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PubMed2005

[Spectral feature-based hyperspectral RS image retrieval].

Oriented to the demands of vast RS information management for RS image retrieval, the applications of spectral features are discussed by taking hyperspectral RS image as an example. It is proposed that spectral features-based retrieval includes two modes: retrieval based on point mask an dpolygon mask. The most key issues in retrieval are spectral features extraction andsimilarity measure. The spectral vector can be used to retrieval directly, and the spectral angle and spectral information divergence (SID) are effective in similarity measure. The local maximum and minimum in reflectance spectral curve, corresponding to reflectance apex and absorption apex, can be used to retrieval also, but effective matching strategy should be adopted. The quantitative indexes for spectral curves such as moment, fractal and entropy are not suitable to retrieval because of poor similarity measure performance.

Algorithms↗

PubMed1996

Information retrieval patterns and needs among practicing general surgeons: a statewide experience.

Information retrieval has progressed from a reliance on traditional print sources to the modern era of computer databases and online networks. Surgeons, many from remote areas not served by professional medical libraries, must develop and maintain skills in information retrieval and management in both electronic and standard formats. One hundred thirty-three New Mexico general surgeons were surveyed to identify their information-seeking patterns in five areas: retrieval purposes, retrieval sources, barriers to access, techniques used, and continuing education needs. Ninety-nine (74.4%) surgeons responded to the survey. Ninety-five percent utilize professional meetings, the medical literature, and physician colleagues as information sources. Only 17% utilize the outreach services of the state's only medical school library. Common retrieval barriers were practice demands (71%), isolation from medical schools (30%), computer illiteracy (28%), and rural environment (25%). Continuing education topics related to information management would be valuable to 61% of the surgeons. Sixty-nine percent believe their current ability to access biomedical information is adequate, despite most frequently accessing their personal libraries for information related to decision-making or patient management. These data suggest that, despite significant information needs, surgeons have not embraced newer forms of information retrieval. It is imperative that surgeons acquire and maintain modern information retrieval skills as a means of remaining up-to-date in their profession. Professional surgical organizations and medical librarians should collaborate on these continuing education ventures.

Chi-Square Distribution↗

PubMed1995

An overview of statistical methods for the classification and retrieval of patient events.

Statistical methods that can support text retrieval are becoming an increasing focus of medical informatics activities. We overview our adaptation of existing knowledge sources to create pseudo-documents for concept based latent semantic indexing. Experience demonstrated this tack of limited practical value, since retrieval performance was invariably unsatisfactory. We discovered this was due in part to the introduction of a vocabulary gap between the queries and the cases we sought to retrieve. In part to address this problem, and to avail our large body of humanly coded text as a knowledge source, we developed a least squares fit alternative for the computer assisted indexing and retrieval of biomedical texts. This technique demonstrates equivalent or superior retrieval performance when compared to all other textual retrieval techniques. It does not depend upon elaborate knowledge bases, lexicons, or thesauri. It is a promising technique for classifying and retrieving the large volumes of clinical text.

Abstracting and Indexing↗

PubMed2004

Embolization and retrieval of the Amplatzer septal occluder.

Embolization and percutaneous retrieval of the Amplatzer septal occluder (ASO) after release have been reported. However, the incidence, the causes of embolization, and the methods for effective retrieval have not been systematically described. In a survey of the ASO company-designated proctors, the incidence of ASO embolization in this group's experience was 0.55% (21 embolizations in 3824 device placements) with a wide range of patient demographics, atrial septal defect (ASD) sizes, and device sizes. Most embolizations occurred because of inadequate rim or undersized devices. Of the 21 embolizations, 15 of the devices were retrieved percutaneously with a gooseneck snare without morbidity or mortality. Six were retrieved at surgery. Of the 21 patients, 12 had ASO closure of their ASDs, and 9 had surgical ASD closure. In vitro, all devices could be retrieved with sheathes 2 Fr sizes larger than their recommended delivery sheath. Any device larger than 26 mm could be retrieved with its delivery sheath. The ability to pull the snared button into a sheath was variable and was assisted by pulling the device from above with a bioptome and by using a rigid notched sheath. Because the incidence of ASO embolization is about 1 in 200 in the most experienced hands, all operators should be prepared with the techniques and equipment required for percutaneous ASO retrieval.

