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Identifying Neuronal Markers to Determine Bodily Self-

Consciousness using the Rubber Hand Illusion and EEG

By: Jasrina Kaushal

Supervised off-campus by: Dr. Georg Northoff

Supervised on-campus by: Dr. Iain McKinnel

Thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of

Science with Honours in Integrated Science

Carleton University

Ottawa, Ontario, Canada

April 2015

© 2015 Jasrina Kaushal

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IDENTIFYING NEURONAL MARKERS TO DETERMINE BODILY SELF-

CONSCIOUSNESS USING THE RUBBER HAND ILLUSION AND EEG

Jasrina Kaushal*1, Marcello Costantini

2, and Georg Northoff

2

1 Department of Integrated Science, Carleton University, Ottawa, Ontario Canada K1S 5B6

2 Mind, Brain Imaging, and Neuroethics Unit, Royal Ottawa Mental Health Centre, Ottawa,

Canada K1Z 7K4

Abstract

The ability to experience one's own body is referred to as bodily self-consciousness. The rubber

hand illusion (RHI), whereby a test subject develops a feeling of ownership of a fake hand, can

be used to study embodiment, one component of bodily self-consciousness. The purpose of this

study is to identify neuronal markers that determine bodily self-consciousness in healthy

individuals. In the first session, participants watched a rubber hand being stroked while their

hidden hand was stroked simultaneously. An introspective self-report was completed by

participants after the RHI to rate their agreement or disagreement with 27 statements

corresponding to their subjective experience of the RHI. The second session consisted of

recording participants’ brain activity during rest using an EEG. Correlational analyses revealed a

linear relation between alpha power, recorded from central electrodes, and embodiment of the

rubber hand. These findings suggest that bodily self-consciousness can ultimately be traced to

the intrinsic activity of the brain and that the Rubber Hand Illusion provides a strong foundation

for studying bodily self-consciousness.

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Table of Contents

Introduction......................................................................................................................................3

Methods............................................................................................................................................9

Results............................................................................................................................................14

Discussion......................................................................................................................................18

References......................................................................................................................................23

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Introduction

In everyday life we do not doubt that our body belongs to us. When we shake hands with

someone, we know which hand belongs to whom. However, this is not always the case for

certain individuals. There are indeed, clinical conditions such as schizophrenia, and eating

disorders in which bodily self-consciousness is altered. For instance, an individual suffering from

anorexia may perceive that their body is slightly larger than it actually is, displaying an altered

sense of bodily self-consciousness. Thus, finding neural markers for bodily self-consciousness

may be clinically relevant.

Consciousness involves the ability to experience or to feel, subjectivity, sentience,

wakefulness, having a sense of the self, and the executive control system of the brain (Farthing,

1992). Simply put, we are conscious when we are awake, aware of the self and the world around

us (Laureys & Tononi, 2009). Consciousness involves complex interconnected and organized

neural mechanisms diffused in several regions of the brain. Although recent neuroscientific and

psychological discoveries have led to the possible basis of consciousness, research remains

unfinished.

The “I” of conscious experience can be explained by self-consciousness. Being aware of

oneself, or of one’s own thoughts and actions are the defining characteristics for self-

consciousness (Costanini, 2014). For one to have an understanding of who they are as an

individual is crucial in determining one's identity. Recent approaches to study self-consciousness

have been to target mechanisms in the brain that are responsible for processing bodily signals

(such as, bodily self-consciousness). Bodily self-consciousness is the representation and

processing of bodily information, and the overall experience of owning a body (Costantini, 2014

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and Blanke, 2012). However, it has been difficult to test for the processes underlying bodily self-

consciousness because the body is always present and we are unable to dissociate the body from

the mind.

Through interoception and exteroception, the brain constantly receives information from

the body (Costantini, 2014). The interoceptive system is associated with autonomic motor

control and receives signals from bodily organs such as the heart, stomach, lungs, etc.

