The mystery of claustral neural circuits and recent updates on its role in neurodegenerative pathology

Abstract

Introduction The claustrum is a structure involved in formation of several cortical and subcortical neural microcircuits which may be involved in such functions as conscious sensations and rewarding behavior. The claustrum is regarded as a multi-modal information processing network. Pathology of the claustrum is seen in certain neurological disorders. To date, there are not enough comprehensive studies that contain accurate information regarding involvement of the claustrum in development of neurological disorders. Objective Our review aims to provide an update on claustrum anatomy, ontogenesis, cytoarchitecture, neural networks and their functional relation to the incidence of neurological diseases. Materials and methods A literature review was conducted using the Google Scholar, PubMed, NCBI MedLine, and eLibrary databases. Results Despite new methods that have made it possible to study the claustrum at the molecular, genetic and epigenetic levels, its functions and connectivity are still poorly understood. The anatomical location, relatively uniform cytoarchitecture, and vast network of connections suggest a divergent role of the claustrum in integration and processing of input information and formation of coherent perceptions. Several studies have shown changes in the appearance, structure and volume of the claustrum in neurodegenerative diseases, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), autism, schizophrenia, and depressive disorders. Taking into account the structure, ontogenesis, and functions of the claustrum, this literature review offers insight into understanding the crucial role of this structure in brain function and behavior.

7,8-dihydroxyflavone enhances long-term spatial memory and alters brain volume in wildtype mice

“…It may work to integrate information from its connections with the mPFC, medial-dorsal thalamus, and BLA to focus attention and coordinate responses of its output structures such as the motor and sensory cortex (Smith et al, 2019 ). The claustrum has been linked to a number of disorders including AD, depression, and Parkinson’s disease (PD; Nikolenko et al, 2021 ). The insular cortex is another well connected brain region that has been shown to have numerous functions including processing of visceral sensations, somatosensory, pain, auditory, taste, experiencing of emotions such as disgust, sadness and happiness, empathy as well as cognitive processes such as decision making and attention (Uddin et al, 2017 ; Evrard, 2019 ).…”

Differentiation of claustrum resting‐state functional connectivity in healthy aging, Alzheimer's disease, and Parkinson's disease

“…The claustrum receives large numbers of inputs from numerous brain regions, including the parietal and medial temporal regions, and projects to the insula and frontal pole (Burman et al, 2011 ; Torgerson et al, 2015 ). Claustrum dysfunction has thus been linked to disruption in episodic memory formation (Schwindt & Black, 2009 ), attentional management (Atlan et al, 2018 ), consciousness (Koubeissi et al, 2014 ), cognitive functions (Krimmel et al, 2019 ), spatial navigation (Jankowski & O'Mara, 2015 ), and mechanisms of information processing across sensory modalities (Nikolenko et al, 2021 ), sexual functions (Redouté et al, 2000 ), and esthetic judgment (Ishizu & Zeki, 2013 ).…”

“…However, we observed significant volume decrease in AD compared with HC. A decreased volume of the claustrum is also associated with the presence of delirium, progression of dementia, and cognitive decline (Nikolenko et al, 2021 ). Abnormalities of the claustrum and insula have also been linked to the presence of positive symptoms in both neurodegenerative and psychiatric conditions (Venneri & Shanks, 2014 ).…”

“…Deficiency in emotional and cognitive social processes has been observed in PD; these include recognition of emotion and facial expression, empathy, understanding complex social interactions, and executive function abilities (Maresca et al, 2020 ; Narme et al, 2013 ). It has also been postulated that the claustrum performs a mediating role in cognition‐related processes (Crick & Koch, 2005 ; Nikolenko et al, 2021 ). In the current study, there was a significant decrease in FC between claustrum and cortical regions associated with social cognition, including insular cortex and temporal pole in the right hemisphere in PD compared with HC.…”

The cognitive dysfunction of claustrum on Alzheimer’s disease: A mini-review

“…Previous studies identified a myriad of brain areas that are involved in AD development, such as the prefrontal cortex (PFC), entorhinal cortex (EC), and hippocampus. While recently, a nucleus located in the forebrain named claustrum (CLA), has gained increasing popularity due to its functions in attention, executive function and memory (Smith et al, 2020;Nikolenko et al, 2021;Whalley, 2022), which are perceived as an integral part of AD cognitive impairment.…”