I’ve been reading articles about what actually happens in the brain when a person thinks of a word. Some of this is theoretical, some experimental.
So first off, from here: this amazing picture is a visualization of neurons firing in a sequence about 200 ms before a person calls up a memory. Each bar is a single neuron firing:
This could any sort of memory. Theoretically (from here), the recollection of a word will call up a number of these firings as the brain’s dictionary is consulted. In other words, when you see the word dog, the associations you have with the word will roll off in these firing patterns. Some of it may be sensory, like the smell of a dog on a rainy day. There may be emotional memories related to long lost friends.
My plan is to continue rambling about these articles. Feel free to add one and share thoughts.
Consider Davidson’s question concerning such patterns. Suppose that the pattern above appears a thousand times, and each time the participant was thinking “dog”.
The experimenter concludes that this pattern is the physical equivalent of the participant thinking “dog”.
On the thousand-and-first test, the pattern appears but the participant claims they were thinking of ice cream.
What can we conclude? Is the correlation falsified? Did the participant lie? Were they mistaken, and were they thinking of “dog” but forgot?
On the thousand-and-second test, the participant claims to be thinking of “dog” but the pattern does not appear. Again, what do we conclude?
is that what happens? Those a well established pattern suddenly not seem to mean what it always had? And does meaning suddenly come to be associated with a different pattern than it always had been before?
Agree! There seems to be a temptation to equate neural activity with signs, or to put it another way, that they ‘signify’. But I say there is a fundamental reflexivity involved in the attempt to explain cognition in physical terms. The neuroscientist’s identification and interpretation of neural processes necessarily employs the very cognitive capacities whose relationship to those processes is being investigated. We cannot step outside cognition to establish, from some independent standpoint, what cognition is.
A physical account of the brain may provide an increasingly sophisticated model of neural operations, even including its capacity to model itself. But such a mode is itself an achievement of cognition: its concepts, observations and interpretations are all constituted within the very process it purports to explain.
This does not invalidate neuroscience, nor does it establish that neural processes cannot be identical with thoughts. Rather, it calls into question the assumption that an objective description of neural activity, however comprehensive, can by itself account for the intentionality and meaningfulness of thought. The aspiration to explain cognition entirely from the outside seems to overlook the fact that the very distinction between an objective physical process and its meaningful apprehension is one that cognition itself makes.
A girl friend has a dog and I may have seen it a thousand times. At no time did it suddenly become an ice cream.
Why would neurons be different. I am not not saying that they are stable I dont know. But if there a philosophical reason to suppose that they are not stable it evades me.
The concept that “neurons that fire together wire together”.
So, if you see a dog eating a bone, the synaptic pathways between “dogs” “eating” and “bones” become stronger.
You then have the idea of a “bone eating dog” and are less surprised to see dogs eating bones. Imdeed, you are comforted by the sight and the comnections are strenghened.
Were you to see a baby gnawing on a bone or a dog eating an ice cream it would create dissonance. Presumably the brain then suppresses the pathways a little.
The other interesting observation is that our thinking is hierarchical. Alsations are dogs, dogs are animals. They all have things in common. So when we learn sonething new we test it against all things in the hierarchy. If dogs eat bones. Naybe Alsations eat bones. The idea has been tested empirically by assessing the speed of answers to questions about thinngs closely and more distantly related in the hierarchy.
I wonder how deep this goes - with just a minimum of initial concepts can we build a complex inner world based on learnt hierarchies and relationships?
A very interesting article, Frank. Thanks for sharing.
Reading the article on the website, it says in the picture below:
Our brains may store memories in specific neuronal firing patterns, visualized here, that are replayed fractions of a second before remembering. Individual neurons are represented by different colors.
Does anyone know why the individual neurons are represented by different colors?
It grasped my attention. I wonder if the colours are important or if they are just a representation of what the researchers did.
