summary: New research shows that the way our minds search for words and concepts in memory may be similar to age-old patterns used by animals to search for food in their environment. Suggests.
This new insight emerged from a neuroimaging study that analyzed brain activity as participants retrieved words related to different concepts from long-term memory. A potential link was observed between the search for external resources such as food and shelter and the way humans search for internally stored concepts.
Such findings could provide an innovative perspective in understanding schizophrenia, in which language and thought disruptions are key symptoms.
Important facts:
- This study shows that the patterns humans use to internally search for memories may be evolutionary and similar to the strategies animals employ to search for resources. I did.
- In memory tasks, humans tend to produce words in clusters or “patches” and shift focus when a patch is exhausted. This is similar to how animals switch food sources.
- As participants switched between memory patches, increased activity in the hippocampus and posterior cerebellum was observed, revealing distinct cognitive processes.
sauce: indiana university
How the mind searches for words and concepts in memory may have its origins in ancient patterns in which humans and nonhuman animals search for food and other resources in their physical environments. It’s a theory that has gained new support from neuroimaging studies that examined brain activity as study participants retrieved words related to different concepts from long-term memory.
In addition to teaching us about the basic strategies people use to find relevant information, this study also helps to treat schizophrenia and other forms of mental illness in which disruption of language and thinking are basic symptoms. It may also inspire new approaches to understanding.
This study was published on October 12, 2023. Proceedings of the National Academy of Sciences By researchers and their collaborators in the Department of Psychological and Brain Sciences, College of Arts and Sciences, Indiana University. The discovery provides neural evidence for a continuity between foraging and the mind in space.
Lead researcher Peter Todd, whose research into the evolutionary roots of cognitive processes sparked the team’s project, found that search patterns for finding external resources such as food, water and shelter are based on internal concepts that humans store in memory. I explained how I can explain how to search for .
“People not only search externally, they also search internally,” said Todd, a professor in IU’s Department of Psychology, Brain Sciences and Cognitive Sciences Program.
“And these strategies, which evolved to help other organisms find what they want in the physical world, influence how we search for information in libraries and on the web, and how we search for information stored there. It looks like we’re also promoting ways of searching in our own heads,’ and that we want to come back to and leverage. ”
The common feature of external and internal search strategies is that when one patch of items with a particular resource concentration is exhausted, they move from that patch to a new patch. For example, if a bear is looking for berries, it will spend time in one bush until it has eaten most of the berries there, so the bear will move to another bush in hopes of finding more.
This pattern of exploiting one patch until it decides it’s time to look for another, or making an “exploitation-exploration trade-off,” allows the organism to control time by deciding when it is advantageous to leave. It is a strategic process that allows you to maximize the amount of food found over time. One place to look for new food sources.
The researchers showed that the search for concepts in the semantic space of memory reproduces a strategic switch between local search in clusters of items and global search for new clusters.
Thirty participants were asked to say every word they could think of in three minutes for each of a series of conceptual categories (animals, food, occupations, etc.) while undergoing functional magnetic resonance imaging (fMRI) of their brain activity. It was done. It starts with a certain letter.
In such memory retrieval tasks, people typically produce words in clusters or patches. So, for example, a participant asked to list animals might start with farm animals until they have no memory of farm animals, then move on to a new cluster consisting of “pets” or “African animals.”
Leveraging the expertise of Josh Brown, a professor in the IU Department of Psychological and Brain Sciences who has used fMRI to study other types of decision-making processes, the researchers investigated the moment of switching between patches and the moment of patch switching. investigated the brain activity of study participants. Search in the patch all the way to the switch.
Nancy Lundin is the study’s lead author and a former Ph.D. student in the IU Department of Psychological and Brain Sciences and the IU Neuroscience Program, he explained: (or move to a new patch).
“We used computational models of semantic and phonological distance, as well as information from participants’ reports about the timing of switching. We found that the hippocampus and posterior cerebellum were more sensitive to switching compared to clustering. “This provides some evidence that these cognitive search processes are meaningfully different.”
Brown, who is also in the IU Cognitive Science and Neuroscience programs, elaborated on what this brain activity means.
This research shows that the hippocampus, a part of the brain that helps form long-term memories, It’s not just a passive way station to store your memories in a more permanent repository. “It’s also a kind of scratchpad that allows you to express these memories and play with them,” he said.
