Un equipo liderado por Sandeep Robert Datta, profesor de neurobiología en el Instituto Blavatnik de la Facultad de Medicina de Harvard, ha modificado de raíz la visión sobre el sentido del olfato al revelar el primer mapa detallado de la organización espacial de los más de mil tipos de receptores olfativos presentes en la nariz de los mamíferos. Tras analizar más de 5,5 millones de neuronas en 300 ratones, los investigadores demostraron que, lejos de la aleatoriedad que suponía la biología desde hace tres décadas, las neuronas olfativas siguen un patrón estructurado: se distribuyen en franjas horizontales superpuestas en función del receptor que expresan, desde la parte superior hasta la inferior de la nariz.

Los científicos descubrieron que la posición de cada receptor depende de un gradiente de ácido retinoico y de la activación coordinada de cientos de genes reguladores, lo que permite que las neuronas olfativas se organicen en franjas precisas y que este patrón se repita en todos los individuos.

Este hallazgo resulta interesante porque rompe con 35 años de creencias sobre el olfato y acerca su comprensión a la de otros sentidos como la visión o el oído. Además, abre la puerta al desarrollo de nuevas terapias para la pérdida del olfato, un problema sin soluciones eficaces y con impacto profundo en la salud y el bienestar.

Los resultados, publicados en la revista Cell, corregirán la interpretación de libros de texto y abren la puerta a explicar por qué la pérdida del olfato por enfermedades o lesiones sigue siendo tan poco conocida y tiene tratamientos insuficientes. Datta subrayó que “el olfato es sumamente misterioso y nuestra comprensión biológica básica está por detrás de la visión, el oído y el tacto”, y enfatizó que su trabajo “aporta orden a un sistema que antes se consideraba carente de él, lo que cambia conceptualmente nuestra forma de pensar sobre su funcionamiento”.

Un hallazgo complementario del estudio es la coincidencia del mapa de receptores en la nariz con los mapas olfativos en el bulbo olfatorio del cerebro, lo que implica una continuidad topográfica desde la percepción molecular en la epitelio nasal hasta el procesamiento cerebral. El equipo validó esta correspondencia tras observar que las posiciones espaciales de los receptores en la nariz predecían con exactitud la localización tridimensional de los glomérulos a los que proyectan las neuronas. En palabras de Datta: “Demostramos que el desarrollo puede lograr esta hazaña de organizar mil receptores olfativos diferentes en un mapa increíblemente preciso que es consistente en todos los animales”.

Los investigadores identificaron el ácido retinoico como factor determinante de la organización: un gradiente de esta molécula a lo largo de la nariz condiciona a cada neurona en la elección de su receptor, asegurando así que el patrón se replique en todos los individuos y que cualquier alteración en este gradiente derive en un desplazamiento del mapa de receptores. Añadir o eliminar ácido retinoico desplazó las posiciones de los receptores hacia arriba o abajo en el epitelio nasal.

En paralelo, los experimentos de manipulación genética demostraron que la identidad espacial de las neuronas precursoras ya codifica información relacionada con su ubicación antes de la expresión del receptor específico. Esta identidad espacial, medida mediante la expresión coordinada de cerca de 250 genes, anticipa el tipo de receptor olfativo que la neurona terminará expresando y, por tanto, expresa un orden biológico profundo, contrario a la hipótesis dominante de aleatoriedad dentro de “zonas” amplias.

Las técnicas empleadas incluyeron la secuenciación de células individuales y análisis transcriptómico espacial, lo que convierte a este tejido en el área neuronal más minuciosamente cartografiada hasta la fecha. “Podría decirse que este es el tejido neuronal más secuenciado de la historia, pero necesitábamos esa cantidad de datos para comprender el sistema”, sostuvo uno de los investigadores.

Durante 35 años, la biología consideró que, a diferencia de los sentidos visual, auditivo y táctil, el olfato carecía de un mapa definido. Lo sustentaba el hecho de que los ratones—con más de 1.100 tipos de receptores olfativos y unos 20 millones de neuronas dedicadas a este sentido—muestran una expresión molecular que, hasta ahora, parecía agruparse en zonas laxas dentro del tejido.

