Cholinergic systems mediate action from movement to higher consciousness.

There is a fundamental link between cholinergic neurotransmitter function and overt and covert actions. Major cholinergic systems include peripheral motor neurons organizing skeletal muscle movements into overt behaviors and cholinergic neurons in the basal forebrain and mesopontine regions that mediate covert actions realized as states of consciousness, arousal, selective attention, perception, and memory. Cholinergic interneurons in the striatum appear to integrate conscious and unconscious actions.

Neural cytoskeleton capabilities for learning and memory.

This paper proposes a physical model involving the key structures within the neural cytoskeleton as major players in molecular-level processing of information required for learning and memory storage. In particular, actin filaments and microtubules are macromolecules having highly charged surfaces that enable them to conduct electric signals. The biophysical properties of these filaments relevant to the conduction of ionic current include a condensation of counterions on the filament surface and a nonlinear complex physical structure conducive to the generation of modulated waves.

Acetylcholine, cognition, and consciousness.

Acetylcholine (ACh) is a neuromodulator inextricably involved with higher mental functions. The organization of central pathways enables this role, as do the complex responses to ACh. This chapter focuses on intradendritic responses to ACh.

Transitions in microtubule C-termini conformations as a possible dendritic signaling phenomenon.

We model the dynamical states of the C-termini of tubulin dimers that comprise neuronal microtubules. We use molecular dynamics and other computational tools to explore the time-dependent behavior of conformational states of a C-terminus of tubulin within a microtubule and assume that each C-terminus interacts via screened Coulomb forces with the surface of a tubulin dimer, with neighboring C-termini and also with any adjacent microtubule-associated protein 2 (MAP2). Each C-terminus can either bind to the tubulin surface via one of the several positively charged regions or can be allowed to explore the space available in the solution surrounding the dimer.

A quantum approach to visual consciousness.

A theoretical approach relying on quantum computation in microtubules within neurons can potentially resolve the enigmatic features of visual consciousness, but raises other questions. For example, how can delicate quantum states, which in the technological realm demand extreme cold and isolation to avoid environmental 'decoherence', manage to survive in the warm, wet brain? And if such states could survive within neuronal cell interiors, how could quantum states grow to encompass the whole brain? We present a physiological model for visual consciousness that can accommodate brain-wide quantum computation according to the Penrose-Hameroff 'Orch OR' model. In this view, visual consciousness occurs as a series of several-hundred-millisecond epochs, each comprising 'crescendo sequences' of quantum computations occurring at approximately 40 Hz.