Classical Autism is part of the autism spectrum disorder with 3 major characteristics: impairment in social skills, communication, and repetitive behaviours. Since the autistic genotype is very broad and varied, no single, determined cause is found for the disorder. Among many theories that have been proposed to explain autism, the intense world theory is a unifying theory with suggestion of hyper-function of local neural pathways. It characterizes autism with hyper-attention, hyper-memory, hyper-perception, as well as hyper-emotionality. Enhanced neural-plasticity, neural micro-circuits, and VPA mice models are used to support the intense world theory. It suggests that classical autism enhances neuronal reactivity across the amygdala and neocortex, thereby amplifying fear processing and memories.
1.4 VPA mice models
Since valproic acid intake during pregnancy was linked to a reasonable risk of giving birth to an autistic child, VPA was given to rats to explore possible alterations.
1.4a Valproic acid with respect to ASD
Since its first introduction on the market in 1974, valproic acid has been used as an antidepressant and anticonvulsant drug for patients with epilepsy and/or depression. However, its possible association with autism has been observed starting in 1994 by Christianson et al. They found that four children they studied were exposed to VPA during pregnancy and all of the four exhibited delayed development and one of them ASD. Following them were Williams and Hesh depicted 6 children with exposure to VPA who developed certain characteristics of autism. Many other researches supported the strong association between valproic acid and ASD including autism. One of them includes the work of Rasalam et al. They described children with exposure to other antiepileptic drugs along with VPA during pregnancy to show signs of ASD. Their finding was that 8.9% of children (5 out of 56) exposed to VPA during pregnancy developed ASD while 11.7% (9 out of 11) who were exposed to VPA along with another antiepileptic drugs developed the disorder. The probability or the exact number of incidence of autism each research teams came up with has a wide variance: however, there certainly is a significant association between autism and VPA intake during pregnancy.
1. Markram, K., Markram, H. The Intense World Theory- A Unifying Theory of the Neurobiology of Autism. Front. Hum. Neurosci. 4:224. doi: 10.3389/fnhum.2010.00224. (2010).
[[toc+1.1 The intense world theory
+++1.2 Enhanced neural-plasticity
++++1.3 Neural micro-circuits
+++++1.4 VPA mice models
+1.4a Valproic acid with respect to autism
+1.4b Experiments using VPA mice models]]
Markram K and Markram H (2010) “The Intense World Theory- A Unifying Theory of the Neurobiology of Autism” Front. Hum. Neurosci. 4:224
This paper by Markram and Markram will be the main paper source for my individual Neurowiki. This paper uses the VPA mice models’ enhanced neuronal reactivity and plasticity to support the intense world theory. Furthermore, this paper introduces and explains changes in neural micro-circuits in relation to autism. I will be focusing on the results from a multi-electrode array on brain slices and how its data examines and upholds hyper-reactivity and hyper-connectivity in the brain regions, such as amygdala and neocortex in the VPA-exposed animals.