Sin embargo, los resultados de Harvard revelan que cada tipo de la enorme familia de receptores ocupa una posición promedio única y predecible a lo largo del eje dorsoventral, lo que confiere al epitelio olfativo un grado de organización anatómica semejante al de otros sistemas sensoriales.

La clave reside en la coordinación de programas genéticos compuestos por centenares de genes reguladores, entre los que predominan factores de transcripción, como la familia NFI, responsables del silenciamiento selectivo mediante heterocromatina de los genes de receptores que no corresponden a la posición espacial de cada célula. Este mecanismo asegura que sólo los receptores apropiados sean activados en las posiciones correctas del epitelio, estabilizando así el mapa a lo largo del tiempo y las generaciones.

Una de las pruebas críticas fue la observación de que la manipulación del gradiente de ácido retinoico o de los componentes del sistema de silenciamiento génico provoca desplazamientos coherentes en el patrón de expresión de los receptores. Además, el análisis de híbridos entre distintas cepas de ratón permitió verificar que cambios en regiones no codificantes del ADN explican las variaciones en la posición espacial de los receptores entre linajes, sin modificar la secuencia funcional de las proteínas.

“Ahora podemos explicar por qué las neuronas vecinas eligen receptores similares y proyectan al mismo lugar en el cerebro”, detallaron los investigadores.

Robert Sandeep remarcó un horizonte concreto: “No podemos solucionar el problema del olfato sin comprender cómo funciona a nivel básico”, expuso. Hoy, la falta de terapias eficaces para la pérdida del olfato, agudizada por fenómenos como la COVID-19, representa una frontera científica no resuelta. El nuevo mapa plantea el diseño de estrategias como terapias con células madre, edición génica o el desarrollo de interfaces cerebro-computadora que restaure la función sensorial precisando exactamente qué receptores y neuronas reconstruir.

El grupo extiende los experimentos a tejido humano para determinar si el patrón descrito en ratones se reproduce en nuestra especie. Según Datta: “El olfato tiene un efecto profundo y generalizado en la salud humana, por lo que recuperarlo no sólo aporta placer y seguridad, sino también bienestar psicológico. Sin comprender este mecanismo, estamos condenados al fracaso en el desarrollo de nuevos tratamientos”.

Los hallazgos modifican la concepción misma de la biología sensorial e instalan un nuevo principio: la organización espacial es universal en todos los sentidos y responde a regulaciones moleculares que trascienden la percepción para influir en salud mental y calidad de vida.

Another assassination attempt targeting Donald Trump at the White House Correspondents’ Dinner adds to a mounting list of threats since he entered politics — a total that now equals what two hands can count.

Just days before the most recent assassination attempt, House Minority Leader Hakeem Jeffries, D-N.Y., said Democrats are in an «era of maximum warfare,» prompting criticism from Republicans that the political rhetoric is pushing citizens to commit political violence. Since the assassination of Turning Point USA founder Charlie Kirk, calls from politicians and activists on both sides to «lower the temperature» have grown into an ongoing national conversation.

Ever since Trump first entered the political sphere in 2015, prominent public figures have referred to him as a «fascist,» a «Nazi,» and he’s been likened to Adolf Hitler. Comparisons to Trump and members of his administrations to Nazi Germany have only grown since he took office in January 2025. Many of Trump’s attempted attackers or assassins have pointed to their belief that Trump was a «White supremacist,» a «bully,» as rationale for their planned attacks.

«President Trump remains completely undeterred, despite the multiple attempts on his life by cowardly individuals,» White House spokeswoman Allison Schuster said. «The President will not allow deranged lunatics to change the fabric of this Country and dictate the American way of life. President Trump and the entire Administration will continue to stand strong and fight for the American people.»

