Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Dual Routes of Responses

(Rolls; Memory, Attention, and Decision Making, 524)




Dual Routes to the Initiation of Actions in response to Stimuli

The inputs from different sensory systems to brain structures such as the orbitofrontal cortex and amygdala allow these brain structures to evaluate the reward- or punishment-related value of incoming stimuli, or of remembered stimuli. The different sensory inputs enable evaluations within the orbitofrontal cortex and amygdala based mainly on the primary (unlearned) reinforcement value for taste, touch, and olfactory stimuli, and on the secondary (learned) reinforcement value for visual and auditory stimuli.

In the case of vision, the 'association cortex' that outputs representations of objects to the amygdala and orbitofrontal cortex is the inferior temporal visual cortex.

One route for the outputs from these evaluative brain structures is via projections directly to structures such as the basal ganglia (including the striatum and ventral striatum) and cingulate cortex to enable implicit, direct behavioural responses based on the reward- or punishment-related evaluation of the stimuli to be made. [rapid response]

The second route is via the language systems of the brain, which allow explicit (verbalizable) decisions involving multistep syntactic planning to be implemented. [contemplated response]