A neural interface device, which comprises: a) a carrier having a carrier sidewall having a first wall thickness and extending along a longitudinal axis from a proximal carrier end to a distal carrier portion, wherein the distal carrier portion has a step transition to a thinner carrier sidewall portion; b) a substrate supported on the thinner carrier sidewall portion; c) at least one electrode supported on the substrate, wherein the electrode is configured for at least one of electrical stimulation of body tissue and sensing of physiological characteristics of the body tissue; wherein the step transition has a height that substantially matches the thickness of the substrate comprising the electrode to provide a smooth transition from the carrier sidewall to the substrate; d) an electrical conductor that extends from the proximal carrier end to the thinner carrier sidewall portion where it is electrically connected to the electrode supported on the substrate, wherein the proximal carrier end is electrically connectable to a medical device; and e) at least one deformable segment of the carrier sidewall intermediate a first carrier sidewall portion and a second carrier sidewall portion, wherein said first and second carrier sidewall portions each have said first wall thickness, and wherein the at least one deformable segment has a second wall thickness that is less than the first wall thickness so that the deformable segment is relatively more pliable than the first and second carrier sidewall portions (16A, 16B); f) wherein the at least one electrical conductor has at least one first coiled section of a relatively higher coiling density and at least one second coiled section of a relatively lower coiling density than the first coiled section; and g) wherein the at least one second coiled section of the lower coiling density is substantially aligned with the at least one deformable segment and the at least one first coiled section of the higher coiling density is aligned with one of the first and second carrier sidewall portions (16A, 16B) having the first wall thickness. a) a carrier having a carrier sidewall having a first wall thickness and extending along a longitudinal axis from a proximal carrier end to a distal carrier portion, wherein the distal carrier portion has a step transition to a thinner carrier sidewall portion; b) a substrate supported on the thinner carrier sidewall portion; c) at least one electrode supported on the substrate, wherein the electrode is configured for at least one of electrical stimulation of body tissue and sensing of physiological characteristics of the body tissue; wherein the step transition has a height that substantially matches the thickness of the substrate comprising the electrode to provide a smooth transition from the carrier sidewall to the substrate; d) an electrical conductor that extends from the proximal carrier end to the thinner carrier sidewall portion where it is electrically connected to the electrode supported on the substrate, wherein the proximal carrier end is electrically connectable to a medical device; and e) at least one deformable segment of the carrier sidewall intermediate a first carrier sidewall portion and a second carrier sidewall portion, wherein said first and second carrier sidewall portions each have said first wall thickness, and wherein the at least one deformable segment has a second wall thickness that is less than the first wall thickness so that the deformable segment is relatively more pliable than the first and second carrier sidewall portions (16A, 16B); f) wherein the at least one electrical conductor has at least one first coiled section of a relatively higher coiling density and at least one second coiled section of a relatively lower coiling density than the first coiled section; and g) wherein the at least one second coiled section of the lower coiling density is substantially aligned with the at least one deformable segment and the at least one first coiled section of the higher coiling density is aligned with one of the first and second carrier sidewall portions (16A, 16B) having the first wall thickness.