Interoceptive signals represent the perception of the body from the inside and include regulation

of homeostasis as well as feelings such as emotions, drives etc. (Suzuki et al, 2013). Whereas the

exteroceptive system represents perception of the body from the outside, guides somatic motor

activity and receives information from the external environment through the five senses: vision,

olfaction, touch, gustatory, and auditory (Costantini, 2014). Through elaboration of the

interoceptive system representations and their incorporation with the exteroceptive system

signals, a sense of self emerges (Suzuki et al, 2013). However, this interaction of exteroceptive

and interoceptive systems in determining the experience of bodily self-consciousness remains

poorly understood today (Suzuki et al, 2013). Bodily self-consciousness is especially difficult to

study because of the constant information flow between the two systems, the distinction between

the physical body, and the experienced subjective body becomes nearly impossible (Costantini,

2014). Thus, neuroscientists have recently began to employ the use of bodily illusions in order to

examine the neural mechanisms underlying bodily self-consciousness. The objective of these

illusions are for participant's to feel a sense of ownership over a synthetic body-part. They have

been used to explore the complex relationships that exist between the brain's representation of

the body and the physical body itself (Moseley, Gallace & Spence, 2012).

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An illusion is described as the brain's failure to produce a subjective experience which

corresponds to reality. Thus, by understanding how the brain fails in this function, gives us a

better understanding on how the basic function is performed as well as the perceptual processes

responsible for the function. Through the use of bodily illusions, it also becomes possible to

influence perceived integration of an external object (such as a synthetic body part) into the

representation of the physical body itself (Longo, 2008). The Rubber Hand Illusion (RHI) is an

example of a bodily illusion that provides a powerful experimental tool to illustrate an

individual's bodily self (Costantini, 2012). In the RHI, participants watch a rubber hand being

stroked while their hidden hand is stroked simultaneously (known as the induction period). This

sensation creates a sense of ownership over the rubber hand, and participants perceive the rubber

hand as actually being part of their own body (Longo, 2008). Although the RHI can be robust,

approximately 30% of participant's do not experience it (Zhou et al, 2014). After the induction

period, most participants also perceive the location of their hand to be closer to the rubber hand

than it actually is. If the rubber hand is stroked asynchronously with regards to the participant's

own hand, then this illusion does not occur (Costantini, 2012). The RHI provides an excellent

approach for studying and manipulating embodiment, and has been so used in several recent

studies (Longo, 2008).

Information from different sensory modalities such as sound, smell, touch, sight and taste

are incorporated together in a phenomenon known as multisensory integration (Stein, Stanford &

Rowland, 2009). This representation of combined modalities allows for meaningful perceptual

experiences and is critical for adaptive behaviours, ultimately increasing the chances of survival

(Costantini, 2008). It has been suggested that bodily self-consciousness is mediated by

multisensory integration (Ehrsson, Holmes & Passingham, 2005). Under normal circumstances,

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bodily self-consciousness appears to be stable, however there is growing data indicating that this

feature is dependent on dynamic multisensory integration of self-related signals and is capable of

change (Suzuki et al, 2013). This is demonstrated in the RHI, as the attribution of the seen rubber

hand to the self is dependent on the integration between the somatic and visual signals from the

hand (Ehrsson, Holmes & Passingham, 2005). In a study conducted by Tsakiris & Haggard

(2005), after synchronous visuotactile stimulation, subjects perceived their hand to be located

significantly closer to the rubber hand compared to asynchronous visuotactile stimulation

(Tsakiris et al, 2007). This also suggests multisensory integration between the tactile experience

of the paintbrush on the participant’s own hand and visually perceived rubber hand occurs in

order for the RHI to elude bodily self-consciousness (Tsakiris et al, 2007).

Other studies demonstrating multisensory integration in humans are the McGurk Effect

(McGurk & MacDonald, 1976) and the cross-modal congruency effect (Spence, Pavani, &

Driver, 1998). The common characteristics within these studies are that they follow the spatial

rule and the temporal rule to exhibit multisensory integration. In the spatial rule, the constituent

unisensory stimuli arise from approximately the same location for a stronger effect of

multisensory integration (Costantini, 2014). While in the temporal rule, the two stimuli must be

exhibited at approximately the same time in order for multisensory integration to be enabled

(Costantini, 2014). This spatiotemporal limitation holds true in the RHI, as the paintbrushes must

be stroked at the same time and the distance between the real hand and rubber hand cannot be too

large in order for the illusion to occur. Because the RHI follows the same perceptual rules

necessary for multisensory integration, it is proposed that this mechanism is essential for bodily

self-consciousness to occur (Costantini, 2014).

