Sphingolipid metabolism governs Purkinje cell patterned degeneration in Atxn1[82Q]/+ mice.

Patterned degeneration of Purkinje cells (PCs) can be observed in a wide range of neuropathologies, but mechanisms behind nonrandom cerebellar neurodegeneration remain unclear. Sphingolipid metabolism dyshomeostasis typically leads to PC neurodegeneration; hence, we questioned whether local sphingolipid balance underlies regional sensitivity to pathological insults. Here, we investigated the regional compartmentalization of sphingolipids and their related enzymes in the cerebellar cortex in healthy and pathological conditions. Analysis in wild-type animals revealed higher sphingosine kinase 1 (Sphk1) levels in the flocculonodular cerebellum, while sphingosine-1-phosphate (S1P) levels were higher in the anterior cerebellum. Next, we investigated a model for spinocerebellar ataxia type 1 (SCA1) driven by the transgenic expression of the expanded Ataxin 1 protein with 82 glutamine (82Q), exhibiting severe PC degeneration in the anterior cerebellum while the flocculonodular region is preserved. In Atxn1[82Q]/+ mice, we found that levels of Sphk1 and Sphk2 were region-specific decreased and S1P levels increased, particularly in the anterior cerebellum. To determine if there is a causal link between sphingolipid levels and neurodegeneration, we deleted the Sphk1 gene in Atxn1[82Q]/+ mice. Analysis of Atxn1[82Q]/+; Sphk1-/- mice confirmed a neuroprotective effect, rescuing a subset of PCs in the anterior cerebellum, in domains reminiscent of the modules defined by AldolaseC expression. Finally, we showed that Sphk1 deletion acts on the ATXN1[82Q] protein expression and prevents PC degeneration. Taken together, our results demonstrate that there are regional differences in sphingolipid metabolism and that this metabolism is directly involved in PC degeneration in Atxn1[82Q]/+ mice.

Contribution of collegial support meetings (CSM) in the management of complex situations of patients with advanced cancer.

PURPOSE: Collegial support meetings (CSM) have been set up in the Gustave Roussy Cancer Center for inpatients whose complex care requires a multi-professional approach involving many participants: oncologists but also health-caregivers, a member of the palliative care team, an intensivist, and a psychologist. This study is aimed at describing the role of this newly multidisciplinary meeting implemented in a French Comprehensive Cancer Center. METHODS: Each week, the health-caregivers decide which situations should be examined, depending on the difficulty of a case. The discussion goes on to include the goal of treatment, the intensity of care, ethical and psychosocial issues, and the patient's life plan. Finally, to obtain feedback from the teams, a survey has been distributed to assess the interest in the CSM. RESULTS: In 2020, 114 inpatients were involved, and 91% were in an advanced palliative situation. During the CSMs, 55% of the discussions focused on whether to continue specific cancer treatment-29% about whether to continue invasive medical care-50% about optimizing supportive care. We estimate that between 65 and 75% of CSMs influenced further decisions. Death occurred during the hospitalization for 35% of the patients that were discussed. The lapse of time between last chemotherapy and death was 24 days (IQR, 28.5). CSMs were well received, since 80% of the teams find these meetings useful. CONCLUSIONS: CSMs reach conclusions for medical and nursing staff involved, in order to improve the management of inpatients with cancer in advanced palliative situation and to define the better goals of care.

Association Between Anxiety and New Organ Failure, Independently of Critical Illness Severity and Respiratory Status: A Prospective Multicentric Cohort Study.

OBJECTIVES: Anxiety results from the anticipation of a threat and might be associated with poor outcome in the critically ill. This study aims at showing that anxiety at admission in critically ill patients is associated with new organ failure over the first 7 days of ICU hospitalization independently of baseline organ failure at admission. DESIGN: Prospective multicenter cohort study. SETTING: Three mixed ICU from April 2014 to December 2017. PATIENTS: Coma-, delirium-, and invasive mechanical ventilation-free patients admitted to the ICU were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: "State anxiety" was assessed using the state component of the State-Trait Anxiety Inventory State. Severity of illness was measured using Simplified Acute Physiology Score II and Sequential Organ Failure Assessment scores. Primary endpoint was a composite of occurrence of death or new organ failure in the first 7 days after admission. Three hundred ninety-one patients were included; 159 of 391 women (40.7%); median age 63 years (49-74 yr); median Simplified Acute Physiology Score II 28 (19-37). Two hundred three out of 391 patients (51.9%) reported moderate to severe anxiety (State-Trait Anxiety Inventory State ≥ 40). One hundred two out of 391 patients (26.1%) developed a new organ failure. After adjustment to Simplified Acute Physiology Score II and Sequential Organ Failure Assessment, State-Trait Anxiety Inventory State greater than or equal to 40 was associated with the primary endpoint (odds ratio, 1.94; 95% CI, 1.18-3.18; p = 0.009) and respiratory failure. In post hoc analysis, State-Trait Anxiety Inventory State greater than or equal to 40 was associated with new organ failure independently and notably of respiratory status at admission (dyspnea-Visual Analogic Scale and PaCO2 ≥ 45 mm Hg). CONCLUSIONS: Moderate to severe anxiety at ICU admission is associated with early occurrence of new organ failure in critically ill patients, independently of respiratory status and severity of critical illness. The causality link could be addressed in an interventional trial.

