Summary: Human number cognition may be rooted in the putamen, a deep brain structure traditionally associated with movement rather than abstract thought. Neurosurgery patients demonstrated activity in this area while processing numbers as symbols, words, and concepts, suggesting that numerical understanding emerged early in evolution.
Researchers also observed activity in expected areas like the parietal lobe, highlighting how different brain regions collaborate in number processing. These findings could improve surgical outcomes by protecting areas crucial for number cognition and open pathways to enhancing math learning through targeted interventions.
Key Facts:
- Number cognition involves the putamen, suggesting early evolutionary origins.
- Collaboration occurs between deep brain regions and the parietal lobe for number processing.
- Findings may improve surgical precision and support math learning innovations.
Source: Oregon Health and Science University
New research reveals the unique human ability to conceptualize numbers may be rooted deep within the brain.
Further, the results of the study by Oregon Health & Science University involving neurosurgery patients suggests new possibilities for tapping into those areas to improve learning among people bedeviled by math.
“This work lays the foundation to deeper understanding of number, math and symbol cognition — something that is uniquely human,” said senior author Ahmed Raslan, M.D., professor and chair of neurological surgery in the OHSU School of Medicine.
“The implications are far-reaching.”
The study published today in the journal PLOS ONE.
Raslan and co-authors recruited 13 people with epilepsy who were undergoing a commonly used surgical intervention to map the exact location within their brains where seizures originate, a procedure known as stereotactic electroencephalography.
During the procedure, researchers asked the patients a series of questions that prompted them to think about numbers as symbols (for example, 3), as words (“three”) and as concepts (a series of three dots).
As the patients responded, researchers found activity in a surprising place: the putamen.
Located deep within the basal ganglia above the brain stem, the putamen is an area of the brain primarily associated with elemental functions, such as movement, and some cognitive function, but rarely with higher-order aspects of human intelligence like solving calculus.
Neuroscientists typically ascribe consciousness and abstract thought to the cerebral cortex, which evolved later in human evolution and wraps around the brain’s outer layer in folded gray matter.
“That likely means the human ability to process numbers is something that we acquired early during evolution,” Raslan said.
“There is something deeper in the brain that gives us this capacity to leap to where we are today.”
Researchers also found activity as expected in regions of the brain that encode visual and auditory inputs, as well as the parietal lobe, which is known to be involved in numerical and calculation-related functions.
From a practical standpoint, the findings could prove useful in avoiding important areas during surgeries to remove tumors or epilepsy focal points, or in placing neurostimulators designed to stop seizures.
“Brain areas involved in processing numbers can be delineated and extra care taken to avoid damaging these areas during neurosurgical interventions,” said lead author Alexander Rockhill, Ph.D., a postdoctoral researcher in Raslan’s lab.
Researchers credited the patients involved in the study.
“We are extremely grateful to our epilepsy patients for their willingness to participate in this research,” said co-author Christian Lopez Ramos, M.D., a neurosurgical resident at OHSU.
“Their involvement in answering our questions during surgery turned out to be the key to advancing scientific understanding about how our brain evolved in the deep past and how it works today.”
Indeed, the study follows previous lines of research involving mapping of the human brain during surgery.
“I have access to the most valuable human data in nature,” Raslan said. “It would be a shame to miss an opportunity to understand how the brain and mind function. All we have to do is ask the right questions.”
In the next stage of this line of research, Raslan anticipates discerning areas of the brain capable of performing other higher-level functions.
In addition to Raslan, Rockhill and Lopez Ramos, co-authors include Hao Tan, M.D., Beck Shafie, Maryam Shahin, M.D., Adeline Fecker, Mostafa Ismail, Daniel Cleary, M.D., and Kelly Collins, M.D., of OHSU; and Caleb Nerison, D.O., now of Lexington Medical Center in South Carolina.
Funding: The research was supported by a grant from the National Institutes of Health’s BRAIN Initiative in support of Rockhill, award 1UG3NS123723-01. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
About this evolutionary neuroscience and numeracy research news
Author: Erik Robinson
Source: Oregon Health and Science University
Contact: Erik Robinson – Oregon Health and Science University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Investigating the Triple Code Model in numerical cognition using stereotactic electroencephalography” by Ahmed Raslan et al. PLOS ONE
Abstract
Investigating the Triple Code Model in numerical cognition using stereotactic electroencephalography
The ability to conceptualize numerical quantities is an essential human trait. According to the “Triple Code Model” in numerical cognition, distinct neural substrates encode the processing of visual, auditory, and non-symbolic numerical representations.
While our contemporary understanding of human number cognition has benefited greatly from advances in clinical imaging, limited studies have investigated the intracranial electrophysiological correlates of number processing.
In this study, 13 subjects undergoing stereotactic electroencephalography for epilepsy participated in a number recognition task.
Drawing upon postulates of the Triple Code Model, we presented subjects with numerical stimuli varying in representation type (symbolic vs. non-symbolic) and mode of stimuli delivery (visual vs. auditory).
Time-frequency spectrograms were dimensionally reduced with principal component analysis and passed into a linear support vector machine classification algorithm to identify regions associated with number perception compared to inter-trial periods.
Across representation formats, the highest classification accuracy was observed in the bilateral parietal lobes.
Auditory (spoken and beeps) and visual (Arabic) number formats preferentially engaged the superior temporal cortices and the frontoparietal regions, respectively.
The left parietal cortex was found to have the highest classification for number dots.
Notably, the putamen exhibited robust classification accuracies in response to numerical stimuli.
Analyses of spectral feature maps revealed that non-gamma frequency, below 30 Hz, had greater-than-chance classification value and could be potentially used to characterize format specific number representations.
Taken together, our findings obtained from intracranial recordings provide further support and expand on the Triple Code Model for numerical cognition.
