An extravascular or intravascular neural interface is disclosed comprising three C-ring portions, with at least two including an electrode, an electrode pair or an electrode array. The portions are formed of a flexible material that is configured to enable the portions to self-size to fit around or against a surface of a target vessel when the neural interface is released at a position along the target vessel. A spinal portion configured to house electrical conductors for the electrodes is connected to one or more portions. The portions may be spaced sufficient apart to permit radial expansion and contraction of a target vessel around or within which the neural interface is placed, to reduce never compression, open trench low-pressure unrestricted blood-flow, and to enhance fluid exchange with the target vessel. The portions may be arranged in a low helix angle forming at least two full turns.本發明揭示一種血管外或血管內神經介面，其包括三個C形環部分，其中至少兩個包含一電極、一電極對或一電極陣列。該等部分係由經構形以使該等部分能夠在該神經介面於沿著一目標血管之一位置處釋放時自行調整大小以圍繞或抵靠該目標血管之一表面配合之一撓性材料形成。經構形以容置該等電極之電導體的一主幹部分連接至一或多個部分。該等部分可充分間隔開以允許該神經介面圍繞其放置或放置於其內之一目標血管之徑向擴張及收縮，減少神經壓迫，敞開溝槽低壓無限制血流，且增強與該目標血管之流體交換。該等部分可以一低螺旋角配置而形成至少兩個完整圈。
