April 2019, ScientificAmerican.com 1April 2019VOLUME 320, NUMBER 4Photograph by Mattia Balsamini
ON THE COVEr
Tapping into the brain’s neural circuits lets people
with spinal cord injuries manipulate computer
cursors and robotic limbs. Early studies underline
the need for technical ad vances that make
brain-machine interfaces faster and more
versatile. The latest versions may begin to realize
the promise of direct neural communication.
Illustration by Mark Ross.48
NEUROTECH
24 The Intention Machine
A new generation of brain-machine
interface can deduce what a person
wants. By Richard Andersen
INFRASTRUCTURE
32 Beyond Seawalls
Fortified wetlands and oyster reefs
can protect shorelines better than
hard structures. By Rowan Jacobsen
PUBLIC HEALTH
38 The Dengue Debacle
In April 2016 children in the Philip-
pines began receiving the world’s
first dengue vaccine. Almost two
years later new research showed
that the vaccine was risky for many
kids. The campaign ground to
a halt, and the public exploded
in outrage. What went wrong?
By Seema Yasmin and
Madhusree Mukerjee
PHYSICS
48 Quantum Gravity
in the Lab
Novel experiments could test
the quantum nature of gravity
on a tabletop. By Tim Folger
MEDICINE
56 A Shot at Regeneration
A once forgotten drug compound
could rebuild damaged organs.
By Kevin Strange and Viravuth Yin
ANIMAL PHYSIOLOGY
62 Shock and Awe
Understanding the electric eel’s
unusual anatomical power.
By Kenneth C. Catania
M ATHEM ATIC S
70 Outsmarting
a Virus with Math
How calculus helped to drive
the fight against HIV.
By Steven Strogatz