351 research outputs found
The Reading Difficulty of Parent Education Materials
It is not necessary to emphasize the fact that reading plays an important part in the education of parents. A more significant problem is that of discovering the characteristics of materials that fall at different levels of difficulty. A solution of this problem would make possible a more effective selection and preparation of materials suitable to the widely differing reading abilities that one finds among adults. The purpose of this investigation is to determine the factors that are associated with difficulty and to learn what the characteristics of materials are at the various levels. To carry out this study the reading difficulty of a series of sixteen selections was determined experimentally and the variation of numerous factors with difficulty was analyzed
The Application of Psychological Classification of Changes Effected through Learning to Problems of Curriculum Construction
Descriptions of the objectives of education have varied from general, all-inclusive statements, to extended lists of details. The inadequacy of general statements has been recognized by curriculum makers and several attempts have been made to develop more detailed classifications. The best-known classifications have used a mixture of general and specific abilities, or of general and specific activities
L2-Proficiency-Dependent Laterality Shift in Structural Connectivity of Brain Language Pathways
Diffusion tensor imaging (DTI) and a longitudinal language learning approach were applied to investigate the relationship between the achieved second language (L2) proficiency during L2 learning and the reorganization of structural connectivity between core language areas. Language proficiency tests and DTI scans were obtained from German students before and after they completed an intensive 6-week course of the Dutch language. In the initial learning stage, with increasing L2 proficiency, the hemispheric dominance of the Brodmann area (BA) 6-temporal pathway (mainly along the arcuate fasciculus) shifted from the left to the right hemisphere. With further increased proficiency, however, lateralization dominance was again found in the left BA6-temporal pathway. This result is consistent with reports in the literature that imply a stronger involvement of the right hemisphere in L2 processing especially for less proficient L2 speakers. This is the first time that an L2 proficiency-dependent laterality shift in the structural connectivity of language pathways during L2 acquisition has been observed to shift from left to right and back to left hemisphere dominance with increasing L2 proficiency. The authors additionally find that changes in fractional anisotropy values after the course are related to the time elapsed between the two scans. The results suggest that structural connectivity in (at least part of) the perisylvian language network may be subject to fast dynamic changes following language learning
Quantifying interictal intracranial EEG to predict focal epilepsy
Intracranial EEG (IEEG) is used for 2 main purposes, to determine: (1) if
epileptic networks are amenable to focal treatment and (2) where to intervene.
Currently these questions are answered qualitatively and sometimes differently
across centers. There is a need for objective, standardized methods to guide
surgical decision making and to enable large scale data analysis across centers
and prospective clinical trials.
We analyzed interictal data from 101 patients with drug resistant epilepsy
who underwent presurgical evaluation with IEEG. We chose interictal data
because of its potential to reduce the morbidity and cost associated with ictal
recording. 65 patients had unifocal seizure onset on IEEG, and 36 were
non-focal or multi-focal. We quantified the spatial dispersion of implanted
electrodes and interictal IEEG abnormalities for each patient. We compared
these measures against the 5 Sense Score (5SS), a pre-implant estimate of the
likelihood of focal seizure onset, and assessed their ability to predict the
clinicians choice of therapeutic intervention and the patient outcome.
The spatial dispersion of IEEG electrodes predicted network focality with
precision similar to the 5SS (AUC = 0.67), indicating that electrode placement
accurately reflected pre-implant information. A cross-validated model combining
the 5SS and the spatial dispersion of interictal IEEG abnormalities
significantly improved this prediction (AUC = 0.79; p<0.05). The combined model
predicted ultimate treatment strategy (surgery vs. device) with an AUC of 0.81
and post-surgical outcome at 2 years with an AUC of 0.70. The 5SS, interictal
IEEG, and electrode placement were not correlated and provided complementary
information.
