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Haley MS, Fontanini A, Maffei A. Inhibitory Gating of Thalamocortical Inputs onto Rat Gustatory Insular Cortex. J Neurosci 2023; 43:7294-7306. [PMID: 37704374 PMCID: PMC10621769 DOI: 10.1523/jneurosci.2255-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 09/06/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023] Open
Abstract
In primary gustatory cortex (GC), a subregion of the insular cortex, neurons show anticipatory activity, encode taste identity and palatability, and their activity is related to decision-making. Inactivation of the gustatory thalamus, the parvicellular region of the ventral posteromedial thalamic nucleus (VPMpc), dramatically reduces GC taste responses, consistent with the hypothesis that VPMpc-GC projections carry taste information. Recordings in awake rodents reported that taste-responsive neurons can be found across GC, without segregated spatial mapping, raising the possibility that projections from the taste thalamus may activate GC broadly. In addition, we have shown that cortical inhibition modulates the integration of thalamic and limbic inputs, revealing a potential role for GABA transmission in gating sensory information to GC. Despite this wealth of information at the system level, the synaptic organization of the VPMpc-GC circuit has not been investigated. Here, we used optogenetic activation of VPMpc afferents to GC in acute slice preparations from rats of both sexes to investigate the synaptic properties and organization of VPMpc afferents in GC and their modulation by cortical inhibition. We hypothesized that VPMpc-GC synapses are distributed across GC, but show laminar- and cell-specific properties, conferring computationally flexibility to how taste information is processed. We also found that VPMpc-GC synaptic responses are strongly modulated by the activity regimen of VPMpc afferents, as well as by cortical inhibition activating GABAA and GABAB receptors onto VPMpc terminals. These results provide a novel insight into the complex features of thalamocortical circuits for taste processing.SIGNIFICANCE STATEMENT We report that the input from the primary taste thalamus to the primary gustatory cortex (GC) shows distinct properties compared with primary thalamocortical synapses onto other sensory areas. Ventral posteromedial thalamic nucleus afferents in GC make synapses with excitatory neurons distributed across all cortical layers and display frequency-dependent short-term plasticity to repetitive stimulation; thus, they do not fit the classic distinction between drivers and modulators typical of other sensory thalamocortical circuits. Thalamocortical activation of GC is gated by cortical inhibition, providing local corticothalamic feedback via presynaptic ionotropic and metabotropic GABA receptors. The connectivity and inhibitory control of thalamocortical synapses in GC highlight unique features of the thalamocortical circuit for taste.
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Affiliation(s)
- Melissa S Haley
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Alfredo Fontanini
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York 11794
- Center for Neural Circuit Dynamics, Stony Brook University, Stony Brook, New York 11794
| | - Arianna Maffei
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York 11794
- Center for Neural Circuit Dynamics, Stony Brook University, Stony Brook, New York 11794
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Intrinsic Excitability in Layer IV-VI Anterior Insula to Basolateral Amygdala Projection Neurons Correlates with the Confidence of Taste Valence Encoding. eNeuro 2023; 10:ENEURO.0302-22.2022. [PMID: 36635250 PMCID: PMC9850927 DOI: 10.1523/eneuro.0302-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/01/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022] Open
Abstract
Avoiding potentially harmful, and consuming safe food is crucial for the survival of living organisms. However, the perceived valence of sensory information can change following conflicting experiences. Pleasurability and aversiveness are two crucial parameters defining the perceived valence of a taste and can be impacted by novelty. Importantly, the ability of a given taste to serve as the conditioned stimulus (CS) in conditioned taste aversion (CTA) is dependent on its valence. Activity in anterior insula (aIC) Layer IV-VI pyramidal neurons projecting to the basolateral amygdala (BLA) is correlated with and necessary for CTA learning and retrieval, as well as the expression of neophobia toward novel tastants, but not learning taste familiarity. Yet, the cellular mechanisms underlying the updating of taste valence representation in this specific pathway are poorly understood. Here, using retrograde viral tracing and whole-cell patch-clamp electrophysiology in trained mice, we demonstrate that the intrinsic properties of deep-lying Layer IV-VI, but not superficial Layer I-III aIC-BLA neurons, are differentially modulated by both novelty and valence, reflecting the subjective predictability of taste valence arising from prior experience. These correlative changes in the profile of intrinsic properties of LIV-VI aIC-BLA neurons were detectable following both simple taste experiences, as well as following memory retrieval, extinction learning, and reinstatement.
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Livneh Y, Andermann ML. Cellular activity in insular cortex across seconds to hours: Sensations and predictions of bodily states. Neuron 2021; 109:3576-3593. [PMID: 34582784 PMCID: PMC8602715 DOI: 10.1016/j.neuron.2021.08.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 02/09/2023]
Abstract
Our wellness relies on continuous interactions between our brain and body: different organs relay their current state to the brain and are regulated, in turn, by descending visceromotor commands from our brain and by actions such as eating, drinking, thermotaxis, and predator escape. Human neuroimaging and theoretical studies suggest a key role for predictive processing by insular cortex in guiding these efforts to maintain bodily homeostasis. Here, we review recent studies recording and manipulating cellular activity in rodent insular cortex at timescales from seconds to hours. We argue that consideration of these findings in the context of predictive processing of future bodily states may reconcile several apparent discrepancies and offer a unifying, heuristic model for guiding future work.
