Nav: Home

There's Waldo!

June 14, 2018

From looking for Waldo to finding your cellphone on a cluttered kitchen table, we are continuously engaged in visual searches. How does the brain do this? How do we know where to look? How do we know when we've found what we are looking for? For the first time, neuroscientists from Caltech have found neurons in the human brain that respond when our targets are spotted. The research involved a collaboration with scientists at Cedars-Sinai Medical Center in Los Angeles, where the data were collected, and West Virginia University.

Writing in the latest issue of the journal Current Biology, the team describes how they recorded the activity of individual visual-targeting neurons in patients with electrodes implanted in their brains for epilepsy treatment. Piggybacking on this unique clinical setup, the researchers had patients search for target images within other pictures--similar to how someone looks for Waldo in the Where's Waldo? books. While they were recording neural activity, they also tracked the patients' eye movements, so they could tell exactly which part of the image the patients were looking at.

When the patient found the target objects, neurons were activated in two areas of the brain: the medial temporal lobe, a region known to be involved in memory and object recognition, and the medial frontal cortex, a region known to be involved in control and decision-making.

"This was the first discovery of cells in the human brain that respond just when you look at a visual target," explains the study's lead author, Shuo Wang (PhD '14), who was a graduate student in Caltech's Computation & Neural Systems program and subsequently a postdoctoral fellow at Caltech when the experiments were done. He is now an assistant professor at West Virginia University.

While a few studies had previously found such neurons in the temporal cortex of monkeys, the experiment had never been done in a human subject. The researchers also found that the neurons in the medial temporal lobe responded about 200 milliseconds later than those in the medial frontal cortex.

"This difference supports the hypothesis that the frontal cortex first detects that a target has been found, and then feeds that signal down to the medial temporal lobe," says Ueli Rutishauser (PhD '08), the senior author on the study in whose laboratory at Cedars-Sinai Medical Center the data were collected. "This points us to specific circuits in the brain involved in the processes required for visual search."

The same team of authors had previously found cells in the medial temporal lobe that encode specific object categories, such as faces, and the present findings add to that prior work.

"We found two distinct populations of neurons in the medial temporal lobe. One population, which we already knew about, recognizes objects in terms of their appearance--for instance, whether something is a face or not," says paper co-author Ralph Adolphs (PhD '93), Caltech's Bren Professor of Psychology, Neuroscience, and Biology; the Allen V. C. Davis and Lenabelle Davis Leadership Chair; and director of the Caltech Brain Imaging Center." A second population, first discovered in this experiment, recognizes objects not in terms of their appearance, but in terms of their goal-directed relevance: whether this was something we were searching for or not, regardless of how it looks."

The scientists say these findings are just the beginning of important work to explain how all these different brain regions work together. A particular strength of the study, they say, was the ability to record target neurons in both the medial temporal lobe and the medial frontal cortex, and the question now is exactly how these brain regions communicate with one another during a visual search task. Impairments in this circuit may underlie some of the attentional impairments that are seen in disorders such as schizophrenia.
-end-
An additional co-author on the paper, "Encoding of target detection during visual search by single neurons in the human brain," is Adam Mamelak, a neurosurgeon at Cedars-Sinai Medical Center and longtime collaborator with the team. The work was funded by the Rockefeller Neuroscience Institute at West Virginia University, the Autism Science Foundation, the Dana Foundation, the Simons Collaboration on the Global Brain, the National Science Foundation, and the National Institutes of Health.

