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Behavioral evidence has shown that older adults are less able to overcome proactive interference in memory than young adults. However, it is unclear what underlies this deficit. Imaging studies in the young suggest overcoming interference may require post-retrieval selection, a process thought to be mediated by the left mid-ventrolateral prefrontal cortex (VLPFC). Further, selection may resolve interference by enhancing or suppressing perceptual processing. The present fMRI study investigated whether age-related changes in VLPFC-mediated post-retrieval selection underlie older adults' deficits in overcoming interference in associative memory. Participants were tasked with remembering which associate (face or scene) objects were paired with most recently during study, under conditions of high or low proactive interference. Behavioral results demonstrated that as interference increased, memory performance decreased similarly across groups. Across groups, activity in the left mid-VLPFC also increased with interference. However, right PFC post-retrieval monitoring effects, but not left mid-VLPFC, distinguished successful vs. unsuccessful resolution of interference for both young and older adults, suggesting selection alone may be insufficient for successful resolution of interference. Age-related memory deficits may be related to reduced recruitment of relational processing effects in the dorsolateral and anterior PFC, as well as reduced memory retrieval effects in the hippocampus. Lastly, results showed evidence that selection may modulate perceptual processing of retrieved memory representations. Namely, activity in the parahippocampal place area (PPA) was greater when participants selected scene, versus face, regardless of accuracy. Further, older adults showed reduced effects in the PPA, possibly reflecting reduced differentiation of perceptual processing. Taken together, these results suggest age-related deficits in overcoming proactive interference are not related to post-retrieval selection, but reduced recruitment of PFC-mediated relational processes, coupled with reduced associative memory retrieval.

There is a large sex difference in the prevalence of attention deficit disorder; yet, little is known about sex differences in prefrontal attention circuitry. We investigated sex differences in the developmental nicotinic excitation of corticothalamic layer VI neurons, which play an important role in attention. Using whole cell recording in prefrontal brain slices, we examined the inward currents elicited by nicotinic stimulation in rodents. We found a prominent sex difference in the currents during the first postnatal month when males had significantly greater α4β2* nicotinic currents. Immunohistochemical analysis of α4YFP mice revealed no sex difference in the pattern or proportion of YFP-positive neurons in layer VI. Further electrophysiological experiments revealed that progesterone is able to rapidly and significantly suppress nicotinic currents in layer VI neurons. This is the first illustration at a cellular level that prefrontal attention circuitry is differently excited by nicotinic stimulation in males and females during development.

There is a large sex difference in the prevalence of attention deficit disorder; yet, little is known about sex differences in prefrontal attention circuitry. We investigated sex differences in the developmental nicotinic excitation of corticothalamic layer VI neurons, which play an important role in attention. Using whole cell recording in prefrontal brain slices, we examined the inward currents elicited by nicotinic stimulation in rodents. We found a prominent sex difference in the currents during the first postnatal month when males had significantly greater α4β2* nicotinic currents. Immunohistochemical analysis of α4YFP mice revealed no sex difference in the pattern or proportion of YFP-positive neurons in layer VI. Further electrophysiological experiments revealed that progesterone is able to rapidly and significantly suppress nicotinic currents in layer VI neurons. This is the first illustration at a cellular level that prefrontal attention circuitry is differently excited by nicotinic stimulation in males and females during development.

The feasibility of using real-time functional magnetic resonance imaging (fMRI) feedback regarding the level of activation in rostromedial prefrontal cortex (rMPFC) to learn improved regulation of this brain area was examined in a group of 5 young adults. Subjects received real-time feedback from the target brain region while engaging in a blocked-design task involving alternating blocks of attempted up-regulation and down-regulation of the target brain region. A transient negative emotional state was induced prior to each scanning session. Subjects completed 6 scanning sessions (a pre-training session, 4 feedback sessions and a post-training session - no feedback was provided for pre and post-training sessions). The guideline strategy provided to subjects of engaging in emotional awareness during up-regulation and bodily awareness during down-regulation was found to consistently regulate the region in the pre-training session prior to the fMRI feedback sessions. This finding is in line with the previously proposed role of the rMPFC in emotional awareness. In contrast to previous real-time fMRI findings, greater recruitment of the region was observed in the pre-training session compared to the post-training session, with a non-significant negative trend observed across feedback sessions. These results suggest that there may be limitations to which the feedback techniques successfully employed for other brain regions extend to yet unexplored brain regions.

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 4 uppsatser.

Thesis (M.A.)--University of Delaware, 2007. / Principal faculty advisor: Anna Klintsova, Dept. of Psychology. Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Thesis (M.A.)--University of Delaware, 2008. / Principal faculty advisor: Jeffrey B. Rosen, Dept. of Psychology. Includes bibliographical references.

Thesis (M.Sc.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Psychiatry. Title from pdf file main screen (viewed on October 31, 2009). Includes bibliographical references.