Superior Colliculus involved in optical pattern recognition

For those interested in the brain structures involved in this process, the essentic form is probably detected by pattern recognition structures in the retina, and passed direct to the superior colliculus without any conscious involvement or awareness at this stage. The superior colliculus activates reflexes turning the head and eye so that the most sensitive part of the retina, the fovea, can analyse the stimulus, whether the pupil of a threatening eye, or the sharp end of a spike. At the same time, information is also sent down a nerve bundle from the retina to the thalamus, where the shape is relayed to other centres (amygdala etc) to initiate the appropriate emotional response; and to the visual cortex, for recognising the object, and determining its location relative to its surroundings. Information also goes to the ascending reticular activating formation, which participates in bringing relevant aspects of the stimulus into consciousness, and then modifying the initial emotional response.

It is not known whether other sentic forms are similarly recognised at the retinal stage, in the superior colliculus, or elsewhere, but it is believed that the inferior colliculus, which handles auditory stimuli, recognises sentic forms from auditory sources, and initiates appropriate instinctive behaviour.