Attenuated frontal and sensory inputs to the basal ganglia in cannabis users
Attenuated frontal and sensory inputs to the basal ganglia in cannabis users
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DOI：
10.1111/adb.12370
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发表时间：
2017-07-01
影响因子：
3.4
通讯作者：
Martin-Santos, Rocio
中科院分区：
文献类型：
--
作者：
Blanco-Hinojo, Laura;Pujol, Jesus;Martin-Santos, Rocio
大量使用大麻与动机降低有关。基底神经节是动力系统的中心，它拥有大脑中最高的大麻素受体密度。额叶通过分离的额叶皮层下回路与基底神经节功能性耦合，传递来自内部自发活动的信息。然而，基底神经节接受来自感觉系统的额外影响，以根据上下文进一步调节有目的的行为。我们假设大麻的使用会影响基底神经节与内部（额叶皮层）和外部（感觉皮层）影响源之间的功能连接。在28名慢性大麻使用者和29名对照者中测量了静息状态功能连接。选定的行为测试包括反应时间，语言流畅性和情感图片的曝光。在禁欲一个月后重复评估。大麻暴露与（1）纹状体与边缘系统额叶-基底神经节回路相关区域之间的正相关性减弱，以及（2）纹状体与梭状回之间的负相关性减弱有关，梭状回在识别重要视觉特征方面至关重要。连接性改变与情感图片引起的低唤醒有关。功能连接的变化有一个趋势，正常化后禁欲。总体结果表明，长期接触大麻后，对基底神经节的额叶和感觉输入会减弱。这种影响与慢性大麻使用的常见行为后果一致，即对内部和外部动机信号的反应性降低。这种对动机系统的微调的损害在禁欲后明显恢复。
Heavy cannabis use is associated with reduced motivation. The basal ganglia, central in the motivation system, have the brain's highest cannabinoid receptor density. The frontal lobe is functionally coupled to the basal ganglia via segregated frontal-subcortical circuits conveying information from internal, self-generated activity. The basal ganglia, however, receive additional influence from the sensory system to further modulate purposeful behaviors according to the context. We postulated that cannabis use would impact functional connectivity between the basal ganglia and both internal (frontal cortex) and external (sensory cortices) sources of influence. Resting-state functional connectivity was measured in 28 chronic cannabis users and 29 controls. Selected behavioral tests included reaction time, verbal fluency and exposition to affective pictures. Assessments were repeated after one month of abstinence. Cannabis exposure was associated with (1) attenuation of the positive correlation between the striatum and areas pertaining to the limbic' frontal-basal ganglia circuit, and (2) attenuation of the negative correlation between the striatum and the fusiform gyrus, which is critical in recognizing significant visual features. Connectivity alterations were associated with lower arousal in response to affective pictures. Functional connectivity changes had a tendency to normalize after abstinence. The results overall indicate that frontal and sensory inputs to the basal ganglia are attenuated after chronic exposure to cannabis. This effect is consistent with the common behavioral consequences of chronic cannabis use concerning diminished responsiveness to both internal and external motivation signals. Such an impairment of the fine-tuning in the motivation system notably reverts after abstinence.