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Neuroscience Feb 1997Comparative neuroanatomical investigations in primates and non-primates have helped disentangle the anatomy of the basal forebrain region known as the substantia... (Review)
Review
Comparative neuroanatomical investigations in primates and non-primates have helped disentangle the anatomy of the basal forebrain region known as the substantia innominata. The most striking aspect of this region is its subdivision into two major parts. This reflects the fundamental organizational scheme for this portion of the forebrain. According to this scheme, two major subcortical telencephalic structures, i.e. the striatopallidal complex and extended amygdala, form large diagonally oriented bands. The rostroventral extension of the pallidum accounts for a large part of the rostral subcommissural substantia innominata, while the sublenticular substantia innominata is primarily occupied by elements of the extended amygdala. Also dispersed across this region is the basal nucleus of Meynert, which is part of a more or less continuous collection of cholinergic and non-cholinergic corticopetal and thalamopetal cells, which stretches from the septum diagonal band rostrally to the caudal globus pallidus. The basal nucleus of Meynert is especially prominent in the primate, where it is sometimes inappropriately applied as a synonym for the substantia innominata, thereby tacitly ignoring the remaining components. In most mammals, the extended amygdala presents itself as a ring of neurons encircling the internal capsule and basal ganglia. The extended amygdala may be further subdivided, i.e. into the central extended amygdala (related to the central amygdaloid nucleus) and the medial extended amygdala (related to the medial amygdaloid nucleus), which generally form separate corridors both in the sublenticular region and along the supracapsular course of the stria terminalis. The extended amygdala is directly continuous with the caudomedial shell of the accumbens, and to some extent appears to merge with it. Together the accumbens shell and extended amygdala form an extensive forebrain continuum, which establishes specific neuronal circuits with the medial prefrontal-orbitofrontal cortex and medial temporal lobe. This continuum is particularly characterized by a prominent system of long intrinsic association fibers, and a variety of highly differentiated downstream projections to the hypothalamus and brainstem. The various components of the extended amygdala, together with the shell of the accumbens, are ideally structured to generate endocrine, autonomic and somatomotor aspects of emotional and motivational states. Behavioral observations support this proposition and demonstrate the relevance of these structures to a variety of functions, ranging from the various elements of the reproductive cycle to drug-seeking behavior. The neurochemical and connectional features common to the accumbens shell and the extended amygdala are especially relevant to understanding the etiology and treatment of neuropsychiatric disorders. This is discussed in general terms, and also in specific relation to the neurodevelopmental theory of schizophrenia and to the neurosurgical treatment of neuropsychiatric disorders.
Topics: Animals; Humans; Mental Disorders; Nervous System Diseases; Substantia Innominata; Telencephalon
PubMed: 9027863
DOI: 10.1016/s0306-4522(96)00405-8 -
Neuron May 2021Although aggressive behaviors are universal and essential for survival, "uncontrollable" and abnormal aggressive behaviors in animals or humans may have severe adverse...
Although aggressive behaviors are universal and essential for survival, "uncontrollable" and abnormal aggressive behaviors in animals or humans may have severe adverse consequences or social costs. Neural circuits regulating specific forms of aggression under defined conditions have been described, but how brain circuits govern a general aggressive response remains unknown. Here, we found that posterior substantia innominata (pSI) neurons responded to several aggression-provoking cues with the graded activity of differential dynamics, predicting the aggressive state and the topography of aggression in mice. Activation of pSI neurons projecting to the periaqueductal gray (PAG) increased aggressive arousal and robustly initiated/promoted all the types of aggressive behavior examined in an activity-level-dependent manner. Inactivation of the pSI circuit largely blocked diverse aggressive behaviors but not mating. By encoding a general aggressive response, the pSI-PAG circuit universally drives multiple aggressive behaviors and may provide a potential target for alleviating human pathological aggression.
Topics: Aggression; Animals; Behavior, Animal; Male; Mesencephalon; Mice; Neural Pathways; Neurons; Substantia Innominata
PubMed: 33740417
DOI: 10.1016/j.neuron.2021.03.002 -
Brain Structure & Function Sep 2008The neuroanatomical research by Heimer and colleagues has focused on the structure of, and connectivity between, basal forebrain regions as well as on the translational... (Review)
Review
The neuroanatomical research by Heimer and colleagues has focused on the structure of, and connectivity between, basal forebrain regions as well as on the translational significance of this research. By outlining several pressing research themes and questions concerning the neuroanatomy of the basal forebrain, as seen from a biopsychologist's perspective, the importance of continuing and expanding neuroanatomical research on the basal forebrain is illustrated.
