**4. Self neuropathology in ASD**

From a neural point of view the self can be viewed as a complex and dynamic representa‐ tion consisting of multiple brain networks [119, 120]. The origins of self begin in infancy and over the first several years of life normally developing children acquire an understanding of different dimensions of self and other. Deviant development in autism is likely to result in a cascade of developmental impairments including dysfunctional self-related processes as outlined above. Various brain regions have been indicated in the pathogenesis of autism in‐ cluding frontal lobes [e.g., 121] cerebellum [122], parietal lobes [123], hippocampus [124] and amygdala [125]*.* The extent of anatomical and functional abnormalities in autism points to a possible core dysfunction in neural processing. In addition, the vast amount of potential ge‐ netic risk factors suggests that multiple or all-emerging functional brain areas are affected during early development [126]. This theory is supported by widespread growth abnormali‐ ties in the brain of children with autism [127, 128].

others and these early experiences are vital for the maturation of the right brain system. Sub‐ stantial behavioural evidence of infants who later developed autism is supporting the theo‐ ry of disrupted intersubjective behaviour. We argue that impairments in neurobiology affecting particularly the RH both cause and interact with defects in personal relatedness

Atypical Sense of Self in Autism Spectrum Disorders: A Neuro-Cognitive Perspective

http://dx.doi.org/10.5772/53680

757

The 'Abnormal Neural Connectivity Theory' proposes that autism is a distributed systemwide brain disorder that restricts the coordination and integration among various brain areas. The original positron emission tomography (PET) study by Horwitz et al. [144] found reduced correlations among frontal cortex, parietal and other brain regions and suggested that autism involves impairment in functional connectivity between frontal cortex and other brain systems*.* More recent studies proposed that autism is a disorder of neural undercon‐ nectivity [145], overconnectivity [146, 147] or both under and overconnectivity in which lo‐ cal connectivity may be relatively dense whereas long-range connectivity between brain

Studies of the cerebral cortex in autism show abnormalities of synaptic and columnar struc‐ ture. Cortical minicolumns are fundamental units of cerebral cortical information process‐ ing. Examination of neurons revealed abnormalities in the size of cortical minicolumns particularly in the frontal and temporal lobes in ASD [152, 153] that could alter overall levels of connectivity within the brain. These findings are in accordance with the observed white matter abnormalities reported particularly in people with ASD [154]. A recent study using functional connectivity MRI (fcMRI) [155] provided further evidence of atypical enhanced functional connectivity suggesting that abnormal connectivity may be linked to develop‐

These studies suggest that connectivity among diverse brain areas may be the core problem in autism. In autism the network connectivity through which various brain areas communi‐ cate with each other are limited, particularly the connections to the frontal cortex [156] which is dominant for self-related processing particularly in the RH. The network model of the self proposed by Stuss et al. [157] suggests that the self is hierarchically organized, with the highest level of the self involved in self-awareness being subserved by frontal lobes. Ear‐ ly developmental impairments in minicolumnar microcircuitry in the frontal cortex in au‐ tism could be the reason for the deficits found in higher order frontal processes [158] which

Another recent neural theory of autism suggests that a dysfunctional mirror neuron system may be fundamental to the aetiology of autism [159, 160]. The existence of mirror neurons in humans has been demonstrated by a number of EEG and imaging studies [e.g. 161]. Mirror neurons are activated in relation both to specific actions performed by self and matching ac‐ tions performed by others, providing a potential bridge between minds [162] and might

are likely to result in fragmented self awareness and identity formation in autism.

and later developing self processes.

regions may be reduced or abnormally patterned [146-151].

mental brain growth disturbances in autism.

**4.3. Mirror neuron system**

**4.2. Abnormal connectivity**

In the following sections we will explore three neural theories implicated in the develop‐ ment of an atypical or different sense of self in individuals with ASD. Apart from the in‐ volvement of the RH in self-related processes a dysfunctional mirror neuron system as well as abnormal connectivity may have a role to play in the atypical developmental tra‐ jectories in ASD.

