Neural pathways or synaptic pathways were the channels within a nervous system for neural signals or neurons to be sent between the brain and other parts of a humanoid. Damage to one's neural pathway could lead to severe neurological damage and even death.
A Nausicaan weapon caused a disruption of the neural pathways of Captain Keene. Doctor Phlox started a cortical regeneration as treatment which would last two or three days. (ENT: "Fortunate Son")
T'Pol's scan of a Vulcan crewmember aboard the Seleya provided the information that his synaptic pathways were severely damaged. (ENT: "Impulse")
The Xindi-Reptilian biorifle weapon was powered by a lifeform resembling an eel. Its neural pathways modulated the weapon's power output. (ENT: "The Shipment")
The neural pathways of Xindi-Reptilians and Xindi-Primates were virtually identical. (ENT: "Stratagem")
In January 2154, Jonathan Archer's synaptic pathways were infiltrated by a unique neurochemical, causing him to become protective of an Xindi-Insectoid hatchery at the expense of NX class starship Enterprise NX-01 and its mission into the Delphic Expanse. (ENT: "Hatchery")
Later, in February 2154, Starfleet officer Hoshi Sato was kidnapped from her post on Enterprise by Dolim's order. Sato's synaptic pathways were altered through a series of parasitic injections into her neocortex. This was to force Sato to break the Xindi-Aquatic encryption protocols, giving Dolim the launch codes to the Xindi weapon. However, Sato initially proved to be resilient to the treatments, and attempted suicide rather than break the encryption protocols. After being recaptured, Sato was given further injections to make her more compliant. (ENT: "The Council", "Countdown")
After her assimilation in 2350, Annika Hansen was placed in a Borg maturation chamber where the hive mind began to restructure her synaptic pathways, leading to her eventual emergence in 2355 as a Borg drone. (VOY: "Collective")
Ribosome infusions could help treat extreme cell damage caused by early neural pathway degeneration. In 2366, Doctor Beverly Crusher attempted to convince Lieutenant Worf to agree to a ribosome infusion to treat the Romulan Patahk. (TNG: "The Enemy")
Benjamin Sisko suffered unusual neural pathway activity in 2373, following exposure to a plasma burst. The condition was associated with odd synaptic potentials and post-neural shock syndrome, and also with a series of prophetic visions. Sisko suffered severe headaches and, eventually, life-threatening depolarization of his central nervous system. The condition was corrected by a neuropolaric induction. He suffered a temporary relapse in 2374. (DS9: "Rapture", "Far Beyond the Stars")
An illegal procedure called accelerated critical neural pathway formation was used during the 24th century that affected neural pathways and generally resulted in increased intelligence, but with high likelihood of dramatic and often unpredictable side effects on the personality of the patient. (DS9: "Doctor Bashir, I Presume")
In 2375, the aliens residing in chaotic space instructed Chakotay on how to escape chaotic space, which had a negative effect on Human neural pathways. (VOY: "The Fight")