Here is a timeline of all the known attacks on President Donald Trump’s life:

UNEARTHED VIDEO REVEALS COLE ALLEN AS QUIET INVENTOR YEARS BEFORE ALLEGED BID TO ASSASSINATE TRUMP

March 12, 2016 — Dayton, Ohio

During his 2016 presidential campaign, Trump held a rally at Wright State University. A 22-year-old protester named Thomas DiMassimo jumped a security barrier and attempted to charge the stage, but he was stopped by Secret Service. DiMassimo claimed he wanted to «bully the bully» and was going to make «some remarks» to Trump and his followers. He was charged with a misdemeanor and was sentenced to a year of probation.

June 18, 2016 — Las Vegas, Nev.

Michael Steven Sandford, a British national, attempted to grab a police officer’s gun while in attendance at Trump’s rally in Las Vegas. Sandford, who is diagnosed with autism, told an arresting officer that he intended to «shoot and kill Trump.» He was sentenced to 12 months and a day in U.S. federal prison, and he was deported back to the United Kingdom after he completed his sentence.

Sept. 6, 2017 — Mandan, N.D.

During President Trump’s visit to Andeavor Mandan Refinery where he delivered a speech on tax reform, Gregory Lee Leingang attempted to drive a stolen forklift into the presidential motorcade. He intended to «flip» Trump’s limousine and kill him, but the forklift got stuck. Leingang was sentenced to 20 years in prison.

MAN ACCUSED OF IRAN-BACKED TRUMP ASSASSINATION PLOT COMPARED HIS PLAN TO BUTLER SHOOTING: FBI

Law enforcement personnel detain Cole Tomas Allen, a suspect in the shooting incident at the White House Correspondents’ Association dinner in Washington, D.C., on April 25, 2026. (Donald J Trump via Truth Social/Handout via Reuters)

November 2017 — Manila, Philippines

During Trump’s visit to the Philippines for the Association of Southeast Asian Nations’ ASEAN 50 Summit, ISIS operatives planned to kill the president, having released several videos threatening Trump’s life. One of the videos includes a picture of Trump with several bullet holes. Just twenty minutes before Trump’s plane landed, Secret Service agents tracked down and apprehended one of the ISIS operatives, who was parked a mile away from Trump’s hotel.

September 2020 — Canada

A Canadian woman mailed to the White House and eight Texas state law enforcement officials a slew of threatening letters and homemade ricin — a deadly toxin. Pascale Cecile Veronique Ferrier, 55, called in the letters for Trump to end his presidential candidacy, and made calls on Twitter that «someone please shoot ‘Trump in the face.’» Border patrol agents stopped Ferrier at the Peace Bridge Border Crossing in Buffalo, N.Y., on Sept. 20, 2020. She was in possession of a loaded firearm and hundreds of rounds of ammunition. She was sentenced to over 21 years in prison.

April 2024 — Iranian plot

Asif Raza Merchant, a Pakistani national and a trained operative of Iran’s Islamic Revolutionary Guard Corps, was sent by the terrorist force to plan and execute political assassinations with intended targets including President Donald Trump, former President Joseph Biden, and U.S. Ambassador to the United Nations Nikki Haley, according to the Eastern District of New York. Merchant arrived in the United States in April 2024 and met with a purported hitmen in June, but in reality were undercover U.S. law enforcement officers. Merchant was convicted in March 2026, but has not yet been sentenced.

NEW BOOK DETAILS SECURITY LAPSES AHEAD OF TRUMP ASSASSINATION ATTEMPT: ‘CLEAR THERE WAS A PROBLEM’

Thomas Matthew Crooks, a 20-year-old from Bethel Park, Pennsylvania, attempted to assassinate former President Donald Trump during a 2024 campaign rally before being shot and killed by Secret Service agents. (Obtained by Fox News Digital)

July 13, 2024 — Butler, Pa.

