Professor Emeritus, Department of Psychology
Ph.D. University of Michigan
M.S. University of Washington
B.S. University of Washington
Research Interests: Cognitive-Neuroscience; Neural mechanisms and structures underlying selective attention
Overview: Michael Posner is Professor Emeritus at the University of Oregon and Adjunct Professor at the Weill Medical College in New York (Sackler Institute).
Dr. Posner's current work deals with genetic and experiential factors in the development of brain networks underlying attention and learning. We are currently examining how changes in white matter might contribute to improved performance. In one study conducted together with the Niell lab we are imposing a theta rhythm on cells in the anterior cingulate of the mouse and examining whether the resultant activity leads to improved myelination in pathways near the cingulate. We are also examining if epigenetic factors related to methylation might account for individual differences in this process.
Differential Involvement of Three Brain Regions During Mouse Skill Learning.
eNeuro. 2019 Aug 01;:
Authors: Weible AP, Posner MI, Niell CM
Human skill learning is marked by a gradual decrease in reaction time and errors as the skill is acquired. To better understand the influence of brain areas thought to be involved in skill learning, we trained mice to associate visual-spatial cues with specific motor behaviors for a water reward. Task acquisition occurred over weeks and performance approximated a power function as often found with human skill learning. Using optogenetics we suppressed the visual cortex, anterior cingulate cortex, or dorsal hippocampus on 20% of trials at different stages of learning. Intermittent suppression of the visual cortex greatly reduced task performance on suppressed trials across multiple stages but did not change the overall rate of learning. In accord with some recent models of skill learning, anterior cingulate cortex suppression produced higher error rates on suppressed trials throughout learning the skill, with effects intensifying in the later stages. This would suggest that cognitive influences mediated by the anterior cingulate continue throughout learning. Suppression of the hippocampus only modestly affected performance, with largely similar effects seen across stages. These results indicate different degrees of visual cortex, anterior cingulate cortex, and dorsal hippocampus involvement in acquisition and performance of this visual-spatial task, and that the structures operate in parallel, and not in series, across learning stages.SIGNIFICANCE STATEMENT Mice resemble humans with improvements in accuracy and speed during skill learning. Through optogenetics, we can suppress different regions of the mouse brain at different stages of training to better understand when each region contributes to learning. Here we found that visual cortex suppression reduced accuracy across all training stages. Suppressing anterior cingulate cortex, a region thought to be important for attention early in training, also reduced accuracy throughout learning. Suppressing the hippocampus, a structure critically involved in associative learning, affected performance more modestly. These findings reveal parallel, rather than serial, involvement of these three structures in a mouse model of skill learning.
PMID: 31371454 [PubMed - as supplied by publisher]
Frontal theta activity and white matter plasticity following mindfulness meditation.
Curr Opin Psychol. 2019 Apr 18;28:294-297
Authors: Tang YY, Tang R, Rothbart MK, Posner MI
Both brain alpha and theta power have been examined in the mindfulness meditation literature and suggested as key biological signatures that potentially facilitate a successful meditative state. However, the exact role of how alpha and theta waves contribute to the initiation and maintenance of a meditative state remains elusive. In this perspective paper, we discuss the role of frontal midline theta (FMθ) activity in brain white matter plasticity following mindfulness meditation. In accordance with the previous studies in humans, we propose that FMθ activity indexes the control needed to maintain the meditation state; whereas alpha activity is related to the preparation needed to achieve the meditative state. Without enough mental preparation, one often struggles with and has difficulty achieving a meditative state. Animal work provides further evidence supporting the hypothesis that mindfulness meditation induces white matter changes through increasing FMθ activity. These studies shed light on how to effectively enhance brain plasticity through mindfulness meditation.
PMID: 31082635 [PubMed - as supplied by publisher]