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Datta D, Perone I, Wijegunawardana D, Liang F, Morozov YM, Arellano J, Duque A, Xie Z, van Dyck CH, Joyce MKP, Arnsten AFT. Nanoscale imaging of pT217-tau in aged rhesus macaque entorhinal and dorsolateral prefrontal cortex: Evidence of interneuronal trafficking and early-stage neurodegeneration. Alzheimers Dement 2024; 20:2843-2860. [PMID: 38445818 PMCID: PMC11032534 DOI: 10.1002/alz.13737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/04/2024] [Accepted: 01/16/2024] [Indexed: 03/07/2024]
Abstract
INTRODUCTION Tau phosphorylated at threonine-217 (pT217-tau) is a novel fluid-based biomarker that predicts onset of Alzheimer's disease (AD) symptoms, but little is known about how pT217-tau arises in the brain, as soluble pT217-tau is dephosphorylated post mortem in humans. METHODS We used multilabel immunofluorescence and immunoelectron microscopy to examine the subcellular localization of early-stage pT217-tau in entorhinal and prefrontal cortices of aged macaques with naturally occurring tau pathology and assayed pT217-tau levels in plasma. RESULTS pT217-tau was aggregated on microtubules within dendrites exhibiting early signs of degeneration, including autophagic vacuoles. It was also seen trafficking between excitatory neurons within synapses on spines, where it was exposed to the extracellular space, and thus accessible to cerebrospinal fluid (CSF)/blood. Plasma pT217-tau levels increased across the age span and thus can serve as a biomarker in macaques. DISCUSSION These data help to explain why pT217-tau predicts degeneration in AD and how it gains access to CSF and plasma to serve as a fluid biomarker.
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Affiliation(s)
- Dibyadeep Datta
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
- Department of PsychiatryYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Isabella Perone
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | | | - Feng Liang
- Department of AnesthesiaCritical Care and Pain MedicineMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Yury M. Morozov
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Jon Arellano
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Alvaro Duque
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Zhongcong Xie
- Department of AnesthesiaCritical Care and Pain MedicineMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | | | - Mary Kate P. Joyce
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
| | - Amy F. T. Arnsten
- Department of NeuroscienceYale UniversitySchool of MedicineNew HavenConnecticutUSA
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Joyce MKP, Wang J, Barbas H. Subgenual and Hippocampal Pathways in Amygdala Are Set to Balance Affect and Context Processing. J Neurosci 2023; 43:3061-3080. [PMID: 36977583 PMCID: PMC10146557 DOI: 10.1523/jneurosci.2066-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 03/02/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
The amygdala, hippocampus, and subgenual cortex area 25 (A25) are engaged in complex cognitive-emotional processes. Yet pathway interactions from hippocampus and A25 with postsynaptic sites in amygdala remain largely unknown. In rhesus monkeys of both sexes, we studied with neural tracers how pathways from A25 and hippocampus interface with excitatory and inhibitory microcircuits in amygdala at multiple scales. We found that both hippocampus and A25 innervate distinct as well as overlapping sites of the basolateral (BL) amygdalar nucleus. Unique hippocampal pathways heavily innervated the intrinsic paralaminar basolateral nucleus, which is associated with plasticity. In contrast, orbital A25 preferentially innervated another intrinsic network, the intercalated masses, an inhibitory reticulum that gates amygdalar autonomic output and inhibits fear-related behaviors. Finally, using high-resolution confocal and electron microscopy (EM), we found that among inhibitory postsynaptic targets in BL, both hippocampal and A25 pathways preferentially formed synapses with calretinin (CR) neurons, which are known for disinhibition and may enhance excitatory drive in the amygdala. Among other inhibitory postsynaptic sites, A25 pathways innervated the powerful parvalbumin (PV) neurons which may flexibly regulate the gain of neuronal assemblies in the BL that affect the internal state. In contrast, hippocampal pathways innervated calbindin (CB) inhibitory neurons, which modulate specific excitatory inputs for processing context and learning correct associations. Common and unique patterns of innervation in amygdala by hippocampus and A25 have implications for how complex cognitive and emotional processes may be selectively disrupted in psychiatric disorders.SIGNIFICANCE STATEMENT The hippocampus, subgenual A25, and amygdala are associated with learning, memory, and emotions. We found that A25 is poised to affect diverse amygdalar processes, from emotional expression to fear learning by innervating the basal complex and the intrinsic intercalated masses. Hippocampal pathways uniquely interacted with another intrinsic amygdalar nucleus which is associated with plasticity, suggesting flexible processing of signals in context for learning. In the basolateral (BL) amygdala, which has a role in fear learning, both hippocampal and A25 interacted preferentially with disinhibitory neurons, suggesting a boost in excitation. The two pathways diverged in innervating other classes of inhibitory neurons, suggesting circuit specificities that could become perturbed in psychiatric diseases.
