Objective Verbal memory difficulties are common among individuals with late-life depression

Objective Verbal memory difficulties are common among individuals with late-life depression (LLD) though there is limited knowledge about disruptions to underlying cerebral circuitry. comparisons. An important region in which the LLD group displayed greater activation than the NDC group was in substandard frontal gyrus (IFG) an area involved in cognitive control and controlled semantic/phonological retrieval and analysis; this region may be critical for LLD patients to consolidate Hesperadin encoded words into memory. Conclusions Functional irregularities found in LLD patients may reflect different modes of processing to-be-remembered information and/or early changes predictive of incipient cognitive decline. Future studies might consider mechanisms that could contribute to these functional differences including HPA-axis functioning and vascular integrity and utilize longitudinal designs in order to understand whether functional changes are predictive of incipient cognitive decline. tests and employed a statistical threshold of < .05. We investigated group differences in recall hits recall intrusion errors recognition hits acknowledgement false positives d′ (a sensitivity index that provides the separation between means of the transmission and noise distributions compared Hesperadin against the standard deviation of the noise distribution) and (a measure of response bias). In calculating d′ and for recall total number of possibly acknowledged items was used to generate the false alarm rate. There was one outlier in the NDC group for acknowledgement false positive errors and this was winsorized so that it was equivalent to the next most poorly performing person within the NDC group. For VBM analysis a two-sample test was performed to assess for group differences in hippocampal volume Hesperadin and functional regions found to be more active in the NDC group relative to the MDD group. To assure that volumetric differences of relevant regions was minimal between the two groups we employed a liberal threshold of < .05 minimum threshold cluster of 80mm3 for all those VBM analyses. Functional images were normalized to fit a MNI canonical template and were smoothed at a 5 mm FWHM. For fMRI data three contrasts of interest were run. First word encoding blocks were compared to silent rehearsal blocks. Second event-related encoding of correctly recalled words were compared to non-recalled words as well as the inverse (encoding of non-recalled compared to recalled words). Finally we tested event-related acknowledged words compared to not acknowledged words as well as the inverse (encoding of non-recognized compared to acknowledged terms). Group analyses with t assessments were conducted with these contrasts run in SPM8. AlphaSim correction (1000 iterations) was utilized for all whole brain analyses balancing height (< .003) and extent (264 mm3) thresholds to achieve a whole brain correction of < .05. For the hippocampal ROI analysis a threshold of < .05 80 Hesperadin was utilized. In a post hoc analysis of activation in the inferor frontal gyrus (IFG) the MarsBaR toolbox (Brett et al. 2002 was used to extract mean transmission switch in IFG region of interest (ROI) for correlation with performance steps of recall acknowledgement d′ and > .31; observe Figure 2). The two groups did not differ in d′ for recall (LLD = 1.11 = .67; NDC = 1.12 = .62) β for recall (LLD = .94 = .05; NDC = .93 = .06) d′ for acknowledgement (LLD = 1.39 = .56; NDC = 1.32 = .58) nor Rabbit Polyclonal to HEN1/2. β for acknowledgement (LLD = .47 SD = .48; Hesperadin NDC = .46 SD = .50). Physique 2 Overall performance DURING RECALL AND Acknowledgement TASKS. Illustrates equivalent overall performance for recall hits and intrusion errors and recognition hits and (FP) errors (all ps > .31). Voxel Based Morphometry Hippocampal volume corrected for whole brain volume was not significantly different between LLD and NDC. The volumes of functional regions found to be more active in NDC relative to LLD (below) were also not significantly different between LLD and NDC. fMRI Activation During Encoding Minus Rehearsal of Words LLD activation for encoding-rehearsal foci are outlined in Table 2 as is usually NDC activation. Relative to LLD greater activation was found in NDC in right middle frontal insula cuneus and caudate left dorsal cingulate precuneus and putamen and bilateral globus.