Brain Energy Crisis in Autism: A Deep Dive

Glucose Metabolism in the Brain — Cracking the Code of the Autism Puzzle

The presentation ‘Astrocyte Glucose Metabolism in Autism – Implications for future research and treatments‘ can be viewed below or downloaded here.

PRESENTATION RECAP:

Impairments in brain energy glucose metabolism, particularly in astrocytes, can account for the emergence of all autism symptoms, regardless of the upstream causes and pathologies such as inflammation or genetic background:

Sensory processing is highly dependent on brain glucose metabolism – impairments in utilisation of this energy source will cause difficulties in processing sensory input and filtering out irrelevant information (such as background noise etc). (See slides for evidence and references)

Avoidance of novel situations/restricted interests/insistence on sameness in autism is caused by the brain preserving brain fuel/avoiding energy-expensive situations. Mental effort and information-processing are very energy-expensive, especially NEW information. Changing environments, attention shifting and processing new information requires much more brain fuel compared to sticking to what is familiar/repetitive/rigid. (See slides for evidence and references)

Social communication impairments in autism are a consequence of brain’s inability to process sensory information, including language and non-verbal social cues, at the same accuracy and speed as neurotypical individuals. This is especially pertinent to ASD children in non-structured social situations, which tend to be extremely fast-changing (typical children are chaotic!) and require lots of attention-shifting and constant processing of new information. Children with autism, for the most part, that WANT to play/be social are simply not able to keep up. (See slides for evidence)

Language/speech processing difficulties in autism can be a consequence of both insufficient energy required for cognition involved in language acquisition and production, as well as difficulties with ‘hearing’ speech while filtering background noise (see above). In some cases, especially non-verbal/minimally verbal, there could be further impairments in brain-muscle coordination/motor dysfunction (also closely linked to brain glucose metabolism).

Stimming/self stimulatory behaviours in autism can be explained by impaired energy metabolism, especially the feedback-loop like and stimulator-trigger interaction between nor/adrenaline (and possibly dopamine) and glucose/glycogen metabolism in astrocytes (are they trying to self-trigger release of reserve energy, to ‘get their brain to light up’?).

Irritability/aggressive behaviours – can often be linked to fluctuations in glucose levels available to the brain (see linked article)

Imbalance in excitatory-inhibitory neurotransmission in autism – astrocytic glucose metabolism is very tightly linked to, and regulates levels of glutamate & GABA in a feedback loop

Male-female ratio in autism can be explained by neuroprotective effects of brain oestrogen in early childhood (protects from inflammation) but also difference in body weight vs brain glucose requirements differences in male vs female children. The shift in glucose utilisation btw brain and rest of the body could be linked to secondary ‘autistic regression’ as well as new onset or worsening of seizures in adolescence.

For further details, references and explanations, as well as the relevance to seizures/epilepsy and Intellectual Disability in autism, refer to presentation slides above.