Numerical processing in parietal cortex

描述（由申请人提供）：该提案旨在了解数字处理的神经基础。为了实现这一点，将训练动物受试者根据闪烁的次数对视觉提示进行分类。他们将通过将眼睛移动到与选择相对应的两个可能的视觉目标之一来报告闪烁的次数是大于还是小于五。数字线索的其他刺激维度将被控制，以确保决策是基于数字的。顶叶皮层与数字处理和决策有关。据推测，后顶叶皮层（PPC）的暂时失活将干扰形成决策的基础上的数字，但不是颜色，信息的能力。PPC中的神经元在空间的选择性区域中对视觉刺激做出反应，并且在眼球运动到该位置之前，反应场（RF）。PPC中神经元的反应表明它们整合信息以引导眼球运动。单个PPC神经元的活动将被记录，以确定它们是否代表数字线索本身和关于数字的决定。为了深入了解数字如何在神经结构中表示，数字线索将被放置在神经元的RF中，并且与数字相关的活动的概况将被量化。此外，选择目标将被放置在神经元的RF中，以测量与指导动物选择的离散信息脉冲的整合相关的神经活动。

DESCRIPTION (provided by applicant): The proposal is aimed at understanding the neural basis of numerical processing. To accomplish this, animal subjects will be trained to categorize a visual cue on the basis of the number of times it flashes. They will report whether the number of flashes is greater or less than five by making an eye movement to one of two possible visual targets that correspond to the choices. Other stimulus dimensions of the number cue will be controlled to insure that decisions are based on number. Parietal cortex has been implicated in both numerical processing and decision-making. It is hypothesized that temporary inactivation of posterior parietal cortex (PPC) will interfere with the ability to form decisions on the basis of number, but not color, information. Neurons in PPC respond to visual stimuli in a selective region of space and before eye movements to that location, the response field (RF). The responses of neurons in PPC suggest that they integrate information in order to guide eye movements. The activity of single PPC neurons will be recorded to determine if they represent the number cue itself and decisions about number. To gain insight into how number is represented in neural structures, the number cue will be placed in the neuron's RF and the profile of activity associated with number will be quantified. In addition, the choice target will be placed in the neuron's RF to measure neural activity associated with the integration of discrete pulses of information that guide the animal's choice.