Intracortical projections do not have to cross the thalamus or other subcortical structures. In case of the visual system, that features many cortical projections, most of them do not enter the thalamus or other subcortical structures (Fig. 1).
Fig. 1. Visual system. source: McGill
All the projections from the LGN to primary cortex (V1 in Fig. 1) and via V2, V3, V4 up to V5 occur without visual information entering the thalamus or other subcortical structures.
Also note that on the cellular scale direct cortico-cortical connections in the cortex are abundant (Fig. 2).
Fig. 2. Local cellular connections in the visual cortex. source: Kang et al. (2014)
Reference
- Kang et al., *Front Syst Neurosci (2014); 8: 172