COVID-19 management in a cancer center: the ICU storm.

A novel coronavirus, SARS-CoV-2, was first reported as a respiratory illness in December 2019 in Wuhan, China. Since then, the World Health Organization (WHO) Emergency Committee declared a global health. COVID-19 has now spread worldwide and is responsible of more than 472,216 persons, out of 9,100,090 officially diagnosed worldwide since 23 of June. In the context of cancer patients, COVID-19 has a severe impact, regarding pulmonary infection but also cancer treatments in this fragile and immunocompromised population, and ICU admission for cancer patients in the context of COVID-19 requires ethical and clinical consideration. In our cancer center, intensivists, oncologists, pharmacists, and hospital administrators had to prepare for a substantial increase in critical care bed capacity (from 10 ICU beds, 6 medical intensive care beds, and 12 surgical intensive care beds, bed capacity was increased to 28 medical intensive care beds with ventilating capacity) and to adapt infrastructure (i.e., ICU beds), supplies (i.e., drugs, ventilators, protective materials), and staff (i.e., nurses and medical staff). Overall, thirty-three COVID-19 patients were admitted in our ICU, 17 cancer-free and 16 with cancer, and 23 required mechanical ventilation, resulting in 4 deaths (of them two patients with cancer). We report here management of a dedicated intensive care unit of a cancer center during the COVID-19 infection pandemic, considering resource allocation and redistribution of healthcare workers.

Recent advances in light patterned optogenetic photostimulation in freely moving mice.

Optogenetics opened the door to a new era of neuroscience. New optical developments are under way to enable high-resolution neuronal activity imaging and selective photostimulation of neuronal ensembles in freely moving animals. These advancements could allow researchers to interrogate, with cellular precision, functionally relevant neuronal circuits in the framework of naturalistic brain activity. We provide an overview of the current state-of-the-art of imaging and photostimulation in freely moving rodents and present a road map for future optical and engineering developments toward miniaturized microscopes that could reach beyond the currently existing systems.

[PAL-PRAT study: Healthcare workers' knowledge and perception of palliative practices in a Cancer Center]. / Quelle connaissance et quelle perception ont les professionnels de santé d'un Centre de lutte contre le cancer à propos des pratiques palliatives encadrées par la loi Claeys-Leonetti : étude PAL PRAT.

INTRODUCTION: The issue of end-of-life care is the subject of a sensitive debate in French society, particularly regarding the possibility for certain patients to have access to medical assistance in dying. The aim of this study was to assess the knowledge and opinion of healthcare providers on the care practices for patients at the end of life, as well as to highlight any specificities in their discourse. METHOD: A survey of healthcare providers' opinions, composed of closed and open questions, that were analyzed using a lexicometric approach, was distributed in a cancer center. RESULTS: The results of the study reveal a good knowledge of the different procedures. Professionals considered that advance directives should be systematically collected; a majority of them differentiated euthanasia from deep continuous sedation and perceived the latter as a means of relieving patients' suffering without inducing death. The different procedures related to the active assistance in dying were known by a majority of professionals and the survey did not identify a dominant trend concerning the will to practice euthanasia if the legal framework allowed it. Half of the participants considered their training insufficient, indicating the need to fill this gap. DISCUSSION: This survey underlines the importance of training and support for the professionals caring for patients in palliative situation and their relatives in France.

[Patient-partnership in a comprehensive cancer centre: Establishment and roles of a patients and caregivers committee]. / Partenariat patient dans un centre de lutte contre le cancer : mise en place et rôles d'un comité de patients et aidants.