Adolescent↗

PubMed1993

The roles of similarity in transfer: separating retrievability from inferential soundness.

Similarity is universally acknowledged to be central in transfer, but recent research suggests that its role is complex. The present research attempts to isolate and compare the determinants of similarity-based access to memory and the determinants of the subjective soundness and similarity of a match. We predicted, based on structure-mapping theory, that subjective soundness would depend on the degree of shared relational structure, particularly higher-order structure such as causal bindings. In contrast, we predicted that memory retrieval would be highly sensitive to surface similarities such as common object attributes. To assess retrievability, in three studies, subjects were asked to read a large set of stories and were later given a set of probe stories that resembled the original stories in systematically different ways; e.g., purely relational analogies, surface-similarity matches, or overall (literal similarity) matches. Subjects were told to write out any of the original stories that came to mind. To assess subjective soundness, independent subjects (and also the same reminding subjects) were asked to rate the inferential soundness of each pair; i.e., how well inferences true of one story would apply to the other. As predicted, subjective soundness was highly related to the degree of common relational structure, while retrievability was chiefly related to the degree of surface similarity. Ratings of the similarity of the pairs did not predict the retrievability ordering, arguing against the possibility that the retrieval ordering simply reflected overall similarity. Further, a fourth study demonstrated that subjects given a forced-choice recognition task could discriminate between possible matches on the basis of relational structure, ruling out the possibility that the poor relational retrieval resulted from forgetting or failing to encode the relational structure. We conclude that there is a dissociation between the similarity that governs access to long-term memory and that which is used in evaluating and reasoning from a present match. We describe a model, called MAC/FAC ("Many are called but few are chosen"), that uses a two-stage similarity retrieval process to model these findings. Finally, we speculate on the implications of this view for learning and transfer.

Adult↗

PubMed2002

"Pray or Prey?" dissociation of semantic memory retrieval from episodic memory processes using positron emission tomography and a novel homophone task.

One problem in studying the neural basis of semantic memory using functional neuroimaging is that it is often difficult to disentangle activation associated with semantic memory retrieval from that associated with episodic memory encoding and retrieval. To address this issue, a novel homophone task was used in which subjects were PET scanned whilst learning a series of real words (e.g., prey). In a subsequent scan, the subjects were presented with homophone pairs (e.g., prey vs pray) and were required to choose the one that had been shown previously. In two corresponding baseline tasks, the subjects were scanned whilst learning and recognizing pronounceable nonwords. Thus, while all of these tasks recruited either episodic memory encoding or retrieval processes, only the homophone tasks involved semantic memory retrieval. A conjunction analysis designed to isolate activation associated with semantic memory retrieval, revealed changes in several left lateral frontal regions (BA 9/10, 9/45), the left middle temporal cortex (BA 21), and in the left inferior temporoparietal cortex (BA 39). In contrast, a conjunction analysis designed to isolate activation associated with episodic memory encoding, revealed significant changes in the left hippocampus, as well as in the frontopolar cortex (BA 10) bilaterally, the left inferior parietal cortex (BA 40), and the left superior temporal gyrus (BA 22, 28). The present results clarify and extend recent attempts to understand the neural basis of semantic memory retrieval, by actively controlling for the confounding effects of episodic memory encoding and retrieval processes.

Acoustic Stimulation↗

PubMed1999

Neuronal correlates of encoding and retrieval in episodic memory during a paired-word association learning task: a functional magnetic resonance imaging study.

The investigation of memory function using functional magnetic resonance imaging (fMRI) is an expanding field of research. The aim of this study was to demonstrate brain-activity patterns related to a word-pair association task employing a whole-brain EPI sequence. Six right-handed, healthy male volunteers (mean age: 27.5 years) took part in the study. fMRI was performed at a field strength of 1. 5 Tesla with 26-32 slices parallel to the AC-PC line, depending on individual brain size. Distributed brain regions were activated in episodic encoding and retrieval with similarities, but also (distinct) differences in activation patterns. Bilateral prefrontal cortical areas were involved when comparing encoding as well as retrieval to the reference condition (nonsense words). Furthermore, activation was observed in cerebellar areas during encoding, and activation in bilateral parietal areas (precuneus and inferior parietal cortex) was differentially more pronounced during retrieval. The activation of left dorsomedial thalamus during retrieval of high imagery-content word-pair associates may point to the role of this structure in episodic retrieval. The direct cognitive subtraction of encoding minus retrieval yielded a differentially larger left prefrontal activation. There was a differentially higher right prefrontal activation during retrieval than during encoding, underlining the proposed right/left asymmetry for episodic memory processes.

