The spinoreticular tract is an ascending pathway in the white matter of the spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

, positioned closely to the lateral spinothalamic tract. The tract is from spinal cord---to reticular formation

Reticular formation

The reticular formation is a part of the brain that is involved in actions such as awaking/sleeping cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli...

--- to thalamus

Thalamus

The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

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It is responsible for automatic responses to pain, such as in the case of injury.

Pathway

The spinoreticular tract utilizes four levels of neurons, unlike most ascending tracts which have first- through third-order neurons. The tract begins with first-order neurons, which immediately synapse with second-order neurons in the posterior horn of the spinal column. These neurons decussate to the opposite side (anterolateral), and travel up the spinal column. It terminates in the brainstem at the medullary-pontine reticular formation. Information is sent from there to the intradmedian nucleus of the thalamic intralaminar nuclei. The thalamic intralaminar nuclei project diffusely to entire cerebral cortex where pain reaches conscious level and promotes behavioral arousal.

It is still undetermined if the spinoreticular tract possesses ipsilateral fibers in addition to those that decussate. It is hypothesized that during development the tract was bilateral, but that the ipsilateral synapses became ineffective during development.