Contribution of the basal forebrain to corticocortical network interactions

Abstract

Basal forebrain (BF) cholinergic neurons provide the cerebral cortex with acetylcholine. Despite the long-established involvement of these cells in sensory processing, attention, and memory, the mechanisms by which cholinergic signaling regulates cognitive processes remain elusive. In this study, we recorded spiking and local field potential data simultaneously from several locations in the BF, and sites in the orbitofrontal and visual cortex in transgenic ChAT-Cre rats performing a visual discrimination task. We observed distinct differences in the fine spatial distributions of gamma coherence values between specific basalo-cortical and cortico-cortical sites that shifted across task phases. Additionally, cholinergic firing induced spatial changes in cortical gamma power, and optogenetic activation of BF increased coherence between specific cortico-cortical sites, suggesting that the cholinergic system contributes to selective modulation of cortico-cortical circuits. Furthermore, the results suggest that cells in specific BF locations are dynamically recruited across behavioral epochs to coordinate interregional cortical processes underlying cognition.

Cholinergic activity reflects reward expectations and predicts behavioral responses

“…The cholinergic system has long been known to strongly influence cortical plasticity. 3 , 43 , 44 , 45 , 46 , 47 A line of studies has demonstrated that pairing auditory stimuli with cholinergic stimulation reorganizes cortical sensory representations, known by the term “receptive field plasticity.” 23 , 24 Furthermore, recent studies showed that cholinergic inputs may even endow primary sensory cortices with non-sensory representations not expected previously. 48 , 49 In particular, Liu et al.…”

Subcortical control of the default mode network: Role of the basal forebrain and implications for neuropsychiatric disorders

“…2 , have focused on the BF as playing a central role in modulation of DMN activity across a number of experimental modalities. The BF has been shown to be a major neuromodulatory hub, supporting broad functional connections with neocortical and subcortical brain regions critical to cognition ( Lin et al, 2015 ; Yang et al, 2017 ; Zaborszky et al, 2018 ; Gombkoto et al, 2021 ). Further, degeneration of BF across age and with certain neuropathological conditions, such as Alzheimer’s disease, has been associated with both functional and cognitive impairment ( Schmitz et al, 2016 ; Markello et al, 2018 ).…”

The Basal Forebrain Cholinergic Nuclei and Their Relevance to Schizophrenia and Other Psychotic Disorders

“…These cell groups can modulate the activity of neurons located in the prefrontal cortices, hippocampi, and amygdala primarily by activating cholinergic receptors ( 16 ). These projections are organized in clusters, based on both topographical and functional principles, which allow for a spatially selective modulation of individual or joint cortical areas ( 25 – 27 ). Briefly, more medial-anterior located neurons of the BFCN project to the medial frontal cortex, while the substantia innominata, the nucleus basalis of Meynert, and the diagonal band neurons project to dorsal regions of prefrontal cortical areas.…”

“…Beyond the structural integrity, evidence suggests that ACh levels are linked with distinct cognitive functions. For instance, it has been shown that transient rises in prefrontal ACh are associated with increased visual cue detection, indicating a link between ACh levels and attention ( 25 ). In support, ACh increases, measured via microdialysis, were related to increased task performance ( 31 ).…”