New research from the University of Guelph on the brain and memory could help in developing therapies for people with schizophrenia and Alzheimer’s disease.
The study by psychology professor Boyer Winters and his research team was published recently in the Journal of Neuroscience.
Their work sheds new light on the internal workings of the brain, specifically regions involved in recognizing and remembering objects.
“Our study suggests that past experience with an object alters the brain circuitry responsible for object recognition,” said Winters.
“It has significant implications for our understanding of multisensory information processing.”
Multisensory integration is an important part of memory, Winters said. For example, if you hold something while blindfolded, chances are you can recognize it by touch if you have seen it before. But how?
Specialized areas of the brain mediate information for sight and touch, Winters said. Some researchers say those regions “talk” to each other, enabling better recognition of an object.
Others believe that the brain integrates information from the senses and stores it in a separate place entirely, and then taps into that area to aid object recognition.
Winters and his team from U of G’s Collaborative Neuroscience Program set out to test which model is correct using rats.
They let some rats briefly explore an object’s tactile and visual characteristics. The next day, the researchers showed the object to the same animals, and compared their responses to rats seeing the object for the first time.
Rats exploring the objects for the first time appeared to use multiple specialized brain regions to recognize the object, while rats with previous exposure tapped into a separate part of their brains to perform the same memory task.
“Knowing what an object looks like enables them to assimilate information in a way that doesn’t happen when there is no pre-exposure,” Winters said.
“Our study suggests there is an assigned region of the brain for memory based on previous experience with objects.”
The more exposure to an object, the more information about it is stored in dedicated parts of the brain, leading to more efficient behavioural responses, Winters said.
The research may help in developing therapies for people with dementia and other brain disorders who cannot recognize highly familiar objects or people, he said.
Source: Boyer Winters – University of Guelph
Image Source: The image is adapted from the University of Guelph press release
Original Research: Abstract for “The Dynamic Multisensory Engram: Neural Circuitry Underlying Crossmodal Object Recognition in Rats Changes with the Nature of Object Experience” by Derek L. Jacklin, Jacob M. Cloke, Alphonse Potvin, Inara Garrett, and Boyer D. Winters in Journal of Neuroscience. Published online January 27 2016 doi:10.1523/JNEUROSCI.3043-15.2016
Abstract
The Dynamic Multisensory Engram: Neural Circuitry Underlying Crossmodal Object Recognition in Rats Changes with the Nature of Object Experience
Rats, humans, and monkeys demonstrate robust crossmodal object recognition (CMOR), identifying objects across sensory modalities. We have shown that rats’ performance of a spontaneous tactile-to-visual CMOR task requires functional integration of perirhinal (PRh) and posterior parietal (PPC) cortices, which seemingly provide visual and tactile object feature processing, respectively. However, research with primates has suggested that PRh is sufficient for multisensory object representation. We tested this hypothesis in rats using a modification of the CMOR task in which multimodal preexposure to the to-be-remembered objects significantly facilitates performance. In the original CMOR task, with no preexposure, reversible lesions of PRh or PPC produced patterns of impairment consistent with modality-specific contributions. Conversely, in the CMOR task with preexposure, PPC lesions had no effect, whereas PRh involvement was robust, proving necessary for phases of the task that did not require PRh activity when rats did not have preexposure; this pattern was supported by results from c-fos imaging. We suggest that multimodal preexposure alters the circuitry responsible for object recognition, in this case obviating the need for PPC contributions and expanding PRh involvement, consistent with the polymodal nature of PRh connections and results from primates indicating a key role for PRh in multisensory object representation. These findings have significant implications for our understanding of multisensory information processing, suggesting that the nature of an individual’s past experience with an object strongly determines the brain circuitry involved in representing that object’s multisensory features in memory.
SIGNIFICANCE STATEMENT The ability to integrate information from multiple sensory modalities is crucial to the survival of organisms living in complex environments. Appropriate responses to behaviorally relevant objects are informed by integration of multisensory object features. We used crossmodal object recognition tasks in rats to study the neurobiological basis of multisensory object representation. When rats had no prior exposure to the to-be-remembered objects, the spontaneous ability to recognize objects across sensory modalities relied on functional interaction between multiple cortical regions. However, prior multisensory exploration of the task-relevant objects remapped cortical contributions, negating the involvement of one region and significantly expanding the role of another. This finding emphasizes the dynamic nature of cortical representation of objects in relation to past experience.
“The Dynamic Multisensory Engram: Neural Circuitry Underlying Crossmodal Object Recognition in Rats Changes with the Nature of Object Experience” by Derek L. Jacklin, Jacob M. Cloke, Alphonse Potvin, Inara Garrett, and Boyer D. Winters in Journal of Neuroscience. Published online January 27 2016 doi:10.1523/JNEUROSCI.3043-15.2016