Topics: Animals; Basal Ganglia; Cerebral Cortex; Cholinergic Fibers; Humans; Neural Pathways; Prosencephalon; Substantia Innominata; Synaptic Transmission
PubMed: 18183419
DOI: 10.1007/s00429-007-0165-x -
Advances in Experimental Medicine and... 1991
Review
Topics: Animals; Biogenic Monoamines; Dopamine; Electrophysiology; Globus Pallidus; Neurotransmitter Agents; Prosencephalon; Substantia Innominata
PubMed: 1685627
DOI: 10.1007/978-1-4757-0145-6_9 -
Neuroradiology Oct 2004To elucidate MR imaging changes of the substantia innominata in Parkinson's disease (PD), using a 1.5-T superconductive MR unit, the thickness of the substantia...
To elucidate MR imaging changes of the substantia innominata in Parkinson's disease (PD), using a 1.5-T superconductive MR unit, the thickness of the substantia innominata was measured on coronal thin-section images in 44 PD patients and 20 age-matched control subjects. We also evaluated the correlation between the thickness of the substantia innominata and mental status in PD patients. Mean thickness of the substantia innominata was 2.3 mm in PD patients, and 2.5 mm in control subjects. Thinning of the substantia innominata was statistically significant in PD patients compared with control subjects, although there were large overlaps. Among the PD patients, thinning was remarkable in cases with dementia. A positive correlation between thickness of substantia innominata and score of Mini-Mental-Status-Examination was also observed in PD patients. Atrophy of the substantia innominata was demonstrated, especially in PD patients with cognitive impairment, on coronal MR images, and this is compatible with the previous pathological reports.
Topics: Adult; Aged; Case-Control Studies; Cognition Disorders; Dementia; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parkinson Disease; Prospective Studies; Psychological Tests; Severity of Illness Index; Substantia Innominata
PubMed: 15316699
DOI: 10.1007/s00234-004-1257-4 -
Cell Reports Nov 2017Aversive stimuli can impact motivation and support associative learning as reinforcers. However, the neural circuitry underlying the processing of aversive reinforcers...
Aversive stimuli can impact motivation and support associative learning as reinforcers. However, the neural circuitry underlying the processing of aversive reinforcers has not been elucidated. Here, we report that a subpopulation of central amygdala (CeA) GABAergic neurons expressing protein kinase C-delta (PKC-δ+) displays robust responses to aversive stimuli during negative reinforcement learning. Importantly, projections from PKC-δ+ neurons of the CeA to the substantia innominata (SI) could bi-directionally modulate negative reinforcement learning. Moreover, consistent with the idea that SI-projecting PKC-δ+ neurons of the CeA encode aversive information, optogenetic activation of this pathway produces conditioned place aversion, a behavior prevented by simultaneous ablating of SI glutamatergic neurons. Taken together, our data define a cell-type-specific neural circuitry modulating associative learning by encoding aversive reinforcement signals.
Topics: Amygdala; Animals; Female; GABAergic Neurons; Glutamic Acid; Male; Mice; Mice, Inbred C57BL; Protein Kinase C-delta; Reward; Substantia Innominata
PubMed: 29141212
DOI: 10.1016/j.celrep.2017.10.062 -
Neurobiology of Aging Jun 2018The relationships between cholinergic system damage and cerebrovascular disease are not entirely understood. Here, we investigate associations between atrophy of the...
The relationships between cholinergic system damage and cerebrovascular disease are not entirely understood. Here, we investigate associations between atrophy of the substantia innominata (SI; the origin of cortical cholinergic projections) and measures of large and small vessel disease; specifically, elongation of the juxtaposed internal carotid artery termination and Cholinergic Pathways Hyperintensity scores (CHIPS). The study (n = 105) consisted of patients with Alzheimer's disease (AD) and/or subcortical ischemic vasculopathy, and elderly controls. AD and subcortical ischemic vasculopathy groups showed greater impingement of the carotid termination on the SI and smaller SI volumes. Both carotid termination elongation and CHIPS were associated independently with smaller SI volumes in those with and without AD. Atrophy of the SI mediated effects of carotid termination elongation on language and memory functions and the effect of CHIPS on attention/working memory. In conclusion, SI atrophy was related to cerebrovascular disease of the large and small vessels and to cognitive deficits in people with and without AD.
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Atrophy; Attention; Carotid Artery Diseases; Cerebrovascular Disorders; Cognition; Cognitive Dysfunction; Dementia, Vascular; Female; Humans; Magnetic Resonance Imaging; Male; Memory, Short-Term; Middle Aged; Organ Size; Substantia Innominata
PubMed: 29505952
DOI: 10.1016/j.neurobiolaging.2018.01.025 -
Journal of Sleep Research Jun 2001We examined the stimulating effect of Substantia Innominata pars anterior (SIa), during the waking state, on the 'central' part of the Mediodorsal nucleus of the...
