striatal memory route

The striatum/putamen stream is where incoming stimuli carrying information are given priority and significance.

brain cellmapping indicates activity in the striatum may predict schizophrenia


In a seminal 2006 research article

Fuerte et al 2006: distraction

... interview with Ross Poldrack
you and your fellow researchers report findings from a study using "functional magnetic resonance imaging" that found "heavy striatal engagement" occurring during multitasking.
What is "heavy striatal engagement"?
What does your research tell us about the cost of task switching while trying to learn?

Russ: "Heavy striatal engagement" is a lot less titillating than it sounds. The striatum is a part of what are called the brain's "basal ganglia." These are a set of brain areas located deep in the brain, which receive input from many parts of the cerebral cortex and then send information back to those same regions via a set of "loops," which are really just connections between several brain areas that loop back on themselves. The basal ganglia are involved in nearly every aspect of thinking and behavior, but we think they play a particular role in selecting which of several actions one will perform in a given situation, and especially in developing new habits and routines.

In the study that you mention, we asked people to learn how to categorize set of cards that were presented on the screen; the subjects had to learn by trial and error, which sets of cards went with each category. In one part of the experiment, they were able to do this while focused on the task. In another part, they had to try to learn another categorization problem while also performing a secondary task, which involved keeping a running count of the number of times that a particular sound happened. This is a difficult multitasking situation!

What we found was that people could learn the categorization task under either single-task or multitasking conditions, but that they learned it differently in the two cases. In the single task conditions, they used a part of the brain called the hippocampus, which is known to be important for creating rich and flexible memories of the past. Fitting with this, when we tested for their ability to generalize the knowledge that they had gained (e.g., by testing using a different kind of test), subjects were able to generalize the knowledge well.
What we saw when subjects learned under multitasking conditions was quite different.

Instead of using the hippocampus, subjects instead used the striatum to learn the task.

Based on this, we suspected that the knowledge that they had gained would not be as flexible, and this is exactly what we found; unlike the problems that they learned under focused conditions, they were not able to generalize the knowledge that they had learned while multitasking when we tested them in a different way. if multitasking doesn't prevent people from learning, it can change how they learn in ways that are not beneficial. it's consistent with the more general fact that people are often very mistaken about how their own minds work. In their book, The Invisible Gorilla illusory thinking (2011), When emotional events like the 9/11 happen, people often report what are called "flashbulb memories," must be correct in which the memory seems like a vivid snapshot of the event. For many years psychologists assumed that these memories must be correct, but since the 1980's a number of studies have shown that such memories can actually be highly inaccurate. Bush gave three different accounts of his memory for the events of that day, two of which had details were not plausible given what we know about the timeline of that morning. George Bush is not particularly special in this regard; in general, there is only a very loose relationship between the accuracy of our memories and how confident we are in them. And this is just one of the many domains in which we misunderstand how our own minds work. Does your research suggest incoming freshmen a decade from now may be less adept at "deep learning" than were the freshmen starting college this year?

Russ: My major concern about the informational environment for today's students is that the bombardment with such a great deal of information at every moment in their lives will reduce their ability to focus their attention on a single source of information. Just as sitting all day can cause muscular imbalances in our hips and butts, spending the entire day flipping between different informational streams without focusing is likely to reduce the strength of the "mental muscles" that allow us to focus when we need to. You can think of today's world as a child-rearing experiment on a grand scale, since humans have never been raised in an environment like this before. Unfortunately, it's not a controlled experiment so we can't exactly test the effect of the intervention. The worst case scenario is that we will one day wake up and realize that we are living in a cognitive dystopia.
We won't realize it until it's too late. How this relates to learning is still an open question, but I think that there is a good argument to be made that the cognitive effects of multitasking could be detrimental to richer forms of learning. The research on media multitasking by Ophir, Nass, and Wagner heavy internet users (2009) has shown that people who are heavy media multitaskers process information in a different way that light multitaskers, in that they are more "breadth-biased": that is, they pay attention broadly, skimming larger amounts of information rather than focusing on particular bits of content.
In particular, they showed that heavy multitaskers were more likely to be distracted by irrelevant information during a working memory task; that is, they had a harder time focusing only on the information that was relevant to the task.
Because the creation of rich memories requires processing information deeply, it is likely that this kind of distractability would reduce the ability to form such memories, though I don't think that idea has been directly tested yet. Cognitive psychology research on multitasking says that less is likely to be better, but it will depend critically on the organization of the activity. The effects of multitasking are due to the frequency of switching between different tasks, rather than the number of tasks being done per se. Thus, if you only have two devices but are switching between them every 10 seconds, you will be worse off than if you have 4 devices but only switch between them every 10 minutes. It's also important to distinguish devices from the activities being used to perform them; most electronic devices can support many different types of activities, and using a single device to switch between four different programs is likely to be no better than switching between four different devices.

