Related Experiment Video

Updated: Feb 17, 2026

Block Building Task Identifies Distinct Groups of Left/Right-hand Choice Patterns After Unilateral Peripheral Nerve Injury
07:06

Block Building Task Identifies Distinct Groups of Left/Right-hand Choice Patterns After Unilateral Peripheral Nerve Injury

Published on: March 21, 2025

1.2K

The origin of human handedness and its role in pre-birth motor control

Valentina Parma1, Romain Brasselet2, Stefania Zoia3

  • 1International School for Advanced Studies (SISSA), Trieste, Italy. vparma@sissa.it.

Scientific Reports
|December 3, 2017
PubMed

Insights

Handedness in humans emerges by 18 gestational weeks, detectable via fetal arm movements during ultrasound. This kinematic analysis accurately predicts postnatal hand dominance, offering insights into early human development.

Area of Science:

  • Developmental Neuroscience
  • Human Embryology
  • Motor Control

Background:

  • Human handedness, predominantly right-handedness, is a well-established trait.
  • The precise timing and developmental origins of handedness during human ontogenesis remain largely unknown.
  • Understanding the emergence of motor biases is crucial for developmental studies.

Purpose of the Study:

  • To investigate the emergence of handedness in human fetuses.
  • To develop a method for inferring fetal handedness from arm movement kinematics.
  • To determine the earliest gestational age at which handedness can be detected.

Main Methods:

  • Kinematic analysis of fetal arm movements recorded via standard ultrasonography from 18 gestational weeks.
  • Classification of fetuses based on postnatal hand dominance at age 9.
  • Utilizing movement times and deceleration estimates for handedness inference.

Main Results:

  • Fetuses exhibited faster dominant hand movements when reaching for precision targets (eyes, mouth).
  • Handedness could be inferred with 89-100% accuracy from 18 gestational weeks.
  • Classification accuracy was consistent between right-handed (86%) and left-handed fetuses.

Conclusions:

  • Fetal motor patterns at 18 gestational weeks predict postnatal handedness.
  • Standard ultrasonography offers a reliable, non-invasive method to study prenatal handedness.
  • This approach advances understanding of early motor development and brain lateralization.

More Related Videos

In Vivo Wireless Optogenetic Control of Skilled Motor Behavior07:52

In Vivo Wireless Optogenetic Control of Skilled Motor Behavior

Published on: November 22, 2021

3.9K
One Dimensional Turing-Like Handshake Test for Motor Intelligence14:05

One Dimensional Turing-Like Handshake Test for Motor Intelligence

Published on: December 15, 2010

28.5K

Related Concept Videos

Hierarchy of Motor Control01:18

Hierarchy of Motor Control

The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
6.4K
Changes in the Appendicular Skeleton with Age01:09

Changes in the Appendicular Skeleton with Age

The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
3.7K
Indirect Motor Pathways01:22

Indirect Motor Pathways

The indirect motor or extrapyramidal pathways originate in the brainstem, the lower portion of the brain that connects it to the spinal cord. They consist of several distinct tracts, each with specialized functions. The four main tracts of the indirect motor pathways are the vestibulospinal tract, the reticulospinal tract, the tectospinal tract, and the rubrospinal tract.
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
3.7K
Direct Motor Pathways01:11

Direct Motor Pathways

The direct motor pathways, also known as the pyramidal tracts, are a group of neural pathways that originate in the brain and descend through the spinal cord. They control the voluntary movement of the body. There are two major direct motor pathways: the corticospinal and the corticobulbar tracts.
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
4.6K
Muscles of the Forearm that Move the Hand and Fingers01:16

Muscles of the Forearm that Move the Hand and Fingers

The muscles of the forearm that move the wrist, hand, and digits are numerous and diverse. They can be classified into two groups based on their location and function — the anterior and posterior compartment muscles.
Anterior Compartment
The anterior compartment muscles originate from the humerus. They primarily function as flexors and are also known as flexor muscles. They typically insert on the carpals, metacarpals, and phalanges. The superficial layer includes the flexor carpi...
2.7K
Lateralization01:28

Lateralization

Brain lateralization refers to the division of mental processes and functions between the two hemispheres of the brain, a phenomenon that optimizes neural efficiency and underpins complex abilities in humans. This specialization allows each hemisphere to perform tasks where it has a comparative advantage, facilitating more refined cognitive capabilities across different domains.
1.1K