Altered hippocampal kainate-receptor mRNA levels in temporal lobe epilepsy patients

This study determined whether hippocampal kainate (KA) receptor mRNA levels were increased or decreased in temporal lobe epilepsy patients compared with nonseizure autopsies. Hippocampal sclerosis (HS; n = 17), nonsclerosis (non-HS; n = 11), and autopsy hippocampi (n = 9) were studied for KA1-2 and GluR5-7 mRNA levels using semiquantitative in situ hybridization techniques, along with neuron densities. Compared with autopsy hippocampi, HS and non-HS cases showed decreased GluR5 and GluR6 hybridization densities per CA2 and/or CA3 pyramid. Furthermore, HS patients demonstrated increased KA2 and GluR5 hybridization densities per granule cell compared with autopsy hippocampi. These findings indicate that chronic temporal lobe seizures were associated with differential changes in hippocampal KA1-2 and GluR5-7 hybridization densities that vary by subfield and pathology group. In temporal lobe epilepsy patients, these results support the hypothesis that pyramidal cell GluR5 and GluR6 mRNA levels are decreased as a consequence of seizures, and in HS patients granule cell KA2 and GluR5 mRNA levels are increased in association with aberrant fascia dentata mossy fiber sprouting and/or hippocampal neuronal loss.     

The effects of irrelevant stimuli: 1. The time course of stimulus–stimulus and stimulus–response consistency effects with Stroop-like stimuli, Simon-like tasks, and their factorial combinations.

[Correction Notice: An erratum for this article was reported in Vol 36(3) of Journal of Experimental Psychology: Human Perception and Performance (see record 2010-10162-008). A key reference for coauthor Gregory T. Stevens’s PhD dissertation was omitted and appears in the correction.] The effects of Simon- and Stroop-like stimuli are examined in isolation and in factorial combinations with different delays between the presentation of the irrelevant and the relevant stimuli. The effects of irrelevant stimuli have different time courses depending on whether they overlap with the relevant stimulus (stimulus-stimulus overlap, Dimensional Overlap [DO] Type 4) or with the response (stimulus-response overlap, DO Type 3). A new, computational, parallel distributed processing (PDP)-type model, DO'97, is presented that is based on the original DO model (S. Kornblum, 1994; S. Kornblum, T. Hasbroucq, & A. Osman, 1990), and it postulates a nonmonotone irrelevant stimulus activation function in addition to 2 temporally ordered, serial, nonindependent stages: a stimulus processing stage and a response production stage. DO'97 is able to simulate the temporal dynamic characteristics of the processes, with good fits to the empirical data of this study and other published studies, at the level of means, variances, and distributional plots. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speed and accuracy of saccadic eye movements: Characteristics of impulse variability in the oculomotor system.

Dynamic characteristics observed in the trajectories of saccadic eye movements revealed systematic variability of the force pulses used to move the eyes. This variability causes saccades to exhibit a linear speed–accuracy trade-off: As the average distance and duration of saccades toward specified target points increase, the standard deviations of saccadic-movement endpoints increase linearly with the saccades' average velocity. The linear trade-off, and other observed stochastic properties of saccades, may be attributed to noise in neuromotor processes and may be described in terms of an impulse-variability model originally designed for characterizing limb movements. According to the model, both eye and limb movements are controlled through stochastic force and time parameters that govern movement kinematics. Such an account may promote a unified conceptual framework for understanding a wide range of motor behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computed tomography-guided biopsy of the spine. A review of 103 patients