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Another important aspect to consider is that oscillary activity is necessary for

multisensory integration and perceptual processing to occur. In the body, functioning cells

create chemical, mechanical, thermal, and faint electrical energy (Hulbert, 1947). Cortical cells

in the brain act in clusters, and their actions such as: perceiving, thinking, initiating voluntary

movements, etc. create faint electrical energy which can be measured using an

electroencephalogram (EEG) (Hulbert, 1947). In EEG experiments, "awake resting state" is one

of the most frequently used experimental condition because it defines a 'baseline' of brain

activity (Laufs et al, 2003). Thus, we can use awake rest-state to measure deviations from

baseline brain activity. In this study, we measured ongoing activity using an EEG during awake

rest state. Neural oscillations, specifically in the alpha wavelength, during baseline represent a

tool that can be used in multisensory integration and perceptual processing. During rest, EEG

oscillary activity has significant effects on perceptual processing, and in representing a measure

to study bodily self-consciousness.

In this study, we investigate neuronal markers that determine bodily self-consciousness

using the RHI, introspective self-reports given after induction period, and recording resting-state

EEG activity in two conditions: eyes closed (EO) and eyes open (EO). Drawing from previous

evidence we predicted that there will be a positive correlation between alpha power, recorded

from central electrodes in both eyes open (EO) and eyes closed (EC) and ownership of the rubber

hand. The EEG component is associated to neuronal markers that can be found when the brain is

at rest. There is variability in the overall sense and feeling of owning a body, and this variability

in bodily self-consciousness can be traced at rest.

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Methods

Participants

Thirty-three healthy undergraduate students were included in the present study.

Participants were recruited through online advertisement and were paid to partake in the

experiment. Three participants reported taking anti-depressant drugs during the time of study and

their results were excluded. All students were right handed as reported by the Edinborough

Handiness Questionnaire, 1975 (EHQ).

Materials

Participants were seated across from the experimenter, facing a table containing an open

ended box with two compartments (Figure 1). One compartment had a transparent cover, and the

other was enclosed with an opaque black cover. Subjects placed one hand in the transparent

compartment with a mirror, and their other hand in the opaque compartment. The life-sized

rubber hand was also visible in the transparent compartment. The rubber hand was aligned with

the participant's hand, approximately shoulder width apart. The participants wore a cape, which

was attached to the front of the box in order to keep their arms out of sight throughout the

experiment.

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Figure 1. Rubber Hand Illusion experimental set-up.

Procedure

The experiment consisted of two sessions. Prior to the experimental trial, one

measurement of proprioceptive drift was taken, in which a ruler was placed above the box and

participants were asked to verbally report the position of their perceived index finger in the

opaque compartment. The purpose of the proprioceptive drift measurement is to identify if a

change of perceived finger location towards the rubber hand correlates with the illusion. To

prevent participants from indicating the same number for each measurement, the ruler was offset

at a different length each trial.

Following the proprioceptive drift, the first session began. The experimenter stroked the

index finger of the rubber hand and the subject's unseen hand simultaneously with two identical

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paintbrushes. The participant was instructed to watch the rubber hand being stroked and

verbalize any sensations they might be feeling. The fingers were stroked for 3 minutes, at a rate

of approximately 1 stroke per second. Following this induction period, a second measure of

proprioceptive drift was recorded.

Subjects were instructed to remove their hand from the box and complete a standard

questionnaire. The subjects were instructed to rate their disagreement or agreement to 27

statements, using a 7-item Likert Scale corresponding to their subjective experience of the RHI.

Responses varied from -3 to +3 in which +3 indicated that the participant "strongly agreed", - 3

that they "strongly disagree" and 0 that they "neither agree nor disagree" with the statements.