#### **4.1. Right hemisphere hypothesis**

The prefrontal cortex plays a vital role in the development of the self as it generates a sense of self and facilitates many links with other parts of the brain. Cognitive neuroscience stud‐ ies have shown that the RH plays a special role in personal relatedness, which is intimately linked to the development of the self. Based largely on recent neuroimaging research evi‐ dence an increasing number of cognitive neuroscientists have emphasized the specific role of the RH in self-related functions [129-132]. Specifically the right dorsomedial prefrontal cortex seems to play a critical role in the development of models of the self [133]. This has been confirmed by several imaging studies, including a recent study of self-evaluation [134]. As described in the previous paragraphs there is substantial research evidence that the RH may be dominant for self-awareness and self-related functions. The psychiatrist and philoso‐ pher Iain McGilchrist [135] provided an extensive exploration of the dominance of the RH in self-related processes.

Elsewhere, Lyons and Fitzgerald [136] put forward the theory that RH impairment leads to a dysfunctional self-development in ASD. There is substantial research evidence linking As‐ perger syndrome to right hemisphere dysfunction [e.g. 137, 138]. The RH is dominant in the first years of human life when the major brain development during critical periods takes place. Results of a cerebral metabolism study in children (aged between 18 days to 12 years) showed that the RH is prominently activated, suggesting that the RH develops earlier than the LH [139]. The RH in implicated during early social interactions [140] including early at‐ tachment processes [141], maternal face and voice recognition [142] as well as the ability to view others in a similar way as the self [143]. The developing self depends on relations with others and these early experiences are vital for the maturation of the right brain system. Sub‐ stantial behavioural evidence of infants who later developed autism is supporting the theo‐ ry of disrupted intersubjective behaviour. We argue that impairments in neurobiology affecting particularly the RH both cause and interact with defects in personal relatedness and later developing self processes.

#### **4.2. Abnormal connectivity**

**4. Self neuropathology in ASD**

756 Recent Advances in Autism Spectrum Disorders - Volume I

ties in the brain of children with autism [127, 128].

jectories in ASD.

self-related processes.

**4.1. Right hemisphere hypothesis**

From a neural point of view the self can be viewed as a complex and dynamic representa‐ tion consisting of multiple brain networks [119, 120]. The origins of self begin in infancy and over the first several years of life normally developing children acquire an understanding of different dimensions of self and other. Deviant development in autism is likely to result in a cascade of developmental impairments including dysfunctional self-related processes as outlined above. Various brain regions have been indicated in the pathogenesis of autism in‐ cluding frontal lobes [e.g., 121] cerebellum [122], parietal lobes [123], hippocampus [124] and amygdala [125]*.* The extent of anatomical and functional abnormalities in autism points to a possible core dysfunction in neural processing. In addition, the vast amount of potential ge‐ netic risk factors suggests that multiple or all-emerging functional brain areas are affected during early development [126]. This theory is supported by widespread growth abnormali‐

In the following sections we will explore three neural theories implicated in the develop‐ ment of an atypical or different sense of self in individuals with ASD. Apart from the in‐ volvement of the RH in self-related processes a dysfunctional mirror neuron system as well as abnormal connectivity may have a role to play in the atypical developmental tra‐

The prefrontal cortex plays a vital role in the development of the self as it generates a sense of self and facilitates many links with other parts of the brain. Cognitive neuroscience stud‐ ies have shown that the RH plays a special role in personal relatedness, which is intimately linked to the development of the self. Based largely on recent neuroimaging research evi‐ dence an increasing number of cognitive neuroscientists have emphasized the specific role of the RH in self-related functions [129-132]. Specifically the right dorsomedial prefrontal cortex seems to play a critical role in the development of models of the self [133]. This has been confirmed by several imaging studies, including a recent study of self-evaluation [134]. As described in the previous paragraphs there is substantial research evidence that the RH may be dominant for self-awareness and self-related functions. The psychiatrist and philoso‐ pher Iain McGilchrist [135] provided an extensive exploration of the dominance of the RH in

