CP v2

Tag: Smegenų stimuliacija

  • Kontaktiniai lęšiai siunčia impulsus į smegenis: pelėms palengvino depresijos požymius

    Kontaktiniai lęšiai siunčia impulsus į smegenis: pelėms palengvino depresijos požymius

    Pietų Korėjos mokslininkai sukūrė eksperimentinius kontaktinius lęšius su mikroskopiniais elektrodais, kurie silpnais elektriniais impulsais veikia tinklainę ir taip gali pasiekti nuotaiką reguliuojančius smegenų tinklus. Tyrimas su pelėmis parodė, kad toks poveikis susilpnino depresijai būdingą elgesį, tačiau iki taikymo žmonėms dar labai toli.

    Akis jau seniai laikoma patogia prieiga medicinos technologijoms, nes tinklainė šviesą paverčia elektriniais signalais, kurie regos nervu keliauja į smegenis. Dėl to kuriami išmanieji lęšiai, skirti stebėti akispūdį sergant glaukoma, vertinti vyzdžio reakcijas ar ieškoti biomarkerių ašarų skystyje.

    Naujausiame darbe pasirinktas kitas tikslas: ne stebėti, o stimuliuoti. Lęšiuose integruoti elektrodai generuoja dvi panašias, bet šiek tiek besiskiriančias dažnio sroves, o jų persidengimas leidžia koncentruoti poveikį giliau esančiuose audiniuose ir tiksliau nukreipti signalą į tam tikrus nervinius kelius.

    „Idėja patraukli, bet šiuo metu tai tik ankstyvas bandymas su pelėmis, o ne paruoštas gydymo metodas žmonėms“, – sakė tyrimą komentavę mokslininkai.

    Eksperimentuose depresiją primenantys požymiai buvo sukelti laboratorinėms pelėms, pasitelkiant streso hormonų modelį. Patys tyrėjai pabrėžia, kad toks modelis neatspindi viso žmonių depresijos sudėtingumo, nes ši būklė gali turėti skirtingas priežastis, simptomus ir eigą.

    Dar vienas svarbus ribojimas yra tai, kad lęšiai buvo uždėti pelėms su pažeistais fotoreceptoriais, tai yra sutrikusia rega. To reikėjo todėl, kad įprasta regos veikla gali „užgožti“ ar iškraipyti stimuliacijos signalus, todėl dabartinė metodika, kaip ji išbandyta, netiktų gyvūnams ar žmonėms su sveika tinklaine.

    Kas trukdo pritaikyti žmonėms

    Specialistai atkreipia dėmesį ir į biomechaninius skirtumus: žmogaus akis nuolat fokusuoja vaizdą keisdama lęšiuko formą, o toks judėjimas gali trukdyti stabiliai perduoti impulsus per ant ragenos esantį kontaktinį lęšį. Be to, realiame gyvenime reikėtų užtikrinti patikimą pritaikymą, sterilumą ir infekcijų prevenciją.

    Praktinių kliūčių kelia ir gamyba: išmanieji lęšiai turi būti itin tiksliai pagaminti, biologiškai suderinami, atsparūs drėgmei ir mechaniniam dėvėjimuisi, o integruota elektronika turi veikti saugiai. Tyrėjai nurodo, kad kol kas tokia technologija būtų brangi ir nepasirengusi masinei komercinei gamybai.

    Neinvazinė smegenų stimuliacija medicinoje tiriama ir taikoma jau seniai, tačiau kontaktiniai lęšiai kaip „kelias“ į smegenis būtų visiškai nauja kryptis. Šis darbas papildo paieškas, kaip sukurti tikslesnius ir patogesnius metodus, bet kol kas tai veikiau koncepcijos įrodymas, o ne artimiausio meto gydymo alternatyva.

    Artimiausi žingsniai, kurių tikisi mokslininkai, būtų bandymai su kitais, į žmones labiau panašiais modeliais, saugumo vertinimas ir sprendimai, kaip stimuliaciją suderinti su normalia regos veikla. Tik tada būtų galima kalbėti apie klinikinių tyrimų perspektyvas.

  • MIT researchers map how focused ultrasound could test the brain circuits behind consciousness

    MIT researchers map how focused ultrasound could test the brain circuits behind consciousness

    Scientists at MIT are advancing plans to use transcranial focused ultrasound, a noninvasive technique that can modulate activity in deep brain regions, to study how conscious experience arises. The approach is laid out in a recent roadmap paper that argues the technology can move consciousness research beyond observation and toward direct tests of cause and effect.