The second part of the experiment consisted of two sessions of rest conditions: eyes open

(EO) and eyes closed (EC) measured using an EEG. An EEG cap with 32 channels was used to

study this resting state. Figure 2 illustrates ongoing activity located in the central electrodes (CZ,

CPZ, and PZ), which were used in the correlational analyses with the self-report questionnaires

given after the RHI. The participants were told to rest for approximately 5 minutes while an EEG

cap was placed on their scalp, connected to Neuroscan with 32 channels. In the EO condition,

participants were instructed to resist the urge to blink to the best of their abilities.

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Figure 2. An EEG cap with 32 Channels, the red region (CZ, CPZ, and PZ or channels 15, 20,

and 25) illustrates on-going activity.

Data Analysis

Pre-processing of information involved importing EEG data from Neuroscan to Matlab.

The files were condensed by down sampling to 500 kHz, removing EKG components

(electrocardiogram; electrical activity of the heart), low-pass 0.5 and high pass 30 filtering, and

individually removing artifacts by eye (this includes eye blinks, horizontal and vertical eye

movements, etc.). In the EO condition an extra step included rejecting components using ICA

(independent component analysis). The ICA function aids in separating additional artifacts

embedded in the data.

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Alpha power was computed using the Fast Fuorier Trasform (FFT). The FFT was used to

decompose complex signals from the EEG into frequencies of interest, namely 5 Hz, 10 Hz, and

15 Hz (theta, alpha, beta). Then, the power in each frequency was correlated with the answers

from the questionnaire. Correlational analysis between scores obtained from the questionnaire

with alpha power were calculated using SPSS Statistics.

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Results

Self-report RHI Questionnaire

Results are displayed in Figure 3 and 4. Questions used in the self-report RHI

questionnaire, with significant questions highlighted, are displayed in Table 1. Results in the

eyes open (EO) condition indicate that alpha power (10 Hz) in channel PZ correlate with

question 2 in the self-report measure, which states: 'it seemed like the rubber hand began to

resemble my real hand' (p= 0.047). Also in the EO condition, alpha power in channel CZ

correlates with question 16: 'it seemed like my hand was out of my control' (p= 0.024). In the EO

condition, alpha power in channel PZ correlates with question 7, 'it seemed like the rubber hand

was in the location where my hand was' (p= 0.039). However, this result was no longer

significant once data from the participant's who recorded taking anti-depressant drugs had been

removed from the study.

There were no significant results found in the eyes closed (EC) condition of the

experiment. There were also no significant results found in the theta (5 Hz) or beta (15 Hz)

powers in both EO and EC conditions. Furthermore, there was no significance found in the

remaining questions from the self-report. Demonstrating that ongoing activity in alpha

wavelength in CZ and PZ regions (Figure 1) during rest in EO condition predicts the strength of

the RHI.

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Figure 3. Channel CZ- Alpha Power Correlation with Question 16.

Figure 2. Channel 15 - Alpha Power Correlation with Question 16

Alpha Power (Hz)

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#1

6

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Figure 4. Channel PZ- Alpha Power Correlation with Question 2

Proprioceptive Drift

Measurements of proprioceptive drift were quantified as the difference between the

perceived index finger location before and after the RHI. Drift towards the rubber hand are

indicated by positive numbers. Results indicate no correlation between proprioceptive drift and

neuronal measures. Thus, proprioceptive drift is insignificant in regards to identifying neuronal

markers to determine bodily self-consciousness.

Figure 4. Channel 25 - Alpha Power Correlation with Question 2

Res

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to

Qu

esti

on

2

Alpha Power (Hz)

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Table 1. Statements and corresponding item number used in Self-Report RHI Questionnaire,

