Graduate Program in Neuroscience, Brandeis University, 415 South Street, Waltham, MA 02453, USA.
Graduate Program in Neuroscience, Brandeis University, 415 South Street, Waltham, MA 02453, USA; Neuroscience Program, Department of Psychology, and Volen National Center for Complex Systems, Brandeis University, 415 South Street, Waltham, MA 02453, USA.
Curr Biol. 2020 Apr 6;30(7):1306-1311.e4. doi: 10.1016/j.cub.2020.01.063. Epub 2020 Mar 19.
Animals need to remember the locations of nourishing and toxic food sources for survival, a fact that necessitates a mechanism for associating taste experiences with particular places. We have previously identified such responses within hippocampal place cells [1], the activity of which is thought to aid memory-guided behavior by forming a mental map of an animal's environment that can be reshaped through experience [2-7]. It remains unknown, however, whether taste responsiveness is intrinsic to a subset of place cells or emerges as a result of experience that reorganizes spatial maps. Here, we recorded from neurons in the dorsal CA1 region of rats running for palatable tastes delivered via intra-oral cannulae at specific locations on a linear track. We identified a subset of taste-responsive cells that, even prior to taste exposure, had larger place fields than non-taste-responsive cells overlapping with stimulus delivery zones. Taste-responsive cells' place fields then contracted as a result of taste experience, leading to a stronger representation of stimulus delivery zones on the track. Taste-responsive units exhibited increased sharp-wave ripple co-activation during the taste delivery session and subsequent rest periods, which correlated with the degree of place field contraction. Our results reveal that novel taste experience evokes responses within a preconfigured network of taste-responsive hippocampal place cells with large fields, whose spatial representations are refined by sensory experience to signal areas of behavioral salience. This represents a possible mechanism by which animals identify and remember locations where ecologically relevant stimuli are found within their environment.
动物需要记住滋养和有毒食物来源的位置才能生存，这一事实需要有一种将味觉体验与特定地点联系起来的机制。我们之前已经在海马体位置细胞[1]中发现了这种反应，这些细胞的活动被认为通过形成动物环境的心理地图来帮助记忆引导行为，而这种地图可以通过经验进行重塑[2-7]。然而，味觉反应是否是位置细胞亚群的固有特性，还是由于经验重新组织空间地图而产生的，目前还不清楚。在这里，我们记录了在大鼠的背侧 CA1 区域中神经元的活动，这些大鼠在一条线性轨道上的特定位置通过口腔内套管接受美味的味觉刺激。我们确定了一组味觉反应细胞，即使在接触味觉之前，它们的位置场也比非味觉反应细胞大，并且与刺激传递区域重叠。然后，味觉反应细胞的位置场由于味觉体验而收缩，导致轨道上的刺激传递区域的代表性更强。味觉反应单元在味觉传递期间和随后的休息期间表现出更多的尖峰涟漪共同激活，这与位置场收缩的程度相关。我们的结果表明，新的味觉体验会在具有大位置场的预先配置的味觉反应海马体位置细胞网络中引发反应，其空间表示通过感觉体验得到精细化，以指示行为显著区域。这代表了动物识别和记住其环境中存在生态相关刺激的位置的一种可能机制。
