Evidence that visual input is routed from the thalamus directly to an emotional control center in the brain has been used to support the claim that

This evidence supports the claim that some emotional reactions may occur without conscious thinking.
Thalamus is a small brain area located above the brain stem, with the main function of sending motor and sensory signals from the spinal cord and the mid-brain structures to the cerebral cortex.

Amygdala is a small brain region, which is part of the limbic system. It is considered the emotional control centre of the brain since it regulates emotions, survival instincts and some memory functions.

It has been proven that visual input is directly sent by the thalamus to the amygdala, which can trigger some emotional responses (such as fear) without any conscious processing.