Autism and The Hyperconnected Brain's Role in an "Overabundance of Consciousness"

            All conscious and unconscious mental processing equates to the     electrical activity of vast collections of neurons each of which has a biological version of thousands of input and ouput wires connected to      other neurons, thus allowing each neuron to influence, and be influenced by, the activity of many others. (Bor, 2012, p. 119)

            In our moment-to-moment lives these neurons are responding to an infinite stream of sensory information. Our ability to amass billions of severed pieces of information into a harmonious perceptual experience lies in the human brain’s exquisite complexity. Our brain’s neural pathways allow information to travel via electrochemical impulses to other regions of the brain where they work together to create a coherent representation of the immediate environment. Although we perceive a largely accurate and efficient representation of the world, it is not a blueprint of the physical information that surrounds our senses, but instead, a continuously evolving model, that has been tweaked from the initial sensory information that we receive.

            The brain frees our mind to consciously experience the world, and so, inextricably, our experiences are tethered by our brain’s limitations. Meaning, we can only ever be aware of the signals that the cells in our body generate and send to the brain in response to interacting with the outside world. That being said, abnormalities in brain structure and/or function can interfere with “normal” conscious experience, and are regularly involved in mental disorders (Bor, 238). In The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning, Bor suggests that all mental disorders can be, “rewritten as disorders of consciousness” (238). In particular, he challenges the prevailing view that autism spectrum disorders deal with a paucity of mental awareness, by describing autism as a disorder of over-consciousness, or an overabundance of awareness (238). A recent study by Keown et al. (2013) provides neurological evidence for Bor’s hypothesis. Furthermore, the results of Keown et al.’s study conflict with previous evidence supporting the traditional theory, which postulates autistic brains have reduced neuronal activity—sometimes called under connectivity theory.

          Using fMRI scans, Keown and colleagues looked at whole-brain functional connectivity and found that autistic brains are functionally hyper-connected in comparison to typically developing children of similar age, gender, and IQ (n = 110). Moreover, the results showed that the pattern of functional hyperconnectivity found among children with autism predicted autistic symptoms such that greater functional connectivity displayed more severe social deviancies. For the remainder of the paper, I will discuss the main findings from Stanford University, one of three independent study sites, which together totaled n = 110. However all findings are discussed under “Supplemental information” in the article. Stanford University findings represent n = 40, 20 children with autism and 20 similar typically developing children.

          At the whole brain level, Keown et al. found that the mean whole-brain regional connectivity was higher in children with autism compared to typically developing children. Within subsystems of the brain, a total of 25% of the total functional connections within primary sensory, 10% within paralimbic, and 19% within association areas showed greater functional connectivity in the autistic group. Across subsystems, mean functional connectivity was greater in children with autism between primary sensory and paralimbic (18%), primary sensory and association (17%), and paralimbic and association areas (17%). No areas between or within subsystem showed greater connectivity in typically developing children compared to autistic children.

In order to identify the possibility of abnormal signal level activity contributing to whole-brain hyperconnectivity in children with autism Keown et al. examined the amplitude of low frequency fluctuations (ALFFs) in the regional fMRI scanner, which measured regional changes in signal level. The fMRI showed that the mean ALFF values were greater for autistic children, representing abnormally high amplitude fluctuations in signals.

          Keown and colleagues also investigated the extent to which functional brain hyperconnectivity is associated with the severity of symptoms characteristic of autism by examining the relationship between whole-brain functional connectivity and Autism Diagnostic Observation Schedule (ADOS) (Lord, 2000) and Autism Diagnostic Interview-Revised (ADI-R) (Lord et al, 1994) scores using regression analysis. Functional brain hyperconnectivity predicted scores on the social domain of both the ADOS (p = 0.002) and the ADI-R (p = 0.04,) such that children who had greater brain hyperconnectivity were more severely impaired socially.  

          Collectively, Keown et al.’s data provides evidence for whole-brain functional hyperconnectivity within and between major subsystems, in conjunction with abnormally high levels of regional signal change caused by an imbalance of excitation and inhibition within local neural systems.

