問題詳情


(C)A team of researchers led by Andrew Huberman, Ph.D., professor of neurobiology andof ophthalmology at Stanford University in California, investigated the role of the ventralmidline thalamus (vMT) in determining how animals respond to visual threats. The thalamusis a brain region that acts as a relay station, taking in sensory information, such as what isseen and heard, and sorting out where in the brain to send that information.   Dr. Huberman and his colleagues showed that the vMT was activated when mice wereconfronted with a threat, specifically a black circle that grew larger on top of their cage,mimicking the experience of something looming over them. When faced with the loomingthreat, the mice spent most of the time freezing or hiding and very little time rattling theirtails, which is typically an aggressive response.    To further investigate the role of vMT, Dr. Huberman’s team used state-of-the-art tools,including designer drugs that allowed specific circuits to be turned on and off. Althoughinactivating the vMT had no effect on freezing and hiding, it eliminated the tail rattlingresponse. Turning on the vMT increased the number of tail shaking responses and caused themice to move around more and spend less time hiding or freezing.    Dr. Huberman’s group also discovered that the vMT sends information primarily to twobrain areas: the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC). Thesecircuits turned out to be critical in determining how the mice reacted to a visual threat.Turning on the circuit that projected to the BLA caused more freezing responses, whileactivating the mPFC circuit increased tail shaking responses.    Dr. Huberman and his team showed that activation of the vMT increased arousal, a stateof heightened alertness. Mice preferred spending more time in a room where they receivedvMT activation, suggesting that turning on that brain circuit made them feel good. Althoughthere may have been a difference in response to the visual threat, either tail shaking orfreezing, the underlying positive feeling was the same for both types of reactions.    “This study may help explain why acts of courage, such as standing up for yourself orfor a cause, or a physical challenge can feel empowering. Experiencing that good feeling canalso make it more likely to respond to future threats in a similar way,” said Dr. Huberman.“Although our study was done in mice, learning more about the vMT may provide someinsight into conditions such as generalized anxiety disorder and post-traumatic stress disorderand we are now pursuing study of the human vMT for that reason.”   Future research is needed to increase understanding of ways in which the vMT circuitaffects behavior and how to develop treatments that can target specific parts of this system.
77. What is the main purpose of this passage?
(A) To pay tribute to Dr. Huberman and his team.
(B) To raise funding for a research project.
(C) To describe an innovative research method.
(D) To introduce a research study.

參考答案

答案：D
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

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