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Showing entries tagged medial prefrontal cortex.  Show all entries

December 4, 2011

Reasons You Should (not) Text and Read


Tap tap tap tap tap Bam Bam Bam *moaning* TAP TAP TAP TAP BAM BAM BA-BAM BAM BAM!

Take a page out of the Dr. Chun and Johnson book: if your roommate is having wild and kinky sex just next door, find someplace else to write your Civil War research paper. Keep in mind, this advice does extend beyond sex as a distraction and a research paper as a task. In the November 17, 2011 issue of Neuron the review Memory: Enduring Traces of Perceptual and Reflective Attention made several assertions about the aggrandizing body of literature concerned with the networks involved in and interactions between attention and memory. Research concerned with the dynamic interplay of memory and attention, currently, is sparse; until very recently, neuroscience research has focused either on attention or memory. Lately, however, researchers have found that their results about attention or memory phenomena cannot be explained without more information about how they are conjoined. The purpose of this review was to assess advances that have been made, possible applications of the results, and hypotheses to be tested in future studies.

Looking back at the poor sap listening to his roommate get it on not five feet away, while he is attempting to concentrate on how Union soldiers mistreated Confederate women and children, made me wonder if he can pay any attention to the task he is supposed to at the moment (his paper). Thankfully, I do not have to conduct a research experiment myself to see if he will succeed: this question was already answered in A general mechanism for perceptual decision-making in the human brain. The answer is simple: if the task you are concentrating on is easily accomplished then the amount of attention you need to devote to it is low (low load), and, unfortunately, distractions will impact your efforts much more than if the task is not easily accomplished. If the task is difficult, the cognitive load will be high and distractions are not as likely to detract from your concentration. I think the paper he is writing has a high cognitive load, but I also am inclined to think that the amount of sensory input he is getting, from task-irrelevant sources, is not low on the cognitive load scale and, therefore, his reflective attention on the paper will suffer.

Beyond informing us how to respond to demanding situations, this review reflects on various findings that have been made, and steps to be taken, in the exploration of the pathways implicated in memory and attention. A major discovery that was made recently, (July 2011) by a conglomeration of researchers from the Netherlands, is that, not only do attention and memory interact, memories of images, (reflective representations specifically) when retrieved, activate the same pathways as though the image was seen twice. The implications are clear: that picture in your head of your long lost lover perfectly replicates what he or she looks like in real life, right? Not quite, all that Oliver et al. discovered is that the same pathways are activated in the perception and recall of a dot or shape, which cannot be extrapolated any further.

However, that is not to say that none of the studies in this review came to similar conclusions; a few even arrived at conclusions, and observed results, that are salient to the human condition. A few of the more scintillating results include, but are not limited to, the fact that when we are not distracted the amount of and detail in which we remember information is extraordinary (implications for people with ADD/ADHD); the harder a task actually is, the more likely we are to focus on it than on distracting stimuli (studying habits); and, the ability of older adults to enhance memory (learn new things), while simultaneously being unable to distinguish false memories from true memories, and remember salient information from the past (memory loss due to aging).

The study of memory and attention interactions is new and, because of the information already gleaned from studies focused solely on attention or memory, certain questions can already be answered about their interactions. I, like the Civil War historian listening to his obnoxious roommate slam his way to a TBI, am not satisfied to simply sit around and listen (in my case about studies that have been performed, in his case sex). I am interested to learn more about attention-memory interactions and, someday, contribute to this fascinating field of study.

Now, who is ready for a pop quiz on the interactions of memory and attention?

Source: http://www.sciencedirect.com/science/article/pii/S0896627311009615
Posted by      Christina U. at 3:00 PM MST
  aidan mary  says:
I really want to take your test, what should I do?
starjack io
Posted on Thu, 15 Aug 2019 9:49 PM MDT by aidan m.

October 19, 2011

Well that's Surprising...ly Negative


Have you ever been surprised to be let down? Or in other words, have you ever expected a certain outcome only to be surprisingly disappointed? Well if you have, ladies and gentlemen, then do not fear; for your dorsal anterior cingulate cortex is functioning properly! And what's that? There's unified model for the long disputed function of the dorsal anterior cingulate cortex? That's right! Both of these birds were hit by the same stone recently when Alexander and Brown produced a computational model "tour de force" to illustrate how negative surprise signals drive dACC (dorsal anterior cingulate cortex) and mPFC (medial prefrontal cortex) responses.
Many theories have been concocted as to what the dorsal anterior cingulate cortex may be responsible for, such as error detection, error likelihood prediction, and conflict monitoring primarily, and even more such as reinforcement-guided decision making, negative reinforcement learning signals, and action value prediction error. Could the dACC be responsible for all of this in the brain? Well, Alexander and Brown's model seems to narrow our spectrum a bit and put an end to this controversy.
While their model agrees with previous theories that the dACC and mPFC predict action-outcome situations, it is uniformly different in the sense that these regions are responsible for multiple predictions for action-outcome situations in parallel, and then these predictions are scaled to their probability of their occurrence. When the predicted outcome doesn't happen, learning rates are modified in order to update action-outcome predictions to the degree necessary to learn from mistakes and find a better solution.
Another important point of this model's representation of multiple predictions of action-outcomes is that different ongoing predictions could account for heterogeneity of neural responses usually observed in single-unit studies. So basically, the dorsal anterior cingulate cortex and medial prefrontal cortex can encode different outcomes simultaneously for the same situation that are being encoded in different groups of neurons! Pretty impressive eh?
So let's just recap. The dorsal anterior cingulate cortex analyzes a particular action, predicts an outcome for this action, and if the action-outcome prediction is negated, then the dACC modifies learning rates so that the brain can learn from its mistakes. And the dACC and mPFC can do this multiple times at once!
So while Alexander and Brown's model is reasonable and presents much more concise data, it is obviously provoking new questions and controversy. Seeing as how consequences of positive and negative surprises are the same according to this new model, what makes a negative surprise more significant or important than a positive surprise? If the dorsal anterior cingulate cortex is responsible for negative surprise predictions and reactions, what is responsible for positive surprise monitoring? As for these questions, we shall see what new models of these mysterious brain regions are presented and what will be discovered for the tasks we perform in daily life. Regardless of what is discovered in the future, we'll all be surprised!

main article:http://www.nature.com/neuro/journal/v14/n10/full/nn.2932.html
Posted by      Mark A. at 4:19 PM MDT
  Christina Uhlir  says:
Mr. Alsberg,

Could you kindly explain the mechanism by which the "tour de force" operates?
Posted on Sun, 23 Oct 2011 2:20 PM MDT by Christina U.




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