Anterior and lateral divisions of the anterolateral sensory pathway.
the anterolateral fibers cross immediately in the anterior commissure of the cord to the opposite anterior and lateral white columns, where they turn upward toward the brain by way of the anterior spinothalamic and lateral spinothalamic tracts. The upper terminus of the two spinothalamic tracts is mainly twofold: (1) throughout the reticular nuclei of the brain stem and (2) in two different nuclear complexes of the thala- mus, the ventrobasal complex and the intralaminar nuclei. In general, the tactile signals are transmitted mainly into the ventrobasal complex, terminating in some of the same tha- lamic nuclei where the dorsal column tactile signals terminate. From here, the signals are transmitted to the somatosensory cortex along with the signals from the dorsal columns. only a small fraction of the pain signals pro- ject directly to the ventrobasal complex of the thalamus. But most pain signals are relayed into the reticular nuclei from there they are relayed into the intrathalamic nuclei.