PURPOSE: This study was performed to evaluate relations among neutrophil count (including its course), type of lesion, treatment, and prognosis in patients with leukemia and perianal infection. METHODS: Medical records of patients with acute and chronic leukemia who were followed during the last five years were reviewed retrospectively. RESULTS: The incidence of perianal infections was found to be 7.3 percent in 259 patients with acute leukemia. Only 1 of 108 patients with chronic leukemia suffered from this problem. Twenty percent of all patients with this complication died as a result of sepsis. Perianal abscess was the sole and obligatory indication for surgical treatment in our patients. There were ten patients in each treatment group. The operative group had better results (9 cures, 1 complication vs. 3 cures, 7 complications). However, median neutrophil count at diagnosis was notably higher in the operative group 1,280/mm3 vs. 96/mm3; P = 0.075). Also, significantly more frequent abscess formations and, consequently, operative treatments were performed in patients with a period of normal neutrophil counts during the infection compared with continuously neutropenic patients (9 operative, 4 nonoperative vs. 1 operative, 6 nonoperative; P = 0.057). Ten cures, three complications vs. two cures, five complications (3 mortalities) were present in patients with and without normal neutrophil counts, respectively (P = 0.062). When only severely neutropenic patients were considered, four patients in the surgery group had normal neutrophil counts before or shortly after surgery. However, only two of eight patients with perianal cellulitis had normal counts during full-course infection (P = 0.06). CONCLUSIONS: The course of the neutrophil count during infection was an important factor affecting the perianal lesion, and indirectly, choice of treatment and prognosis. A period of normal counts during infection usually led to well bordered and fluctuant lesions, and the prognosis was acceptable with operative treatment. However, continuously neutropenic patients developed nonfluctuating indurations. We found disappointing results with nonoperative treatment of such patients. In all studies, regarding treatment of perianal infections in neutropenic patients, the course of the neutrophil count and indications for surgery should be clarified to get reliable results.     

Hippocampal AMPA and NMDA mRNA levels and subunit immunoreactivity in human temporal lobe epilepsy patients and a rodent model of chronic mesial limbic epilepsy

This study compared temporal lobe epilepsy patients, along with kindled animals and self sustained limbic status epilepticus (SSLSE) rats for parallels in hippocampal AMPA and NMDA receptor subunit expression. Hippocampal sclerosis patients (HS), non-HS cases, and autopsies were studied for: hippocampal AMPA GluR1-3 and NMDAR1&2b mRNA levels using in situ hybridization: GluR1, GluR2/3, NMDAR1, and NMDAR2(a&b) immunoreactivity (IR); and neuron densities. Similarly, spontaneously seizing rats after SSLSE, kindled rats, and control animals were studied for: fascia dentata neuron densities: GluR1 and NMDAR2(a&b) IR; and neo-Timm's staining. In HS and non-HS cases, the mRNA hybridization densities per granule cell, as well as molecular layer IR, showed increased GluR1 (relative to GluR2/3) and increased NMDAR2b (relative to NMDAR1) compared to autopsies. Likewise, the molecular layer of SSLSE rats with spontaneous seizures demonstrated more neo-Timm's staining, and higher levels of GluR1 and NMDAR2(a&b) IR compared to kindled animals and controls. These results indicate that hippocampal AMPA and NMDA receptor subunit mRNAs and their proteins are differentially increased in association with spontaneous, but not kindled, seizures. Furthermore, there appears to be parallels in fascia dentata AMPA and NMDA receptor subunit expression between HS (and non-HS) epileptic patients and SSLSE rats. This finding supports the hypothesis that spontaneous seizures in humans and SSLSE rats involve differential alterations in hippocampal ionotrophic glutamate receptor subunits. Moreover, non-HS hippocampi were more like HS cases than hippocampi from kindled animals with respect to glutamate receptors; therefore, hippocampi from kindled rats do not accurately model human non-HS cases, despite some similarities in neuron densities and mossy fiber axon sprouting.     