In oncology, the place of patients has a natural and strong legitimacy. Cancer is a common disease, with many singularities but also common features between pathologies, with issues ranging from prevention to possible palliative phases or post-cancer, and conducive to both individual and collective decision-making processes. Patient engagement is now essential at all levels of the healthcare system, from simple information to real involvement (co-construction). For 20 years, Gustave-Roussy, a comprehensive cancer centre in Villejuif, has implemented specific reflection and actions, embodied by the creation of a patients and caregivers committee and complemented by an institutional steering body that illustrates the transformation of "working for" into "working with". At the level of direct care, the main works promoted concern shared-decision-making between patient and professional and accompanying patients. At the institutional level, we find the expertise of hospital projects or services, the development of institutional documents (information and advance directives form, etc.), and internal evaluation (audit). At the political level, participation in Unicancer's patient-experience working group has allowed for a better coordinated deployment with other centers. Unicancer has developed a lexical guide defining patient resources, peer helpers, trainers, evaluators and coordinators. This partnership approach is beneficial for patients, their loved ones, caregivers, and must be amplified and give rise to new research work.

[Shared decision-making: ethical issues]. / Prise de décision partagée : enjeux éthiques.

SHARED DECISION-MAKING: ETHICAL ISSUES. Shared decision-making is a decision-making model and a model of interaction between healthcare professionals and healthcare users. Putting together medical-scientific data, experience, values and preferences of the caregiver on the one hand, and knowledge, needs, expectations, values andpreferences of the patient on the other, leads, if both parties wish so, to a discussion followed by a decision based on a common agreement. Cancer area, either in screening or treatment, in the curative or palliative phase, is well suited to shared decision-making. Shared decision-making is based on ethical principles and classical philosophical streams. Autonomy principle is in the foreground but must not become "an ethical injunction". The relationship between caregiver and patient should recognize above all ability and willingness to participate, or not, in decision-making. Key issues are those of mutual listening, uncertainty recognition and the role of emotions as powerful ethical levers.

PRISE DE DÉCISION PARTAGÉE : ENJEUX ÉTHIQUES. La prise de décision partagée est, parmi d'autres, un modèle d'interaction et de prise de décision entre professionnel de santé et usager du système de santé. La mise en commun des données médico-scientifiques, de l'expérience, des valeurs et préférences du soignant, d'un côté, et des savoirs, besoins, attentes, valeurs et préférences du patient, de l'autre, aboutit, si les deux parties le souhaitent, à une discussion suivie d'une décision prise ensemble et fondée sur un accord commun. La prise en charge du cancer offre un grand nombre de situations propices à ce partage décisionnel, que ce soit pour le dépistage ou le traitement, en phase curative ou palliative. La prise de décision partagée s'appuie sur des principes éthiques et des courants classiques de la philosophie. Mais si elle place au premier plan le principe d'autonomie, celle-ci ne doit pas devenir « une injonction éthique ¼. La relation entre personne malade et soignant reconnaît avant tout la capacité et la volonté de participer, ou non, à la prise de décision. Les enjeux sont ceux de l'écoute réciproque, de la reconnaissance de l'incertitude et du rôle des émotions comme leviers éthiques puissants.

[End of life and cancer: Understanding the ethical issues of voluntary assisted dying]. / Fin de vie et cancer : comprendre en 2023 les enjeux de la demande d'aide active à mourir.

In its advice No. 139 entitled "Ethical issues related to end-of-life situations: autonomy and solidarity", the National Ethics Committee opens for the first time in France the way to a possible active assistance in dying (assisted suicide or euthanasia). Such an ethical, legal and medical evolution would have major consequences in the palliative approach proposed to cancer patients. This clarification aims to enlighten the reflection, in a very complex societal debate. About thirty issues of the supporters and opponents of the legalization of active assistance in dying are first detailed. The values of autonomy and freedom are confronted with those of medical care and solidarity; the individual approach clashes with the collective interest; the interest of the patient and the place of the physician are considered from different angles. Finally, we propose a reflective path, in order to examine step by step the stakes, by examining successively the diagnosis of end of life conditions in France, then the questions asked and the proposals about: suicide; the principle of active assistance in dying; the procedures for reviewing a request for active assistance in dying; the modalities of implementation (assisted suicide or euthanasia); the place of the physician as agent of this decision. Only an analytical approach will make it possible to avoid amalgams and cognitive biases in a debate that closely mixes rationality and emotions.

[Facilitators and barriers to shared decision-making in France in 2021: National survey in cancer]. / Leviers et freins à la prise de décision partagée en France en 2021 : enquête nationale auprès des patients atteints de cancer.

