Older news items (pre-2010) brought over from the old website
Why it’s so hard to disrupt your routine
New research has added to our understanding of why we find it so hard to break a routine or overcome bad habits. The problem lies in the competition between the striatum and the hippocampus. The striatum is involved with habits and routines, for example, it records cues or landmarks that lead to a familiar destination. It’s the striatum that enables you to drive familiar routes without much conscious awareness. If you’re travelling an unfamiliar route however, you need the hippocampus, which is much ‘smarter’. The mouse study found that when the striatum was disrupted, the mice had trouble navigating using landmarks, but they were actually better at spatial learning. When the hippocampus was disrupted, the converse was true. This may help us understand, and treat, certain mental illnesses in which patients have destructive, habit-like patterns of behavior or thought. Obsessive-compulsive disorder, Tourette syndrome, and drug addiction all involve abnormal function of the striatum. Cognitive-behavioral therapy may be thought of as trying to learn to use one of these systems to overcome and, ultimately, to re-train the other.
[931] Lee, A. S., Duman R. S., & Pittenger C.
(2008). A double dissociation revealing bidirectional competition between striatum and hippocampus during learning.
Proceedings of the National Academy of Sciences. 105(44), 17163 - 17168.
http://www.eurekalert.org/pub_releases/2008-10/yu-ce102008.php
Brain's voluntary chain-of-command ruled by not 1 but 2 captains
Previous research has shown a large number of brain regions (39) that are consistently active when people prepare for a mental task. It’s been assumed that all these regions work together under the command of one single region. A new study, however, indicates that there are actually two independent networks operating. The cingulo-opercular network (including the dorsal anterior cingulate/medial superior frontal cortex, anterior insula/frontal operculum, and anterior prefrontal cortex) is linked to a "sustain" signal — it turns on at the beginning, hums away constantly during the task, then turns off at the end. In contrast, the frontoparietal network (including the dorsolateral prefrontal cortex and intraparietal sulcus) is active at the start of mental tasks and during the correction of errors. The findings may help efforts to understand the effects of brain injury and develop new strategies to treat such injuries.
Dosenbach, N.U.F. et al. 2007. Distinct brain networks for adaptive and stable task control in humans. Proceedings of the National Academy of Sciences, 104 (26), 11073-11078.
http://www.physorg.com/news101478606.html
Planning is goal-, not action-, oriented
Studies in which monkeys were asked to perform a complex task involving several discrete steps have revealed that the brain's "executive" center, in the lateral prefrontal cortex, plans behaviors not by specifying movements required for given actions, but rather the events that will result from those actions.
Mushiake, H. et al. 2006. Activity in the Lateral Prefrontal Cortex Reflects Multiple Steps of Future Events in Action Plans. Neuron, 50, 631–641.
http://www.eurekalert.org/pub_releases/2006-05/cp-tbe051106.php
Time really does fly when you’re busy
We all know that time goes faster when we’re busy, but though scientists have long tried to prove a link between attention and time estimation, it has been difficult to design an experimental manipulation that only manipulates attention and not other, potentially confounding variables. But now, it seems, two researchers have managed to do it – and the finding is clear. Results showed that an attentionally demanding search task produced a large underestimation of time, and that as the amount of attention increased, so did the underestimation of time. Note that the study involved prospective estimates of time (participants knew in advance that they would be asked how long the task took), rather than retrospective.
Chaston, A. & Kingstone, A. 2004. Time estimation: The effect of cortically mediated attention. Brain and Cognition, 55 (2), 286-289.
http://www.eurekalert.org/pub_releases/2004-08/uoa-spt080604.php
More light shed on how episodic memories are formed
A rat study has revealed more about the workings of the hippocampus. Previous studies have identified “place cells” in the hippocampus – neurons which become more active in response to a particular spatial location. Activity in the hippocampus while rats searched for food in a maze where the starting and ending point was varied, has found that, while some cells signaled location alone, others were also sensitive to recent or impending events – i.e., activation depended upon where the rat had just been or where it intended to go. This finding helps us understand how episodic memories are formed – how, for example, a spatial location can trigger a reminder of an intended action at a particular time, but not others.
Suzuki, W. A. (2003). Episodic Memory Signals in the Rat Hippocampus. Neuron, 40(6), 1055–1056. doi:10.1016/S0896-6273(03)00806-7
http://www.eurekalert.org/pub_releases/2003-12/msh-ta121503.php
Imaging confirms role of frontal lobes in planning
New research provides the first neuro-imaging evidence that the brain's frontal lobes play a critical role in planning and choosing actions.
Connolly, J.D., Goodale, M.A., Menon R.S. & Munoz, D.P. 2002. Human fMRI evidence for the neural correlates of preparatory set.Nature Neuroscience, 5 (12),1345–1352.
Role of prefrontal cortical regions in goal-directed behavior
Goal-directed behaviour depends on keeping relevant information in mind (working memory) and irrelevant information out of mind (behavioural inhibition or interference resolution). Prefrontal cortex is essential for both working memory and for interference resolution, but it is unknown whether these two mental abilities are mediated by common or distinct prefrontal regions. An imaging study found there was a high degree of overlap between the regions activated by load and interference, while no region was activated exclusively by interference. The findings suggest that, within the circuitry engaged by this task, some regions are more critically involved in the resolution of interference whereas others are more involved in the resolution of an increase in load.
Bunge, S.A., Ochsner, K.N., Desmond, J.E., Glover, G.H. & Gabrieli J.D.E. (2001). Prefrontal regions involved in keeping information in and out of mind. Brain, 124 (10), 2074-2086.