title: Associative learning deficiencies underlying aberrant feeding in the valproate rat model of autism

authors: Lawson, Katsiaryna

subjects: autism spectrum disorder

abstract: Autism spectrum disorder (ASD) is a heterogenous neurodevelopmental condition 
prevalent in over 1% of the global population. Aberrant feeding behaviours and 
feeding dysregulation are a prevalent and understudied difficulty. Individuals with 
ASD often present with poor health outcomes, including over/under eating, obesity, 
and restrictive feeding associated with poor dietary habits, however the underlying 
mechanisms are poorly understood. Here we propose an explanation for some 
neural mechanisms that may be responsible for feeding dysregulation present in 
ASD. We demonstrate that valproate rat models of ASD (VPA ASD) have a blunted 
neural response to LiCl-induced conditioned taste aversion and show 
transcriptional changes in the arcuate nucleus of the hypothalamus. Findings of this 
study also show that VPA ASD rats have significantly higher neural activation in the 
nucleus accumbens and the dorsal vagal complex in response to food, compared to 
controls. Our research suggests that some of the feeding abnormalities seen in 
people with ASD may stem from signalling deficiencies in brain areas involved in 
associative learning responses following ingestion of foods that cause malaise. 
Extremely restrictive feeding behaviours seen in ASD phenotypes may be caused by 
difficulties identifying foods that make them sick. These findings contribute to 
understanding neuromolecular drivers of anomalous feeding behaviours in people 
with ASD.

text: Associative learning deficiencies underlying aberrant feeding in the valproate rat model of autism Autism spectrum disorder (ASD) is a heterogenous neurodevelopmental condition 
prevalent in over 1% of the global population. Aberrant feeding behaviours and 
feeding dysregulation are a prevalent and understudied difficulty. Individuals with 
ASD often present with poor health outcomes, including over/under eating, obesity, 
and restrictive feeding associated with poor dietary habits, however the underlying 
mechanisms are poorly understood. Here we propose an explanation for some 
neural mechanisms that may be responsible for feeding dysregulation present in 
ASD. We demonstrate that valproate rat models of ASD (VPA ASD) have a blunted 
neural response to LiCl-induced conditioned taste aversion and show 
transcriptional changes in the arcuate nucleus of the hypothalamus. Findings of this 
study also show that VPA ASD rats have significantly higher neural activation in the 
nucleus accumbens and the dorsal vagal complex in response to food, compared to 
controls. Our research suggests that some of the feeding abnormalities seen in 
people with ASD may stem from signalling deficiencies in brain areas involved in 
associative learning responses following ingestion of foods that cause malaise. 
Extremely restrictive feeding behaviours seen in ASD phenotypes may be caused by 
difficulties identifying foods that make them sick. These findings contribute to 
understanding neuromolecular drivers of anomalous feeding behaviours in people 
with ASD.

year: 2025-04

title: The effect of climate and environmental change on the megafaunal moa of New Zealand in the absence of humans

authors: Rawlence, Nicolas J.

subjects: ancient DNA

abstract: New Zealand offers a unique opportunity to investigate the response of extinct megafaunal ecosystems to major changes in climate and habitat prior to human settlement. Prior to this point (late 13th Century AD) New Zealand contained a diverse avian megafauna dominated by nine species of large flightless ratite moa (Dinornithiformes). We used ancient DNA approaches to generate mitochondrial DNA sequence data from 39 crested moa (Pachyornis australis) and 145 heavy-footed moa (Pachyornis elephantopus) specimens. In combination with radiocarbon dating and dietary isotope analysis we examined the effects of Late Pleistocene and Holocene climate and environmental change on the phylogeography, palaeodemographics, and eventual extinction of Pachyornis. We show that Pachyornis changed altitudinal, longitudinal and latitudinal ranges through the Late Quaternary in response to alterations in the distribution of suitable habitat. However, we found no evidence for large-scale change in population sizes during the past 40,000 radiocarbon years BP (approximately 44,000 calendar years BP), or significant changes in δ ¹³C and δ ¹⁵N isotope signatures over this time period. The results suggest that crested moa tracked habitat through time with little consequence to population size. For the more broadly distributed heavy-footed moa, changes in climate and habitat distribution may have promoted phylogeographic structuring. Overall this study suggests that the likelihood of megafaunal extinction in New Zealand was greatly reduced in the absence of humans.

text: The effect of climate and environmental change on the megafaunal moa of New Zealand in the absence of humans New Zealand offers a unique opportunity to investigate the response of extinct megafaunal ecosystems to major changes in climate and habitat prior to human settlement. Prior to this point (late 13th Century AD) New Zealand contained a diverse avian megafauna dominated by nine species of large flightless ratite moa (Dinornithiformes). We used ancient DNA approaches to generate mitochondrial DNA sequence data from 39 crested moa (Pachyornis australis) and 145 heavy-footed moa (Pachyornis elephantopus) specimens. In combination with radiocarbon dating and dietary isotope analysis we examined the effects of Late Pleistocene and Holocene climate and environmental change on the phylogeography, palaeodemographics, and eventual extinction of Pachyornis. We show that Pachyornis changed altitudinal, longitudinal and latitudinal ranges through the Late Quaternary in response to alterations in the distribution of suitable habitat. However, we found no evidence for large-scale change in population sizes during the past 40,000 radiocarbon years BP (approximately 44,000 calendar years BP), or significant changes in δ ¹³C and δ ¹⁵N isotope signatures over this time period. The results suggest that crested moa tracked habitat through time with little consequence to population size. For the more broadly distributed heavy-footed moa, changes in climate and habitat distribution may have promoted phylogeographic structuring. Overall this study suggests that the likelihood of megafaunal extinction in New Zealand was greatly reduced in the absence of humans.

year: 2012

title: The Niupepa Collection: Opening the blinds on a window to the past

authors: Keegan, Te Taka Adrian Gregory

subjects: computer science

abstract: This paper describes the building of a digital library collection of historic newspapers. The newspapers (Niupepa in Maori), which were published in New Zealand during the period 1842 to 1933, form a unique historical record of the Maori language, and of events from an historical perspective. Images of these newspapers have been converted to digital form, electronic text extracted from these, and the collection is now being made available over the Internet as a part of the New Zealand Digital Library (NZDL) project at the University of Waikato.

text: The Niupepa Collection: Opening the blinds on a window to the past This paper describes the building of a digital library collection of historic newspapers. The newspapers (Niupepa in Maori), which were published in New Zealand during the period 1842 to 1933, form a unique historical record of the Maori language, and of events from an historical perspective. Images of these newspapers have been converted to digital form, electronic text extracted from these, and the collection is now being made available over the Internet as a part of the New Zealand Digital Library (NZDL) project at the University of Waikato.

year: 1999-12