INTRODUCTION: Shared-decision making (SDM) combines clinical expertise of the healthcare professional with patient's knowledge, values and preferences. This survey explores from a patient perspective, the implementation, facilitators and barriers of SDM in oncology in France in 2021. PATIENTS AND METHODS: From August to October 2021, the digital platform Cancer contribution conducted an online survey relayed by 11 patient associations. RESULTS: Out of 916 responses, 727 were analyzed: 394 from patients with hematological malignancies [HM], 185 with breast cancer [BC], 93 with other solid tumors [ST] and 55 with multiple cancers [MC]. Among the participants, 47.2 % reported that they participated in a decision about their health management, with a significant variation according to the pathology (BC 43.8 %, HM 41.1 %, ST 57 %, MC 60 %, P=0.01), and regardless of age and gender. Two-thirds felt comfortable with the shared decision-making process, in relation with the time allocated and the information provided, regardless of the pathology. In addition, emotions, uncertainty and lack of information are the main reasons quoted by patients to explain their lack of ease in making a decision related to their health. CONCLUSIONS: In this survey, less than half of the patients declared that they have been enrolled in a SDM approach, this rate varying according to the type of solid tumor or hematological malignancy. This study shows that to improve the implementation of SDM in routine clinical practice in cancer, sufficient time and use of decision aids are needed.

[Implementation of a multimodal strategy for information and collection of advance directives in a comprehensive cancer center]. / Mise en place d'une stratégie multimodale d'information et de recueil des directives anticipées dans un Centre de lutte contre le cancer (CLCC).

INTRODUCTION: In France, advance directives (AD) remain unknown and underused by healthcare users and professionals. This is particularly true in oncology. This work was carried out with patients and caregivers of a Comprehensive Cancer Center to improve their appropriation and information. METHODS: The project, built by the Ethics Committee, the Patients Committee and the Palliative Care Team, made it possible to develop over 6 months a training program, an information procedure and several original documents. RESULTS: A total of 34 one-hour training courses for all professionals were organized. A procedure for making information available, including the right to draft ADs, has been implemented. This procedure is personalized, gradual and multi-professional. When a patient wishes to write his AD, he is accompanied by a dedicated team and benefits from a specific form, which enlighten values and preferences before addressing the desired level of therapeutic commitment. Communication elements were diffused, and a specific training on "anticipated discussions" was created. A dedicated space in the computerized chart makes it possible to locate the existence of ADs and to display them instantaneously. DISCUSSION - CONCLUSION: Based on the observation of the obstacles to the use of ADs, the strategy we implemented aims to provide information that is both efficient and ethically respectful for both patients and caregivers. ADs are only one element facilitating autonomy and anticipation, and must be associated with a shared continuous definition of the project and of the goals of care.

A flexible two-photon fiberscope for fast activity imaging and precise optogenetic photostimulation of neurons in freely moving mice.

We developed a flexible two-photon microendoscope (2P-FENDO) capable of all-optical brain investigation at near cellular resolution in freely moving mice. The system performs fast two-photon (2P) functional imaging and 2P holographic photostimulation of single and multiple cells using axially confined extended spots. Proof-of-principle experiments were performed in freely moving mice co-expressing jGCaMP7s and the opsin ChRmine in the visual or barrel cortex. On a field of view of 250 µm in diameter, we demonstrated functional imaging at a frame rate of up to 50 Hz and precise photostimulation of selected groups of cells. With the capability to simultaneously image and control defined neuronal networks in freely moving animals, 2P-FENDO will enable a precise investigation of neuronal functions in the brain during naturalistic behaviors.

Purkinje cell microzones mediate distinct kinematics of a single movement.

The classification of neuronal subpopulations has significantly advanced, yet its relevance for behavior remains unclear. The highly organized flocculus of the cerebellum, known to fine-tune multi-axial eye movements, is an ideal substrate for the study of potential functions of neuronal subpopulations. Here, we demonstrate that its recently identified subpopulations of 9+ and 9- Purkinje cells exhibit an intermediate Aldolase C expression and electrophysiological profile, providing evidence for a graded continuum of intrinsic properties among PC subpopulations. By identifying and utilizing two Cre-lines that genetically target these floccular domains, we show with high spatial specificity that these subpopulations of Purkinje cells participate in separate micromodules with topographically organized connections. Finally, optogenetic excitation of the respective subpopulations results in movements around the same axis in space, yet with distinct kinematic profiles. These results indicate that Purkinje cell subpopulations integrate in discrete circuits and mediate particular parameters of single movements.