Elsewhere, Lyons and Fitzgerald [136] put forward the theory that RH impairment leads to a dysfunctional self-development in ASD. There is substantial research evidence linking As‐ perger syndrome to right hemisphere dysfunction [e.g. 137, 138]. The RH is dominant in the first years of human life when the major brain development during critical periods takes place. Results of a cerebral metabolism study in children (aged between 18 days to 12 years) showed that the RH is prominently activated, suggesting that the RH develops earlier than the LH [139]. The RH in implicated during early social interactions [140] including early at‐ tachment processes [141], maternal face and voice recognition [142] as well as the ability to view others in a similar way as the self [143]. The developing self depends on relations with The 'Abnormal Neural Connectivity Theory' proposes that autism is a distributed systemwide brain disorder that restricts the coordination and integration among various brain areas. The original positron emission tomography (PET) study by Horwitz et al. [144] found reduced correlations among frontal cortex, parietal and other brain regions and suggested that autism involves impairment in functional connectivity between frontal cortex and other brain systems*.* More recent studies proposed that autism is a disorder of neural undercon‐ nectivity [145], overconnectivity [146, 147] or both under and overconnectivity in which lo‐ cal connectivity may be relatively dense whereas long-range connectivity between brain regions may be reduced or abnormally patterned [146-151].

Studies of the cerebral cortex in autism show abnormalities of synaptic and columnar struc‐ ture. Cortical minicolumns are fundamental units of cerebral cortical information process‐ ing. Examination of neurons revealed abnormalities in the size of cortical minicolumns particularly in the frontal and temporal lobes in ASD [152, 153] that could alter overall levels of connectivity within the brain. These findings are in accordance with the observed white matter abnormalities reported particularly in people with ASD [154]. A recent study using functional connectivity MRI (fcMRI) [155] provided further evidence of atypical enhanced functional connectivity suggesting that abnormal connectivity may be linked to develop‐ mental brain growth disturbances in autism.

These studies suggest that connectivity among diverse brain areas may be the core problem in autism. In autism the network connectivity through which various brain areas communi‐ cate with each other are limited, particularly the connections to the frontal cortex [156] which is dominant for self-related processing particularly in the RH. The network model of the self proposed by Stuss et al. [157] suggests that the self is hierarchically organized, with the highest level of the self involved in self-awareness being subserved by frontal lobes. Ear‐ ly developmental impairments in minicolumnar microcircuitry in the frontal cortex in au‐ tism could be the reason for the deficits found in higher order frontal processes [158] which are likely to result in fragmented self awareness and identity formation in autism.

#### **4.3. Mirror neuron system**

Another recent neural theory of autism suggests that a dysfunctional mirror neuron system may be fundamental to the aetiology of autism [159, 160]. The existence of mirror neurons in humans has been demonstrated by a number of EEG and imaging studies [e.g. 161]. Mirror neurons are activated in relation both to specific actions performed by self and matching ac‐ tions performed by others, providing a potential bridge between minds [162] and might have a role to play in self related processes. Mirror neurons may enable us to understand the actions of others by mapping the actions of other people to our own motor system and so allow a shared representation of actions. In addition to understanding the action of others this so-called 'mirroring' might also allow the automatic experience of the intention and emotion of the other person as suggested by Kaplan and Iacoboni [163].

domain. In contrast, there have been suggestions that this different sense of self might be a contributory factor to the significant talents and special skills present in a majority of indi‐ viduals with ASD. Happè & Vital [178] put forward the notion that diminished self-aware‐

Atypical Sense of Self in Autism Spectrum Disorders: A Neuro-Cognitive Perspective

http://dx.doi.org/10.5772/53680

759

[1] Kircher T, David AS. Introduction: The Self And Neuroscience. In: Kircher T, David A.S. (eds) The Self in Neuroscience and Psychiatry, Cambridge: Cambridge Universi‐

[2] Kanner L. Autistic Disturbances of Affective Contact. Nervous Child 1943;2: 217-50.

[4] Cohen DJ. The pathology of the Self in primary childhood autism and Gilles de la Tourette Syndrome. Psychiatric Clinics of North America 1980; 3 (3): 383-402.

