scholarly journals A lateral hypothalamus to basal forebrain neurocircuit promotes feeding by suppressing responses to anxiogenic environmental cues

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1640 ◽  
Author(s):  
Ryan M. Cassidy ◽  
Yungang Lu ◽  
Madhavi Jere ◽  
Jin-Bin Tian ◽  
Yuanzhong Xu ◽  
...  
Keyword(s):  
Lateral Hypothalamus ◽  
Basal Forebrain ◽  
Gabaergic Neurons ◽  
Inhibitory Input ◽  
Environmental Cues ◽  
Diagonal Band ◽  
Diagonal Band Of Broca ◽  
External Signals

Animals must consider competing information before deciding to eat: internal signals indicating the desirability of food and external signals indicating the risk involved in eating within a particular environment. The behaviors driven by the former are manifestations of hunger, and the latter, anxiety. The connection between pathologic anxiety and reduced eating in conditions like typical depression and anorexia is well known. Conversely, anti-anxiety drugs such as benzodiazepines increase appetite. Here, we show that GABAergic neurons in the diagonal band of Broca (DBBGABA) are responsive to indications of risk and receive monosynaptic inhibitory input from lateral hypothalamus GABAergic neurons (LHGABA). Activation of this circuit reduces anxiety and causes indiscriminate feeding. We also found that diazepam rapidly reduces DBBGABA activity while inducing indiscriminate feeding. Our study reveals that the LHGABA→DBBGABA neurocircuit overrides anxiogenic environmental cues to allow feeding and that this pathway may underlie the link between eating and anxiety-related disorders.

Identification of barosensitive neurons in the mediobasal forebrain using juxtacellular labeling

1999 ◽  
Vol 276 (6) ◽  
pp. R1766-R1771
Author(s):  
Gilbert J. Kirouac ◽  
Quentin J. Pittman
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Basal Forebrain ◽  
Dendritic Morphology ◽  
Olfactory Tubercle ◽  
Diagonal Band ◽  
Arterial Blood ◽  
Discharge Rates ◽  
Diagonal Band Of Broca ◽  
Acute Changes

Previous investigations suggest a possible role in cardiovascular regulation for neurons of the mediobasal forebrain. The present study was designed to determine the location and morphology of basal forebrain neurons that respond to acute changes in arterial blood pressure. Extracellular recordings of single units were done in α-chloralose- or urethan-anesthetized rats. The effect of cardiovascular pressor (phenylephrine, 1–2 μg/kg iv) and depressor (sodium nitroprusside, 0.5–1 μg/kg iv) events on the discharge rates of units was determined. Some of the neurons tested were subsequently filled with biocytin using the juxtacellular method. Brain sections were processed using the avidin-biotin complex reaction to reveal a Golgi-like appearance of the neuron. Of 32 neurons located in the horizontal limb of the diagonal band of Broca (hDB), 13 (41%) were found to be excited by depressor events. Barosensitive biocytin-labeled cells were located in all regions of the hDB and had small- to medium-sized cell bodies with sparse and simple dendritic morphology. Only 2 of 47 neurons tested in the region of the olfactory tubercle, islands of Calleja (IC), and ventral pallidum responded to changes in arterial blood pressure. The results of the present investigation suggest a role in the regulation of cardiovascular function for neurons of the hDB. The findings also suggest that most neurons in the olfactory tubercle, including the IC complex, do not respond to acute changes in arterial blood pressure.

scholarly journals Interconnection and synchronization of neuronal populations in the mouse medial septum/diagonal band of Broca

2015 ◽  
Vol 113 (3) ◽  
pp. 971-980 ◽  
Author(s):  
Richardson N. Leão ◽  
Zé H. Targino ◽  
Luis V. Colom ◽  
André Fisahn
Keyword(s):  
Action Potentials ◽  
Theta Rhythm ◽  
Medial Septum ◽  
Gabaergic Neurons ◽  
Action Potential Firing ◽  
Neuronal Populations ◽  
Diagonal Band ◽  
Potential Firing ◽  
Diagonal Band Of Broca ◽  
Hippocampal Theta

