Structure and function of dual‐source cholinergic modulation in early vision

Abstract

Behavioral states such as arousal and attention have profound effects on sensory processing, determining how-even whether-a stimulus is perceived. This state-dependence is believed to arise, at least in part, in response to inputs from subcortical structures that release neuromodulators such as acetylcholine, often nonsynaptically. The mechanisms that underlie the interaction between these nonsynaptic signals and the more point-to-point synaptic cortical circuitry are not well understood. This review highlights the state of the field, with a focus on cholinergic action in early visual processing. Key anatomical and physiological features of both the cholinergic and the visual systems are discussed. Furthermore, presenting evidence of cholinergic modulation in visual thalamus and primary visual cortex, we explore potential functional roles of acetylcholine and its effects on the processing of visual input over the sleep-wake cycle, sensory gain control during wakefulness, and consider evidence for cholinergic support of visual attention. K E Y W O R D SLGN, macaque, neuromodulation, primate, V1, visual cortex

A unified model of the task-evoked pupil response

“…Over the past 80 years, measuring pupil size has become a popular tool for inferring arousal level [21]. Inexpensive, non-invasive, and high fidelity, pupil size recordings have many advantages over the alternatives, i.e., measurement of spiking activity in neuromodulatory loci [26, 14], whole brain imaging [32, 78], and in-vivo biochemical recordings [79, 80]. Indeed, a large number of recent publications have linked pupil size with behavior [41, 11, 34, 81, 82, 83, 40, 32], or neural signals [29, 26, 10, 25, 31, 30, 32].…”

Towards a Unified View on Pathways and Functions of Neural Recurrent Processing

“…Cholinergic receptors can be divided into muscarinic and nicotinic groups, which have differing prevalence across cortical layers and can be found on inhibitory as well as excitatory neurons. Thus, basal forebrain projections can engage a diversity of mechanisms, which is a theme outside the scope of this review and for which we refer to other reviews (e.g., [91]).…”

The elephant in the room: understanding the pathogenesis of Charles Bonnet syndrome

“…The neurotransmitters in the brain play a role in modulating vision. It is possible acetylecholine may also have a role in the presence of hallucinations when sensory input is reduced …”

“…It is possible acetylecholine may also have a role in the presence of hallucinations when sensory input is reduced. 58,59 The existing evidence paints a picture of a complex interplay of risk factors in the pathogenesis of CBS. Perhaps age-related structural or vascular changes in the areas described above render them more vulnerable to produce abnormal activity when deprived of input, either by visual impairment or sensory deprivation.…”