Neuroscientists uncover neural mechanisms of object recognition

July 13, 2011, Carnegie Mellon University
Certain brain injuries can cause people to lose the ability to visually recognize objects -- for example, confusing a harmonica for a cash register. Neuroscientists from Carnegie Mellon University and Princeton University examined the brain of a person with object agnosia, a deficit in the ability to recognize objects that does not include damage to the eyes or a general loss in intelligence, and have uncovered the neural mechanisms of object recognition. The results, published by Cell Press in the July 15th issue of the journal Neuron, describe the functional neuroanatomy of object agnosia and suggest that damage to the part of the brain critical for object recognition can have a widespread impact on remote parts of the cortex. These findings will force researchers to rethink basic assumptions of visual neuroscience. Credit: Carnegie Mellon University and Princeton University

Certain brain injuries can cause people to lose the ability to visually recognize objects — for example, confusing a harmonica for a cash register.

Neuroscientists from Carnegie Mellon University and Princeton University examined the brain of a person with object agnosia, a deficit in the ability to recognize objects that does not include damage to the eyes or a general loss in intelligence, and have uncovered the of . The results, published by Cell Press in the July 15th issue of the journal Neuron, describe the functional neuroanatomy of object agnosia and suggest that damage to the part of the brain critical for object recognition can have a widespread impact on remote parts of the cortex.

"One of the persisting controversies in the field of visual neuroscience concerns the regions of cortex that subserve the human ability to recognize objects as efficiently and accurately as we do, and it's been an elusive topic until now," said Marlene Behrmann, professor of psychology at CMU and a renowned expert in using brain imaging to study the visual perception system.

To gain new insight into the neural basis of object recognition, the research team used neuroimaging and behavioral investigations to study visual and object-selective responses in the cortex of healthy controls and a participant called SM who, following selective brain damage to the right hemisphere of the brain, exhibited object agnosia.

The researchers discovered that the functional organization of the "lower" visual cortex, where the image from the retina is initially processed, was similar in SM and control subjects. However, SM exhibited decreased object-selective responses in the brain tissue in and around the brain lesion, and in more distant cortical areas that are also known to be involved in object recognition. Unexpectedly, the decrease in object-selective responses was also observed in corresponding locations of SM's structurally intact left hemisphere.

"What was perhaps the most dramatic, controversial and counter-intuitive result was that while the lesion was in the right hemisphere, and quite small, we found that the same region in the left hemisphere was also not operating normally," Behrmann said.

She added, "These results will force us in the field to step back a little and rethink the way we understand the relationship between brain and behavior. We now need to take into account that there are multiple parts of the brain that underlie object recognition, and damage to any one of those parts can essentially impair or decrease the ability to normally recognize objects."

Additionally, the researchers found that an area of the brain called the right lateral fusiform gyrus is vital for object recognition. There also appeared to be some functional reorganization in intact regions of SM's damaged right hemisphere, suggesting that neural plasticity is possible even when the brain is damaged in adulthood.

"To our knowledge, this study constitutes the most extensive functional analysis of the neural substrate underlying object agnosia and offers powerful evidence concerning the neural representations mediating object perception in normal vision," said Christina Konen, a postdoctoral fellow at Princeton and lead author of the study.

Explore further: Researchers uncover how the brain processes faces

Related Stories

Researchers uncover how the brain processes faces

May 31, 2011
Each time you see a person that you know, your brain rapidly and seemingly effortlessly recognizes that person by his or her face.

Recommended for you

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 ...

A 'touching sight': How babies' brains process touch builds foundations for learning

January 16, 2018
Touch is the first of the five senses to develop, yet scientists know far less about the baby's brain response to touch than to, say, the sight of mom's face, or the sound of her voice.

Brain zaps may help curb tics of Tourette syndrome

January 16, 2018
Electric zaps can help rewire the brains of Tourette syndrome patients, effectively reducing their uncontrollable vocal and motor tics, a new study shows.

Researchers identify protein involved in cocaine addiction

January 16, 2018
Mount Sinai researchers have identified a protein produced by the immune system—granulocyte-colony stimulating factor (G-CSF)—that could be responsible for the development of cocaine addiction.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

hush1
not rated yet Jul 13, 2011
Without knowing the exact specifics or nature of the injury, I can assert with confidence the only missing link to this associative memory function is a single chemical substance deficiency. Why the brain is no longer able to balance out this deficiency I do not know. I'm sure you will tell me, eventually.

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.