adopted from Longo, et al

Item Corresponding Statement

1 It seemed like I was looking directly at my own hand, rather than at the rubber hand

2 It seemed like the rubber hand began to resemble my real hand

3 It seemed like the rubber hand belonged to me

4 It seemed like the rubber hand was my hand

5 It seemed like the rubber hand was part of my body

6 It seemed like my hand was in the location where the rubber hand was

7 It seemed like the rubber hand was in the location where my hand was

8 It seemed like the touch I felt was caused by the paintbrush touching the rubber hand

9 It seemed like I could have moved the rubber hand if I had wanted

10 It seemed like I was in control of the rubber hand

11 It seemed like my own hand became rubbery

12 It seemed like I was unable to move my hand

13 It seemed like I could have moved my hand if I had wanted to

14 It seemed like I couldn't really tell where my hand was

15 It seemed like my hand had disappeared

16 It seemed like my hand was out of my control

17 It seemed like my hand was moving towards the rubber hand

18 It seemed like the rubber hand was moving towards my hand

19 It seemed like I had three hands

20 I found that experience enjoyable

21 I found that experience interesting

22 The touch of the paintbrush on my finger was pleasant

23 I had the sensation of pins and needles in my hand

24 I had the sensation that my hand was numb

25 It seemed like the experience of my hands was less vivid than normal

26 I found myself liking the rubber hand

27 It seemed like I was feeling the touch of paintbrush in the location where I saw the rubber

hand being touched

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Discussion

The present findings provide a systematic attempt to recognize neuronal markers that

determine bodily self-consciousness in healthy individuals. By combining an experimental

manipulation of the experience of one's own body through the use of a bodily illusion, and a

structured neurological approach to measure overall experience through recordings from a 32-

channel EEG cap, we were able to examine the experience of bodily self-consciousness. Our

findings suggest that psychometric methods can be a useful tool in determining the underlying

neuronal mechanisms responsible for the experience of bodily self-consciousness. In particular,

we demonstrated that ongoing activity in alpha wavelength in CZ and PZ regions during rest in

the EO condition predicts the strength of the RHI. The CZ region is located in the central zone,

or midpoint of the brain, and the PZ region is located in the upper tempoparitetal area of the

brain. If an individual displays increased alpha activity in those cortical brain regions during rest

with eyes open, they are more likely to experience the RHI, and subsequently have heightened

awareness of bodily self-consciousness.

Healthy participants viewed the experimenter stoke the rubber hand and their unseen

hand simultaneously. Phenomenology of the RHI was measured by self-report questionnaires

adapted from Longo et al. (Longo et al, 2008). Results indicated that participants experienced the

illusion and gained ownership of the rubber hand. These findings are consistent with previous

studies that suggest alpha power is associated with self-relatedness and inhibition of attention to

the external world, leading to increased limb ownership (Yeh et al, 2014). Increased alpha

powers are correlated to stronger self focus processing. Alpha power is increased when an

individual does not pay attention to their environment but pay attention to themselves.

Furthermore, alpha activity over central areas of the brain have been correlated to sensorimotor

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processing such as motion perception, overall movements, and motor imagery. This also

demonstrates why there were only significant results in the alpha power as opposed to the theta

(5 Hz) or beta (15 Hz) powers. Thus, alpha power frequency (which can be recorded from an

EEG) is a key feature in the process underlying bodily self-consciousness.

There were no significant results found in the EC condition, which is rather surprising as

most literature exhibits an association between greater alpha activity during awake-rest in EC.

The 'Berger Effect' states that there is either an increase or disappearance of alpha band

oscillations during eyes open (Yet et al, 2014). However, in the current study we found the exact

opposite, with an increase of alpha during EO. There are a few plausible reasons behind the

increased alpha activity during EO rather than EC condition. Alpha activity is blocked when an

individual is attentively processing mental operations, processing external information, or is

entering deep sleep (Laufs et al, 2013). Perhaps during the EC phase, the participants were in

deep thought or were in deep relaxation, entering the first stage of sleep. Because the participants

are undergraduate students, it is an assumption that they are busy with school work, possibly

stressed and/or tired. Simply put, it is possible that some of these students were ruminating,

ultimately producing a decrease in alpha activity during EC. Whereas in EO, they are more

awake and inhibiting the processing of external stimuli. Undergraduate students do not

accurately depict an entire population, and results may have been varied had a different sub-set

population were used this study.

Our data has broad clinical implications, as results from this study can be used to

compare to alpha activity among psychiatric disorders in which individuals have distorted

perceptions of their own body.