Adult↗

PubMedDate not supplied

Embolization and transcatheter retrieval of coils and devices.

Embolizations of coils and devices are well-known complications of transcatheter procedures performed in order to occlude extracardiac or intracardiac shunts. A review of the literature and of our experience was performed to provide a succinct review of existing transcatheter retrieval techniques. After embolization of a coil or device, the appropriate initial procedure involves repositioning of the coil or device using a snare or bioptome to a location where harm to the patient is minimized. The subsequent retrieval technique depends on the characteristics of the coil or device involved. Coils may be retrieved using a bioptome or a snare. Devices must be snared, often in specific places. Both may be pulled into long or short, appropriately sized retrieval sheaths. To minimize potential morbidities associated with these retrievals and to maximize efficacy of retrieval, operators performing transcatheter coil or device occlusions must be familiar with retrieval techniques.

Cardiac Catheterization↗

PubMedDate not supplied

Retrievable IVC square stent filter: experimental study.

PURPOSE: In vitro and in vivo evaluation of a new retrievable, home-made, inferior vena cava (IVC) Square stent filter (SSF) with two trapping levels. METHODS: In vitro, the SSF was compared in a flow model with the stainless steel Greenfield filter (SGF) for emboli-trapping efficiency by serially passing 300 emboli of 3 and 6 mm in diameter and 15-30 mm in length in each type of filter. Nine swine were used for the in vivo testing of the SSF for deployment and retrievability, emboli-trapping efficiency, stability, and self-centering ability and two were used (total of 11 swine) for testing repositioning and retrievability of the SSF at 2 weeks and for gross and histologic IVC changes at 2 months. RESULTS: In vitro, the SSF and SGF had similar efficiency in trapping large emboli but the SSF had significantly better efficiency than the SGF for trapping all sizes of emboli (91.7% vs 81%), medium size emboli (93% vs 80%), and small emboli (86% vs 69%). Efficiency decreased in both filters from the first to the fifth embolus in each series but was still significantly better for the SSF. With the SSF, 89% of emboli were caught at the primary and 11% at the secondary filtration level. In the nine animals used for acute studies, the SSF was easily placed in all 27 attempts, assumed a central position 26 times, and was easily retrieved in 21 of 22 attempts. One tilted filter needed additional manipulation for retrieval. During emboli injection in five swine, the SSF had 97.2% emboli-trapping efficiency and demonstrated good stability. In the two animals used for longer-term evaluation, the filters were easily retrieved 2 weeks after implantation. Histologic evaluation at 2 months showed neointimal proliferation around the SSF wires in contact with the IVC wall, which was otherwise normal. CONCLUSION: The SSF is a promising filter. It is easy to place and retrieve, is stable after placement, and has high efficiency for trapping emboli. Promising results justify further experimental and eventual clinical studies with a commercially manufactured SSF.

Animals↗

PubMed2006

Removal of retrievable self-expandable urethral stents: experience in 58 stents.

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n = 21), stent migration (n = 19), formation of tissue hyperplasia around or inside of the stent (n = 14), stent deformity (n = 3), and severe pain (n = 1). The mean time the stents remained in place was 64.8 +/- 42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n = 2), untied drawstrings (n = 3), and polyurethane membrane disruption/separation (n = 4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use.

Adult↗

PubMed2006

Retrievable inferior vena cava filters: initial clinical results.