[5] Lutz J. Zum Verstaendnis Des Autismus Infantum Als Einer Ich-Bewusstseins-, Ich-Aktivitaets- Und Ich-Einpraegungsstoerung. Acta Paedopsychiatrica 1968; 35, 161.

[6] Powell S, Jordan R. Being Subjective About Autistic Thinking And Learning To

[7] Frith U. Autism: Explaining The Enigma. Oxford: Blackwell; 1989, 2nd Edition; 2003.

[8] Hobson RP. On The Origins Of Self And The Case Of Autism. Development And

[9] Hobson RP, Meyer JA. Foundations For Self And Other: A Study In Autism. Devel‐

[10] Stern DN. The Interpersonal World Of The Infant. New York: Basic Books; 1985.

[11] Neisser U. Five kinds of self-knowledge. Philosophical Psychology 1988;1(1): 35-58.

[3] Asperger H. Frühkindlicher Autismus, Medizinische Klinik 1974;69: 2024-27.

ness in ASD might be advantageous in the development of these special gifts.

and Michael Fitzgerald2

\*Address all correspondence to: viktorialyons@yahoo.co.uk

Learn. Educational Psychology 1993;13: 359-370.

Psychopathology 1990;2: 163-81.

opmental Science 2005;8: 481-91.

**Author details**

Viktoria Lyons1

**References**

1 Blackrock, Co. Dublin, Ireland

2 Trinity College Dublin, Ireland

ty Press; 2003. p2.

Research has demonstrated that mirror neuron activity correlates with empathy [164] and social competence in general [165]. It has been suggested that mirror neurons are a prerequi‐ site for the normal development of self-recognition, imitation, theory of mind, empathy, in‐ tersubjectivity and language [166, 167]. Furthermore, mirror neurons are likely to play a central role in self-awareness. To quote Ramachandran and Oberman [168] 'they may enable humans to see themselves as others see them, which may be an essential ability for selfawareness and introspection' (p.41). Developmental data suggest that there is higher imita‐ tive behaviour in children that can self-recognise, possibly facilitated by mirror neurons, in contrast to those who cannot [169]. Providing support for a RH hypothesis in self-related functions are recent imaging studies [170, 171] indicating that a frontoparietal 'mirror' net‐ work is associated with self-recognition processes.

Several recent functional brain-imaging studies have found evidence of mirror neuron dys‐ function in individuals with ASD in social mirroring tasks [172], motor facilitation [173], and imitation [174]. A fMRI study [175] revealed that individuals with autism showed a different pattern of brain activity during cognitive tasks relating to self-referential processing. The au‐ thors concluded that a core deficit in autism might be related to the construction of a sense of self in its relation with others. Echoing Hobson [176] Iacoboni [177] suggests that primary intersubjectivity is the basis for the development of the neural systems associated with inter‐ nal and external self-related processes. Failure or abnormal development of a fully function‐ ing mirror neuron system in the autistic infant is likely to result in a cascade of developmental impairments including dysfunctional self-related processes.

## **5. Conclusion**

The centrality of an impaired sense of self in autism has been the focus of research for many decades. The development of self-awareness is a complex process that involves integration of information from many sources and coordination across the brain systems involved in self-related concepts. A sense of self emerges from the activity of the brain in interaction with other selves. There is substantial evidence that early deficits in self-development in‐ cluding impaired relations with others result in a fragmented and atypical sense of self in ASD. In this review we have presented evidence that a great majority of self-related process‐ es that are mediated to a significant extent by the right hemisphere are impaired in individ‐ uals with ASD. Additional lines of investigation indicate that an unintegrated sense of self in autism is also potentially associated with abnormal functional connectivity and an im‐ paired mirror neuron system. Consequences of this atypical sense of self are the well-docu‐ mented impairments individuals with ASD experience in the social and communication domain. In contrast, there have been suggestions that this different sense of self might be a contributory factor to the significant talents and special skills present in a majority of indi‐ viduals with ASD. Happè & Vital [178] put forward the notion that diminished self-aware‐ ness in ASD might be advantageous in the development of these special gifts.
