Miocene surface uplift and orogenic evolution of the southern Andean Plateau (central Puna), northwestern Argentina.

We present stable hydrogen-isotope analyses of volcanic glass ([Formula: see text]Dg) and radiometric ages (U-Pb zircon, U-Th calcite, AMS14C) from deformed sedimentary deposits in the vicinity of the intermontane Pocitos Basin in the central Puna of the Andean Plateau at about 24.5°S. Our results demonstrate 2-km surface uplift since the middle to late Miocene and protracted shortening that persists until the present day, while other sectors of the Puna show evidence for tectonically neutral and/or extensional settings. These findings are at odds with previous studies suggesting near-modern elevations (4 km) of the Puna Plateau since the late Eocene and formation of the intermontane Miocene Arizaro-Pocitos Basin associated with gravitational foundering of a dense lithosphere. Geophysical and geochemical data support the removal of continental lithosphere beneath the Puna, but the timing and mechanisms by which this removal occurs have remained controversial. We hypothesize that intermontane basin formation in the central Puna is the result of crustal shortening since about 20 Ma, followed by rapid surface uplift, likely related to lithospheric delamination.

Milankovitch-paced erosion in the southern Central Andes.

It has long been hypothesized that climate can modify both the pattern and magnitude of erosion in mountainous landscapes, thereby controlling morphology, rates of deformation, and potentially modulating global carbon and nutrient cycles through weathering feedbacks. Although conceptually appealing, geologic evidence for a direct climatic control on erosion has remained ambiguous owing to a lack of high-resolution, long-term terrestrial records and suitable field sites. Here we provide direct terrestrial field evidence for long-term synchrony between erosion rates and Milankovitch-driven, 400-kyr eccentricity cycles using a Plio-Pleistocene cosmogenic radionuclide paleo-erosion rate record from the southern Central Andes. The observed climate-erosion coupling across multiple orbital cycles, when combined with results from the intermediate complexity climate model CLIMBER-2, are consistent with the hypothesis that relatively modest fluctuations in precipitation can cause synchronous and nonlinear responses in erosion rates as landscapes adjust to ever-evolving hydrologic boundary conditions imposed by oscillating climate regimes.

Updated Results of the COVID-19 in MS Global Data Sharing Initiative: Anti-CD20 and Other Risk Factors Associated With COVID-19 Severity.

BACKGROUND AND OBJECTIVES: Certain demographic and clinical characteristics, including the use of some disease-modifying therapies (DMTs), are associated with severe acute respiratory syndrome coronavirus 2 infection severity in people with multiple sclerosis (MS). Comprehensive exploration of these relationships in large international samples is needed. METHODS: Clinician-reported demographic/clinical data from 27 countries were aggregated into a data set of 5,648 patients with suspected/confirmed coronavirus disease 2019 (COVID-19). COVID-19 severity outcomes (hospitalization, admission to intensive care unit [ICU], requiring artificial ventilation, and death) were assessed using multilevel mixed-effects ordered probit and logistic regression, adjusted for age, sex, disability, and MS phenotype. DMTs were individually compared with glatiramer acetate, and anti-CD20 DMTs with pooled other DMTs and with natalizumab. RESULTS: Of 5,648 patients, 922 (16.6%) with suspected and 4,646 (83.4%) with confirmed COVID-19 were included. Male sex, older age, progressive MS, and higher disability were associated with more severe COVID-19. Compared with glatiramer acetate, ocrelizumab and rituximab were associated with higher probabilities of hospitalization (4% [95% CI 1-7] and 7% [95% CI 4-11]), ICU/artificial ventilation (2% [95% CI 0-4] and 4% [95% CI 2-6]), and death (1% [95% CI 0-2] and 2% [95% CI 1-4]) (predicted marginal effects). Untreated patients had 5% (95% CI 2-8), 3% (95% CI 1-5), and 1% (95% CI 0-3) higher probabilities of the 3 respective levels of COVID-19 severity than glatiramer acetate. Compared with pooled other DMTs and with natalizumab, the associations of ocrelizumab and rituximab with COVID-19 severity were also more pronounced. All associations persisted/enhanced on restriction to confirmed COVID-19. DISCUSSION: Analyzing the largest international real-world data set of people with MS with suspected/confirmed COVID-19 confirms that the use of anti-CD20 medication (both ocrelizumab and rituximab), as well as male sex, older age, progressive MS, and higher disability are associated with more severe course of COVID-19.

