Tag Archives: mind

Brain


The autobiographical self places the transient core self into a longer time frame.

Objects which the transient core self are able to relate to organism changes are now associated with past instances. The transient core self is also able to formulate longer range plans because it now has access to memory. As those associated memories themselves are treated as objects, the self is constantly re-created and contextualised into the past, into notions of self and identity.

Damasio postulates that the autobiographical self is also pre-language. Animals are likely to have autobiographical selves. He also postulates that the complexity of the autobiographical self depends on the richness of association the organism’s brain is capable of. Humans for example are not only able to process many objects at the same time but are also be able to hold deeper and more complexly linked associations with each of those objects.

As far as describing the neuroanatomical basis for the autobiographical self, Damasio becomes sketchier. He describes convergence and disposition zones which hold implicit records of knowledge and which are activated, placing them in higher order cortices (effectively the majority of the cerebral cortex that are not the early sensory cortices).

At this point, in spite of an interesting description of transient global amnesia where a patient effectively appears to loose its capacity to create the associations for autobiographical memory, it seemed to me that Damasio was beginning to hit the barrier between scienctific hypothesis and informed speculation.

Nevertheless, his description of a conscious self as being created at every moment due to interactions between the state of the body, the effect of external stimuli and automatically associated dispositions, made a lot of sense to me.

The other thing I got from the book was the extent to which emotions are felt after they’ve occured. That consciousness or awareness of emotions as we know it is actually an overlay, a kind of post-factor diagnosis based on signals from the body. Damasio summarises this process into five steps:
1) engagement of object with emotion inducer resulting in early internal representations of the object
2) Processing of the early representation activates neural sites preset to respond to that particular class of inducer
3) Emotion inducer sites trigger a number of responses in the body and other brain sites.
4) First-order neural maps in subcortical and cortical regions represent change in body state. Feelings emerge.
5) Pattern of emotion inducer site activity is mapped to second-order neural maps relating changes to the proto-self with the emotion inducing object. The beginnings of causal knowledge emerges.

It’s only after stage 5 that we become conscious of what is happening. This is quite in line with LeDoux’s detailed examination of fear.

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Brain


The Damasio book which I’m crawling through at a snail’s pace due to social factors beyond my control is heating up.

To sum up, he breaks the self or rather representations of the self within the brain into the following ever closer to human sentiency levels:

The Proto-Self. The protoself is the foundation of the self. Higher levels of the self are not conscious of this layer. The proto-self consists of brain images of the fundamentals of the body – maps of the internal milieu, viscera, vestibular system and musculoskeletal frame. Brain structures required for the protoself include several brainstem nuclei which regulate body states and map body signals, the hypothalamus and basal forebrain which maintains the current state of the internal milieu and assists in regulating it, the insular cortex, the S1 cortices and the medial parietal cortices which are part of the somatosensory cortices. These structures produce what Damasio calls first-order maps of the organism.

As an organism interacts with objects, first-order maps of the organism are modified by first-order maps of objects. Structures which create first-order maps are early sensory cortices (eg visual and auditory cortices). However, the proto-self is not awareness of the casual relationship between first-order maps of object and organism. The integration required for this is provided by the next layer, the transient core-self.

Note that first order sensorimotor maps are not necessary for the proto-self in the sense that disruption of structures which produce these first order object maps do not disrupt the proto-self.

The Transient Core-Self. The transient coreself produces second-order maps of the changes in first-order maps of the organism and the object, thus casually relating one to the other. This is a non-verbal process and is the start of consciousness.

So, as the brain forms images of an object (through first-order maps of the object) and these images affect first-order maps of the organism, another level of brain structure creates a swift non-verbal account of the events that are taking place in varied brain regions activated as a consequence of the object-organism reaction. Damasio suggest that are multiple core consciousness generating structures which he lists as the superior colliculi, the entire cingulate cortex, the thalamus and some prefrontal cortices.

As there are always objects (objects can also be memories), the core-self is continously generated and thus appears to be continuous in time.

My notes: The core-self can be considered the intuitive and indivisible “I” which eludes further breakdown on introspection and which disappears when one is unconscious. Note also that the transient core-self is not the self that makes decisions, it is the awareness of “self” versus “object”. Damasio is quite interesting in that his hypotheses basically states there can be no self without objects, that the self is a dynamic entity which results from interaction.

My notes: As all this is language independent, the proto and core self is not just the domain of the humans. Looking into the cat’s eyes after reading this chapter was quite something. Awareness, consciousness, the sense of self as being different from other, the cat had it all.

Next: the autobiographical self and extended consciousness.

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Aphasia


Reading Damasio’s The Emotional Brain which frankly could be a little more concise and generous with the science and a little leaner on the exposition, I happened on an interesting little snippet about people who’ve suffered damage to the language areas of the brain, Broca’s and Wernike’s area, to such an extent that they are almost literally without language. Classified as global aphasics, they cannot read or understand words and are unable to produce speech beyond stereotypical words, largely curse words. Intuitively enough, this also affects deaf sign language users in much the same way.

So, two points that are interesting about that.

According to Damasio global aphasics are still clearly conscious, self-aware and self-reflexive. The question then remains whether these people still have language as a means of thought and self-awareness but are now permenantly trapped in world where every form of external language is incomprehensible and one’s internal language is inexpressible. Hence, simple gestures and facial expressions as well as tone can be understood but everything else has fallen away.

The alternative which Damasio favours is that self-awareness and consciousness is not dependent on language, that is our mind and sense of self, is not language dependent. Possibly, global aphasics would then think in loosely structured images that have to bear close resemblence to objects. Unfortunately, it’s difficult to tell which is the case as global aphasics can generally draw simple sketches to communicate but this ability is true in either case, ie whether aphasics have language or not.

The second thing of interest is that little end note about how stereotypical words, especially swear words and non language emotional expressions are still generally expressible. This leads me to think that curse words are emotional expressions that can stand by themselves without any need for meaning, functioning similarly to growls, meows, barks and hisses. In other words, swear words, through association with stressful emotional situations and training through expression are extended means by which our sub-cortical emotional structures communicate. I might be out on a limb there but that explains why it can sometimes be quite difficult to not swear – our sub-cortical structures generally get first dibs in reaction.

The following link provides a good summary of aphasias.

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