一項研究說,，大腦回路可能是以一種類似于互聯(lián)網(wǎng)的互相連接的反饋網(wǎng)絡(luò)方式組織起來,?？茖W(xué)家長久以來認(rèn)為大腦是一種自上而下的等級，最晚進(jìn)化出來部分（諸如新皮層）處于命令鏈的頂端,。但是近來的報告提示了一個反饋網(wǎng)絡(luò)回路,。為了研究大腦回路的結(jié)構(gòu)，Richard H. Thompson 和Larry W. Swanson對稱為背內(nèi)側(cè)伏核的大鼠腦區(qū)域的1立方毫米應(yīng)用了一種實驗性的回路追蹤技術(shù),。該區(qū)域因為其被認(rèn)為在獎賞和渴求的過程中起作用而稱為“快樂的熱區(qū)”,。這組作者發(fā)現(xiàn)，在這個被認(rèn)為控制著食欲,、壓力和抑郁的區(qū)域內(nèi)廣為分布的灰質(zhì)群之間存在一系列的互聯(lián)連接,。這組作者報告說，這些連接形成了一系列縱向的回路,。此外,，該區(qū)域是包括了皮層、基底神經(jīng)節(jié),、丘腦和下丘腦在內(nèi)的前腦的一個大反饋回路的一部分,；對該區(qū)域的神經(jīng)輸入和輸出進(jìn)行測繪提示了反饋網(wǎng)絡(luò)而非等級結(jié)構(gòu)的特征。這組作者說,，這些發(fā)現(xiàn)意味著這種追蹤技術(shù)可能用于構(gòu)建整個神經(jīng)系統(tǒng)的一個連線圖,。（生物谷Bioon.com）
生物谷推薦原文出處：
PNAS doi: 10.1073/pnas.1009112107
Hypothesis-driven structural connectivity analysis supports network over hierarchical model of brain architecture
Richard H. Thompson and Larry W. Swanson1
Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
The brain is usually described as hierarchically organized, although an alternative network model has been proposed. To help distinguish between these two fundamentally different structure-function hypotheses, we developed an experimental circuit-tracing strategy that can be applied to any starting point in the nervous system and then systematically expanded, and applied it to a previously obscure dorsomedial corner of the nucleus accumbens identified functionally as a “hedonic hot spot.” A highly topographically organized set of connections involving expected and unexpected gray matter regions was identified that prominently features regions associated with appetite, stress, and clinical depression. These connections are arranged as a longitudinal series of circuits (closed loops). Thus, the results do not support a rigidly hierarchical model of nervous system organization but instead indicate a network model of organization. In principle, the double-coinjection circuit tracing strategy can be applied systematically to the rest of the nervous system to establish the architecture of the global structural wiring diagram, and its abstraction, the connectome.