Positioned roughly 150 yards atop a building outside the security perimeter at Trump’s Butler rally, assassin Thomas Matthew Crooks fired approximately eight shots from his AR-15 rifle — hitting Trump in the ear and killing an attendee, Corey Comperatore, 50. It was the closest attempt on Trump’s life. Crooks, 20, was killed by a member of the Secret Service counter sniper team. Little is known about Crooks, who acted alone with no criminal history. The attempted assassination has intensified scrutiny over the Secret Service.

Sept. 15, 2024 — West Palm Beach, Fla.

A little more than two months after Butler, a Secret Service agent found Ryan Wesley Routh hiding in a bush near a fence surrounding Trump’s West Palm Beach golf course after noticing the barrel of a rifle poking out. Routh fled and was later apprehended. Routh was sentenced to life in prison in February after being convicted for his assassination attempt on Trump. In a letter outlining his reasoning for assassinating Trump, Routh accused the president of being a threat to democracy, and accused Trump of being a «pedophile» and a «rapist.»

February 2026, Palm Beach, Fla.

Austin Tucker Martin, a 21-year-old from North Carolina, breached Mar-a-Lago’s perimeter carrying a gas can and shotgun. Secret Service agents confronted Martin, ordering him to lay down his weapons, but he refused. Martin was fatally shot by the Secret Service agents. At the time of the incident, Trump was at the White House. Martin’s motive remains unknown.

ARMED MAN SHOT AND KILLED AFTER ‘UNAUTHORIZED ENTRY’ INTO MAR-A-LAGO: SECRET SERVICE

Ryan W. Routh, suspected of attempting to assassinate former President Donald Trump at his West Palm Beach golf course, stands handcuffed between two Martin County Sheriff’s deputies after his arrest during a traffic stop near Palm City, Fla., on Sept. 15, 2024. (Martin County Sheriff’s Office/Handout via REUTERS)

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April 25, 2026, Washington, D.C.

The most recent alleged attempted assassin, Cole Tomas Allen, a 31-year-old school teacher from California, rushed the lobby doors leading to the Washington Hilton Hotel ballroom where the dinner was held. He fired several shots before Secret Service agents tackled him to the ground, stopping Allen from breaching the ballroom. Acting Attorney General Todd Blanche said that based on the evidence collected, which includes a manifesto, investigators suspect that Allen sought to kill as many high-ranking cabinet officials as possible, including President Donald Trump.

An 89-year-old gunman allegedly opened fire inside two Athens government buildings Tuesday, wounding at least four people in a rare outbreak of violence that rattled Greece’s tightly controlled gun landscape and ended with his arrest hours later.

Police said the suspect first stormed a social security office, went up to the fourth floor and fired, striking an employee in the leg. Officials said the gunman warned one worker to duck before pulling the trigger, though he didn’t appear to specifically target the employee he hit.

«He went in, went up to the fourth floor, raised his shotgun, told an employee to duck and hit another one,» Alexandros Varveris, head of Greece’s National Social Security Fund, told state broadcaster ERT radio.

The wounded man was treated at the scene, but the suspect fled and later opened fire again inside a courthouse in another part of the city, where several people were wounded.

NINE DEAD, 13 IN SECOND TURKISH MASS SHOOTING IN TWO DAYS

Authorities said at least three women, all court employees, suffered minor injuries from ricocheting pellets, while media reported that a fourth woman was taken to a hospital as a precaution.

People leave a courthouse after a gunman opened fire, wounding several people in Athens on Tuesday, April 28, 2026. (Petros Giannakouris/AP)

Surveillance video aired by local media showed a man calmly walking down the street carrying what appeared to be a short-barreled shotgun.

SYNAGOGUE IN LONDON TARGETED IN ATTEMPTED ‘ANTISEMITIC HATE CRIME,’ UK POLICE SAY

Police later arrested the suspect near the city of Patra, about 130 miles west of Athens, and recovered the weapon.

A policeman speaks with a woman outside a courthouse in Athens after a gunman opened fire, wounding several people, on April 28, 2026. (Petros Giannakouris/AP)

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The motive remains unclear, though state media reported the man left documents behind at the courthouse outlining his grievances.

The Associated Press contributed to this report.