Saturday, March 13, 2010

Specific neural events are coincedent with specific mental images

An interesting study that raises further questions

In the study, Maguire and her colleagues Martin Chadwick, Demis Hassabis, and Nikolaus Weiskopf showed 10 people each three very short films before brain scanning. Each movie featured a different actress and a fairly similar everyday scenario.

The researchers scanned the participants' brains while the participants were asked to recall each of the films. The researchers then ran the imaging data through a computer algorithm designed to identify patterns in the brain activity associated with memories for each of the films.

Finally, they showed that those patterns could be identified to accurately predict which film a given person was thinking about when he or she was scanned.

The results imply that the traces of episodic memories are found in the brain, and are identifiable, even over many re-activations, the researchers said.

The results reinforce the findings of a 2008 US study that showed similar scans can determine what images people are seeing based on brain activity.


The basic idea seems to be that it is possible through use of the algorithm, in concert with an appropriately sensitive scanner, to tell which episodic memory I am having right now, provided that my hippocampal brain activity during the actual first experience was scanned and recorded using a similar device/algorithm.

Questions that would probably be cleared up if I had access to the full text: the study involved several individuals. Were the patterns detected for particular episodes similar across individuals? If so, closely similar? On that basis, would it not be possible to tell when any individual was having experience of the girl in the red dress?

If such similarities exist across individuals, how far does it go, how thoroughgoing is it? Do you and I have similar neural events when we see a black cat? If so, it would indeed be possible to "read thoughts" as the headline suggests.

Do similar patterns fire when less concrete cogitations are going on? Say two people are struggling with a particular mathematical problem. Will their neural activity be similarly located, and will the patterns be similar?

Eleanor Maguire, the primary researcher, has also done some work showing that you can tell where in a 'virtual room' someone is standing simply by making use of the scanner results.

In the new study, Hassabis, Maguire, and their colleagues asked four participants to navigate to target locations within a virtual reality room while their brains were scanned with a functional magnetic resonance imager (fMRI). fMRI measures blood flow related to neural activity in the brain. They then applied a sophisticated analytical procedure known as multivariate pattern classification to see if they could relate the pattern of brain activity to each individual's location in virtual space.

And it worked. The pattern they uncovered reflected the participants' memory for where they were, the researchers explained, since once they had reached their final destination, there were no visual cues to discern one target spot from another. The activity they examined spanned some two to five million of the 40 million or so cells in the hippocampus, Hassabis noted.


This summation of that research does seem to suggest that they are finding consistencies of pattern across individuals, and that they wish to do larger scale studies:


"By showing it is possible to detect and discriminate between memories of adjacent spatial positions, our combination of non-invasive in vivo high-resolution fMRI and multivariate analyses opens up a new avenue for exploring episodic memory at the population level," the researchers wrote. "In the future it may be feasible to decode individual episodic memory traces from the activity of neuronal ensembles in the human hippocampus."

This all seems to suggest the mental properties are very tightly connected to brain states, in that they are properties of collections of neurons. To employ a term of Mill's, there is a very tight concomitance of variation between mental states of particular sorts and neural states, or rather particular patterns of neural activity.

My hunch is that this research will find cross-individual and cross-cultural similarities, and concomitance of subjective report and neural pattern. That result would be supportive of the claim that mental properties are in fact a special sort of physical property, had only by brains, and probably by no other sort of thing. Yes, brains can have first person properties. No, individual neurons cannot do this, no more than individual water molecules can be wet. But, the subjectivity human brains have is no more a separately existing entity from our brains than is the wetness of collections of water molecules. What is more, the phenomenology of that subjective experience is something we can see has regular concomitance to various neural events, down to quite specific levels.

That's my guess at any rate, for what it's worth.

CIA drone remote pilots: unlawful combatants

An interesting brief article in the WAPO, by Gary Solis, an adjunct professor at Georgetown. The gist is that, since our drone pilots are killing enemy, or providing intel that is used to kill enemy, they are legitimate targets for enemy forces (AQ etc.) Also, they meet the legal definition of unlawful combatants, because they are un-uniformed civilian employees of the U.S. government, not members of our armed forces. This status opens them up for targeting by the enemy, or, in the unlikely event of capture by said enemy, to the equally unlikely prospects of military or civilian trial by our barbarian enemy. Some snippets:


In terms of international armed conflict, those CIA agents are, unlike their military counterparts but like the fighters they target, unlawful combatants. No less than their insurgent targets, they are fighters without uniforms or insignia, directly participating in hostilities, employing armed force contrary to the laws and customs of war. Even if they are sitting in Langley, the CIA pilots are civilians violating the requirement of distinction, a core concept of armed conflict, as they directly participate in hostilities.


..we kill terrorists who take a direct part in hostilities because their doing so negates their protection as civilians and renders them lawful targets. If captured, the unlawful acts committed during their direct participation makes them subject to prosecution in civilian courts or military tribunals. They are not entitled to prisoner-of-war status.

I would point out an undeveloped distinction in the short piece. I believe it takes a bit off the 'heads up, and watch your backside' flavor of the piece. Notice the bolded type. It is true that terrorists are typically not state actors, and it is also obviously true they also do unlawful things during hostilities.

In fact, that is stating things too lightly. The essence of their hostility is unlawful. Their targets of preference, typically the first targets they choose, indeed their modus operandi is to seek out unarmed defenseless, and obviously non-uniformed civilians. Because they do this, they are liable to prosecution for violations of the laws of war, both customary and codified. They are liable for two reasons. Their status as non-traditional combatants, and for carrying out war crimes.

Now, compare their situation with those of the drone pilots at Langley (or wherever else they may be). By the customary and codified laws of war, they too are unlawful combatants, because they are not military personnel. However, who do they target? Combatants. If civilians are killed by drone attacks, to use some terminology from the hoary doctrine of double effect, those casualties are the foreseen but unintended consequence of legitimate targeting. Such casualties are avoided if possible, accepted only as a last resort unavoidable consequence. In fact attacks are often called off because of the risk of inordinate civilian deaths. So, to be fair, military tribunals, and even international bodies such as the ICRC would have to take into account this important distinction between our folks and theirs when considering the case of drone pilots. On purely moral grounds, there is a significant distinction to be made, which should also be the basis of a legal distinction, if it is not already. The laws of war, both codified and customary are not some unchanging mass. They change with the technology of war, as they should, to reflect relevant moral distinctions.

Jonathan Winters: On Cars

From 1962