As I sat to write this comment on Morsella et al.'s action-based synthesis of the science of consciousness, I found myself forced to examine the events that eventually led to my current situation. According to Morsella et al.'s passive frame theory (PFT), the contents that entered into my deliberations would be perceptual representations of external events (e.g., the computer screen in front of me, or the letters that appear on the screen as I type), as well as perceptual representations activated by unconscious corollary discharges, such as my urge to turn my head, look away from the screen, and close my eyes as I try to figure out what to write next. As I turn away, I find myself focusing on PFT's assertion that the contents of perceptual representations are encapsulated. Just then, Proffitt's (Reference Proffitt2006) economy of action (EoC) theory and Gibson's (Reference Gibson1979) theory of direct perception enter my conscious field at roughly the same time. Suddenly, I see myself at a pub, engaged in arguments with dear friends about whether or not perception requires representations. I laugh out loud. Then I realize I have been sitting for some time, my left elbow propped on the desk, my head in my hand, my eyes closed. Eyes open, I realize that I have a co-author on this paper and have yet to include any of his material. I look for the email he sent me, copy a particularly clever section, and paste it into this comment.
My coauthor writes: “While I agree that consciousness influences skeletomotor activity, memories influence reflexive responses within the skeletomotor system as well. This challenges Morsella et al.'s commitment toward conceptualizing cognition using a modular approach. There are many studies, both neural and perceptual, that show how action-based memories are integrated into efference streams affecting planned skeletomotor action. Specifically, motor-cortical regions associated with action planning are more active when viewing dancers whose expertise is similar to one's own (Calvo-Merino et al. Reference Calvo-Merino, Glaser, Grèzes, Passingham and Haggard2005), suggesting that the observation of another's actions activates past action plans associated with moving oneself. If so, one's perceptions should be influenced by the observation of another's actions when they elicit motor-cortical activation associated with acting. Perceived distance estimates increase when observing another carry a weighted backpack only if the observer previously carried the weighted backpack and is now not carrying the backpack. That is, only after the observer has developed backpack-carrying memories, are distance estimates affected by the observation of another's actions (Vinson et al. Reference Vinson, Jordan and Hund2015). Findings such as these suggest that memories are driven into the very makeup of efference streams within one's skeletomotor system (possibly stored in cerebellar cortical networks; see Jordan Reference Jordan2013). Thus, cognition cannot be modular when past actions are nested within the very nature of the contents that constitute perception.”
Seeing my name, particularly when paired with “2013,” reminds me to mention that the “memories” my co-author is referring to are due to the fact that neurons in the motor cortex project collaterals to very specific locations in the cerebellum, all of which recursively innervate the cortical neurons from which they receive input. These very same cerebellar neurons receive input from the afferent systems influenced by the movements resulting from motor neuron stimulation. As a result, neurons in the cerebellum allow one to embody “command-feedback” regularities, or, if you like, successful movement-effect memories. As a result, the neural activity in the cerebellum is neither wholly “motor” nor “sensory.” It is simultaneously both, and neither. Recognizing the neither “sensory” nor “motor” nature of the “memories” entailed in cortico-cerebellar circuits is important because these cerebellar neurons recursively influence motor cortex. As a result, the content of the neural activity in the motor cortex is rendered neither “motor” nor “sensory.” It, too, is simultaneously both. This dissolving of the sensory-motor divide strongly challenges the “motor-sensory,” “perception-action,” “input-output” distinctions that lie at the heart of PFT.
I read over the preceding paragraph, just to make sure I've not generated a plateful of Escher spaghetti. No – it works, and it only potentially sounds bizarre because of our historical, theoretical commitment to conceptualizing perception as input and action as output. Then I remember to mention the fairly recent discovery that almost every area of the cortex shares recursive coupling with the cerebellum, just as is the case with the motor cortex (Koziol et al. Reference Koziol, Budding and Chidekel2011; Schmahmann Reference Schmahmann2001). This means activity in most, if not all, cortical areas is continuously, recursively influenced by the cerebellum. In short, activity in the cortex is continuously primed by the recursive “memories” stored in cortico-cerebellar circuitry.
I scratch my back, trying to remember why I started writing about the cerebellum. I look at the screen and remember. If the contents of the conscious field are there to help determine which pattern of skeletomuscular behavior is expressed at any given moment, then the bizarre, seemingly distorted pattern of thoughts described above should not have been conscious. But they were. As I read back over them, I realize that almost every moment of change in content could very well have reflected a moment of planning conflict – not about what my body would do at that moment, but what my “thoughts” would “do” at that moment. Thinking about encapsulation led to my thinking about Proffitt (Reference Proffitt2006) and Gibson (Reference Gibson1979). Thinking about Proffitt and Gibson led to my thinking about representations and friends in a pub. In each case, the content of the thoughts seemed to reflect conflicts emerging from previous thoughts. Apparently, Morsella and colleagues are correct: Consciousness is about conflicts – but not just skeletomotor conflicts. Rather, as a result of the fact that cortical activity is continuously primed by the memory content entailed in cortico-cerebellar circuitry, the cortical activity associated with perception, and action, and cognition is always potentially in conflict. That is, attempting to maintain a given thought, perception, or action will result in conflicts as both exogenous contextual factors, and endogenous memories will prime actions, perceptions, and cognitions that are inconsistent with what I am attempting to do. In short, as I work to make any one thing happen in perception, action, or cognition, it will inevitably be in conflict with the myriad other things I could have possible done, and “consciousness” will entail this ebb and flow of conflicts.
As I rest my head on the desk and close my eyes, I feel a sense of satisfaction. I suddenly remember my co-author and the need to send him the final draft. Will the conflicts never cease?
