Bach’s Cortical Conductor Theory

Cognitive scientist Joscha Bach posits a functional explanation for phenomenal consciousness, the cortical conductor theory (CTC), where “cortical structures are the result of reward-driven learning, based on signals of the motivational system, and the structure of the data that is being learned.”

Critical is the “conductor,” which is “a computational structure that is trained to regulate the activity of other cortical functionality. It directs attention, provides executive function by changing the activity and parameterization and rewards of other cortical structures, and integrates aspects of the processes that it attended to into a protocol. This protocol is used for reflection and learning” (Bach, 2019).

The Conductor and Cortical Orchestra

Bach has CTC's “elementary agents” as columns in the cerebral cortex that “self-organize into the larger organizational units of the brain areas as a result of developmental reinforcement learning. The activity of the cortical orchestra is highly distributed and parallelized, and cannot be experienced as a whole.”

However, its performance is coordinated by the conductor, which is not a homunculus, “but like the other instruments, a set of dynamic function approximators” (situated in prefrontal cortex^[1]). Whereas most cortical instruments, he says, “regulate the dynamics and interaction of the organism with the environment (or anticipated, reflected and hypothetical environments), the conductor regulates the dynamics of the orchestra itself.” The process is based on signals of the motivational system and it provides executive function, resolves conflicts between cortical agents, and regulates their activities (Bach, 2019).

“The conductor is the only place where experience is integrated,” Bach states. “Information that is not integrated in the protocol cannot become functionally relevant to the reflection of the system, to the production of its utterances, the generation of a cohesive self model, and it cannot become the object of access consciousness.”

Without the conductor, he asserts, our brain can still perform most of its functions, but we would be “sleepwalkers, capable of coordinated perceptual and motor action, but without central coherence and reflection.”

Consciousness as Memory of Attention

Memories empower Bach's theory. “Memories can be generated by reactivating a cortical configuration via the links and parameters stored at the corresponding point in the protocol. Reflective access to the protocol is a process that can itself be stored in the protocol, and by accessing this, a system may remember having had experiential access.”

For phenomenal consciousness, Bach claims “it is necessary and sufficient that a system can access the memory of having had an experience—the actuality of experience itself is irrelevant.”

Phenomenal consciousness, according to Bach, “may simply be understood as the most recent memory of what our prefrontal cortex attended to. Thus, conscious experience is not an experience of being in the world, or in an inner space, but a memory. It is the reconstruction of a dream generated [by] more than fifty brain areas, reflected in the protocol of a single region. By directing attention to its own protocol, the conductor can store and recreate a memory of its own experience of being conscious” (Bach, 2019).

Unlike Integrated Information Theory, Bach says CTC is a functionalist model of consciousness, with similarity to other functionalist approaches, such as the ones suggested by Dennett and Graziano (Bach, 2019).

Footnote

[1]. Bach notes, “In the human brain, the functionality of the conductor is likely facilitated via the dorsolateral prefrontal cortex, anterior cingulate cortex, and anterior insula. The conductor has attentional links into most regions” (Bach, 2019).