Anticoagulation is the accepted therapy for patients with thromboembolic disease. When contraindications to anticoagulant therapy are present, however, interruption of the inferior vena cava (IVC) may prevent pulmonary embolism (PE). The objective of this study was to report our early technical and clinical results with retrievable IVC filters (IVCFs) for the prevention of PE. One hundred and twenty-seven multitrauma patients between December 1, 2002, and December 31, 2004, underwent placement of Gunther-Tulip (n = 49), Recovery (n = 41), or OptEase (n = 37) retrievable IVCFs under real-time intravascular ultrasound (IVUS) guidance. All patients had abdominal X-rays to verify filter location. Prior to IVCF retrieval, all patients underwent femoral vein color flow ultrasonography to rule out deep vein thrombosis (DVT) and vena-cavography to assess the IVCF for trapped emboli, filter tilt, or retrained thrombus. Thirty-nine patients died of their injuries; no deaths were related to IVCF placement. One PE occurred during follow-up after filter retrieval, and two femoral vein insertion-site DVTs occurred. One hundred twenty (94.4%) of IVCFs were placed without complication at the L2-3 level, as verified by abdominal X-rays. Filter-related complications included three groin hematomas (2.9%) and three IVCFs misplaced in the right iliac vein early in our experience (2.3%); these filters were uneventfully retrieved and replaced in the IVC within 24 hr. Sixty-six patients underwent uneventful retrieval of IVCFs after DVT or PE anticoagulation prophylaxis was initiated. Forty-five IVCFs were not removed: 41 due to contraindications due to anticoagulation and four because of trapped thrombus within the filter. The role of retrievable IVCFs continues to evolve, but in this study of 127 patients, prophylactic temporary IVCF placement was simple and safe, prevented fatal PE, and served as an effective "bridge" to anticoagulation. Further investigation of this bedside IVUS technique and the role of temporary IVCFs in different patient populations is warranted.

Adolescent↗

PubMed1993

Effect of changes in the intrahippocampal vasopressin on memory retrieval and relearning.

Previous results have indicated the involvement of the hippocampus in the behavioral effect of vasopressin, with a better effect when the peptide was injected in the ventral part rather than in the dorsal part of this structure. The purpose of the present study was to determine, in mice, whether the injection of vasopressin or vasopressin antisera into the ventral hippocampus has an effect on retrieval and relearning of a Go-No Go visual discrimination task and, if so, to what extent this involvement of the vasopressin system depends on the integrity of the medial amygdaloid nucleus, the main source of vasopressin innervation in the ventral hippocampus in rats. In the first experiment, we showed that pretest microinjection of Arg8-vasopressin (25 pg per animal) in the ventral hippocampus alleviated forgetting observed after a prolonged interval of 24 days between the acquisition of information and its retrieval. This enhancing effect was characterized by better retrieval and relearning in vasopressin-treated mice than those in control mice. Conversely, an immunoneutralization of endogenous vasopressin in the ventral hippocampus by the microinjection of vasopressin antisera (1/10 dilution) resulted in the drastic impairment of retrieval and relearning. Since the lack of an observable change in a locomotor activity test might explain these results, we postulated that the vasopressin system in the ventral hippocampus is involved in retrieval processes. Moreover, the effects of these treatments in a nonassociative context suggest that the effect of vasopressin could be dependent on the contextual paradigm used. In the second experiment, we localized vasopressin immunoreactive fibers in the CA1-CA2 ventral hippocampal fields and CA4-gyrus dentatus region, and vasopressin perikarya in the medial amygdaloid nucleus. Then, the projection of vasopressin cells from the medial amygdaloid nucleus to the ventral hippocampus was evaluated by studying changes in vasopressin immunoreactive fiber density in the ventral hippocampus after a lesion of the medial amygdaloid nucleus. The results showed the almost complete disappearance of vasopressin fibers in the CA1-CA2 hippocampal fields after the medial amygdaloid lesion. In contrast, vasopressin fibers in the CA4 and gyrus dentatus region remain unchanged. On the basis of our immunohistochemical results, our third experiment tested the repercussions of the change in vasopressin innervation in the ventral hippocampus, due to the medial amygdaloid lesion, on the effects of exogenously administered vasopressin on both retrieval and relearning processes. The medial amygdaloid lesion induced a deleterious effect on retrieval without really affecting the ability to relearn. No observable change in locomotor activity could explain this impairment.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2006

Thorough sonographic oocyte retrieval during in vitro fertilization produces results similar to ovarian wedge resection in patients with clomiphene citrate-resistant polycystic ovarian syndrome.

