Circuit mechanisms underlying simple forms of visual memory

简单形式的视觉记忆背后的电路机制

• 批准号: BB/X009386/1
• 负责人: Leon Lagnado
• 金额: $ 61.02万
• 依托单位: University of Sussex
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX009386%2F1
• 关键词: Circuit; mechanisms; underlying; simple; forms

Animals must navigate a constantly changing environment and learn which aspects of that environment are important and which are not. To allow this, the brain must adjust how visual information is processed to suppress neural responses to features that are of no revelance to the animal while amplifying information that is useful, for instance indicating food or danger. Such "plasticity" is a general property of the brain and can occur on different time-scales. Changes over seconds, such as adjusting visual sensitivity to a darker room, is called adaptation. Other processes can occur over days. Habituation, for instance, can inhibit neural responses to a repeated stimulus when it does not provide useful information. But if the same stimulus is paired with food or drink, habituation is blocked and responses can instead be enhanced. This project aims to understand how fast adaptation and these simple forms of long-term memory are linked and whether the same neural circuits can control both. We will do this by studying how visual stimuli generate neural responses in the cerebral cortex using awake mice and specialized optical microscopes that allow the electrical activity of large numbers of neurons to be observed in real-time as changes in light emission from each neuron. An important general mechanism of plasticity in the brain is to change the strength of the connections between neurons. These neurons can be either excitatory or inhibitory and it is changes in the balance between the excitation and inhibition that a neuron receives that determines whether its response is increased or decreased. Our particular focus will be on how inhibitory neurons of different types are connected into different circuits that determine the responses of the excitatory neurons. We have recently obtained new information about how inhibitory neurons can increase or decrease responses on time-scales of seconds and our general hypothesis is that the connections within these same circuits are either strengthed or weakened to establish simple forms of visual memory such as habituation or Pavlovian learning. We will test ideas about the underlying circuits by observing the activity of different components of these circuits (that is to say different types of neurons) as well as artificially increasing or decreasing their activity on a second-to-second basis. The information from this project will help us understand how neurons in the brain adjust sensory processing on different time-scales to allow a mammal to operate in a changing world.

动物必须适应不断变化的环境，并学习环境的哪些方面是重要的，哪些是不重要的。为了做到这一点，大脑必须调整视觉信息的处理方式，以抑制神经对与动物无关的特征的反应，同时放大有用的信息，例如指示食物或危险。这种“可塑性”是大脑的一般特性，可以在不同的时间尺度上发生。几秒钟内的变化，如调整视觉灵敏度以适应更暗的房间，称为适应。其他过程可能会持续数天。例如，习惯化可以抑制神经对重复刺激的反应，当它不提供有用的信息时。但是，如果同样的刺激与食物或饮料配对，习惯性就会被阻止，反应反而会增强。该项目旨在了解快速适应和这些简单形式的长期记忆之间的联系，以及相同的神经回路是否可以控制两者。我们将通过研究视觉刺激如何在大脑皮层中产生神经反应来实现这一点，使用清醒的小鼠和专用光学显微镜，可以实时观察大量神经元的电活动，作为每个神经元发光的变化。大脑可塑性的一个重要的一般机制是改变神经元之间连接的强度。这些神经元可以是兴奋性的或抑制性的，并且神经元接收的兴奋和抑制之间的平衡的变化决定了其响应是增加还是减少。我们将特别关注不同类型的抑制性神经元如何连接到决定兴奋性神经元反应的不同回路中。我们最近获得了关于抑制性神经元如何在秒的时间尺度上增加或减少反应的新信息，我们的一般假设是，这些回路内的连接要么被加强要么被削弱，以建立简单形式的视觉记忆，如习惯化或巴甫洛夫学习。我们将通过观察这些回路的不同组成部分（也就是不同类型的神经元）的活动以及人为地每秒增加或减少它们的活动来测试关于底层回路的想法。该项目的信息将帮助我们了解大脑中的神经元如何在不同的时间尺度上调整感觉处理，以使哺乳动物能够在不断变化的世界中运作。