (especially when there is significant pathology in the brain), but it also conceals a great deal. Magnetoencephalography (MEG) slightly lifts this veil with its high spatial resolution. Techniques such as functional MRI (fMRI) and functional near-infrared spectroscopy (fNIRS) can only provide indirect information about brain activity through blood flow, while positron emission tomography (PET) offers insights into molecular composition.

There has been ample discussion about these methods, and their limitations are well known: low temporal resolution in fMRI, the need for shielded rooms for MEG recordings, and challenges in interpreting fNIRS data. These technologies are evolving in a clearly defined and largely predictable direction. Each faces local technical challenges that still need to be addressed. For instance, a primary task for MEG remains the comprehensive development of optically pumped magnetometers, which could significantly simplify signal registration. However, while effective, these methods follow already established paths.

Even still resonant, yet undeniably in-demand areas—such as brain-computer interfaces, biofeedback, and neuroprosthetics—are becoming part of the conventional scientific landscape.

Alongside this, directions are emerging that currently do not conform to the mainstream in neurotechnology or lack a veneer of innovation but could potentially offer new insights into brain research and complement existing trends. Let’s discuss some of them.

The Second Breath of Glial Cells

In the mid-19th century, a group of scientists discovered a special type of brain cells known as “neuroglia” (German: “neuroklein”). For a long time, it was believed that these cells were solely responsible for supporting neuronal functions. Classic functions of glia include providing structural support to neurons, supplying nutrients, maintaining ionic homeostasis, ensuring myelination of axons, neutralizing neuroinflammation, and more.

It is ironic that after the discovery of this new cell type, which, by some estimates, makes up 33–66 percent of the brain's total mass, it seemed to be ignored for nearly two centuries in favor of discoveries related exclusively to neurons. This oversight may be due to the more apparent functional properties of neurons, as well as the limitations of histological methods of research available at the time—interest in glia arose more from a structural and morphological perspective.

Only in the 20th century, with new research, was it cautiously suggested that glia is also functionally involved in brain activity. Unlike neurons, glia does not generate action potentials. However, it has been established that the excitatory neurotransmitter glutamate increases calcium concentration in astrocytes (one of the groups of glial cells). Notably, this calcium signal can spread over distances hundreds of times greater than the size of the astrocyte itself. This occurs through the processes by which astrocytes connect with blood vessels, other astrocytes, or neuronal synapses. Thus, astrocytic calcium signals can serve as an independent pathway for information exchange, separate from the one already existing between neurons. Additionally, these calcium waves can directly influence neurons, causing their excitation.

Other facts indicating the functional role of glia include its ability to selectively respond to neuronal activation depending on neurotransmitters or brain structures that provide it; its capacity to regulate excitatory levels in the cortex through network resynchronization; and its ability to support short-term memory through glutamate production, among others. There is no doubt that further exploration of glial functions will reveal new ways of effectively interacting with nervous tissue.

The Universe of the Brain in Miniature

One of the important tasks of neuroscience is to study the development of the nervous system. This could be key to unraveling the mechanisms of many diseases. Given that a living brain is often difficult to access for direct research, methods for its modeling are being developed. One such method is the use of organoids—miniature structures grown from stem cells that mimic the architecture and functioning of the brain.

How far does the use of organoids go in simulating brain development? It has been found that organoids can be grown for nine months without risks of cell death or loss. The grown organoids can reach sizes of several millimeters in diameter. Furthermore, some of the organoids can exist and develop in laboratory conditions for up to seven years. Undoubtedly, this development is not comparable to that of a real brain. However, the molecular structure of organoids indicates the formation of homologs of cortical layers of neurons, intermediate structures, the forebrain, and so on. The neurons within the organoids, possessing standard components (dendrites, axons, etc.), can form synaptic connections, exhibit spontaneous coordinated activity, and even respond to external stimuli (such as light exposure).

Moreover, organoids can perform complex targeted tasks: for instance, 800,000 artificially grown neurons learned to play a computer ping-pong-like game in five minutes. The training was facilitated by electrical feedback from an artificial external environment.

Although organoids currently represent a reductionist and largely unstable model of the brain, they are already being used for disease modeling. By growing organoids from cells of sick individuals, it is possible not only to identify the mechanisms of disease development at early stages but also to determine therapeutic targets and treatment methods. A striking example of such research is the modeling of the brain's reaction to the Zika virus, which had an outbreak in South and Central America in 2015. Infection of organoids with the Zika virus revealed disruptions in the neuroepithelium that could lead to apoptosis of cells and the formation of microcephaly—reduction in brain volume. This explains the symptoms observed in cases of virus transmission from mother to fetus.

The Sixth Sense and the Sixth Finger

“What is it like to be a bat?”—thus philosopher Thomas Nagel titled his famous article, which is seldom omitted in discussions about the philosophy of consciousness. Despite the incomprehensibility of the inner worlds of different species (and different carriers of consciousness), neurotechnologies open up possibilities for its approximation. In particular, modern methods of neurostimulation are used for sensory feedback, restoration of lost functions (such as vision or hearing), and more.

A more nontrivial form of these applications is known as sensory substitution and augmentation. In some cases, this is achieved through conceptually simple means, where information from one modality is replaced by information from another. For example, in BrainPort devices, electrical tactile stimulation based on signals from external devices—microphones, cameras, etc.—is applied to the front surface of the tongue, densely populated with receptors.

This allows blind or deaf individuals to interpret the received impulses as visual or auditory stimuli. In cases of vestibular disorders, tongue stimulation based on head position information helps maintain balance. Improvements are observed even after using such devices. Interestingly, over time, patients begin to note that they no longer need to exert additional mental effort to transform tactile or electrical signals into the perception of sound or images—they begin to "feel them in their heads."

Speaking of expanding sensory perceptions, many possibilities arise thanks to optogenetics. In this approach, light-sensitive proteins—opsins—are introduced into the cells. Subsequently, cells can be "turned on" and "off" through light exposure. By introducing red-sensitive opsins into the retina, researchers successfully trained monkeys to distinguish colors previously inaccessible to them.

A more grotesque example of sensory augmentation that opens access to new sensations is the implantation of small but very powerful neodymium magnets into the tips of fingers. These magnets, when exposed to electromagnetic fields, allow individuals to "feel" them, engaging