eprintid: 3093
rev_number: 7
eprint_status: archive
userid: 69
dir: disk0/00/00/30/93
datestamp: 2016-02-19 12:59:25
lastmod: 2016-09-13 10:00:02
status_changed: 2016-02-19 12:59:25
type: article
metadata_visibility: show
creators_name: Furey, Maura L.
creators_name: Ricciardi, Emiliano
creators_name: Schapiro, Mark B.
creators_name: Rapoport, Stanley I.
creators_name: Pietrini, Pietro
creators_id: 
creators_id: emiliano.ricciardi@imtlucca.it
creators_id: 
creators_id: 
creators_id: pietro.pietrini@imtlucca.it
title: Cholinergic Enhancement Eliminates Modulation of Neural Activity by Task Difficulty in the Prefrontal Cortex during Working Memory
ispublished: pub
subjects: RC0321
divisions: CSA
full_text_status: none
abstract: Previously, we demonstrated that enhancing cholinergic activity during a working memory (WM) task improves performance and reduces blood flow in the right anterior middle/superior frontal cortex, an area known to be important for WM. The purpose of this study was to evaluate the interaction between WM task demands and cholinergic enhancement on neural responses in the prefrontal cortex. Regional cerebral blood flow (rCBF) was measured using H215O and positron emission tomography, as 10 young healthy volunteers performed a parametrically varied match-to-sample WM for faces task. For each item, a picture of a face was presented, followed by a delay (1, 6, 11, or 16 sec), then by the presentation of two faces. Subjects were instructed to identify which face they previously had seen. For control items, nonsense pictures were presented in the same spatial and temporal manner. All conditions were performed during an intravenous infusion of saline and physostigmine (1 mg/hr). Subjects were blind to the substance being infused. Reaction time increased significantly with WM delay, and physostigmine decreased reaction time across delay conditions. Significant task-related rCBF increases during saline infusion were seen in superior frontal, middle frontal, and inferior frontal regions, and the response magnitudes in the regions increased systematically with task difficulty. In all of these prefrontal regions, physostigmine administration significantly reduced rCBF during task, particularly at longer task delays, so that no correlation between task delay and rCBF was observed. In the ventral visual cortex, physostigmine increased rCBF at longer task delays in medial regions, and decreased rCBF over delay conditions in lateral cortical areas. These results indicate that, during cholinergic potentiation, brain activity in prefrontal regions is not modulated by increases in WM task demands, and lends further support to the hypothesis that cholinergic modulation enhances visual processing, making the task easier to perform, and thus, compensate for the need to recruit prefrontal cortical regions as task demands increase.
date: 2008
date_type: published
publication: Journal of Cognitive Neuroscience
volume: 20
number: 7
publisher: MIT Press Journals
pagerange: 1342-1353
id_number: 10.1162/jocn.2008.20092
refereed: TRUE
issn: 0898-929X
official_url: http://www.mitpressjournals.org/doi/abs/10.1162/jocn.2008.20092?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&#.VscQ3PLhDIV
citation:   Furey, Maura L. and Ricciardi, Emiliano and Schapiro, Mark B. and Rapoport, Stanley I. and Pietrini, Pietro  Cholinergic Enhancement Eliminates Modulation of Neural Activity by Task Difficulty in the Prefrontal Cortex during Working Memory.  Journal of Cognitive Neuroscience, 20 (7).  pp. 1342-1353.  ISSN 0898-929X      (2008)