Ultrafast light targeting for high-throughput precise control of neuronal networks.

Two-photon, single-cell resolution optogenetics based on holographic light-targeting approaches enables the generation of precise spatiotemporal neuronal activity patterns and thus a broad range of experimental applications, such as high throughput connectivity mapping and probing neural codes for perception. Yet, current holographic approaches limit the resolution for tuning the relative spiking time of distinct cells to a few milliseconds, and the achievable number of targets to 100-200, depending on the working depth. To overcome these limitations and expand the capabilities of single-cell optogenetics, we introduce an ultra-fast sequential light targeting (FLiT) optical configuration based on the rapid switching of a temporally focused beam between holograms at kHz rates. We used FLiT to demonstrate two illumination protocols, termed hybrid- and cyclic-illumination, and achieve sub-millisecond control of sequential neuronal activation and high throughput multicell illumination in vitro (mouse organotypic and acute brain slices) and in vivo (zebrafish larvae and mice), while minimizing light-induced thermal rise. These approaches will be important for experiments that require rapid and precise cell stimulation with defined spatio-temporal activity patterns and optical control of large neuronal ensembles.

Development of a Decision-Aid Form (DAF) for the stratification of care in a French comprehensive cancer center, a tool to support identification of care goals.

BACKGROUND: For cancer patients, life-threatening complications may be difficult to anticipate, which can lead to complex medical decision-making processes. Since 2015, the Gustave Roussy Cancer Center has used a Decision-Aid Form (DAF), which contains an estimated gradation of care in cases where patients' conditions worsen. In this study, we assessed the acceptability of the DAF and the predictive value of the proposed stratification of care with regard to care delivered and patient's outcomes. METHODS: During a 5-month period, all patients who had been transferred from Site 1 to Site 2 of the hospital were prospectively included. RESULTS: A DAF was completed for 89.3% of the 206 patients included. Planned stratification of care was indicated in nearly all cases. The involvement of the palliative care team was indicated in only 29% of the DAF. The value of the WHO/ECOG Performance Status (PS) was limited. Finally, the field "information for patients and relatives" was infrequently completed. Although the possibility of transfer to the Intensive Care Unit was proposed for two-thirds of the patients, 76% of the 35 patients experiencing an acute event received only medical or palliative care. Overall, the level of therapeutic commitment suggested by the DAF was most often revised towards less aggressive care. CONCLUSIONS: The results of our study suggest that implementing an advanced stratification record is possible in a French cultural setting. To achieve complete cultural acceptance, our large integrated institutional program continues to play a key role in anticipating intent, tracing and sharing information with patients and their relatives.

Ethical issues related to the COVID-19 pandemic in patients with cancer: experience and organisations in a French comprehensive cancer centre.

BACKGROUND: The COVID-19 pandemic has aggressively reached the most vulnerable, not only the elderly but also patients with chronic conditions such as cancer. In this study, we present the outlines of ethical thinking and the measures implemented to try to respect our basic values of care, in the specific environment of an oncology hospital. METHODS: Our ethics committee created an ethical watch system based on 24/7 shifts to assist practitioners in their daily decisions. We discuss the challenges faced by patients with cancer during the pandemic, such as access to critical care and ethical dilemmas in the context of resource scarcity, as well as the issue of isolation of patients. We also debate the restrictions in access to oncology care in a health context strongly 'prioritised' against COVID-19. RESULTS: In all areas of an ethical dilemma, either for sorting out access to critical care or for the dramatic consequences of prolonged isolation of patients, our common thread was our attempt to protect, whenever possible, the principles of deontological ethics by strictly resisting utilitarian pressure. Respecting democratic health decision-making processes is a cornerstone of ethically relevant decisions, including in the context of a sanitary crisis. CONCLUSION: The role of an ethics committee related to real-life situations includes not only a reflexive perspective in respect of fundamental principles, but also the help to enlighten and resolve ethical dilemmas in complex clinical situations. This ethical watch team assists physicians in decision-making, promoting the supportive and palliative dimension of care with a holistic approach.

Implementation of shared decision-making and patient-centered care in France: Towards a wider uptake in 2022.

