Science 28Feb2020

IMAGE: HAAS

ET AL.

SCIENCE sciencemag.org 28 FEBRUARY 2020 • VOL 367 ISSUE 6481 995

NEUROSCIENCE

Speech versus music

in the brain

To what extent does the per-

ception of speech and music

depend on different mecha-

nisms in the human brain?

What is the anatomical basis

underlying this specialization?

Albouy et al. created a corpus

of a cappella songs that contain

both speech (semantic) and

music (melodic) information

and degraded each stimu-

lus selectively in either the

temporal or spectral domain.

Degradation of temporal

information impaired speech

recognition but not melody

recognition, whereas degrada-

tion of spectral information

impaired melody recognition

but not speech recognition.

Brain scanning revealed a

right-left asymmetry for speech

and music. Classification of

speech content occurred

exclusively in the left auditory

cortex, whereas classification

of melodic content occurred

only in the right auditory cortex.

—PRS

Science, this issue p. 1043

ECOLOGICAL SPECIATION

Resisting extinction

Prevailing evolutionary wisdom

tells us that ecological differ-

entiation leads to speciation.

Whether this pattern can be

seen over paleontological time,

however, has been difficult to

test. Knope et al. looked at a

dataset of thousands of modern

and extinct marine groups and

found the relationship to be

more complex than expected.

Ecological diversification is

associated with lower rates of

origination, and the taxonomical

richness seemingly associ-

ated with these groups is due

to resistance to extinction.

Furthermore, the researchers

found that the strong asso-

ciation between ecological

differentiation and taxonomic

diversity is a recent develop-

ment shaped by extinction

events over time. —SNV

Science, this issue p. 1035

FLUID DYNAMICS

Machine-learning

fluid flow

Quantifying fluid flow is rel-

evant to disciplines ranging

from geophysics to medicine.

Flow can be experimentally

visualized using, for example,

smoke or contrast agents, but

extracting velocity and pressure

fields from this information is

tricky. Raissi et al. developed

a machine-learning approach

to tackle this problem. Their

method exploits the knowledge

of Navier-Stokes equations,

which govern the dynamics of

fluid flow in many scientifically

relevant situations. The authors

illustrate their approach using

examples such as blood flow in

an aneurysm. —JS

Science, this issue p. 1026

TUMOR IMMUNOLOGY

Getting a hold on MDSCs

Myeloid-derived suppressor

cells (MDSCs) are immune cells

that mediate immune suppres-

sion and are correlated with

progressing cancer. How these

cells arise and whether they can

be therapeutically targeted akin

to exhausted T cells are areas of

active investigation. A persistent

challenge in studying MDSCs

has been the identification of

MDSC-specific cell-surface

markers that can facilitate their

RESEARCH

PLANT SCIENCE

Wavy walls built by nanofilaments

I

n the model plant Arabidopsis, pavement cells fit together

with the lobes and curves of jigsaw puzzle pieces. Such

complex cell shapes, in plants, were generally thought to

be driven by turgor pressure. Haas et al. now show that

the extracellular cell wall can actively shape the cell it

contains without relying on turgor pressure. Nanofilaments

of pectin homogalacturonan in the cell wall shift between

crystalline and anisotropic phases according to whether they

are methylated. The shift in form drives changes in cell wall

shape that stand independent of turgor pressure. —PJH

Science, this issue p. 1003

IN SCIENCE JOURNALS

Edited by Michael Funk

Cryo-fracture scanning electron microscopy image of Arabidopsis

cotyledon tissue colored to highlight exterior (brown) and internal (green)

regions and anticlinal cell walls (magenta)

Published by AAAS