Gabaergic and cholinergic basal forebrain and preoptic-anterior hypothalamic projections to the mediodorsal nucleus of the thalamus in the cat

Gritti, Ivana; Mariotti, Maurizio; Mancia, M

doi:10.1016/s0306-4522(97)00573-3

Cited by 62 publications

(59 citation statements)

References 94 publications

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“…Cholinergic projections from basal forebrain show a preference for mediodorsal and intralaminar thalamic nuclei (31,(35)(36)(37)(38). Dopaminergic projections from the ventral tegmental area in the rat target primarily the reticular nucleus, zona incerta, and mediodorsal nucleus (39).…”

Section: Discussionmentioning

confidence: 99%

Thalamocortical synchronization during induction and emergence from propofol-induced unconsciousness

Flores

Hartnack

Fath

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

151

130

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General anesthesia (GA) is a reversible drug-induced state of altered arousal required for more than 60,000 surgical procedures each day in the United States alone. Sedation and unconsciousness under GA are associated with stereotyped electrophysiological oscillations that are thought to reflect profound disruptions of activity in neuronal circuits that mediate awareness and cognition. Computational models make specific predictions about the role of the cortex and thalamus in these oscillations. In this paper, we provide in vivo evidence in rats that alpha oscillations (10-15 Hz) induced by the commonly used anesthetic drug propofol are synchronized between the thalamus and the medial prefrontal cortex. We also show that at deep levels of unconsciousness where movement ceases, coherent thalamocortical delta oscillations (1-5 Hz) develop, distinct from concurrent slow oscillations (0.1-1 Hz). The structure of these oscillations in both cortex and thalamus closely parallel those observed in the human electroencephalogram during propofol-induced unconsciousness. During emergence from GA, this synchronized activity dissipates in a sequence different from that observed during loss of consciousness. A possible explanation is that recovery from anesthesiainduced unconsciousness follows a "boot-up" sequence actively driven by ascending arousal centers. The involvement of medial prefrontal cortex suggests that when these oscillations (alpha, delta, slow) are observed in humans, self-awareness and internal consciousness would be impaired if not abolished. These studies advance our understanding of anesthesia-induced unconsciousness and altered arousal and further establish principled neurophysiological markers of these states.anesthesia | prefrontal cortex | thalamus | coherence | propofol G eneral anesthesia (GA) is a reversible drug-induced state consisting of unconsciousness, analgesia, amnesia, akinesia, and physiological stability (1). In the United States nearly 60,000 surgical procedures are conducted under GA every day, making GA one of the most common manipulations of the brain and central nervous system in medicine (1). The molecular mechanisms by which anesthetic drugs alter brain function have been well characterized (2, 3). Detailed analyses of neural circuitand systems-level mechanisms of GA are more recent (1, 4, 5). Understanding the system-wide effects of anesthetic drugs is necessary in order to understand how these drugs produce states of altered arousal and unconsciousness.One of the most commonly used anesthetic drugs is 2,6-diisopropylphenol (propofol), a GABA-A receptor agonist (6). Electroencephalogram (EEG) recordings in humans during gradual induction of unconsciousness with propofol show the appearance of frontal β oscillations (15-30 Hz) at the onset of sedation, followed by the appearance of coherent frontal α (8-12 Hz) oscillations (7-10) and widespread slow (0.1-1 Hz) and δ (1-4 Hz) oscillations (7, 11, 12) when subjects no longer respond to sensory stimuli. Biophysical models of neuronal dy...

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Section: Discussionmentioning

confidence: 99%

Thalamocortical synchronization during induction and emergence from propofol-induced unconsciousness

Flores

Hartnack

Fath

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

151

130

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“…However, given the relatively large size of these GADϩ cells, it is likely that they are projection neurons and could project to cortical areas (Gritti et al, 1997). On the other hand, given the full range of cell sizes among projecting cells, it is also possible that they could project to subcortical regions, including the thalamus (Asanuma and Porter, 1990;Gritti et al, 1998) and posterior hypothalamus or brainstem (Gritti et al, 1994). Accordingly, they could be involved in attenuating cortical or subcortical activity in a slow tonic manner during slow wave sleep.…”

Section: Discussionmentioning

confidence: 99%

Discharge Profiles of Juxtacellularly Labeled and Immunohistochemically Identified GABAergic Basal Forebrain Neurons Recorded in Association with the Electroencephalogram in Anesthetized Rats