We present the evolution of patient-centered care (PCC) and shared decision-making (SDM) in France since 2017, highlighting advantages and drawbacks of their implementation at the macro level. We then focus on several key policy and legislative milestones that are aimed to develop PCC and SDM. These milestones underline the importance of patient movements to support and fund the development of research and practice in the field. We shall conclude by presenting the growing research agenda and selected key topics. These key topics notably include the increase in both patient and healthcare professional trainings on PCC and SDM provided by healthcare users' and patients' representatives. PCC and SDM continue to be central preoccupations at the macro level, supported by public health policies and patients/healthcare users' actions. This overview, however, suggests that although implementation initiatives have increased since 2017, implementation remains scarce in routine clinical practice. Funding, not only for research projects, but for the implementation of PCC and SDM in real-life settings (e-decision aids, clinical guidelines integrating PCC/SDM, human resources dedicated to PCC/SDM, etc.) are needed to promote sustained adoption. More systematic training for both healthcare professionals and patients is also warranted for a true acculturation to occur.

Diagnostic strategy for hematology and oncology patients with acute respiratory failure: randomized controlled trial.

RATIONALE: Respiratory events are common in hematology and oncology patients and manifest as hypoxemic acute respiratory failure (ARF) in up to half the cases. Identifying the cause of ARF is crucial. Fiberoptic bronchoscopy with bronchoalveolar lavage (FO-BAL) is an invasive test that may cause respiratory deterioration. Recent noninvasive diagnostic tests may have modified the risk/benefit ratio of FO-BAL. OBJECTIVES: To determine whether FO-BAL in cancer patients with ARF increased the need for intubation and whether noninvasive testing alone was not inferior to noninvasive testing plus FO-BAL. METHODS: We performed a multicenter randomized controlled trial with sample size calculations for both end points. Patients with cancer and ARF of unknown cause who were not receiving ventilatory support at intensive care unit admission were randomized to early FO-BAL plus noninvasive tests (n = 113) or noninvasive tests only (n = 106). The primary end point was the number of patients needing intubation and mechanical ventilation. The major secondary end point was the number of patients with no identified cause of ARF. MEASUREMENTS AND MAIN RESULTS: The need for mechanical ventilation was not significantly greater in the FO-BAL group than in the noninvasive group (35.4 vs. 38.7%; P = 0.62). The proportion of patients with no diagnosis was not smaller in the noninvasive group (21.7 vs. 20.4%; difference, -1.3% [-10.4 to 7.7]). CONCLUSIONS: FO-BAL performed in the intensive care unit did not significantly increase intubation requirements in critically ill cancer patients with ARF. Noninvasive testing alone was not inferior to noninvasive testing plus FO-BAL for identifying the cause of ARF. Clinical trial registered with www.clinicaltrials.gov (NCT00248443).

Region-specific preservation of Purkinje cell morphology and motor behavior in the ATXN1[82Q] mouse model of spinocerebellar ataxia 1.

Purkinje cells are the primary processing units of the cerebellar cortex and display molecular heterogeneity that aligns with differences in physiological properties, projection patterns, and susceptibility to disease. In particular, multiple mouse models that feature Purkinje cell degeneration are characterized by incomplete and patterned Purkinje cell degeneration, suggestive of relative sparing of Purkinje cell subpopulations, such as those expressing Aldolase C/zebrinII (AldoC) or residing in the vestibulo-cerebellum. Here, we investigated a well-characterized Purkinje cell-specific mouse model for spinocerebellar ataxia type 1 (SCA1) that expresses human ATXN1 with a polyQ expansion (82Q). Our pathological analysis confirms previous findings that Purkinje cells of the vestibulo-cerebellum, i.e., the flocculonodular lobes, and crus I are relatively spared from key pathological hallmarks: somatodendritic atrophy, and the appearance of p62/SQSTM1-positive inclusions. However, immunohistological analysis of transgene expression revealed that spared Purkinje cells do not express mutant ATXN1 protein, indicating the sparing of Purkinje cells can be explained by an absence of transgene expression. Additionally, we found that Purkinje cells in other cerebellar lobules that typically express AldoC, not only display severe pathology but also show loss of AldoC expression. The relatively preserved flocculonodular lobes and crus I showed a substantial fraction of Purkinje cells that expressed the mutant protein and displayed pathology as well as loss of AldoC expression. Despite considerable pathology in these lobules, behavioral analyses demonstrated a relative sparing of related functions, suggestive of sufficient functional cerebellar reserve. Together, the data indicate that mutant ATXN1 affects both AldoC-positive and AldoC-negative Purkinje cells and disrupts normal parasagittal AldoC expression in Purkinje cells. Our results show that, in a mouse model otherwise characterized by widespread Purkinje cell degeneration, sparing of specific subpopulations is sufficient to maintain normal performance of specific behaviors within the context of the functional, modular map of the cerebellum.