“When subjects have to try something different, such as switching to a new part of the semantic space, this activity occurs in the hippocampus. This means that something is happening that helps generate new ideas. It suggests that you are discovering something new or trying something different.”
Lundin, now a postdoctoral fellow in the Department of Psychiatry and Behavioral Health at The Ohio State University School of Medicine, similarly said that this study is a recent study, as well as that of her doctoral advisor and co-author of the study. (including). Bill Hetrick of IU’s Department of Psychological and Brain Sciences describes the understudied role of the cerebellum in cognitive processes.
Historically, the cerebellum was thought to be primarily involved in motor coordination and control.
“Here, we show that posterior regions of the cerebellum have recently been implicated in cognitive processes and are involved in switching to new parts of cognitive space in both semantic and phonetic word retrieval tasks. I understand,” she said.
clinical significance
As a clinical psychologist, Lundin sees this research as a foundation for her future plans to study the organization of language and thought in individuals with psychosis and other forms of psychopathology. .
As she pointed out, schizophrenia was a term first coined by Swiss psychiatrist Eugen Bleuler in 1908, and from its inception it was characterized by loose associations, or fragmentation of thought, language, behavior, and emotion. characterized as a disability.
“A lot of research is being done to understand thought disorders and disorganized speech in psychosis,” Lundin says.
“One of the questions that my colleagues and I continue to explore is, ‘Are these cognitive foraging processes, decisions about when to explore and use, relevant to the organization of speech and thought in psychosis?’ That is, do some people stay in the conceptual patch too long or too early, using suboptimal foraging strategies?”
Lundin is currently examining these cognitive search strategies in psychiatric patients in several studies.
So far, “we have found some differences in the patterns of local exploitation and global exploration during semantic search between psychotic patients and neurotypical individuals,” she said.
However, more work remains to be done. She will soon be collecting new data at the hospital where she works to better understand how freer everyday conversations are related to the foraging processes investigated in the current study. We are planning to start.
And there is strong hope that this new way of conceptualizing how we search for words and concepts in memory “could really get to the root of the disease and point to new treatments for people suffering from mental illness.” She said she was holding a .
Other authors include Brendan T. Johns of McGill University’s Department of Psychology; Michael N. Jones, Indiana University Department of Psychological and Brain Sciences and Cognitive Science Program; John R. Purcell, Indiana University Department of Psychological and Brain Sciences and Neuroscience Program, and Department of Psychiatry, Rutgers University Brain Health Institute. William P. Hetrick, Department of Psychological and Brain Sciences, Indiana University School of Medicine, Department of Psychiatry and Neuroscience Program; Brian F. O’Donnell, Department of Psychological and Brain Sciences, Indiana University School of Medicine, Department of Psychiatry and Neuroscience Program.
About this neuroscience and schizophrenia research news
author: barbara brasher
sauce: indiana university
contact: Barbara Brosher – Indiana University
image: Image credited to Neuroscience News
Original research: Closed access.
“Neural evidence for switch processes during semantic and phonological search in human memory” by Peter Todd et al. PNAS
abstract
Neural evidence for switch processes during semantic and phonological search in human memory
Humans may retrieve words from memory by exploring and exploiting “semantic space” in the same way that non-human animals search for resources in physical space. This has been studied using verbal fluency tests (VFTs) in which participants produce words belonging to semantic or phonological categories within a limited amount of time. People generate bursts of related items during VFT. This is called “clustering” and “switching.”
In the strategic foraging model, cognitive search behavior is guided by a monitoring process that detects associated performance degradation and triggers the searcher to look for new patches or clusters in memory after the current patch is exhausted. I am assuming that.
Another line of research has proposed that this behavior can be explained by non-strategic, undirected search processes, such as random walks with or without random jumps to new parts of the semantic space.
This study contributes to this theoretical debate by testing neural evidence for strategically timed switches during memory retrieval. Thirty participants performed categorical and character VFT during functional MRI. Responses were classified as cluster or switch events based on computational metrics of similarity and participant ratings.
The results showed greater activation in the hippocampus and posterior cerebellum during switching than clustering, even when controlling for response time and linguistic distance.
Additionally, these regions exhibited ramping activity, which increased during intrapatch search leading up to the switch.
The findings support the strategic foraging model and reveal how neural switch processes can guide memory retrieval in a manner similar to foraging in spotted spatial environments.