California Institute of Technology

Related Neurons Articles:

New tool to identify and control neurons
One of the big challenges in the Neuroscience field is to understand how connections and communications trigger our behavior.
Neurons that regenerate, neurons that die
In a new study published in Neuron, investigators report on a transcription factor that they have found that can help certain neurons regenerate, while simultaneously killing others.
How neurons use crowdsourcing to make decisions
When many individual neurons collect data, how do they reach a unanimous decision?
Neurons can learn temporal patterns
Individual neurons can learn not only single responses to a particular signal, but also a series of reactions at precisely timed intervals.
A turbo engine for tracing neurons
Putting a turbo engine into an old car gives it an entirely new life -- suddenly it can go further, faster.
Brain neurons help keep track of time
Turning the theory of how the human brain perceives time on its head, a novel analysis in mice reveals that dopamine neuron activity plays a key role in judgment of time, slowing down the internal clock.
During infancy, neurons are still finding their places
Researchers have identified a large population of previously unrecognized young neurons that migrate in the human brain during the first few months of life, contributing to the expansion of the frontal lobe, a region important for social behavior and executive function.
How many types of neurons are there in the brain?
For decades, scientists have struggled to develop a comprehensive census of cell types in the brain.
Molecular body guards for neurons
In the brain, patterns of neural activity are perfectly balanced.
Engineering researchers use laser to 'weld' neurons
University of Alberta researchers have developed a method of connecting neurons, using ultrashort laser pulses -- a breakthrough technique that opens the door to new medical research and treatment opportunities.

Related Neurons Reading:

The Neuron: Cell and Molecular Biology
by Irwin B. Levitan (Author), Leonard K. Kaczmarek (Author)

The Fourth Edition of The Neuron provides a comprehensive first course in the cell and molecular biology of nerve cells. The book begins with properties of the many newly discovered ion channels that have emerged through mapping of the genome. These channels shape the way a single neuron generates varied patterns of electrical activity. Covered next are the molecular mechanisms that convert electrical activity into the secretion of neurotransmitter hormones at synaptic junctions between neurons. The following section examines the biochemical pathways that are linked to the action of... View Details


The Neuron: Cell and Molecular Biology
by Irwin B. Levitan (Author), Leonard K. Kaczmarek (Author)

The third edition of The Neuron provides a comprehensive first course in the cell and molecular biology of nerve cells. The first part of the book covers the properties of the many ion channels that shape the way a single neuron generates varied patterns of electrical activity, as well as the molecular mechanisms that convert electrical activity into the secretion of neurotransmitter hormones at synaptic junctions between neurons. The second part covers the biochemical pathways that are linked to the action of neurotransmitters and can alter the cellular properties of neurons or... View Details


The Myth of Mirror Neurons: The Real Neuroscience of Communication and Cognition
by Gregory Hickok (Author)

An essential reconsideration of one of the most far-reaching theories in modern neuroscience and psychology.

In 1992, a group of neuroscientists from Parma, Italy, reported a new class of brain cells discovered in the motor cortex of the macaque monkey. These cells, later dubbed mirror neurons, responded equally well during the monkey’s own motor actions, such as grabbing an object, and while the monkey watched someone else perform similar motor actions. Researchers speculated that the neurons allowed the monkey to understand others by simulating their actions in its... View Details


From Neurons to Neighborhoods : The Science of Early Childhood Development
by Committee on Integrating the Science of Early Childhood Development (Author), Youth, and Families Board on Children (Author), National Research Council (Author), Committee on Integrating the Science of Early Childhood Development (Author), Jack P. Shonkoff (Editor), Deborah A. Phillips (Editor)

How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media.

How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a... View Details


From Photon to Neuron: Light, Imaging, Vision
by Philip Nelson (Author)

A richly illustrated undergraduate textbook on the physics and biology of light

Students in the physical and life sciences, and in engineering, need to know about the physics and biology of light. Recently, it has become increasingly clear that an understanding of the quantum nature of light is essential, both for the latest imaging technologies and to advance our knowledge of fundamental life processes, such as photosynthesis and human vision. From Photon to Neuron provides undergraduates with an accessible introduction to the physics of light and offers a unified view... View Details


From Neuron to Brain
by John G. Nicholls (Author), A. Robert Martin (Author), David A. Brown (Author), Mathew E. Diamond (Author), David A. Weisblat (Author), Paul A. Fuchs (Author)

From Neuron to Brain, Fifth Edition, provides a readable, up-to-date book for use in undergraduate, graduate, and medical school courses in neuroscience. As in previous editions, the emphasis is on experiments made by electrical recordings, molecular and cellular biological techniques, and behavioral studies on the nervous system, from simple reflexes to cognitive functions. Lines of research are followed from the inception of an idea to new findings being made in laboratories and clinics today.

