Predicting grip movements of the hand by measuring brain cell activity

January 22, 2015, German Primate Center
Researchers at the DPZ built this robothand. They analyse the brain activity of non human primates during the execution of hand grasping movements. This neuronal information, recorded with fine electrodes in the cortex, could one day be used to control a robotic hand as a prosthesis for paralyzed people. Credit: Sebastian Lehmann

Tying shoelaces, stirring coffee, writing letters, playing the piano. From the usual daily routine to demanding activities: Our hands are used more frequently than any other body part. Through our highly developed fine motor skills, we are able to perform grasping movements with variable precision and power distribution. This ability is a fundamental characteristic of the hand of primates. Until now, it was unclear how hand movements are planned in the brain.

The most recent research project of Stefan Schaffelhofer, Andres Agudelo-Toro and Hansjörg Scherberger from the German Primate Center has shown how different grasping movements in the brain are controlled in rhesus monkeys. Using electrophysiological measurements in those areas of the brain that are responsible for the planning and execution of , the scientists could predict a variety of positions through the analysis of exact neural signals. In initial experiments, the application of decrypted grip types was transferred to a robot hand. The results of the study will be incorporated in the future development of neuroprostheses, which will be used to enable paralyzed patients the recovery of hand functions (The Journal of Neuroscience, 2015).

"We wanted to find out how different hand movements are controlled by the brain and whether it was possible to use the activity of nerve cells to predict different grip types", says Stefan Schaffelhofer, neuroscientist in the Neurobiology Laboratory of the DPZ.

Within the framework of his PhD thesis, he intensively dealt with those brain areas of the cerebral cortex, which are responsible for the planning and execution of hand movements. In the course of his studies, he found out that visual information for objects that can be gripped, especially their three-dimensional shape and size are mainly processed in the AIP region. The transmission of the visual characteristics of an object in corresponding movement commands is mainly controlled in the areas F5 and M1.

To research the regulation of various grip movements in these regions of the brain in detail, the activity was recorded from neurons with so-called multi electrode arrays. The researchers have trained the to repeatedly grasp 50 objects of different shapes and sizes. In order to identify the grip types and to compare them with the neural signals, an electromagnetic data glove was used to record all the finger and hand movements of monkeys.

"Prior to the start of a grasping movement, we have illuminated all the objects so that the monkeys could see them and recognize their shape," said Stefan Schaffelhofer. "The subsequent grasping movement then took place in the dark with a short delay. We were then able to separate the responses of the neurons to the visual stimuli in motor signals as well as examine the phase of motion planning."

Hand movements in the primate brain are controlled by the brain areas AIP, F5 and M1. Credit: Stefan Schaffelhofer

Based on the activity of measured during the planning and execution of the grasping movements, scientists could subsequently draw conclusions on the applied grip types. The predicted grips were compared to the actual hand configurations in the experiment.

"The activity of the measured brain cells is strongly dependent on the grip that was applied. Based on these neural differences, we can calculate the hand movement of the animal" says Stefan Schaffelhofer. "In the planning phase we predicted hand configurations with an accuracy of up to 86% and 92% for the gripping phase.

The decrypted hand configurations were subsequently successfully transferred to a robotic hand. With this, the scientists have shown that a large number of different hand configurations can be decoded and used from neuronal planning and execution signals. A finding, that is of great importance for the future of especially paraplegic patients where the connection between the brain and limbs no longer functions.

"The results of our study are very important for the development of neural-controlled prosthetic hands. They show where and especially how the controls grasping movements", Stefan Schaffelhofer summarizes. "Unlike other applications, our method allows a prediction of the grip types in the planning phase of the movement. In future, this can be used to generate neural interface to read, interpret and control the motoric signals."

Explore further: Remapping the damaged brain

More information: Schaffelhofer, S., Agudelo-Toro, A. and Scherberger, H. (2015): "Decoding a wide range of hand configurations from macaque motor, premotor and parietal cortices." The Journal of Neuroscience 35(3):1068-1081.

Related Stories

Remapping the damaged brain

January 6, 2015
Scientists at the RIKEN Center for Life Science Technologies, along with researchers from the AIST Human Technology Research Institute in Japan, have identified a time-dependent interplay between two brain regions that contributes ...

Research determines how the brain computes tool use

May 8, 2013
(Medical Xpress)—With a goal of helping patients with spinal cord injuries, Jason Gallivan and a team of researchers at Queen's University's Department of Psychology and Centre for Neuroscience Studies are probing deep ...

A brain area responsible for grasping

April 4, 2014
(Medical Xpress)—The research group led by Silvia Arber at the Friedrich Miescher Institute for Biomedical Research and the Biozentrum of the University of Basel has shown that limb motor control is regulated by a selective ...

Providing simple neural signals to brain implants could stand in for body's own feedback system

November 25, 2014
In new research that brings natural movement by artificial limbs closer to reality, UC San Francisco scientists have shown that monkeys can learn simple brain-stimulation patterns that represent their hand and arm position, ...

Researchers model how neurons work together

June 18, 2014
A newly-developed, highly accurate representation of the way in which neurons behave when performing movements such as reaching could not only enhance understanding of the complex dynamics at work in the brain, but aid in ...

Thumbs-up for mind-controlled robotic arm (w/ Video)

December 16, 2014
A paralysed woman who controlled a robotic arm using just her thoughts has taken another step towards restoring her natural movements by controlling the arm with a range of complex hand movements.

Recommended for you

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

Miles Davis is not Mozart: The brains of jazz and classical pianists work differently

January 16, 2018
Keith Jarret, world-famous jazz pianist, once answered in an interview when asked if he would ever be interested in doing a concert where he would play both jazz and classical music: "No, that's hilarious. [...] It's like ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.