Acute disseminated encephalomyelitis following vaccination against SARS-CoV-2: A case report.

Acute disseminated encephalomyelitis (ADEM) is an inflammatory emyelinating disease of the central nervous system that is usually considered a monophasic disease Post-vaccination ADEM has been associated with several vaccines, however, there is scarce information related to SARS-CoV-2 vaccines. We present the case of a 26- year-old female who suffered from ADEM four weeks after Gam-COVID-Vac administration.

[Atypical clinical manifestations as a form of presentation in multiple sclerosis]. / Manifestaciones clínicas atípicas como forma de presentación de la esclerosis múltiple.

The atypical clinical features in multiple sclerosis (MS) have been rarely reported and suggest the possibility of an alternative diagnosis. The aim was to describe the clinical and demographic characteristics of MS patients who debuted with atypical symptoms and to estimate the sensitivity, specificity and positive predictive value (PPV) for MS diagnosis. A retrospective analysis of clinical records was performed. The following data were recorded: patients with MS diagnosis according to current diagnostic criteria at the time of diagnosis, type of symptom at the onset, time to second relapse, presence of oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and radiological red flags on MRI. A descriptive and inferential analysis was performed using the chi square test, and sensitivity, specificity and PPV were calculated. Six hundred two patients were diagnosed with MS, of which 22 (3.65%) had an atypical clinical presentation. 54.5% were women. The mean age was 29 years (SD ± 11.7). The most common atypical symptom was peripheral facial palsy (27%). The PPV for atypical onset was 6.14%; p < 0.001. Sensitivity and specificity of these symptoms to MS diagnosis were 3.65% and 19%, respectively. In our research, the presence of atypical symptoms at the onset of MS was very low. Other diseases must be excluded, taking into account their low sensitivity, specificity and PPV.

Las manifestaciones clínicas atípicas al inicio de la esclerosis múltiple (EM) son poco frecuentes y sugieren la posibilidad de un diagnóstico alternativo. El objetivo fue describir las características clínicas en la EM con síntomas atípicos al inicio, y estimar la sensibilidad, especificidad y valor predictivo positivo (VPP) para el diagnóstico de EM. Se trata de un análisis retrospectivo de historias clínicas. Se registraron los siguientes datos: pacientes con diagnóstico de EM acorde a los criterios diagnósticos correspondientes, tipo de síntoma de inicio, tiempo hasta la segunda recaída, presencia de bandas oligoclonales en el líquido cefalorraquídeo (LCR) y de banderas rojas radiológicas en la Resonancia Magnética de encéfalo (RMN). Se realizó un análisis descriptivo e inferencial utilizando la prueba de chi cuadrado y se calcularon la sensibilidad, la especificidad y el VPP. Seiscientos dos pacientes tuvieron un diagnóstico final de EM, de los cuales 22 (3.7%) tuvieron una presentación clínica atípica. El 54.5% eran mujeres. La edad promedio fue de 29 años (DE ± 11.7). El síntoma atípico más frecuente fue parálisis facial periférica aislada (6/22). El VPP para el inicio atípico fue de 6.1%; p < 0001. La sensibilidad y especificidad de estos síntomas al diagnóstico de EM fueron del 3.7% y 19%, respectivamente. En nuestra cohorte, demostramos que la presencia de síntomas atípicos como presentación de la EM es poco frecuente. Es mandatorio la exclusión de otras enfermedades, teniendo en cuenta su baja sensibilidad, especificidad y VPP.