A major change is that this edition begins with the anatomy and physiology of the... View Details


The 7 Secrets of Neuron Leadership: What Top Military Commanders, Neuroscientists, and the Ancient Greeks Teach Us about Inspiring Teams
by W. Craig Reed (Author), Gordon R. England (Foreword)

Leadership techniques backed by the world's most effective teams

The 7 Secrets of Neuron Leadership offers a diverse collection of wisdom and practical knowledge to help you build and lead your most effective team yet. Written by a former U.S. Navy diver, this book draws from the author's experiences and beyond to reveal key truths about the nature of teamwork, and expose the core of effective team leadership. You'll go back to ancient Greece to discover the nine personality types and the seven types of love that form the foundation of human interaction, and learn how... View Details


From Neuron to Brain: A Cellular and Molecular Approach to the Function of the Nervous System, Fourth Edition
by John G. Nicholls (Author), A. Robert Martin (Author), Bruce G. Wallace (Author), Paul A. Fuchs (Author)

In the 25 years since From Neuron to Brain was first published, the authors' aim has remained constant—to describe how nerve cells go about their business of transmitting signals, how the signals are put together, and how, out of this integration, higher functions emerge. The new Fourth Edition, while maintaining this focus, has been completely reformatted and updated.

The emphasis, as before, is on experiments, and on the way they are carried out. Using a narrative approach, the authors follow a line from the original inception of a new idea to an account of research being done today.... View Details


Neurons in Action 2: Tutorials and Simulations using NEURON
by John W. Moore (Author), Ann E. Stuart (Author)

Note: Purchase of Neurons in Action 2 provides the user with a 180-day online subscription.

Neurons in Action 2 is the second version of a unique software learning tool that combines hyperlinked text with NEURON simulations of laboratory experiments in neurophysiology. Version 2 features nine new tutorials introducing new channel types, single-channel simulations, and a redesigned interface. Neurons in Action's moving graphs provide insight into nerve function that is simply not possible with conventional,... View Details


From Neuron to Brain: A Cellular and Molecular Approach to the Function of the Nervous System
by John G. Nicholls (Author), A. Robert Martin (Author), Bruce G. Wallace (Author)

Up-to-date third edition which presents a coherant description of the nervous system from the perspective of modern work on molecular biology, cellular and developmental biology, biophysics, neurophysiology, neurochemistry and neuroanatomy. The scope of the book has been broadened with entirely new chapters on the biophysics and molecular biology of membrane channels, indirect mechanisms of synaptic transmission, the cellular and molecular biology of synaptic transmission, nervous system development, sensory receptors and systems, and motor systems. To accommodate this new information other... View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Person You Become
Over the course of our lives, we shed parts of our old selves, embrace new ones, and redefine who we are. This hour, TED speakers explore ideas about the experiences that shape the person we become. Guests include aerobatics pilot and public speaker Janine Shepherd, writers Roxane Gay and Taiye Selasi, activist Jackson Bird, and fashion executive Kaustav Dey.
Now Playing: Science for the People

#479 Garden of Marvels (Rebroadcast)
This week we're learning about botany and the colorful science of gardening. Author Ruth Kassinger joins us to discuss her book "A Garden of Marvels: How We Discovered that Flowers Have Sex, Leaves Eat Air, and Other Secrets of the Way Plants Work." And we'll speak to NASA researcher Gioia Massa about her work to solve the technical challenges of gardening in space.