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There has been an association between disruptions in bodily self consciousness and

individuals suffering from disorders of body representation and illusory body perceptions

(Heydrich et al, 2010). Recent approaches for the clinical implications of bodily self-

consciousness can be found in reports of patients which had brain damage resulting in deficits in

processing bodily signals (Blanke, 2012). A well-known example was conducted by neurologist

Josef Gerstmann whom described two patients with damage to their right temporoparietal cortex,

which ultimately lead to a loss of ownership for their left arm and hand (Blanke, 2012). They

were diagnosed as somatoparaphrenia; a disorder in which patients have somatosensory and/or

motor deficits and deny ownership of the entire side of their body, or a limb (Valler & Ronchi,

2008). Other patients with somatoparaphrenia may display the opposite pattern and mis-attribute

their limb as belonging to someone else, or self-attribute someone else’s limb as their own

(Blanke, 2012). This suggests that the brain regions of the right temporoparietal cortex plays a

key role in the processing of bodily self-consciousness. It is also a region in which on-going

alpha activity is prominent, as displayed in our data.

Other research highlights the importance of multisensory bodily processing in patients

suffering from various forms of conditions such as strokes, tumors, migraines, and psychiatric

disorders such as anorexia, body dysmorphic disorder, and schizophrenia (Heydrich et al, 2010).

Symptoms associated with these disorders in which patients display alterations in perceptual

bodily self-consciousness include: body part displacement, experience of absence of body part,

misidentification of one’s own body part, disconnection of a body part from the body, and

phantom limbs (Heydrich et al, 2010). In regards to schizophrenia, research suggests that

patients display a weaker sense of body ownership over a rubber hand compared to healthy

individuals. More specifically, it has been found that ownership of the rubber hand correlated

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with the negative symptoms associated with schizophrenia (Ferri et al, 2013). The underlying

mechanisms responsible for the negative symptoms may have common features with

mechanisms responsible for processing the RHI (Ferri et al, 2013). As the RHI provides a strong

basis in determining what processes may be involved in these symptoms, much research must be

done until an exact basis can be found. However, it is apparent that disturbed body ownership

displayed in individuals suffering from schizophrenia may contribute to some of the psychotic

symptoms exhibited (Thakkar et al, 2011). Thus, it is vital that an individual is able to recognize

themselves, and process bodily self-consciousness otherwise they may suffer from the symptoms

indicated.

Transcranial Magnetic Stimulation (TMS) is a non-invasive tool used to stimulate nerve

cells through magnetic fields from a coil placed adjacent to the scalp, which carry short lasting

electrical currents to the brain (Siebner, 2008). TMS is most commonly used to treat individuals

suffering from major depressive disorder; in which electrical currents stimulate nerve cells

primarily in the frontal region which is associated with mood regulation. Particular clinical

applications to the current study are the possibility to investigate the therapeutic potential of

TMS as a unique treatment modality for individuals suffering from bodily perception disorders.

More specifically, through the use of Repetitive TMS (rTMS), which utilizes group pulses of

stimulation at specific frequencies to attain a constant train of activation power over a short

period of time (Jin et al, 2005). The current study examined alpha power in relation to exhibiting

higher processing of bodily self-consciousness. Patients suffering from various bodily perception

disorders such as schizophrenia, have been documented to have reduced alpha activity,

contributing to their symptoms and overall weakened sense of bodily self-consciousness (Jin et

al, 2005). RTMS can be used to modulate alpha powers, and it is plausible that as alpha power is

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altered, this can ultimately manipulate and create a heightened sense of bodily self-

consciousness. RTMS has been intensively studied and employed for the treatment of depressive

disorders, and unfortunately there is only a small number of reports for its clinical implications

on bodily perception disorders. For a future study it would be fascinating to examine if rTMS

could be used to modify alpha activity in patients with schizophrenia, and if this ultimately

increased their bodily self-consciousness by administrating the RHI before and after rTMS. It is

important for an individual to have a sense of bodily self-consciousness in order for them to

determine their own unique identity. If methods such as rTMS could increase alpha powers, and

ultimately enhance an individuals' bodily self-consciousness this could help improve the quality

of the life for that individual by alleviating their symptoms and aiding in establishing a sole

identity. While various parameters for the efficacy of this form of therapy for bodily perception

disorders most be fully investigated, hopefully the current study provides a step in the right

direction for further research examining bodily self-consciousness.

