Imaging the Limbic System in Parkinson’s Disease—A Review of Limbic Pathology and Clinical Symptoms

Abstract

The limbic system describes a complex of brain structures central for memory, learning, as well as goal directed and emotional behavior. In addition to pathological studies, recent findings using in vivo structural and functional imaging of the brain pinpoint the vulnerability of limbic structures to neurodegeneration in Parkinson’s disease (PD) throughout the disease course. Accordingly, dysfunction of the limbic system is critically related to the symptom complex which characterizes PD, including neuropsychiatric, vegetative, and motor symptoms, and their heterogeneity in patients with PD. The aim of this systematic review was to put the spotlight on neuroimaging of the limbic system in PD and to give an overview of the most important structures affected by the disease, their function, disease related alterations, and corresponding clinical manifestations. PubMed was searched in order to identify the most recent studies that investigate the limbic system in PD with the help of neuroimaging methods. First, PD related neuropathological changes and corresponding clinical symptoms of each limbic system region are reviewed, and, finally, a network integration of the limbic system within the complex of PD pathology is discussed.

Connectomic Networks and Their Impact on Clinical Outcomes in Glioma Treatment: A Review

“…The brainstem and forebrain have limbic nodes with projections to higher cortical areas that contribute to behavioral and action modulation in response to internal and external stimuli. 103,106 As a network involving some of the most primitive brain structures, the foundation of the limbic system is promoting survival through regulating responses to external and internal stimuli. The brainstem and forebrain nodes of the limbic system govern regulatory processes such as respiration and contribute to how we adapt to stressors including emotional, immune, and cognitive stimuli.…”

“…104 Moreover, the functions of the limbic system were further understood to include regulation of homeostatic, autonomic, and neuroendocrinological functions. 103 104 105 The limbic system also plays a role in anxiety and aggression as well as reward and addiction. 103 106…”

“…In 1878, Broca suggested the limbic system's role was primarily olfactory. 103,104 It was not until Papez discovered the "Papez circuit" that the role of the limbic network expanded to include memory and emotional processing. The hypothalamus, mamillary bodies, and fornix were identified as limbic structures as well as the amygdala, septal area, hippocampus, and cingulate cortex.…”

“…103 104 105 The limbic system also plays a role in anxiety and aggression as well as reward and addiction. 103 106…”

“…[103][104][105] The limbic system also plays a role in anxiety and aggression as well as reward and addiction. 103,106 Because of the extensive role of the limbic system, its pathways are far-reaching and extend between most of the integral cortices and nodes in the brain. The brainstem and forebrain have limbic nodes with projections to higher cortical areas that contribute to behavioral and action modulation in response to internal and external stimuli.…”