Associations of Disease-Modifying Therapies With COVID-19 Severity in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: People with multiple sclerosis (MS) are a vulnerable group for severe coronavirus disease 2019 (COVID-19), particularly those taking immunosuppressive disease-modifying therapies (DMTs). We examined the characteristics of COVID-19 severity in an international sample of people with MS. METHODS: Data from 12 data sources in 28 countries were aggregated (sources could include patients from 1-12 countries). Demographic (age, sex), clinical (MS phenotype, disability), and DMT (untreated, alemtuzumab, cladribine, dimethyl fumarate, glatiramer acetate, interferon, natalizumab, ocrelizumab, rituximab, siponimod, other DMTs) covariates were queried, along with COVID-19 severity outcomes, hospitalization, intensive care unit (ICU) admission, need for artificial ventilation, and death. Characteristics of outcomes were assessed in patients with suspected/confirmed COVID-19 using multilevel mixed-effects logistic regression adjusted for age, sex, MS phenotype, and Expanded Disability Status Scale (EDSS) score. RESULTS: Six hundred fifty-seven (28.1%) with suspected and 1,683 (61.9%) with confirmed COVID-19 were analyzed. Among suspected plus confirmed and confirmed-only COVID-19, 20.9% and 26.9% were hospitalized, 5.4% and 7.2% were admitted to ICU, 4.1% and 5.4% required artificial ventilation, and 3.2% and 3.9% died. Older age, progressive MS phenotype, and higher disability were associated with worse COVID-19 outcomes. Compared to dimethyl fumarate, ocrelizumab and rituximab were associated with hospitalization (adjusted odds ratio [aOR] 1.56, 95% confidence interval [CI] 1.01-2.41; aOR 2.43, 95% CI 1.48-4.02) and ICU admission (aOR 2.30, 95% CI 0.98-5.39; aOR 3.93, 95% CI 1.56-9.89), although only rituximab was associated with higher risk of artificial ventilation (aOR 4.00, 95% CI 1.54-10.39). Compared to pooled other DMTs, ocrelizumab and rituximab were associated with hospitalization (aOR 1.75, 95% CI 1.29-2.38; aOR 2.76, 95% CI 1.87-4.07) and ICU admission (aOR 2.55, 95% CI 1.49-4.36; aOR 4.32, 95% CI 2.27-8.23), but only rituximab was associated with artificial ventilation (aOR 6.15, 95% CI 3.09-12.27). Compared to natalizumab, ocrelizumab and rituximab were associated with hospitalization (aOR 1.86, 95% CI 1.13-3.07; aOR 2.88, 95% CI 1.68-4.92) and ICU admission (aOR 2.13, 95% CI 0.85-5.35; aOR 3.23, 95% CI 1.17-8.91), but only rituximab was associated with ventilation (aOR 5.52, 95% CI 1.71-17.84). Associations persisted on restriction to confirmed COVID-19 cases. No associations were observed between DMTs and death. Stratification by age, MS phenotype, and EDSS score found no indications that DMT associations with COVID-19 severity reflected differential DMT allocation by underlying COVID-19 severity. DISCUSSION: Using the largest cohort of people with MS and COVID-19 available, we demonstrated consistent associations of rituximab with increased risk of hospitalization, ICU admission, and need for artificial ventilation and of ocrelizumab with hospitalization and ICU admission. Despite the cross-sectional design of the study, the internal and external consistency of these results with prior studies suggests that rituximab/ocrelizumab use may be a risk factor for more severe COVID-19.

[Importance of the forewarning system and assistance center selection in acute stroke]. / Importancia del sistema de preaviso y elección del centro asistencial en el accidente cerebrovascular agudo.

Acute ischemic stroke (AIS) is a time-dependent emergency, since the greatest impact depends on the time elapsed to treatment. The objective of this work was to analyze door to needle (DTN) and start treatment (STT) times and the effect of pre-notification system (PNS) and the appropriate choice of the healthcare center on these variables. An observational study with data obtained from records of patients admitted to the Stroke Unit (SU) was conducted between August 2015 to December 2019. We analyzed the number of intravenous thrombolytic treatments (IVT), DTN and STT and compared them according to PNS use, direct arrival at the center with SU or arrival at another center for subsequent referral. An overall of 472 patients were hospitalized during the studied period and the treatment was performed in 143 out of 265 patients. One hundred thirty-seven patients arrived from another center, 70 received IVT. Average DNT with PNS and without PNS were 41 ± 23 and 81 ± 44 minutes, respectively (p = 0.001). STT on direct arrival to SU was 159 ± 59 minutes and to another center for referral was 199 ± 44 (p = 0.001). The use of a PNS and the direct choice of a center where IVT is performed significantly improve treatment.