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Affiliation(s)
- Mary Kate P Joyce
- Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, Massachusetts 022152
- Graduate Program in Neuroscience, Boston University and School of Medicine, Boston, Massachusetts 02118
| | - Jingyi Wang
- Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, Massachusetts 022152
| | - Helen Barbas
- Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, Massachusetts 022152
- Graduate Program in Neuroscience, Boston University and School of Medicine, Boston, Massachusetts 02118
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts 02118
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Arnsten AFT, Joyce MKP, Roberts AC. The Aversive Lens: Stress effects on the prefrontal-cingulate cortical pathways that regulate emotion. Neurosci Biobehav Rev 2023; 145:105000. [PMID: 36529312 PMCID: PMC9898199 DOI: 10.1016/j.neubiorev.2022.105000] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/08/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022]
Abstract
ARNSTEN, A.F.T., M.K.P. Joyce and A.C. Roberts. The Aversive Lens: Stress effects on the prefrontal-cingulate cortical pathways that regulate emotion. NEUROSCI BIOBEHAV REV XXX-XXX, 2022. The symptoms of major-depressive-disorder include psychic pain and anhedonia, i.e. seeing the world through an "aversive lens". The neurobiology underlying this shift in worldview is emerging. Here these data are reviewed, focusing on how activation of subgenual cingulate (BA25) induces an "aversive lens", and how higher prefrontal cortical (PFC) areas (BA46/10/32) provide top-down regulation of BA25 but are weakened by excessive dopamine and norepinephrine release during stress exposure, and dendritic spine loss with chronic stress exposure. These changes may generate an attractor state, which maintains the brain under the control of BA25, requiring medication or neuromodulatory treatments to return connectivity to a more flexible state. In line with this hypothesis, effective anti-depressant treatments reduce the activity of BA25 and restore top-down regulation by higher circuits, e.g. as seen with SSRI medications, ketamine, deep brain stimulation of BA25, or rTMS to strengthen dorsolateral PFC. This research has special relevance in an era of chronic stress caused by the COVID19 pandemic, political unrest and threat of climate change.
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Affiliation(s)
- Amy F T Arnsten
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA.
| | - Mary Kate P Joyce
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA.
| | - Angela C Roberts
- Department Physiology, Development and Neuroscience, and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3DY, UK.
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Abstract
Humans engage in many daily activities that rely on working memory, the ability to hold and sequence information temporarily to accomplish a task. We focus on the process of working memory, based on circuit mechanisms for attending to relevant signals and suppressing irrelevant stimuli. We discuss that connections critically depend on the systematic variation in laminar structure across all cortical systems. Laminar structure is used to group areas into types regardless of their placement in the cortex, ranging from low-type agranular areas that lack layer IV to high-type areas that have six well-delineated layers. Connections vary in laminar distribution and strength based on the difference in type between linked areas, according to the "structural model" (Barbas H, Rempel-Clower N. Cereb Cortex 7: 635-646, 1997). The many possible pathways thus vary systematically by laminar distribution and strength, and they interface with excitatory neurons to select relevant stimuli and with functionally distinct inhibitory neurons that suppress activity at the site of termination. Using prefrontal pathways, we discuss how systematic architectonic variation gives rise to diverse pathways that can be recruited, along with amygdalar and hippocampal pathways that provide sensory, affective, and contextual information. The prefrontal cortex is also connected with thalamic nuclei that receive the output of the basal ganglia and cerebellum, which may facilitate fast sequencing of information. The complement of connections and their interface with distinct inhibitory neurons allows dynamic recruitment of areas and shifts in cortical rhythms to meet rapidly changing demands of sequential components of working memory tasks.
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Affiliation(s)
- Helen Barbas
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts.,Graduate Program in Neuroscience, Boston University , Boston, Massachusetts
| | - Jingyi Wang
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts
| | - Mary Kate P Joyce
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Graduate Program in Neuroscience, Boston University , Boston, Massachusetts
| | - Miguel Ángel García-Cabezas
- Neural Systems Laboratory, Boston University , Boston, Massachusetts.,Department of Health Sciences, Boston University , Boston, Massachusetts
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García-Cabezas MÁ, Joyce MKP, John YJ, Zikopoulos B, Barbas H. Mirror trends of plasticity and stability indicators in primate prefrontal cortex. Eur J Neurosci 2017; 46:2392-2405. [PMID: 28921934 DOI: 10.1111/ejn.13706] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/22/2017] [Accepted: 08/24/2017] [Indexed: 12/21/2022]
Abstract
Research on plasticity markers in the cerebral cortex has largely focused on their timing of expression and role in shaping circuits during critical and normal periods. By contrast, little attention has been focused on the spatial dimension of plasticity-stability across cortical areas. The rationale for this analysis is based on the systematic variation in cortical structure that parallels functional specialization and raises the possibility of varying levels of plasticity. Here, we investigated in adult rhesus monkeys the expression of markers related to synaptic plasticity or stability in prefrontal limbic and eulaminate areas that vary in laminar structure. Our findings revealed that limbic areas are impoverished in three markers of stability: intracortical myelin, the lectin Wisteria floribunda agglutinin, which labels perineuronal nets, and parvalbumin, which is expressed in a class of strong inhibitory neurons. By contrast, prefrontal limbic areas were enriched in the enzyme calcium/calmodulin-dependent protein kinase II (CaMKII), known to enhance plasticity. Eulaminate areas have more elaborate laminar architecture than limbic areas and showed the opposite trend: they were enriched in markers of stability and had lower expression of the plasticity-related marker CaMKII. The expression of glial fibrillary acidic protein (GFAP), a marker of activated astrocytes, was also higher in limbic areas, suggesting that cellular stress correlates with the rate of circuit reshaping. Elevated markers of plasticity may endow limbic areas with flexibility necessary for learning and memory within an affective context, but may also render them vulnerable to abnormal structural changes, as seen in neurologic and psychiatric diseases.
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Affiliation(s)
- Miguel Á García-Cabezas
- Neural Systems Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave, Boston, MA, 02215, USA
| | - Mary Kate P Joyce
- Neural Systems Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave, Boston, MA, 02215, USA
| | - Yohan J John
- Neural Systems Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave, Boston, MA, 02215, USA
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Boston University, Boston, MA, USA
| | - Helen Barbas
- Neural Systems Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave, Boston, MA, 02215, USA
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