Automated electrophysiology to investigate the role of interneurons in Alzheimer's disease

Alzheimer’s disease is a progressive neurodegenerative disease, accounting for about two thirds of dementia cases. Despite significant efforts to diagnose and cure Alzheimer’s disease, there are still no effective therapeutics to halt disease progression. While the conventional understanding attributes memory loss to the buildup of amyloid and tau proteins, emerging evidence suggests that cognitive decline in Alzheimer’s disease may stem from neuronal circuit dysregulation rather than protein aggregation. Specifically, alterations in the excitability of inhibitory interneurons may contribute to circuit dysfunction, although the evolution of this dysregulation across brain regions and over time remains poorly understood. To address this gap, this work systematically investigated the emergence of parvalbumin interneuron dysfunction in Alzheimer’s disease, hypothesizing their early involvement in vulnerable brain regions. To study these parvalbumin interneurons at the single cell level, with sufficient spatial and temporal resolution, this thesis will utilize patch clamp electrophysiology. The patch clamp technique is remains necessary for fully elucidating cell-type-specific behavior, although it is difficult and time-intensive. While patch clamp systems have emerged that automate certain aspects of the procedure, there remain challenges that can be remedied with improved automation techniques. To overcome these obstacles, several strategies have been developed to improve the success rates and facilitate the execution of automated, high-throughput investigations. In the initial identification of cells within acute brain slices, a deep learning methodology automatically nominates neurons for subsequent automated experiments. Addressing concerns regarding pipette localization errors, a convolutional neural network, specifically ResNet101, has been adapted and trained to autonomously detect and rectify the misplacement of pipette tips during automated in vitro patch clamp experiments. Furthermore, to facilitate investigations into synaptic connections between neurons, a method named patch-walking was demonstrated in brain slices, enabling efficient finding of synaptic connections. Passive and active properties of parvalbumin interneurons and excitatory neurons were measured in the entorhinal cortex, the medial prefrontal cortex, the primary visual cortex, and the secondary motor cortex. We identified the entorhinal and medial prefrontal cortices as vulnerable regions in a mouse model of Alzheimer’s disease, suggesting the parvalbumin interneurons in these regions are interesting therapeutic targets.

Date

2024-05-17

Resource Type

Text

Resource Subtype

Dissertation

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