Integration of Self‐Assembled Epitaxial BiFeO3–CoFe2O4 Multiferroic Nanocomposites on Silicon Substrates

Perovskite‐spinel epitaxial nanocomposite thin films are commonly grown on single crystal perovskite substrates, but integration onto a Si substrate can greatly increase their usefulness in devices. Epitaxial BiFeO₃–CoFe₂O₄ nanocomposites consisting of CoFe₂O₄ pillars in a BiFeO₃ matrix are grown on (001) Si with two types of buffer layers: molecular beam epitaxy (MBE)‐grown SrTiO₃‐coated Si and pulsed‐laser‐deposited (PLD) Sr(Ti_0.65Fe_0.35)O₃/CeO₂/yttria‐stabilized ZrO₂/Si. The nanocomposite grows with the same crystallographic orientation and morphology as that observed on single crystal SrTiO₃ when the buffered Si substrates are smooth, but roughness of the Sr(Ti_0.65Fe_0.35)O₃ promoted additional CoFe₂O₄ pillar orientations with 45° rotation. The nanocomposites on MBE‐buffered Si show very high magnetic anisotropy resulting from magnetoelastic effects, whereas the hysteresis of nanocomposites on PLD‐buffered Si can be understood as a combination of the hysteresis of the Sr(Ti_0.65Fe_0.35)O₃ film and the CoFe₂O₄ pillars.     

Correction to Kornblum et al.

Reports an error in "Dimensional overlap: Cognitive basis for stimulus-response compatibility--A model and taxonomy" by Sylvan Kornblum, Thierry Hasbroucq and Allen Osman (Psychological Review, 1990[Apr], Vol 97[2], 253-270). In this article, erroneous data were included in Figure 2. The figure and original caption are corrected in the erratum. (The following abstract of the original article appeared in record 1990-18942-001.) The classic problem of stimulus–response (S-R) compatibility (SRC) is addressed. A cognitive model is proposed that views the stimulus and response sets in S-R ensembles as categories with dimensions that may or may not overlap. If they do overlap, the task may be compatible or incompatible, depending on the assigned S-R mapping. If they do not overlap, the task is noncompatible regardless of the assigned mapping. The overlapping dimensions may be relevant or not. The model provides a systematic account of SRC effects, a taxonomy of simple performance tasks that were hitherto thought to be unrelated, and suggestive parallels between these tasks and the experimental paradigms that have traditionally been used to study attentional, controlled, and automatic processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Does motor programming necessitate response execution?": Correction.

Reports an error in the original article by A. Osman et al (Journal of Experimental Psychology: Human Perception and Performance, 1990, Vol 16[1], 183–298). In Table 3 on page 192, 2 responses for high-complexity sequences should read "1 Ri?+?3 Li or 1 Li?+?3 Ri.' (The following abstract of this article originally appeared in record 1990-13808-001.) The complexity of a movement is known to affect the time it takes to initiate the movement. This effect is thought to reflect changes in the duration of processes that operate on a motor program. This question addressed here is whether programming a movement compels the start of its overt execution. If it does, then the programming processes may be said to occur after the "point of no return.' We report results from an empirical procedure and a theoretical analysis designed to study processes before and after this point separately. According to our results, changes in the complexity of a movement affect only the prior set of processes. From this we argue that motor programming does not necessitate response execution and that the point of no return occurs very late in the information-processing system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of stimulus–response mapping and irrelevant stimulus–response and stimulus–stimulus overlap in four-choice Stroop tasks with single-carrier stimuli.

The purpose of this study was to investigate whether and how stimulus–stimulus (SS) and stimulus–response (SR) consistency and SR congruence effects combine to produce the Stroop effect. Two experiments were conducted with 4-choice tasks in which SS and SR consistency and SR congruence effects were examined in isolation as well as in the Stroop task. The experiments were so designed as to remove the confound between SS and SR consistency that is ordinarily found in standard Stroop tasks and to pit SS consistency against the logical recoding hypothesis (A. Hedge & N. W. A. Marsh, 1975). The results indicate that SS and SR consistency both contribute to the Stroop effect and that they interact. This finding supports models such as the dimensional overlap model (e.g., S. Kornblum & J. W. Lee, 1995) that distinguish between SS and SR overlap. Simulation results from an interactive activation network, modeled after the dimensional overlap model, provide reasonable fits to the experimental data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)