Where is self awareness in the brain

About 10 percent of his insula remains and only 1 percent of his anterior cingulate cortex. Roger cannot remember much of what happened to him between and , and he has great difficulty forming new memories. He cannot taste or smell either. But he still knows who he is. He recognizes himself in the mirror and in photographs, and his behavior is relatively normal. In a paper published earlier this year postdoctoral researcher Carissa L.

Philippi of the University of Wisconsin—Madison and neuroscientist David Rudrauf of the University of Iowa and their colleagues investigated the extent of Roger's self-awareness. In a mirror-recognition task, for example, a researcher pretended to brush something off of Roger's nose with a tissue that concealed black eye shadow.

Fifteen minutes later the researcher asked Roger to look at himself in the mirror. Roger immediately rubbed away the black smudge on his nose and wondered aloud how it got there. The researchers also showed Roger pictures of himself, of people he knew and of strangers.

He almost always recognized himself and never mistook another person for himself. He did sometimes have difficulty recognizing a photo of his face when it appeared by itself on a black background, without any hair or clothing.

Roger also distinguished the sensation of tickling himself from the feeling of someone else tickling him and consistently found the latter more stimulating. He anticipated that the researcher would notice his sweaty armpits and used humor to preempt any awkwardness.

In another task, Roger had to use a computer mouse to drag a blue box from the center of a computer screen toward a green box in one of the corners of the screen. In some cases, the program gave him complete control over the blue box; in other cases, the program restricted his control.

Roger easily discriminated between sessions in which he had full control and times when some other force was at work. But there are some puzzling evolutionary gaps. Gorillas, for instance, usually fail the test — with the notable exception of the recently deceased Koko — yet our more distant primate relatives, the orangutans, pass it.

Also, the self-aware elite contains some bizarre anomalies such as pigeons, manta rays , ants and even a robot. Some of these findings — particularly with ants and pigeons — are contested. Researchers have tried to explain away others, arguing, for example, that gorillas have mentally regressed since their split from the other ape lineages because they face fewer pressures in their environment. But the recent discovery in monkeys is harder to dismiss.

Last year, Liangtang Chang and colleagues at the Shanghai Institutes for Biological Sciences, China, released video footage of a small group of rhesus macaques interacting with a mirror.

It shows the monkeys contorting their bodies, tugging at their facial hair, inspecting their fingertips and making flashy displays of their genitals, all the while keeping their eyes on their reflections. They are captivated, leaving little doubt they recognise themselves. Yet, rhesus macaques have consistently failed the mirror test. What changed?

In fact, there is anecdotal evidence of macaques in the lab showing a sudden interest in mirrors after being fitted with bulky neural recording devices that protrude from their heads. To test this, they taught the monkeys to link vision and movement by giving them a food reward for touching a projected laser dot. At first, the researchers shone the laser where the monkeys could easily see it, then gradually worked up to shining it in places only visible in the mirror.

Fast-forward a few weeks of practice, and they passed the face-mark test with flying colours. That, in turn, raises the possibility that self-awareness is much more widespread than we think.

So, what do we know about the evolution of this prized trait? Many psychologists and anthropologists hold that there is a hierarchy of consciousness that corresponds with increasing brain complexity. At its base is the minimal consciousness attributed to animals with simple nervous systems.

These minds are thought to be permanently adrift in a sea of raw sensory experiences, tossed around between perceptions such as colour, hunger, warmth and fear, with little awareness of their meaning. Few minds are sophisticated enough to experience the world differently — through an introspective lens. Even then, they may have a limited sense of self.

Smart animals like chimps and dolphins can recognise themselves in a mirror, but have they led us up the garden path? Figure 2. After the placebo, the ligand was mainly bound in the medial-inferior prefrontal cingulate cortex, and right and left insula. In hippocampal regions there were small foci of increased binding potential. The GABA receptors are constructed as ligand ion channels. According to Stephens et al. The pore allows passage of negative chloride ions, and, hence, the generation of electrical pulses when stabilized in an open conformation.

This stabilization occurs by binding of GABA to the complex. The binding is not specific for GABA. The affinity of other molecules, whether physiologic, including dopamine, and foreign molecules depends on the protein composition of the five pentameric molecules constituting the pore and determine the function of the synapse.

The subtype composition of the pentameric pore is abnormal in addiction. Related to this, a number of studies suggest that altered GABA neurotransmission plays an important role in substance addiction Lingford-Hughes et al. In premature infants, functional MR imaging together with diffusion tensor imaging-based tractography has been used to study the relationship between performance on the Bayley Scales of Infant Development and early myelination Cui et al. The Bayley Scales of Infant Development is a developmental play task that derives a developmental quotient rather than an intelligence quotient.

The authors confirmed such a link by showing that scores on the Bayley Scales of Infant Development were significantly associated with cingulate fractional anisotropy and radial diffusivity Cui et al.

This suggests that interconnecting axonal pathways within the default mode network are of critical importance already in the early neurocognitive development of infants. A positive response is usually present at about 2 years of age.

A recent review showed that the default mode network follows an inverse U-shape, where it is weaker in children and elderly and stronger in adults. Cognitive function is positively correlated with default mode network functional connectivity Mak et al.

In later childhood and adulthood, disturbance of the paralimbic network is linked to severe pathology. Thus, deficient GABA neurotransmission is prominent in disorders with poor self-awareness and self-monitoring such as addiction Lingford-Hughes et al. Even in the vegetative state also termed unresponsive wakefulness syndrome, Laureys et al. Finally, a large clinical study of the possible therapeutic effect of apomorphine, a dopaminergic drug, is now underway Sanz et al. This was indeed the case.

Therefore, normal interaction between these transmitters in the medial paralimbic system seems to be fundamental for brain function. The basal forebrain part of the system is not only regulated by dopamine. It is also a prominent site of cholinergic activity. Thereby it promotes functions related to conscious experiences such as attention, learning and memory, and sleep-wake alternation Lin et al. The widespread dysfunction of self-awareness in disease is likely to be a consequence of the exceedingly high oxygen demand of the paralimbic network.

The high oxygen requirement is considered to be the result of dense concentrations of parvalbumin GABAergic interneurons in the richly connected hubs of the paralimbic network. In particular, the fast gamma oscillations are susceptible to metabolic disruptions because of their high energy-demand Kann et al. Until recently, conscious experience and self-awareness were considered off-limits for the natural sciences.

The risk is evident for arriving at two parallel worlds: a mental and a physical, without understanding how they interact. This limitation has impeded our understanding of the biological function of self-awareness, and how it may account for disease. We have here reported data showing that self-awareness and conscious experience can be disturbed by electrophysiological manipulation of the paralimbic network Lou et al.

Therefore, we may conclude that the network is instrumental for these functions. Newer data reviewed here also strengthen the conclusion by showing that dopaminergic agents may stimulate conscious experience via GABA receptors in the paralimbic network.

The low performance-monitoring group underestimated their disability and showed broad attentional deficits. Neural activity within what has been termed the fronto-parietal control network was abnormal in patients with impaired self-awareness. The dorsal anterior cingulate cortex is a key part of this network that is involved in performance-monitoring. This region showed reduced functional connectivity to the rest of the fronto-parietal control network at 'rest'.