A new study reveals that hormones that play a crucial role in maintaining blood sugar, metabolism and growth could also influence memory and learning. The study could pave the way for a new strategy to restore brain plasticity and memory, especially in conditions like Alzheimer’s and dementia.
The study by researchers from Max Planck Florida Institute for Neuroscience, USA, found that hormones called insulin-like growth factors (IGF) facilitate connections between the neurons in the hippocampus region.
Insulin, IGF-1 and IGF-2 are part of IGF hormone family that control blood sugar, metabolism and growth. In the brain, they attach to receptors that help neurons grow and connect better (synaptic plasticity), enhancing cognition, the researchers found.
“This family [IGF family] is quite important and expressed widely in our body, so it will be important to know how they help us to maintain health, including brain health,” lead researcher Dr Xun Tu told Happiest Health.
Their study is published in Science Advances.
Researchers tagged a fluorescent marker on the receptors that attach to the IGF molecules in the hippocampus region. They noticed that the receptors crowded around growing synapses, especially on the neuron’s dendritic spines, improving synaptic strength. Dendritic spines are the arms of the neurons that connect to the next neuron, and strong dendritic connections are the ‘backbone’ of synaptic plasticity.
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To countercheck, they disrupted IGF production in the hippocampal neurons. This resulted in disrupting the growth of the synapses.
Even though IGF has been related to learning and memory, nothing has connected them to synaptic plasticity in the hippocampus. “Our study discovered a new molecular mechanism underlying synaptic plasticity,” says Dr Tu. Synaptic plasticity fuels memory formation by strengthening neuron connections, and this study brings that link to a core memory-affecting region of the brain—the hippocampus.
“The crucial involvement of autocrine IGF-IGF1Receptor signalling in synaptic plasticity in the hippocampus suggests that this mechanism may play a fundamental role in learning and memory processes,” said the authors in the paper.
This work reveals that the IGF autocrine mechanism is a crucial player in synaptic plasticity and could be critical in maintaining cognitive health, says lead researcher Dr Ryohei Yasuda in a statement. This study sheds light on how memories could be coded. Such an understanding could facilitate new research avenues, with the potential to counter cognitive decline in dementia and Alzheimer’s.
