How does the brain create our perception of reality?

New findings explore how patterns of brain activity shape the way we perceive the world

Reports and Proceedings

SOCIETY FOR NEUROSCIENCE

WASHINGTON, D.C. — New findings from studies in both people and animals are revealing clues about how sensory information and cognitive processes interact in the brain to produce our perception of the world. The findings were presented at Neuroscience 2021, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.

Sensory inputs, such as sights, sounds, and touches, yield rich information about the external world. But our perception and interpretation of sensations are heavily shaped by cognitive processes such as attention, expectation, and memory. A better understanding of the neural basis of perceptual phenomena will help clarify both ordinary experiences — such as the ability to pick a single voice out of a noisy background — and disorders in which perception is altered — such as attention-deficit/hyperactivity disorder, autism, schizophrenia, and Alzheimer’s disease.

Today’s new findings show:

• In mice, a specific type of brain cell called a PV neuron improves the ability to distinguish a target sound from background noise (i.e., the cocktail party problem) (Kamal Sen, Boston University).
• The feeling of ownership over one’s body while experiencing an event strengthens the memory representation of that event in the hippocampus, a brain region involved in learning and memory (Heather Iriye, Karolinska Institute, Sweden).
• In humans and monkeys, imagining an object’s movement activates motion-sensitive areas of the brain, suggesting that both species can simulate versions of the world in similar ways (David Sheinberg, Brown University).
• A novel technique involving non-invasive transcranial magnetic stimulation (TMS) informed by real-time scalp EEG recordings enhanced human visual perception by modulating communication between frontal and visual brain regions (Nitzan Censor, Tel-Aviv University, Israel).

“The neuroscience findings presented today demonstrate the importance of comparative brain studies in long-standing issues in human perception and cognition,” said Sabine Kastner, a professor at Princeton University who studies visual perception and attention. “These advances show how research in different model systems can come together to inform our understanding of the human brain, from the neurobiological mechanisms of perception to our subjective perceptual experiences.”

This research was supported by national funding agencies including the National Institutes of Health and private funding organizations. Find out more about sensory perception and the brain on BrainFacts.org.

Mechanisms of Perception Press Conference Summary

• Patterns of brain activity at different levels, from individual cells to multi-region networks, are revealing how cognitive processes shape perceptions of sensory information.
• Animal studies can explore the mechanistic underpinnings of perceptual phenomena, while functional imaging studies in humans allow for the investigation of subjective experiences.

PV Neurons Enhance Cortical Coding in the Cocktail Party Problem

Kamal Sen, kamalsen@bu.edu, Abstract P442.10

• The brain mechanisms that enable a listener to select and follow a specific sound in a noisy environment — sometimes called the cocktail party problem — are poorly understood and may be impaired in people with disorders such as hearing impairment and autism.
• In mice, activity of a specific cell type in the auditory cortex, called the PV neuron, improved the brain’s ability to select target sounds amid competing sounds.
• PV neurons enhanced the timing and patterns of cortical neuron firing in response to target sounds, offering a potential strategy for designing better hearing-assistive devices.

Body Ownership and the Neural Processes of Memory Encoding and Reinstatement

Heather Iriye, heather.iriye@ki.se, Abstract P505.02

• The feeling of body ownership — the perception of one’s body as one’s own — during an experience is thought to contribute to how accurately and vividly we are able to remember and reexperience events.
• Researchers combined virtual reality with brain imaging to manipulate participants’ sense of body ownership within immersive videos using a perceptual full-body illusion.
• The more participants could remember about events experienced with body ownership, the stronger the representation of that event in the hippocampus one week later.
• Insights into how to optimize memory formation and preserve the ability to relive past experiences could guide interventions for cognitive disorders such as Alzheimer’s disease.

The Neural Bases of Simulation in the Primate Brain

David Sheinberg, David_Sheinberg@brown.edu, Abstract P775.01

• Perception depends on both information received from our senses and sophisticated cognitive processes such as simulation — internally manipulating rich mental models of the world to imagine experiences one has never had.
• The design of a novel simulation condition, where a ball falls through an obstacle filled space, revealed that animals, like people, appear to use internal simulation to solve this task.
• Functional magnetic resonance imaging showed that simulation of movement by monkeys activates motion-sensitive areas of the brain even though no external motion is being sensed.
• The findings may have implications for the detailed study and treatment of psychiatric disorders in which simulated experiences become confused with reality, such as schizophrenia and post-traumatic stress disorder.

Closed-loop EEG-TMS Modulation of Frontal-occipital Communication Enhances Visual Perception

Nitzan Censor, censornitzan@tauex.tau.ac.il, Abstract P767.09

• Visual perception is shaped by coordinated communication between frontal and visual brain regions.
• Researchers used a novel combination of non-invasive transcranial magnetic stimulation (TMS) of frontal regions and real-time scalp electroencephalography (EEG) recordings of brain activity in visual regions to synchronize activity between the regions.
• The TMS-EEG procedure enhanced participants’ performance on a visual detection-attention task.
• These findings suggest visual perception can be augmented by real-time modulation of communication between distant brain regions.  

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About the Society for Neuroscience

The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.