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Updated: Jul 7, 2025
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
Protracted neuronal recruitment in the temporal lobes of young children
Marcos Assis Nascimento1,2, Sean Biagiotti3, Vicente Herranz-Pérez4,5
1Department of Neurological Surgery, University of California, San Francisco, CA, USA. marcos.assisnascimento@ucsf.edu.
Insights
Human brain development continues after birth, with young neurons migrating to the entorhinal cortex (EC) for up to three years. These late-arriving inhibitory interneurons are crucial for sensory and spatial processing.
Area of Science:
- Neuroscience
- Developmental Biology
- Neuroanatomy
Background:
- The entorhinal cortex (EC), located in the temporal lobe, is vital for memory and sensory integration.
- Postnatal development of the EC is thought to be limited, with neurogenesis and migration largely complete by birth.
Purpose of the Study:
- To investigate the presence and nature of neuronal migration into the human entorhinal cortex during postnatal development.
- To characterize the cell types and origins of these migrating neurons and their potential functional implications.
Main Methods:
- Immunostaining and single-nucleus RNA sequencing were employed.
- Analysis focused on germinal zones, the EC migratory stream, and the postnatal EC in human brain tissue.
- Comparative analysis was performed using rhesus macaque brain tissue.
Main Results:
- Significant postnatal neuronal migration into the human EC was identified, persisting tangentially for ~1 year and radially for ~3 years.
- No equivalent migration was observed in rhesus macaques.
- Migrating cells originated from the caudal ganglionic eminence and differentiated into LAMP5+RELN+ inhibitory interneurons.
Conclusions:
- The human EC receives a substantial influx of inhibitory interneurons postnatally, challenging previous assumptions.
- These late-arriving interneurons may play a critical role in shaping sensory and spatial processing during early childhood.
- The findings have implications for understanding EC function and its vulnerability in conditions like Alzheimer's disease.
Abstract:
The temporal lobe of the human brain contains the entorhinal cortex (EC). This region of the brain is a highly interconnected integrative hub for sensory and spatial information; it also has a key role in episodic memory formation and is the main source of cortical hippocampal inputs1-4. The human EC continues to develop during childhood5, but neurogenesis and neuronal migration to the EC are widely considered to be complete by birth. Here we show that the human temporal lobe contains many young neurons migrating into the postnatal EC and adjacent regions, with a large tangential stream persisting until the age of around one year and radial dispersal continuing until around two to three years of age. By contrast, we found no equivalent postnatal migration in rhesus macaques (Macaca mulatta). Immunostaining and single-nucleus RNA sequencing of ganglionic eminence germinal zones, the EC stream and the postnatal EC revealed that most migrating cells in the EC stream are derived from the caudal ganglionic eminence and become LAMP5+RELN+ inhibitory interneurons. These late-arriving interneurons could continue to shape the processing of sensory and spatial information well into postnatal life, when children are actively interacting with their environment. The EC is one of the first regions of the brain to be affected in Alzheimer's disease, and previous work has linked cognitive decline to the loss of LAMP5+RELN+ cells6,7. Our investigation reveals that many of these cells arrive in the EC through a major postnatal migratory stream in early childhood.