OBJECTIVE: The purpose of this study was to compare the effectiveness of a thorough sonographic oocyte retrieval to a routine in vitro fertilization retrieval to induce ovulation, pregnancy, and endocrine changes in patients with polycystic ovarian syndrome in their post-in vitro fertilization cycles. STUDY DESIGN: Sixty-four patients from a tertiary infertility clinic, with clomiphene citrate-resistant polycystic ovarian syndrome and who were undergoing in vitro fertilization, were assigned randomly into 2 groups. Group 1 (n = 34) had a thorough (every possible follicle punctured) sonographic oocyte retrieval, and group 2 (n = 30) had a routine (only follicles that were likely to contain oocytes) in vitro fertilization retrieval. These patients who did not conceive in their in vitro fertilization cycle were monitored with ultrasound scanning for evidence of ovulation, pregnancy, before and after day 3 gonadotropin, and steroid hormone levels. Analysis of variance and the Student t test were used for statistical significance. RESULTS: Ovulation rates of 53% (18/34) and cumulative pregnancy rate of 44% (8/18) were observed in group 1, with no ovulations in group 2. Significant decreases in luteinizing hormone/FSH ratio (4.1 to 1.7) and testosterone (1.2 to 0.7 ng/mL) occurred after treatment in the thorough sonographic oocyte retrieval group, with no change after routine in vitro fertilization. Operating time was increased significantly in the thorough sonographic oocyte retrieval group (45 vs 24 minutes) in group 2. CONCLUSION: Thorough sonographic oocyte retrieval during in vitro fertilization cycle can produce significant improvements in the endocrinologic abnormalities, ovulation, and pregnancies that are comparable with ovarian wedge resection in patients with clomiphene citrate-resistant polycystic ovarian syndrome.

Clomiphene↗

PubMed2006

Extended interval for retrieval of vena cava filters is safe and may maximize protection against pulmonary embolism.

BACKGROUND: Retrieval of optional vena cava filters (VCF) has been demonstrated to be safe and feasible in injured patients in 4 recent studies. However, 2 pulmonary emboli PE were reported in these studies with mean implant durations less than 19 days. In light of these occurrences, we changed our practice for VCF retrieval when patients had recovered from their injuries and at least 30 days after their discharge, or had been stable on therapeutic anticoagulation for deep venous thrombosis (DVT) or PE for at least 2 weeks. The aim of the current study was to assess the safety of this approach. METHODS: A review of prospectively collected data on optional VCF over a 16-month period. The filters were inserted prophylactically per an institutional practice guideline or for the presence of DVT or PE with a contraindication and/or complication to anticoagulation. All patients underwent duplex imaging of the lower extremities and had pre- and post- retrieval cavagrams. Demographics, duration of implantation, and complications were recorded. RESULTS: Eighty-three patients had optional VCF inserted since the change in our clinical practice. Indications included prophylaxis for high-risk trauma patients (n = 58), DVT or PE with acute contraindication to therapeutic anticoagulation (n = 22), or complications of anticoagulation (n = 3). Two patients developed lower extremity DVT after filter insertion and 1 patient developed a vena cava thrombosis. Retrieval was successful in 47 of 54 cases (87%) attempted. Median implantation duration was 142 days (range 17-475). A filter strut fracture occurred during retrieval without further consequences. No post-insertion or post-retrieval PE occurred in this study. CONCLUSION: Extended intervals for retrieval of VCF are safe and may maximize protection against pulmonary embolism.

Adolescent↗

PubMed2006

Early experience with the retrievable OptEase vena cava filter in high-risk trauma patients.

OBJECTIVES: Prophylactic vena cava filters (VCF) are efficient in preventing pulmonary embolism. Filter retrieval avoids the potential long-term complications of permanent VCF. Clinical evaluation was focused on filter-related complications and feasibility of retrieval in high-risk trauma patients. METHODS: Analysis of single-institution consecutive case series of patients who received a prophylactic OptEase VCF after multiple trauma between 08/2003 and 12/2004. Data were collected prospectively. RESULTS: A total of 37 OptEase filters were inserted prophylactically after multiple trauma (median patient age 35 years, range, 17-73 years, median ISS 41, range, 17-59). All patients had contraindications for pharmacological prophylaxis for thromboembolic events. 32 filters (86%) were retrieved after 16 days (range, 7-25 days). 12 of 33 filters (36%) demonstrated trapped clots/thrombosis within the filter structure on pre-retrieval cavography. Two patients received anticoagulation before filter retrieval due to filter thrombosis (6%). Symptomatic PE was observed in 1 patient (3%) 5 days after VCF retrieval. Minor caudal filter migration was observed in 1 patient (3%). Overall mortality was 3%. CONCLUSIONS: Retrieval of the OptEase filter is safe and feasible. Temporary filter placement avoids possible long-term complications of permanent VCF. It is an efficient form of PE prophylaxis when temporary contraindications to anticoagulation are present.