    Consciousness remains a central unsolved problem in neuroscience because most tools either record brain signals or reach only surface areas without surgery. Focused ultrasound can concentrate acoustic energy through the skull onto small targets, potentially enabling precise stimulation of subcortical structures that are difficult to access with other noninvasive methods.

    A tool for cause and effect

    Many studies link conscious perception to patterns seen in EEG or brain imaging, but those signals often show correlation rather than causation. By changing neural activity in a controlled way and tracking what a person reports experiencing, researchers hope to identify which circuits are necessary for awareness and which are downstream side effects.

    MIT researchers Daniel Freeman and Matthias Michel, along with collaborators at the University of Florida and Harvard-affiliated Brigham and Women’s Hospital, argue that focused ultrasound could help narrow the search for the neural substrate of conscious perception. Their paper, published in Neuroscience and Biobehavioral Reviews, describes experimental designs intended for healthy volunteers.

    Testing rival theories of consciousness

    The roadmap highlights how the method could evaluate competing ideas about where consciousness is generated in the brain. Some accounts emphasize higher-level cognitive processes and the prefrontal cortex, while others suggest that specific perceptual regions, posterior networks, or deeper structures may be sufficient to generate conscious experience.

    Because the technology can target areas millimeters across, researchers say it may be possible to compare the effects of stimulating different nodes in these proposed networks. The goal is not only to see brain activity change, but to determine whether those changes reliably alter perception, awareness, or subjective reports.

    From vision to pain and beyond

    Early experiments are expected to start with the visual system, where researchers can tightly control stimuli and measure perception. Similar logic could be applied to pain, a domain where reflexive responses can occur before a person consciously feels discomfort, raising questions about which brain circuits produce the experience itself.

    While focused ultrasound has drawn growing interest for potential therapeutic uses, the authors frame it as a basic-science instrument for probing fundamental mechanisms. They also caution that, as with any emerging method, careful safety standards, calibration, and replication will determine how widely it can be adopted in mainstream neuroscience.

    At MIT, the work is part of a broader push to build a cross-disciplinary community around consciousness research, including regular discussions among neuroscientists and philosophers. For proponents, the appeal is straightforward: a noninvasive way to reach deeper brain targets could provide the most direct experimental leverage the field has had in decades.

  • Brain stimulation linked to small boost in generosity: What a new PLOS Biology study found

    Brain stimulation linked to small boost in generosity: What a new PLOS Biology study found

    Non-invasive brain stimulation that nudges two brain regions to operate in sync may slightly increase generous choices, according to a study published in PLOS Biology on February 10. Researchers say the results add evidence that specific brain-network communication can shape social decision-making.

    The international team, led by Jie Hu of East China Normal University with collaborators at the University of Zurich, tested whether coordinating activity between frontal and parietal areas affects altruism. These regions are often associated with goal-directed behavior and higher-level reasoning during complex choices.

    Testing generosity in a lab game

    The experiment included 44 participants who completed 540 rounds of a standard behavioral task known as the Dictator Game. In each round, a participant decided how to split money with another person, with the amounts varying across decisions.

    During the task, the researchers applied transcranial alternating current stimulation, a technique designed to influence brain rhythms through weak electrical currents delivered via the scalp. The goal was to encourage synchrony between the targeted frontal and parietal regions at specific oscillation frequencies.

    Gamma synchrony showed the clearest shift

    When stimulation was set to strengthen gamma-band synchrony between the two regions, participants became modestly more likely to choose larger splits for the other person. The effect was most apparent even in situations where giving more meant the participant would take less than their counterpart.

    Using computational modeling, the team reported that the stimulation appeared to change how people weighed outcomes, increasing the importance placed on the other person’s payoff. The authors described this as a measurable shift in value computations rather than a simple preference for equal splits.

    Limits and what comes next

    The researchers noted they did not directly record neural activity during stimulation, meaning the intended brain synchrony was inferred rather than confirmed in real time. They suggested future studies combining stimulation with EEG could verify how brain signals change and how long any behavioral effects last.

    Coauthor Christian Ruff said the work helps link a specific communication pattern between brain regions to altruistic choices, while Hu emphasized the study’s attempt to demonstrate cause and effect. The team cautioned that the increase in generosity was small and the findings do not imply a tool for controlling behavior outside controlled research settings.