The medial septum/diagonal band of Broca (MS/DBB) is crucial for hippocampal theta rhythm generation (4–12 Hz). However, the mechanisms behind theta rhythmogenesis are still under debate. The MS/DBB consists, in its majority, of three neuronal populations that use acetylcholine, GABA, or glutamate as neurotransmitter. While the firing patterns of septal neurons enable the MS/DBB to generate rhythmic output critical for the generation of the hippocampal theta rhythm, the ability to synchronize these action potentials is dependent on the interconnectivity between the three major MS/DBB neuronal populations, yet little is known about intraseptal connections. Here we assessed the connectivity between pairs of MS/DBB neurons with paired patch-clamp recordings. We found that glutamatergic and GABAergic neurons provide intraseptal connections and produce sizable currents in MS/DBB postsynaptic cells. We also analyzed linear and nonlinear relationships between the action potentials fired by pairs of neurons belonging to various MS/DBB neuronal populations. Our results show that while the synchrony index for action potential firing was significantly higher in pairs of GABAergic neurons, coherence of action potential firing in the theta range was similarly low in all pairs analyzed. Recurrence analysis demonstrated that individual action potentials were more recurrent in cholinergic neurons than in other cell types. Implementing sparse connectivity in a computer model of the MS/DBB network reproduced our experimental data. We conclude that the interplay between the intrinsic membrane properties of different MS/DBB neuronal populations and the connectivity among these populations underlie the ability of the MS/DBB network to critically contribute to hippocampal theta rhythmogenesis.

scholarly journals The diagonal band of broca continually regulates olfactory-mediated behaviors by modulating odor-evoked responses within the olfactory bulb

2020 ◽  
Author(s):  
Inna Schwarz ◽  
Monika Müller ◽  
Irina Pavlova ◽  
Jens Schweihoff ◽  
Fabrizio Musacchio ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Basal Forebrain ◽  
Behavioral Responses ◽  
Brain Regions ◽  
Evoked Responses ◽  
Response Modulation ◽  
Top Down ◽  
Diagonal Band ◽  
Diagonal Band Of Broca ◽  
Interneuron Activity

AbstractSensory perception is modulated in a top-down fashion by higher brain regions to regulate the strength of its own input resulting in the adaptation of behavioral responses. In olfactory perception, the horizontal diagonal band of broca (HDB), embedded in the basal forebrain modulates olfactory information processing by recruiting olfactory bulb (OB) interneuron activity to shape excitatory OB output. Currently, little is known about how specific HDB to OB top down signaling affects complex olfactory-mediated behaviors. Here we show that the olfactory bulb is strongly and differentially innervated by HDB projections. HDB-silencing via tetanus toxin lead to reduced odor-evoked Ca2+-responses in glomeruli of the main OB, underscoring the HDB’s role in odor response modulation. Furthermore, selective, light-mediated silencing of only HDB to OB afferents completely prevented olfactory-mediated habituation and discrimination behaviors. Notably, also social habituation and discrimination behaviors were affected. Here we provide evidence for a novel tri-synaptic paraventricular nucleus (PVN)-HDB-OB axis responsible for modulating these types of behavior. Thus, HDB to OB projections constitute a central top-down pathway for olfactory-mediated habituation and discrimination.

scholarly journals Estimation of the Total Number of Cholinergic Neurons Containing Estrogen Receptor-α in the Rat Basal Forebrain

2002 ◽  
Vol 50 (7) ◽  
pp. 891-902 ◽  
Author(s):  
Riitta A. Miettinen ◽  
Giedrius Kalesnykas ◽  
Esa H. Koivisto
Keyword(s):  
Estrogen Receptor ◽  
Basal Forebrain ◽  
Cholinergic Neurons ◽  
Estrogen Receptor Α ◽  
Medial Septum ◽  
Nucleus Basalis ◽  
Cell Counting ◽  
Double Immunostaining ◽  
Diagonal Band ◽  
Diagonal Band Of Broca

This study was undertaken to estimate the total number of cholinergic cells and the percentage of cholinergic cells that contain estrogen receptor-α (ERα) in the rat basal forebrain. Double immunostaining for choline acetyltransferase (ChAT) and ERα was carried out on 50-μm-thick free-floating sections. Because routine mounting method causes considerable flattening of the sections, we embedded immunostained sections in Durcupan, an epoxy resin known to cause virtually no shrinkage. When this procedure was used the section thickness was well preserved, individual cells could be clearly identified, and subcellular localization of ERα immunoreactivity was easy to verify. Cell counting in these sections revealed that the rat basal forebrain contains 26,390 ± 1097 (mean ± SEM) cholinergic neurons. This comprises 9674 ± 504 in the medial septum-vertical diagonal band of Broca, 9403 ± 484 in the horizontal diagonal band of Broca, and 7312 ± 281 in the nucleus basalis. In these nuclei, 60%, 46%, and 14% of the cholinergic neurons were colocalized with ERα, respectively. We believe that our results are an improvement on existing data because of the better distinction of individual neurons that the Durcupan embedding method brings.

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