Researchers discover new memory network in brain. The human medial temporal lobe (MTL) is critical for memory, but it varies greatly between individuals, making its study challenging. Using in-depth imaging of individuals, a recent study uncovered a neocortical network associated with the medial temporal lobe, revealing the profound content and potential evolutionary development of human memory.
The medial temporal lobe (MTL) is the seat of the human memory system. Broadly speaking, it includes the hippocampus, parahippocampal cortex, periumbilical cortex, and medial cortex.
"One of the challenges in studying the MTL is that it has large inter-individual differences in anatomy. Therefore, previous studies have used group average data, blurring the anatomical details between different subregions of the human MTL, which are very close to each other. It is like taking 1,000 different The faces are averaged together to study the facial structure. We get the important organizing principles of a face - the position of the eyes and nose, the position of the mouth - but we completely lose the specific important details," explains Daniel Reznik of MPICBS, first author of the study.
According to him, another challenge in studying human MTL is that this brain region is strongly affected by susceptible artifacts, so the ability to obtain high-quality signals from this brain region is very limited. In the current study, the scientists addressed these challenges in MTL imaging and ultimately explored the distributed cortical anatomy associated with different subregions of the human temporal lobe.
"So, instead of collecting data from many different people, we collected a large number of data from the same person, which greatly improved the anatomical precision of our study. We combined our expertise in high-field imaging, neuroanatomy and cognitive neuroscience to study temporal lobe anatomy in great detail. This allowed us to identify cortical networks associated with the human medial temporal lobe that were unknown in previous studies of human memory." Daniel-Reznik concludes and adds: "Similar cortical networks exist in animals, and perhaps the most exciting finding is that, compared to non-human primates, we now have evidence that new cortical pathways may exist in the human memory system."
Christian Doeller, Head of the Department of Psychology at MPICBS, added: "These new findings are important because even after many years of research on human memory, no one really knew how areas in the MTL are connected to the rest of the human brain. We are particularly interested in connections in the medial cortex because this is where the earliest One of the brain regions affected by Alzheimer's disease. "Our findings identify anatomical constraints on the operation of human memory function and have implications for studying the evolutionary development of temporal lobe circuits in different species. For example, data from non-human primates show only slight connections between the medial and frontal cortex - in contrast, we found that these connections are more pronounced in humans."
Daniel-Reznik added: "Because one of the networks connected to the human medial cortex is also involved in social processing, we suspect that this is an evolutionarily young network that may have evolved after widespread expansion of the human cortex."