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Affiliation(s)
- Yoav Livneh
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Mark L Andermann
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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Yiannakas A, Kolatt Chandran S, Kayyal H, Gould N, Khamaisy M, Rosenblum K. Parvalbumin interneuron inhibition onto anterior insula neurons projecting to the basolateral amygdala drives aversive taste memory retrieval. Curr Biol 2021; 31:2770-2784.e6. [PMID: 33930301 DOI: 10.1016/j.cub.2021.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/08/2020] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
Memory retrieval refers to the fundamental ability of organisms to make use of acquired, sometimes inconsistent, information about the world. Although memory acquisition has been studied extensively, the neurobiological mechanisms underlying memory retrieval remain largely unknown. Conditioned taste aversion (CTA) is a robust associative paradigm, through which animals can be trained to express aversion toward innately appetitive tastants. The anterior insula (aIC) is indispensable in the ability of mammals to retrieve associative information regarding tastants that have been previously linked with gastric malaise. Here, we show that CTA memory retrieval promotes cell-type-specific activation in the aIC. Using chemogenetic tools in the aIC, we found that CTA memory acquisition requires activation of excitatory neurons and inhibition of inhibitory neurons, whereas retrieval necessitates activation of both excitatory and inhibitory aIC circuits. CTA memory retrieval at the aIC activates parvalbumin (PV) interneurons and increases synaptic inhibition onto activated pyramidal neurons projecting to the basolateral amygdala (aIC-BLA). Unlike innately appetitive taste memory retrieval, CTA retrieval increases synaptic inhibition onto aIC-BLA-projecting neurons that is dependent on activity in aIC PV interneurons. PV aIC interneurons coordinate CTA memory retrieval and are necessary for its dominance when conflicting internal representations are encountered over time. The reinstatement of CTA memories following extinction is also dependent on activation of aIC PV interneurons, which increase the frequency of inhibition onto aIC-BLA-projecting neurons. This newly described interaction of PV and a subset of excitatory neurons can explain the coherency of aversive memory retrieval, an evolutionary pre-requisite for animal survival.
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Affiliation(s)
- Adonis Yiannakas
- Sagol Department of Neuroscience, University of Haifa, Mount Carmel, Haifa, Israel.
| | | | - Haneen Kayyal
- Sagol Department of Neuroscience, University of Haifa, Mount Carmel, Haifa, Israel
| | - Nathaniel Gould
- Sagol Department of Neuroscience, University of Haifa, Mount Carmel, Haifa, Israel
| | - Mohammad Khamaisy
- Sagol Department of Neuroscience, University of Haifa, Mount Carmel, Haifa, Israel
| | - Kobi Rosenblum
- Sagol Department of Neuroscience, University of Haifa, Mount Carmel, Haifa, Israel; Center for Gene Manipulation in the Brain, University of Haifa, Mount Carmel, Haifa, Israel.
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Ohla K. Flexible and dynamic representations of gustatory information. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Boughter JD, Fletcher M. Rethinking the role of taste processing in insular cortex and forebrain circuits. CURRENT OPINION IN PHYSIOLOGY 2021; 20:52-56. [PMID: 33681544 DOI: 10.1016/j.cophys.2020.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Over the years, many approaches towards studying the taste-responsive area of insular cortex have focused on how basic taste information is represented, and how lesions or silencing of this area impact taste-focused behaviors. Here, we review and highlight recent studies that imply that insular cortex does not contain a "primary" taste cortex in the traditional sense. Rather, taste is employed in concert with other internal and external sensory modalities by highly interconnected regions of insular cortex to guide ingestive decision-making, especially in context of estimating risk and reward. In rodent models, this may best be seen in context of foraging behaviors, which require flexibility and are dependent on learning and memory processes.
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Affiliation(s)
- John D Boughter
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, 855 Monroe Ave., Memphis TN 38163 USA
| | - Max Fletcher
- Department of Anatomy & Neurobiology, University of Tennessee Health Science Center, 855 Monroe Ave., Memphis TN 38163 USA
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Jensterle M, Rizzo M, Janez A. Glucagon-Like Peptide 1 and Taste Perception: From Molecular Mechanisms to Potential Clinical Implications. Int J Mol Sci 2021; 22:ijms22020902. [PMID: 33477478 PMCID: PMC7830704 DOI: 10.3390/ijms22020902] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/03/2021] [Accepted: 01/15/2021] [Indexed: 12/14/2022] Open
Abstract
Preclinical studies provided some important insights into the action of glucagon-like peptide 1 (GLP-1) in taste perception. This review examines the literature to uncover some molecular mechanisms and connections between GLP-1 and the gustatory coding. Local GLP-1 production in the taste bud cells, the expression of GLP-1 receptor on the adjacent nerves, a functional continuum in the perception of sweet chemicals from the gut to the tongue and an identification of GLP-1 induced signaling pathways in peripheral and central gustatory coding all strongly suggest that GLP-1 is involved in the taste perception, especially sweet. However, the impact of GLP-1 based therapies on gustatory coding in humans remains largely unaddressed. Based on the molecular background we encourage further exploration of the tongue as a new treatment target for GLP-1 receptor agonists in clinical studies. Given that pharmacological manipulation of gustatory coding may represent a new potential strategy against obesity and diabetes, the topic is of utmost clinical relevance.
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Affiliation(s)
- Mojca Jensterle
- Diabetes and Metabolic Diseases, Division of Internal Medicine, Department of Endocrinology, University Medical Centre Ljubljana, Zaloška Cesta 7, 1000 Ljubljana, Slovenia;
- Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Zaloška Cesta 7, 1000 Ljubljana, Slovenia
| | - Manfredi Rizzo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of South Carolina, Columbia, SC 29208, USA;
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90133 Palermo, Italy
| | - Andrej Janez
- Diabetes and Metabolic Diseases, Division of Internal Medicine, Department of Endocrinology, University Medical Centre Ljubljana, Zaloška Cesta 7, 1000 Ljubljana, Slovenia;
- Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Zaloška Cesta 7, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +386-1-522-3114; Fax: +386-1-522-9359
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