2000

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The basal forebrain ostensibly plays a dual role in the modulation of cortical activation and behavioral state. It is essential for stimulating cortical activation in association with waking (and paradoxical sleep), yet also important for attenuating cortical activation and promoting slow wave sleep. Using juxtacellular recording and labeling of neurons with Neurobiotin followed by immunohistochemical staining for glutamic acid decarboxylase (GAD), we studied the discharge properties of identified GABAergic basal forebrain neurons in relation to electroencephalographic (EEG) activity in urethane-anesthetized rats to determine the part or parts that they may play in this dual role.The GABAergic neurons displayed distinct discharge profiles in relation to somatosensory stimulation-evoked cortical activation. Whereas a significant minority increased its average discharge rate, the majority decreased its average discharge rate in association with cortical activation. Moreover, subgroups displayed distinct discharge patterns related to different cortical activities, including very regular high-frequency tonic spiking within a gamma EEG frequency range and rhythmic cluster spiking within a theta-like frequency range during cortical activation. During irregular slow EEG activity in absence of stimulation, one subgroup displayed spike bursts correlated with cortical slow oscillations. As relatively large in size and also antidromically activated from the cortex, many GABAergic neurons recorded were considered to be cortically projecting and thus capable of directly modulating cortical activity. Subgroups of GABAergic basal forebrain neurons would thus have the capacity to promote cortical activation by modulating gamma or theta activity and others to attenuate cortical activation by modulating irregular slow oscillations that normally occur during slow wave sleep.

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“…In consideration of the findings of Smith et al (1993Smith et al ( , 1995 and Leanza (1998) and of Wu et al (2000), who showed 1,000 -2,000 cholinergic neurons in the rat HDB/MBN vs. approximately 55,000 ChAT-ir cells in the BFB of common marmoset, respectively, our data lend further support to the hypothesis that the complexity of the BFB cholinergic system can be regarded as a phylogenetic correlate of the differentiation of the cerebral cortex. In addition, the rabbit HDB consists of approximately the same amount of ChAT-ir cells as the MS, which is a hallmark of macrosmatic rodents (Brashear et al, 1986) and carnivores (Gritti et al, 1998), whereas the relative number of HDB cholinergic cells is much lower in the microsmatic primates . In contrast, the dorsal striatum (NCa and Pu) closely resembles that of primates, inasmuch as the capsula interna provides a clear structural separation between the two nuclei.…”

Section: Distribution Of Chat-ir Neuronsmentioning

confidence: 99%

Rabbit forebrain cholinergic system: Morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus

Varga

Härtig

Grosche

et al. 2003

J of Comparative Neurology

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Although the rabbit brain, in particular the basal forebrain cholinergic system, has become a common model for neuropathological changes associated with Alzheimer's disease, detailed neuroanatomical studies on the morphological organization of basal forebrain cholinergic nuclei and on their output pathways are still awaited. Therefore, we performed quantitative choline acetyltransferase (ChAT) immunocytochemistry to localize major cholinergic nuclei and to determine the number of respective cholinergic neurons in the rabbit forebrain. The density of ChAT-immunoreactive terminals in layer V of distinct neocortical territories and in hippocampal subfields was also measured. Another cholinergic marker, the low-affinity neurotrophin receptor (p75(NTR)), was also employed to identify subsets of cholinergic neurons. Double-immunofluorescence labeling of ChAT and p75(NTR), calbindin D-28k (CB), parvalbumin, calretinin, neuronal nitric oxide synthase (nNOS), tyrosine hydroxylase, or substance P was used to elucidate the neuroanatomical borders of cholinergic nuclei and to analyze the neurochemical complexity of cholinergic cell populations. Cholinergic projection neurons with heterogeneous densities were found in the medial septum, vertical and horizontal diagonal bands of Broca, ventral pallidum, and magnocellular nucleus basalis (MBN)/substantia innominata (SI) complex; cholinergic interneurons were observed in the caudate nucleus, putamen, accumbens nucleus, and olfactory tubercule, whereas the globus pallidus was devoid of cholinergic nerve cells. Cholinergic interneurons were frequently present in the hippocampus and to a lesser extent in cerebral cortex. Cholinergic projection neurons, except those localized in SI, abundantly expressed p75(NTR), and a subset of cholinergic neurons in posterior MBN was immunoreactive for CB and nNOS. A strict laminar distribution pattern of cholinergic terminals was recorded both in the cerebral cortex and in CA1-CA3 and dentate gyrus of the hippocampus. In summary, the structural organization and chemoarchitecture of rabbit basal forebrain may be considered as a transition between that of rodents and that of primates.

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Gabaergic and cholinergic basal forebrain and preoptic-anterior hypothalamic projections to the mediodorsal nucleus of the thalamus in the cat

Cited by 62 publications

References 94 publications

Thalamocortical synchronization during induction and emergence from propofol-induced unconsciousness

Thalamocortical synchronization during induction and emergence from propofol-induced unconsciousness

Discharge Profiles of Juxtacellularly Labeled and Immunohistochemically Identified GABAergic Basal Forebrain Neurons Recorded in Association with the Electroencephalogram in Anesthetized Rats

Rabbit forebrain cholinergic system: Morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus

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