Adolescent↗

PubMed2004

Transmyometrial oocyte retrieval and pregnancy rates.

OBJECTIVE: To determine whether transvaginal, ultrasound-guided oocyte retrieval performed through the myometrium has a negative impact on IVF pregnancy rates. DESIGN: Retrospective cohort study. SETTING: Academic hospital and research center. PATIENT(S): A total of 5,115 IVF cycles performed at the Brigham and Women's Hospital between 1998 and 2001 were evaluated. In 85 cycles (1.7%), the oocyte retrieval needle passed through the myometrium because of ovarian position during retrieval. Each of these cases was matched to a control cycle by age, attempt number, and date of retrieval. INTERVENTION(S): Transmyometrial oocyte retrieval. MAIN OUTCOME MEASURE(S): Pregnancy rates. RESULT(S): There were no statistically significant differences in pregnancy rates between cases and controls. Cases were more likely than controls to have underlying tubal disease and adhesions as the primary cause of infertility. The groups did not differ significantly in terms of age, attempt number, estradiol level, follicle number, days stimulated, ampules of gonadotropins administered, number of eggs, number of embryos, or quality of embryos. CONCLUSION(S): Transmyometrial oocyte retrieval is an uncommon event. Clinicians and patients can be reassured that transmyometrial oocyte retrieval does not seem to decrease IVF pregnancy rates; however, a larger study with greater power might reveal a statistically significant difference.

Adult↗

PubMed2004

Characterizing spatial and temporal features of autobiographical memory retrieval networks: a partial least squares approach.

Conway (Conway, M.A., 1992. A structural model of autobiographical memory. In: Conway, M.A., Spinnler, H., Wagenaar, W.A. (Eds.), Theoretical Perspectives on Autobiological Memory. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 167-194) proposed that two types of autobiographical memories (AMs) exist within a hierarchical AM system: unique, specific events and repeated, general memories. There is little research on whether retrieval of these AMs relies on different neural substrates. To investigate this issue, we used a multivariate image analysis technique, spatiotemporal partial least squares (PLS), to identify distributed patterns of activity most related to AM tasks that we have found to be associated with a medial and left-lateralized network. Using PLS, specific and general memories were more strongly associated with different parts of this retrieval network. Specific AM retrieval was associated more with activation of regions involved in imagery in episodic memory, including the left precuneus, left superior parietal lobule and right cuneus, whereas general AM retrieval was associated with activation of the right inferior temporal gyrus, right medial frontal cortex, and left thalamus. These two patterns emerged at different lags after stimulus onset, with the general AM pattern peaking between 2 and 6 s, and the specific AM pattern between 6 and 8 s. These lag differences are consistent with Conway's theory which posits that general AMs are the preferred level of entry to the AM system. A seed PLS analysis revealed that the regions functionally connected to the hippocampus during retrieval did not differentiate specific from general AM retrieval, which confirms our earlier univariate analysis indicating that some aspects of the memory retrieval network are shared by these memories.

Adult↗

PubMed2004

Dorsolateral prefrontal cortex involvement in memory post-retrieval monitoring revealed in both item and associative recognition tests.

Post-retrieval monitoring is a process that contributes to episodic memory retrieval by allowing people to evaluate the relevance of retrieved information in relation to the task requirements. Previous studies have suggested that post-retrieval monitoring is supported by the dorsolateral prefrontal cortex (DLPFC). In this study, we used functional magnetic resonance imaging (fMRI) to evaluate involvement of the DLPFC in post-retrieval monitoring in two different recognition tests (item recognition and associative recognition). The item recognition memory test required subjects to make old/new judgments and the associative recognition memory test required them to make intact/rearranged judgments. Because the post-retrieval monitoring demand increases during old (hits) relative to new (correct rejections) item recognition trials, and also during rearranged (correct rejections) relative to intact (hits) associative recognition trials, we evaluated the brain activation associated with the interaction of Memory test (item versus associative) by Recognition trial (hit versus correct rejection). As expected, the DLPFC was activated in this interaction as well as for both old relative to new item recognition trials and rearranged relative to intact associative recognition trials. This study provides strong evidence that DLPFC activation supports post-retrieval monitoring across different types of recognition tasks.

Adult↗