I am posting below comments from Spratling’s article addressing the role of attention (by the cognitive mind) in information processing. It must be recalled that information is only generated by a mind (matter cannot generate information), and all information that is transmitted must be encoded (within neural codes to which my books and blogs have spoken).
“Attention is a top-down process that operates via cortical feedback projections. . . . Attention modulates the sensory-driven activation of cells, . . . such that activity in response to an attended stimulus is increased in amplitude and duration. . . . increased attention has effects similar to increasing the contrast or saliency of the stimulus. . . . In the absence of a stimulus, attention increases the rate of spontaneous firing (the author makes no mention of the causal effects of a cognitive mind, and I have shared in my more recent blogs that attention, intent and will likely generate wave forms with amplitude, frequency and phase that can tunnel through voltage barriers of ionic channels and synaptic components to increase ‘the rate of spontaneous firing’ in neural networks) . . . . attention is used to multiplicatively modulate the synaptic strengths of intra-cortical connections so that attended information can be selectively routed to higher cortical regions. . . . modulatory affects could also be achieved by employing neurons that have two functionally distinct dendrites (apical and basal dendrites).”
I continue with this author’s comments that address the complex feedforward and feedback activities that are known to operate in information transmission through interconnected neural networks. Cognition involves such interconnectedness in a top-down fashion. Stimulation and inhibition both operate within and between neural cortical modules to strengthen and direct the transmission of spike train trajectories through selected neural networks, a process that involves synchronization and entrainment as discussed in my recent blogs. I have proposed that linguistically encoded wave forms generated by the mind (e.g. attention) gain direction through neural networks to bring about specific activities (e.g. moving an arm) by entraining modular wave forms whose amplitudes, frequencies and phases are in synchrony with them, establishing coherent wave forms that transmit specified information through neural synaptic networks. The question that is being considered is how apical pyramidal tufts relate to this process. Note in the following excerpt how words (italicized) are used that reflect the cognitive activity of a mind!
“Feedback modulates activity generated by feedforward processing. such modulation may play a role in tasks such as recall, priming and attention. . . . by influencing activation each dendrite can affect learning in a biologically plausible manner. Neurons are likely to learn correlations between the separate information streams targeting the apical and basal dendrites. Apical inputs can therefore influence learning at the basal dendrite and may be considered a source of reinforcement or supervision. This interpretation is bolstered by the fact that the apical dendrites in layer I not only receive projections from other cortical regions but are also targeted by the limbic system; a widely projecting set of interconnected brain structures concerned with emotion and memory.” I offer that the neurons of the material brain cannot do all these functions! It is the mind that accomplishes correlations, interpretations, supervision, recall and learning. Memories are recalled from archived neural codes situated within the liaison brain (e.g. supplementary motor area) discussed in my books.
In my next blog I will return to the article by Spruston and consider in more detail the possible role of pyramidal apical tufts in cognition. Read on.