Analysis of active neural circuits and synaptic mechanisms of memory
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Date
2018-10-31
Authors
DeBlander, Leah
Journal Title
Journal ISSN
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Publisher
University of Oregon
Abstract
One feature of the brain is that different parts of it respond to different stimuli. This means not all brain regions or neurons within those regions are active at a given moment. This feature of the brain gives it the ability to encode and store a wide range of stimuli that are then used to make predictions about a changing external environment. Activation of non-overlapping neural populations is fundamental to the ability to encode a wide range of stimuli to represent a changing environment. To examine the limits of this idea we used genetic tools to label active cell populations following a neutral stimulus presentation or a learned negative association with the same stimulus. The study examined the degree of similarity between these active populations by comparing key features of the active neurons including gene expression and monosynaptic inputs.
Another feature of the brain is its ability to store information. In a neural population recently activated by a salient stimulus, molecular processes occur that result in the formation and maintenance of a memory. Collectively these processes are referred to as plasticity, and act on short and long time scales to strengthen the connections between active neurons and weaken the connections between inactive ones. Plasticity processes are not only necessary for the formation and storage of memories but also for wiring up the nervous system during development. A molecule called ZIP has been shown to erase memories months after formation and specifically affects plasticity on longer time scales. However, the effects of ZIP on the developing brain are not well understood and difficult to study using ZIP’s typical delivery method of injection into the brain. To facilitate a developmental study of ZIP’s effects, we made a genetic tool that can specify where and when ZIP is delivered to the brain. Results of the study indicated that males were particularly vulnerable to ZIP during early development while females were unaffected.
Together these results provide insight into the limits of information coding potential at the anatomical level and reveal a fundamental difference in plasticity processes in males and females.
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Keywords
Memory, Neuroanatomy, Neurodevelopment, Neurosciences, Synaptic plasticity, Viral tracing