Russ: "Information overload" can mean many different things, so let's first define what we are talking about. When a person goes online to find information, they are presumably trying to actively hold onto some amount of information in memory; psychologists refer to this as "working memory." When I talk about "information overload," I am specifically referring to what happens when the amount of information that we are trying to hold in working memory becomes too large, such that it can't all be held onto. We actually know quite a bit about how working memory is implemented in the brain, much of which comes from recordings of neurons in the brains of monkeys while they hold information in mind. What has been shown is that when a monkey holds information in mind for a short period, individual brain cells in the prefrontal cortex turn on and remain active as long as the information needs to be held in mind, then they turn off. In humans, we can see this with functional MRI; areas of the prefrontal cortex become active whenever we have to hold information in mind, and especially if we have to work with that information (such as doing mental arithmetic).

The important question is what happens when we hit our limit, and this is not as well understood. In some parts of the brain, it seems that activity increases until we hit our memory limit and then stays constant. This is related to each individual's memory capacity, such that people with greater visual memory capacity show greater increases in brain activity as the amount of information to remember increases.
In other parts of the brain, however, it seems that information overload can actually cause activity to go down. This has been seen particularly in the prefrontal cortex, where some studies have found an "inverted-U" relation between working memory load and brain activity. That is, activity goes up until memory starts to get overloaded, and then it starts going down. Not all studies have found this kind of a decrease with memory overload. We know that information overload can be stressful, but another thing that neuroscience has shown is that stress can actually make information overload worse. Research by Amy Arnsten Stress on memory They have found that as the amount of adrenaline in the brain increases (as it does when we are stressed), the ability of individual brain cells to hold onto information starts to break down due to the activity of a particular kind of receptor in the prefrontal cortex.
This research suggests that information overload may be a vicious cycle - information overload causes us to be stressed, and the stress then further reduces our ability to deal with more information. One lesson to take away from this is that anything that can help reduce stress (such as relaxation, meditation, or yoga) may help improve our ability to deal with information overload. It's also worth noting the parallels between the specific complaint that you mentioned ("sorting through irrelevant information from online searches") and the issues with filtering of irrelevant information that I mentioned above. Without more research it's hard to say for sure, but it may well be the case that the breadth-based cognitive style that is associated with heavy multitasking makes it even more difficult to deal with all of the irrelevant information that one encounters when searching the Internet.


the disability in schizophrenia is not having enough new hippocampus cells to sort out the overwhelming intrusion of external sensory perception overload
Fuerte et al 2006: distraction

How and where would the brain deal with this surplus stimuli/information, pointless information, unwanted, that has some how 'got in' to the striatal memory route, where it will have to be checked for salience, been given dopamine high value, needing attention and a response.


abnormal salience especially when distractors are present

salience


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What is going on in overload is a bypassing of the selecting process of the hippocampal networkingsystems ,
ending up instead in the basal ganglia mid-brain striatal memorising stream, going on to the networks where procedural skills are stored.
The striatum/putamen stream is where incoming stimuli carrying information are given significance