We examined the stimulating effect of Substantia Innominata pars anterior (SIa), during the waking state, on the 'central' part of the Mediodorsal nucleus of the thalamus (MD), combining electrophysiological and anatomical techniques in restrained, undrugged, unanaesthetized cats. Thalamic MD units were recorded, after electrical stimulation of the Substantia Innominata, at 1 Hz, with a single pulse or short trains of four pulses. Responses were studied by poststimulus histograms. In about 64 of the 84 recorded MD neurones (76%), stimulation of the Substantia Innominata, during the waking state, induced a brief cell excitation, followed first by prolonged inhibition of firing and then by a strong excitatory rebound discharge; after this comes a second sequence of inhibition and excitation, of decreasing amplitude. After stimulation of the Substantia Innominata, the MD units tended to start a repetitive discharge at 4--7 Hz. To investigate the connections of Substantia Innominata cells upon the areas where MD units were recorded we injected horseradish peroxidase wheat germ agglutinin (WGA-HRP), combined with immunohistochemistry for glutamic acid decarboxylase (GAD) and choline acetyl transferase (ChAT). Of the total population of retrogradely labelled cells in the Substantia Innominata 53% were GAD positive while less than 16% were ChAT positive. The GAD positive MD-projecting cells in the Substantia Innominata were triangular to fusiform and small to medium in size. These findings indicate that GABAergic input from the Substantia Innominata may contribute to increasing the hyperpolarizing inhibitory pressure on MD cells in the 'central' part during slow wave sleep (SWS).
Topics: Animals; Cats; Electric Stimulation; Male; Nerve Net; Substantia Innominata; Thalamus; Wakefulness
PubMed: 11422728
DOI: 10.1046/j.1365-2869.2001.00246.x -
International Journal of Geriatric... Jun 2017Several cholinergic nuclei, and in particular the nucleus basalis of Meynert, are localised to the substantia innominata in the basal forebrain. These nuclei provide...
OBJECTIVES
Several cholinergic nuclei, and in particular the nucleus basalis of Meynert, are localised to the substantia innominata in the basal forebrain. These nuclei provide major cholinergic innervation to the cerebral cortex and hippocampus, and have an essential role in cognitive function. The aim of this study was to investigate volumetric grey matter (GM) changes in the substantia innominata from structural T1 images in Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and healthy older participants using voxel-based morphometry.
METHODS
Participants (41 DLB, 47 AD and 39 controls) underwent 3 T T1 magnetic resonance imaging and cognitive assessments. Voxel-based morphometry analysis used SPM8 with a substantia innominata brain mask to define the subspace for voxel GM analyses. Group differences, and selected behavioural and clinical correlates, were assessed.
RESULTS
Compared with that in controls, bilateral GM loss in the substantia innominata was apparent in both AD and DLB. Relative to controls, significant bilateral GM loss in the substantia innominata was observed in DLB and AD. In DLB, significant associations were also observed between substantia innominata GM volume loss, and the levels of cognitive impairment and severity of cognitive fluctuations.
CONCLUSIONS
Relative to that controls, atrophy of the substantia innominata was apparent in DLB and AD, and is associated with specific clinical manifestations in DLB. © 2016 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons Ltd.
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Atrophy; Case-Control Studies; Female; Gray Matter; Humans; Lewy Body Disease; Magnetic Resonance Imaging; Male; Substantia Innominata
PubMed: 27197956
DOI: 10.1002/gps.4500 -
AJNR. American Journal of Neuroradiology Jan 2002The substantia innominata can be visualized on coronal thin-section T2-weighted MR images. The purpose of this study was to investigate the morphologic changes of the...
BACKGROUND AND PURPOSE
The substantia innominata can be visualized on coronal thin-section T2-weighted MR images. The purpose of this study was to investigate the morphologic changes of the substantia innominata in normal aging by using MR imaging and to determine whether the changes in this structure on MR images were specific to Alzheimer disease (AD).
METHODS
The thickness of the substantia innominata was measured on the coronal T2-weighted image obtained through the anterior commissure in 39 healthy control subjects (age range, 25-86 y; mean age, 62 y); 39 patients with AD; and 36 patients with non-AD dementia, including vascular dementia, frontotemporal dementia, and Parkinson disease with dementia.
RESULTS
In the control subjects, the thickness of the substantia innominata significantly decreased with age. Compared with age-matched control subjects, both patients with AD and patients with non-AD dementia had significant atrophy of the substantia innominata. The thickness of the substantia innominata significantly correlated with scores from the Mini-Mental State Examination in patients with AD but not in patients with non-AD dementia.
CONCLUSION
MR analysis reveals age-related shrinkage of the substantia innominata. Atrophy of the substantia innominata, which reflects degeneration in the nucleus basalis of Meynert, is pronounced both in patients with AD and in those with non-AD dementia. MR imaging features in this structure may not be specific to AD.
Topics: Adult; Age Factors; Aged; Aged, 80 and over; Alzheimer Disease; Atrophy; Dementia; Dementia, Vascular; Diagnosis, Differential; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Parkinson Disease; Reference Values; Substantia Innominata
PubMed: 11827872
DOI: No ID Found