El accidente cerebrovascular (ACV) es una urgencia tiempo dependiente, ya que las conductas de mayor impacto pronóstico dependen del tiempo trascurrido. El objetivo de este trabajo fue analizar nuestros tiempos puerta aguja (TPA), comienzo aguja (TCA) y el efecto que tiene sobre estos el sistema preaviso y la elección adecuada del centro asistencial. Se realizó un estudio observacional con datos obtenidos de historias clínicas de pacientes internados en la unidad de ACV. Analizamos el número de tratamientos trombolíticos endovenosos, entre agosto 2015 y diciembre 2019. Comparamos TPA según utilización de pre-aviso, llegada directa por sus propios medios vs. en ambulancia sin pre-aviso, y TCA según llegada directa al centro con unidad de ACV vs. llegada a otro centro para posterior derivación. De 265 pacientes en ventana terapéutica, se realizó tratamiento en 143. Llegaron 137 pacientes derivados de otro centro, 70 recibieron tratamiento trombolítico. El TPA con sistema preaviso y sin preaviso fue 41 ± 23 (media ± DE) y 81 ± 43 minutos, respectivamente (p = 0.001). El TPA con llegada directa por sus propios medios 79 ± 43 y en ambulancia sin preaviso 84 ± 44 minutos (p = 0.7) a unidad de ACV. El TCA en llegada directa a unidad de ACV fue 159 ± 59 y a otro centro para su derivación 199 ± 44 minutos (p = 0.001). La utilización de un sistema de preaviso y la elección directa de un centro con unidad de ACV son medidas clave para reducir los tiempos de tratamiento.

Importancia del sistema de preaviso y elección del centro asistencial en el accidente cerebrovascular agudo / Importance of the forewarning system and assistance center selection in acute stroke

Resumen El accidente cerebrovascular (ACV) es una urgencia tiempo dependiente, ya que las conductas de mayor impacto pronóstico dependen del tiempo trascurrido. El objetivo de este trabajo fue analizar nuestros tiempos puerta aguja (TPA), comienzo aguja (TCA) y el efecto que tiene sobre estos el sistema preaviso y la elección adecuada del centro asistencial. Se realizó un estudio observacional con datos obtenidos de histo rias clínicas de pacientes internados en la unidad de ACV. Analizamos el número de tratamientos trombolíticos endovenosos, entre agosto 2015 y diciembre 2019. Comparamos TPA según utilización de pre-aviso, llegada directa por sus propios medios vs. en ambulancia sin pre-aviso, y TCA según llegada directa al centro con unidad de ACV vs. llegada a otro centro para posterior derivación. De 265 pacientes en ventana terapéutica, se realizó tratamiento en 143. Llegaron 137 pacientes derivados de otro centro, 70 recibieron tratamiento trombolítico. El TPA con sistema preaviso y sin preaviso fue 41 ± 23 (media ± DE) y 81 ± 43 minutos, respectivamente (p = 0.001). El TPA con llegada directa por sus propios medios 79 ± 43 y en ambulancia sin preaviso 84 ± 44 minutos (p = 0.7) a unidad de ACV. El TCA en llegada directa a unidad de ACV fue 159 ± 59 y a otro centro para su derivación 199 ± 44 minutos (p = 0.001). La utilización de un sistema de preaviso y la elección directa de un centro con unidad de ACV son medidas clave para reducir los tiempos de tratamiento.

Abstract Acute ischemic stroke (AIS) is a time-dependent emergency, since the greatest impact depends on the time elapsed to treatment. The objective of this work was to analyze door to needle (DTN) and start treatment (STT) times and the effect of pre-notification system (PNS) and the appropriate choice of the healthcare center on these variables. An observational study with data obtained from records of patients admitted to the Stroke Unit (SU) was conducted between August 2015 to December 2019. We analyzed the number of intravenous thrombolytic treatments (IVT), DTN and STT and compared them according to PNS use, direct arrival at the center with SU or arrival at another center for subsequent referral. An overall of 472 patients were hospitalized during the studied period and the treatment was performed in 143 out of 265 patients. One hundred thirty-seven patients arrived from another center, 70 received IVT. Average DNT with PNS and without PNS were 41 ± 23 and 81 ± 44 minutes, respectively (p = 0.001). STT on direct arrival to SU was 159 ± 59 minutes and to another center for referral was 199 ± 44 (p = 0.001). The use of a PNS and the direct choice of a center where IVT is performed significantly improve treatment