Quantitative, interictal IEEG significantly improved upon pre-implant
estimates of network focality and predicted treatment with precision
approaching that of clinical experts.Comment: 25 pages, 4 Figures, 1 tabl
Functional definition of seizure provides new insight into post-traumatic epileptogenesis
Experimental animals’ seizures are often defined arbitrarily based on duration, which may lead to misjudgement of the syndrome and failure to develop a cure. We employed a functional definition of seizures based on the clinical practice of observing epileptiform electrocorticography and simultaneous ictal behaviour, and examined post-traumatic epilepsy induced in rats by rostral parasagittal fluid percussion injury and epilepsy patients evaluated with invasive monitoring. We showed previously that rostral parasagittal fluid percussion injury induces different types of chronic recurrent spontaneous partial seizures that worsen in frequency and duration over the months post injury. However, a remarkable feature of rostral parasagittal fluid percussion injury is the occurrence, in the early months post injury, of brief (<2 s) focal, recurrent and spontaneous epileptiform electrocorticography events (EEEs) that are never observed in sham-injured animals and have electrographic appearance similar to the onset of obvious chronic recurrent spontaneous partial seizures. Simultaneous epidural-electrocorticography and scalp-electroencephalography recordings in the rat demonstrated that these short EEEs are undetectable by scalp electrocorticography. Behavioural analysis performed blinded to the electrocorticography revealed that (i) brief EEEs lasting 0.8–2 s occur simultaneously with behavioural arrest; and (ii) while behavioural arrest is part of the rat's behavioural repertoire, the probability of behavioural arrest is greatly elevated during EEEs. Moreover, spectral analysis showed that EEEs lasting 0.8–2 s occurring during periods of active behaviour with dominant theta activity are immediately followed by loss of such theta activity. We thus conclude that EEEs lasting 0.8–2 s are ictal in the rat. We demonstrate that the assessment of the time course of fluid percussion injury-induced epileptogenesis is dramatically biased by the definition of seizure employed, with common duration-based arbitrary definitions resulting in artificially prolonged latencies for epileptogenesis. Finally, we present four human examples of electrocorticography capturing short (<2 s), stereotyped, neocortically generated EEEs that occurred in the same ictal sites as obvious complex partial seizures, were electrographically similar to rat EEEs and were not noted during scalp electroencephalography. When occurring in the motor cortex, these short EEEs were accompanied by ictal behaviour detectable with simultaneous surface electromyography. These data demonstrate that short (<2 s) focal recurrent spontaneous EEEs are seizures in both rats and humans, that they are undetectable by scalp electroencephalography, and that they are typically associated with subtle and easily missed behavioural correlates. These findings define the earliest identifiable markers of progressive post-traumatic epilepsy in the rat, with implications for mechanistic and prophylactic studies, and should prompt a re-evaluation of the concept of post-traumatic silent period in both animals and humans
Representation of the verb's argument-structure in the human brain
<p>Abstract</p> <p>Background</p> <p>A verb's argument structure defines the number and relationships of participants needed for a complete event. One-argument (intransitive) verbs require only a subject to make a complete sentence, while two- and three-argument verbs (transitives and ditransitives) normally take direct and indirect objects. Cortical responses to verbs embedded into sentences (correct or with syntactic violations) indicate the processing of the verb's argument structure in the human brain. The two experiments of the present study examined whether and how this processing is reflected in distinct spatio-temporal cortical response patterns to isolated verbs and/or verbs presented in minimal context.</p> <p>Results</p> <p>The magnetoencephalogram was recorded while 22 native German-speaking adults saw 130 German verbs, presented one at a time for 150 ms each in experiment 1. Verb-evoked electromagnetic responses at 250 – 300 ms after stimulus onset, analyzed in source space, were higher in the left middle temporal gyrus for verbs that take only one argument, relative to two- and three-argument verbs. In experiment 2, the same verbs (presented in different order) were preceded by a proper name specifying the subject of the verb. This produced additional activation between 350 and 450 ms in or near the left inferior frontal gyrus, activity being larger and peaking earlier for one-argument verbs that required no further arguments to form a complete sentence.</p> <p>Conclusion</p> <p>Localization of sources of activity suggests that the activation in temporal and frontal regions varies with the degree by which representations of an event as a part of the verbs' semantics are completed during parsing.</p
The Function and Organization of Lateral Prefrontal Cortex: A Test of Competing Hypotheses
The present experiment tested three hypotheses regarding the function and organization of lateral prefrontal cortex (PFC). The first account (the information cascade hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the timing with which cue stimuli reduce uncertainty in the action selection process. The second account (the levels-of-abstraction hypothesis) suggests that the anterior-posterior organization of lateral PFC is based on the degree of abstraction of the task goals. The current study began by investigating these two hypotheses, and identified several areas of lateral PFC that were predicted to be active by both the information cascade and levels-of-abstraction accounts. However, the pattern of activation across experimental conditions was inconsistent with both theoretical accounts. Specifically, an anterior area of mid-dorsolateral PFC exhibited sensitivity to experimental conditions that, according to both accounts, should have selectively engaged only posterior areas of PFC. We therefore investigated a third possible account (the adaptive context maintenance hypothesis) that postulates that both posterior and anterior regions of PFC are reliably engaged in task conditions requiring active maintenance of contextual information, with the temporal dynamics of activity in these regions flexibly tracking the duration of maintenance demands. Activity patterns in lateral PFC were consistent with this third hypothesis: regions across lateral PFC exhibited transient activation when contextual information had to be updated and maintained in a trial-by-trial manner, but sustained activation when contextual information had to be maintained over a series of trials. These findings prompt a reconceptualization of current views regarding the anterior-posterior organization of lateral PFC, but do support other findings regarding the active maintenance role of lateral PFC in sequential working memory paradigms
- …