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