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As I sat to write this comment on Morsella et al.'s action-based synthesis of the science of consciousness, I found myself forced to examine the events that eventually led to my current situation. According to Morsella et al.'s passive frame theory (PFT), the contents that entered into my deliberations would be perceptual representations of external events (e.g., the computer screen in front of me, or the letters that appear on the screen as I type), as well as perceptual representations activated by unconscious corollary discharges, such as my urge to turn my head, look away from the screen, and close my eyes as I try to figure out what to write next. As I turn away, I find myself focusing on PFT's assertion that the contents of perceptual representations are encapsulated. Just then, Proffitt's (Reference Proffitt2006) economy of action (EoC) theory and Gibson's (Reference Gibson1979) theory of direct perception enter my conscious field at roughly the same time. Suddenly, I see myself at a pub, engaged in arguments with dear friends about whether or not perception requires representations. I laugh out loud. Then I realize I have been sitting for some time, my left elbow propped on the desk, my head in my hand, my eyes closed. Eyes open, I realize that I have a co-author on this paper and have yet to include any of his material. I look for the email he sent me, copy a particularly clever section, and paste it into this comment.
My coauthor writes: “While I agree that consciousness influences skeletomotor activity, memories influence reflexive responses within the skeletomotor system as well. This challenges Morsella et al.'s commitment toward conceptualizing cognition using a modular approach. There are many studies, both neural and perceptual, that show how action-based memories are integrated into efference streams affecting planned skeletomotor action. Specifically, motor-cortical regions associated with action planning are more active when viewing dancers whose expertise is similar to one's own (Calvo-Merino et al. Reference Calvo-Merino, Glaser, Grèzes, Passingham and Haggard2005), suggesting that the observation of another's actions activates past action plans associated with moving oneself. If so, one's perceptions should be influenced by the observation of another's actions when they elicit motor-cortical activation associated with acting. Perceived distance estimates increase when observing another carry a weighted backpack only if the observer previously carried the weighted backpack and is now not carrying the backpack. That is, only after the observer has developed backpack-carrying memories, are distance estimates affected by the observation of another's actions (Vinson et al. Reference Vinson, Jordan and Hund2015). Findings such as these suggest that memories are driven into the very makeup of efference streams within one's skeletomotor system (possibly stored in cerebellar cortical networks; see Jordan Reference Jordan2013). Thus, cognition cannot be modular when past actions are nested within the very nature of the contents that constitute perception.”
Seeing my name, particularly when paired with “2013,” reminds me to mention that the “memories” my co-author is referring to are due to the fact that neurons in the motor cortex project collaterals to very specific locations in the cerebellum, all of which recursively innervate the cortical neurons from which they receive input. These very same cerebellar neurons receive input from the afferent systems influenced by the movements resulting from motor neuron stimulation. As a result, neurons in the cerebellum allow one to embody “command-feedback” regularities, or, if you like, successful movement-effect memories. As a result, the neural activity in the cerebellum is neither wholly “motor” nor “sensory.” It is simultaneously both, and neither. Recognizing the neither “sensory” nor “motor” nature of the “memories” entailed in cortico-cerebellar circuits is important because these cerebellar neurons recursively influence motor cortex. As a result, the content of the neural activity in the motor cortex is rendered neither “motor” nor “sensory.” It, too, is simultaneously both. This dissolving of the sensory-motor divide strongly challenges the “motor-sensory,” “perception-action,” “input-output” distinctions that lie at the heart of PFT.
I read over the preceding paragraph, just to make sure I've not generated a plateful of Escher spaghetti. No – it works, and it only potentially sounds bizarre because of our historical, theoretical commitment to conceptualizing perception as input and action as output. Then I remember to mention the fairly recent discovery that almost every area of the cortex shares recursive coupling with the cerebellum, just as is the case with the motor cortex (Koziol et al. Reference Koziol, Budding and Chidekel2011; Schmahmann Reference Schmahmann2001). This means activity in most, if not all, cortical areas is continuously, recursively influenced by the cerebellum. In short, activity in the cortex is continuously primed by the recursive “memories” stored in cortico-cerebellar circuitry.
I scratch my back, trying to remember why I started writing about the cerebellum. I look at the screen and remember. If the contents of the conscious field are there to help determine which pattern of skeletomuscular behavior is expressed at any given moment, then the bizarre, seemingly distorted pattern of thoughts described above should not have been conscious. But they were. As I read back over them, I realize that almost every moment of change in content could very well have reflected a moment of planning conflict – not about what my body would do at that moment, but what my “thoughts” would “do” at that moment. Thinking about encapsulation led to my thinking about Proffitt (Reference Proffitt2006) and Gibson (Reference Gibson1979). Thinking about Proffitt and Gibson led to my thinking about representations and friends in a pub. In each case, the content of the thoughts seemed to reflect conflicts emerging from previous thoughts. Apparently, Morsella and colleagues are correct: Consciousness is about conflicts – but not just skeletomotor conflicts. Rather, as a result of the fact that cortical activity is continuously primed by the memory content entailed in cortico-cerebellar circuitry, the cortical activity associated with perception, and action, and cognition is always potentially in conflict. That is, attempting to maintain a given thought, perception, or action will result in conflicts as both exogenous contextual factors, and endogenous memories will prime actions, perceptions, and cognitions that are inconsistent with what I am attempting to do. In short, as I work to make any one thing happen in perception, action, or cognition, it will inevitably be in conflict with the myriad other things I could have possible done, and “consciousness” will entail this ebb and flow of conflicts.
As I rest my head on the desk and close my eyes, I feel a sense of satisfaction. I suddenly remember my co-author and the need to send him the final draft. Will the conflicts never cease?