Manifestaciones clínicas atípicas como forma de presentación de la esclerosis múltiple / Atypical clinical manifestations as a form of presentation in multiple sclerosis

Resumen Las manifestaciones clínicas atípicas al inicio de la esclerosis múltiple (EM) son poco frecuentes y sugieren la posibilidad de un diagnóstico alternativo. El objetivo fue describir las características clínicas en la EM con síntomas atípicos al inicio, y estimar la sensibilidad, especificidad y valor predictivo posi tivo (VPP) para el diagnóstico de EM. Se trata de un análisis retrospectivo de historias clínicas. Se registraron los siguientes datos: pacientes con diagnóstico de EM acorde a los criterios diagnósticos correspondientes, tipo de síntoma de inicio, tiempo hasta la segunda recaída, presencia de bandas oligoclonales en el líquido cefalorraquídeo (LCR) y de banderas rojas radiológicas en la Resonancia Magnética de encéfalo (RMN). Se realizó un análisis descriptivo e inferencial utilizando la prueba de chi cuadrado y se calcularon la sensibilidad, la especificidad y el VPP. Seiscientos dos pacientes tuvieron un diagnóstico final de EM, de los cuales 22 (3.7%) tuvieron una presentación clínica atípica. El 54.5% eran mujeres. La edad promedio fue de 29 años (DE ± 11.7). El síntoma atípico más frecuente fue parálisis facial periférica aislada (6/22). El VPP para el inicio atípico fue de 6.1%; p < 0001. La sensibilidad y especificidad de estos síntomas al diagnóstico de EM fueron del 3.7% y 19%, respectivamente. En nuestra cohorte, demostramos que la presencia de síntomas atípicos como presentación de la EM es poco frecuente. Es mandatorio la exclusión de otras enfermedades, teniendo en cuenta su baja sensibilidad, especificidad y VPP.

Abstract The atypical clinical features in multiple sclerosis (MS) have been rarely reported and suggest the possibility of an alternative diagnosis. The aim was to describe the clinical and demographic characteristics of MS patients who debuted with atypical symptoms and to estimate the sensitivity, specificity and positive predictive value (PPV) for MS diagnosis. A retrospective analysis of clinical records was performed. The following data were recorded: patients with MS diagnosis according to current diagnostic criteria at the time of diagnosis, type of symptom at the onset, time to second relapse, presence of oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and radiological red flags on MRI. A descriptive and inferential analysis was performed using the chi square test, and sensitivity, specificity and PPV were calculated. Six hundred two patients were diagnosed with MS, of which 22 (3.65%) had an atypical clinical presentation. 54.5% were women. The mean age was 29 years (SD ± 11.7). The most common atypical symptom was peripheral facial palsy (27%). The PPV for atypical onset was 6.14%; p < 0.001. Sensitivity and specificity of these symptoms to MS diagnosis were 3.65% and 19%, respectively. In our research, the presence of atypical symptoms at the onset of MS was very low. Other diseases must be excluded, taking into account their low sensitivity, specificity and PPV.

Upper Limb Dexterity in Patients with Multiple Sclerosis: An Important and Underrated Morbidity.

BACKGROUND: Scales to assess disability in multiple sclerosis (MS) rarely provide reliable data on actual global impairment. Upper limb dysfunction is usually overlooked, which has a negative effect on patient well-being. We sought to analyze associations among upper limb dexterity, lower limb speed, and Expanded Disability Status Scale (EDSS) score; the difference in upper limb dexterity between patients with EDSS scores less than 5 and 5 or greater; and the associations that upper limb dexterity, lower limb speed, and EDSS score have with health-related quality of life measurements and depression. METHODS: A total of 140 adults with MS were evaluated using the Nine-Hole Peg Test, Timed 25-Foot Walk test, EDSS, Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire, and Beck Depression Inventory. Thorough descriptive-analytical research was conducted using the Spearman correlation, multiple linear regression, and structural equation modeling. RESULTS: Upper limb dexterity was more closely related to EDSS score than lower limb speed (r = 0.43 vs 0.29, R 2 = 0.38) and was greatest in patients with EDSS scores less than 5 (P < .01). Moreover, upper limb dexterity was negatively associated with EDSS score and the MusiQoL questionnaire (rS = -0.557 to -0.321, P < .05). The correlation that depression has with upper limb dexterity loss was higher than the one it has with lower limb speed (0.098 vs 0.066, t > 1.96). CONCLUSIONS: Upper limb dexterity is associated with global disability, depression, and health-related quality of life. We advocate for the assessment of upper limb dexterity in patients with MS to adopt a better approach to their functional impairment.