          This imbalance of neural excitation and inhibition that is likely the cause of hyperconnectivity seen in autistic children’s’ brains is in line with a relatively new theory that suggests the imbalance of excitation and inhibition in neural pathways is due to enhanced glutamate and low GABA neurotransmitter activity. This chemical imbalance could be the reason behind aberrant cognitive and behavioral symptoms characteristic of autism spectrum disorders. Taken together, the neurophysiological evidence provided by Keown et al. in addition to previous experimental findings of imbalanced activity between excitatory and inhibitory neurotransmitters in autistic brains, a unified theory of autism seems to be emerging, one in which an abundance of consciousness fits very well.

          As discussed earlier, our perceptual world is engendered and reciprocally bound by our neural conduits. Our cognition and behavior are thus also distinctly linked to the limitations of our sensory systems. For example, in a normally developed brain, a typical neuron will only fire if it receives a certain number of inputs from other neurons. However, as Keown and colleagues’  fMRI data suggests, the hyperconnective brain of an autistic child has enhanced functional whole-brain connections, causing abnormal neural firing. Particularly, as previous studies have found, increased synaptic excitation or decreased synaptic inhibition. The evidence of hyperactive neurons provides objectivity to key behavioral and cognitive manifestations found in autism, as well as Bor’s subjective description of autism as a disorder of increased consciousness. Key behavioral markers of autism include: rituals and rules, hypersensitivity to pressure, sound, or sight, and poor social skills. On a minute-to-minute basis, we are unaware of much of the sensory information that is inflicting our senses. It seems as though, however, in the case of the hyperactive autistic brain, more sensory information is burst into awareness with greater frequency, strength, and duration (decreased sensory adaptation).

          In the words of Bor, “If autistics have a wider consciousness than others, from the main thesis of this book it would follow that they would then also have a more patterned, structured mind. This I would argue, is one of the hallmark features of autism…” (241).

          That is, rules and rituals that are common habits of those with autism may be ways of coping with constant sensory overload, and may have neural correlates. Keown et al. (2013) postulates that brain hyperconnectivity may result in the isolation of certain neural regions that function in higher-level cognitive processing, which could be responsible for poor social skills. Keown et al. (2013) also discusses the possibility that brain hyperconnectivity could impede the functioning of neurons involved with integrating incoming sensory information, which may contribute to both social aberrations and the tendency towards regularity and patterns.

          An infinite amount of sensory stimuli surrounds us on a minute-to-minute basis, and yet we experience a coherent and detailed representation of our world because of our senses’ amazing ability to effortlessly extract and modify this information. However, abnormalities in structure and function of the nervous system can also cause distortions of awareness, and therefore conscious experience, as is the case with autism and many other disorders. Future neurological testing should focus on identifying if such hyperconnective brain biomarkers are present in children younger than 7 years, as well as if such biomarkers are present in autistic children with severe verbal disabilities (Keown, 2013).

Below is a link to a video featured on autismspeaks.org. Video by: Marisabel Fernandez and Alexander Bernard of Ringling College.
          -Simulation of what perception might be like for a non-verbal autistic child with   sensory issues

http://www.autismspeaks.org/news/news-item/sensory-overload-film-wins-prestigious-design-award?utm_source=/lomethods/index.php?option=com_media&view=images&tmpl=component&e_name=jform_articletext&asset=com_content&author=&utm_medium=text-link&utm_content=Sensory%20Overload%20Film%20Wins%20Prestigious%20Design%20Award%20&utm_campaign=mostpopular

Bor, D. (2012). The Ravenous Brain: How the Science of Consciousness Explains Our Insatiable Search for Meaning (pp. 106-243). New York, NY: Basic Books.

Supekar, K., Uddin, L. Q., Khouzman, A., Phillips, J., Gaillard, W. D., Kenworthy, L. E., & Yerys, B. E. (2013, November 14). Brain hyperconnectivity in children with autism and its links to social deficits. Cell Reports, 5(3), 738-747. Retrieved October 16, 2014