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References:

1. Costantini, Marcello. (2014). Body perception, awareness, and illusions. Cognitive Science. 2

2. Blanke, Olaf. (2012). Multisensory brain mechanisms of bodily self-consciousness. Nature

Reviews: Neuroscience. 13: 556-571.

3. Ehrsson, Henrik., Holmes, Nicholas., & Passingham, Richard. (2005). Touching a rubber

hand: feeling of body ownership is associated with activity in multisensory brain areas.

The Journal of Neuroscience. 25:45, 10564-10573.

4. Farthing, G. (1992). The Psychology of Consciousness. Prentice Hall.

5. Ferri, F., Costantini, M., Salone, A., Iorio, G., Martinotti, G., Chiarelli, A., Gallese, V.

(n.d.). Upcoming tactile events and body ownership in schizophrenia. Schizophrenia

Research.

6. Heydrich, Lukas., Dieguez, Sebastian., Grunwald, Thomas., Seeck, Margitta., Blanke, Olaf.

(2010). Illusory own body perceptions: Case reports and relevance for bodily self-

consciousness. Consciousness and Cognition. 19:3, 702-710.

7. Hubert, Harold (1947). EEG: Electroencephalography. Journal of Criminal Law and

Criminology. 37:6, 494-497.

8. Jin, Yi., Potkin, G. Steven., Kemp, S. Aaron., Huerta, T. Steven., Alva, Gustavo., Min Thai,

Trung., Carreon, Danilo., & Bunney, E. William Jr. (2005). Therapeutic effects of

individualized alpha frequency transcranial magnetic stimulation (αTMS) on the negative

symptoms of schizophrenia. Schizophrenia Bulletin. 32 (3): 556-561.

9. Laureys, S. & Tononi, G. (2009) (Eds). The Neurology of Consciousness: Cognitive

Neuroscienceand Neuropathology. Academic Press/Elsevier Ltd.

10. Longo, M., Schuur, F., Kammers, M., Tsakiris, M., & Haggard, P. (2008). What is

embodiment? A psychometric approach. Science Direct, 107: 978-998.

11. Moseley, Lorimer., Gallace, Alberto., & Spence, Charles. (2012). Bodily illusions in health

and disease: physiological and clinical perspectives and the concept of a cortical 'body

matrix'. Neuroscience and Biobehavioral Reviews. 36:1, 34-36.

12. Siebner, R. Hartwig., Hartwigsen, Gesa., Kassuba, Tanja., Rothwell, C. John. (2008). How

does transcranial magnetic stimulation modify neuronal activity in the brain?

Implications for studies of cognition. Cortex. 45:9, 1035-1042.

24

13. Stein, BE.; Stanford, TR.; Rowland, BA. (2009). The neural basis of multisensory

integration in the midbrain: its organization and maturation. Hear Res 258 (1-2): 4–15.

14. Su-Ling, Yeh., Timothy, Lane., Jifan, Zhou., Ting-yi, Lin., Chia-Hsin, Kuo., & Chen-Yun,

Teng. (2014). Difference between eyes-closed and eyes-open resting state alpha power is

an indicator of susceptibility to the rubber hand illusion. Journal of Vision, 14:10.

15. Suzuki, Keisuke., Garfinkle, Sarah., Critchley, Hugo., Seth, Anil. (2013). Multisensory

integration across exteroceptive and interoceptive domains modulates self-experience in

the rubber hand illusion. Neuropsychologia. 51:13, 2909-1917.

16. Thakkar, K., Nichols, H., Mcintosh, L., Park, S., & Herzog, M. (2011). Disturbances in

Body Ownership in Schizophrenia: Evidence from the Rubber Hand Illusion and Case

Study of a Spontaneous Out-of-Body Experience. PLoS ONE.

17. Vallar, Giuseppe., & Ronchi, Roberta. (2008). Somatoparaphrenia: a body delusion. A

review of the neuropsychological literature.192:3, 533-551.