Brain Function Assessment of Patients with Multiple Sclerosis in the Expanded Disability Status Scale: A Proposal for Modification.

BACKGROUND: There is no consensus regarding assessment of the brain function functional system (FS) of the Expanded Disability Status Scale (EDSS) in patients with multiple sclerosis (MS). We sought to describe brain function FS assessment criteria used by Argentinian neurologists and, based on the results, propose redefined brain function FS criteria. METHODS: A structured survey was conducted of 113 Argentinian neurologists. Considering the survey results, we decided to redefine the brain function FS scoring using the Brief International Cognitive Assessment for MS (BICAMS) battery. For 120 adult patients with MS we calculated the EDSS score without brain function FS (basal EDSS) and compared it with the EDSS score after adding the modified brain function FS (modified EDSS). RESULTS: Of the 93 neurologists analyzed, 14% reported that they did not assess brain function FS, 35% reported that they assessed it through a nonstructured interview, and the remainder used other tools. Significant differences were found in EDSS scores before and after the inclusion of BICAMS (P < .001). Redefining the brain function FS, 15% of patients modified their basal EDSS score, as did 20% of those with a score of 4.0 or less. CONCLUSIONS: The survey results show the importance of unifying the brain function FS scoring criteria in calculating the EDSS score. While allowing more consistent brain function FS scoring, including the modified brain function FS led to a change in EDSS score in many patients, particularly in the lower range of EDSS scores. Considering the relevance of the EDSS for monitoring patients with MS and for decision making, it is imperative to further validate the modified brain function FS scoring.

Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods.

Although Earth's climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2-5.5 Ma and with the Messinian Salinity Crisis from ∼6.0-5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear. We address this question using erosion rates of ancient watersheds to constrain Mio-Pliocene climatic conditions in the south-central Andes near 30° S. Our results show two slowdowns in erosion rate, one from ∼6.1-5.2 Ma and another from 3.6 to 3.3 Ma, which we attribute to periods of continental aridity. This view is supported by synchrony with other regional proxies for aridity and with the timing of glacial ?cold" periods as recorded by marine proxies, such as the M2 isotope excursion. We thus conclude that aridity in the south-central Andes is associated with cold periods at high southern latitudes, perhaps due to a northward migration of the Southern Hemisphere westerlies, which disrupted the South American Low Level Jet that delivers moisture to southeastern South America. Colder glacial periods, and possibly associated reductions in atmospheric CO2, thus seem to be an important driver of Mio-Pliocene ecological transitions in the central Andes. Finally, this study demonstrates that paleo-erosion rates can be a powerful proxy for ancient continental climates that lie beyond the reach of most lacustrine and glacial archives.

Miocene orographic uplift forces rapid hydrological change in the southern central Andes.

Rainfall in the central Andes associated with the South American Monsoon and the South American Low-Level Jet results from orographic effects on atmospheric circulation exerted by the Andean Plateau and the Eastern Cordillera. However, despite its importance for South American climate, no reliable records exist that allow decoding the evolution of thresholds and interactions between Andean topography and atmospheric circulation, especially regarding the onset of humid conditions in the inherently dry southern central Andes. Here, we employ multi-proxy isotope data of lipid biomarkers, pedogenic carbonates and volcanic glass from the Eastern Cordillera of NW Argentina and present the first long-term evapotranspiration record. We find that regional eco-hydrology and vegetation changes are associated with initiation of moisture transport via the South American Low-Level Jet at 7.6 Ma, and subsequent lateral growth of the orogen at 6.5 Ma. Our results highlight that topographically induced changes in atmospheric circulation patterns, not global climate change, were responsible for late Miocene environmental change in this part of the southern hemisphere. This suggests that mountain building over time fundamentally controlled habitat evolution along the central Andes.