Auditory-phonetic projection and lexical structure in the recognition of sine-wave words

Speech remains intelligible despite the elimination of canonical acoustic correlates of phonemes from the spectrum. A portion of this perceptual flexibility can be attributed to modulation sensitivity in the auditory-to-phonetic projection, although signal-independent properties of lexical neighborhoods also affect intelligibility in utterances composed of words. Three tests were conducted to estimate the effects of exposure to natural and sine-wave samples of speech in this kind of perceptual versatility. First, sine-wave versions of the easy and hard word sets were created, modeled on the speech samples of a single talker. The performance difference in recognition of easy and hard words was used to index the perceptual reliance on signal-independent properties of lexical contrasts. Second, several kinds of exposure produced familiarity with an aspect of sine-wave speech: (a) sine-wave sentences modeled on the same talker; (b) sine-wave sentences modeled on a different talker, to create familiarity with a sine-wave carrier; and (c) natural sentences spoken by the same talker, to create familiarity with the idiolect expressed in the sine-wave words. Recognition performance with both easy and hard sine-wave words improved after exposure only to sine-wave sentences modeled on the same talker. Third, a control test showed that signal-independent uncertainty is a plausible cause of differences in recognition of easy and hard sine-wave words. The conditions of beneficial exposure reveal the specificity of attention underlying versatility in speech perception.     

Frontotemporal neural systems supporting semantic processing in Alzheimer’s disease

We hypothesized that semantic memory for object concepts involves both representations of visual feature knowledge in modality-specific association cortex and heteromodal regions that are important for integrating and organizing this semantic knowledge so that it can be used in a flexible, contextually appropriate manner. We examined this hypothesis in an fMRI study of mild Alzheimer’s disease (AD). Participants were presented with pairs of printed words and asked whether the words matched on a given visual–perceptual feature (e.g., guitar, violin: SHAPE). The stimuli probed natural kinds and manufactured objects, and the judgments involved shape or color. We found activation of bilateral ventral temporal cortex and left dorsolateral prefrontal cortex during semantic judgments, with AD patients showing less activation of these regions than healthy seniors. Moreover, AD patients showed less ventral temporal activation than did healthy seniors for manufactured objects, but not for natural kinds. We also used diffusion-weighted MRI of white matter to examine fractional anisotropy (FA). Patients with AD showed significantly reduced FA in the superior longitudinal fasciculus and inferior frontal-occipital fasciculus, which carry projections linking temporal and frontal regions of this semantic network. Our results are consistent with the hypothesis that semantic memory is supported in part by a large-scale neural network involving modality-specific association cortex, heteromodal association cortex, and projections between these regions. The semantic deficit in AD thus arises from gray matter disease that affects the representation of feature knowledge and processing its content, as well as white matter disease that interrupts the integrated functioning of this large-scale network.     

The impact of empathy on burnout in medical students: new findings

Introduction: Research on medical students has shown they are at a higher risk for burnout and that this burnout may become more prevalent as they advance in medical school. The literature, thus far, has not explored the construct of ,emotional empathy and whether this can impact burnout in medical students. Objective: To understand the relationship between empathy (Empathic Concern [EC] and Personal Distress [PD]) and burnout in medical students. Method: Five successive classes of medical students enrolled at a new medical school were given the Maslach Burnout Inventory and Davis’ Interpersonal Reactivity Index over the course of three successive years (n = 353). Two dimensions of empathy were evaluated to determine if they have an impact on three dimensions of burnout (Emotional Exhaustion/EE, Depersonalization/DP, Personal Accomplishment/PA). Results: data was analyzed using a linear mixed model for each of the three components of burnout based on gender, age, year in medical school, and two types of empathy: EC, and PD. Conclusion: It was discovered that students with high levels of EC had statistically lower scores of burnout over time while students with high levels of PD empathy showed statistically higher scores of burnout over three years. Implications for these findings are discussed.     

Quantifier comprehension in corticobasal degeneration

In this study, we investigated patients with focal neurodegenerative diseases to examine a formal linguistic distinction between classes of generalized quantifiers, like "some X" and "less than half of X." Our model of quantifier comprehension proposes that number knowledge is required to understand both first-order and higher-order quantifiers. The present results demonstrate that corticobasal degeneration (CBD) patients, who have number knowledge impairments but little evidence for a deficit understanding other aspects of language, are impaired in their comprehension of quantifiers relative to healthy seniors, Alzheimer's disease (AD) and frontotemporal dementia (FTD) patients [F(3,77)=4.98; p<.005]. Moreover, our model attempts to honor a distinction in complexity between classes of quantifiers such that working memory is required to comprehend higher-order quantifiers. Our results support this distinction by demonstrating that FTD and AD patients, who have working memory limitations, have greater difficulty understanding higher-order quantifiers relative to first-order quantifiers [F(1,77)=124.29; p<.001]. An important implication of these findings is that the meaning of generalized quantifiers appears to involve two dissociable components, number knowledge and working memory, which are supported by distinct brain regions.     

Large-scale neural network for sentence processing

Our model of sentence comprehension includes at least grammatical processes important for structure-building, and executive resources such as working memory that support these grammatical processes. We hypothesized that a core network of brain regions supports grammatical processes, and that additional brain regions are activated depending on the working memory demands associated with processing a particular grammatical feature. We used functional magnetic resonance imaging (fMRI) to test this hypothesis by comparing cortical activation patterns during coherence judgments of sentences with three different syntactic features. We found activation of the ventral portion of left inferior frontal cortex during judgments of violations of each grammatical feature. Increased recruitment of the dorsal portion of left inferior frontal cortex was seen during judgments of violations of specific grammatical features that appear to involve a more prominent working memory component. Left posterolateral temporal cortex and anterior cingulate were also implicated in judging some of the grammatical features. Our observations are consistent with a large-scale neural network for sentence processing that includes a core set of regions for detecting and repairing several different kinds of grammatical features, and additional regions that appear to participate depending on the working memory demands associated with processing a particular grammatical feature.     

Investing in Success: Key Strategies for Building Quality in After-School Programs

This paper examines the relation between the implementation quality of after-school literacy activities and student reading gains. The data are from an evaluation of a multi-site after-school program in California in which continuous program quality improvement strategies were implemented to improve the delivery of a new balanced literacy program. Strategies included: (1) targeted staff training throughout the year, (2) regular observations and coaching of staff, and (3) the use of data to measure progress. Programs struggled to successfully implement these strategies early in the initiative, but gradually improved the quality and consistency of their use. Program quality, as measured through observations, also increased. Results suggested that the size of student reading gains were positively correlated with the quality of literacy programming provided by each instructor.     

Modulation sensitivity in the perceptual organization of speech

In a spoken utterance, a talker expresses linguistic constituents in serial order. A listener resolves these linguistic properties in the rapidly fading auditory sample. Classic measures agree that auditory integration occurs at a fine temporal grain. In contrast, recent studies have proposed that sensory integration of speech occurs at a coarser grain, approximate to the syllable, on the basis of indirect and relatively insensitive perceptual measures. Evidence from cognitive neuroscience and behavioral primatology has also been adduced to support the claim of sensory integration at the pace of syllables. In the present investigation, we used direct performance measures of integration, applying an acoustic technique to isolate the contribution of short-term acoustic properties to the assay of modulation sensitivity. In corroborating the classic finding of a fine temporal grain of integration, these functional measures can inform theory and speculation in accounts of speech perception.     

Volunteer Mentoring Relationships With Minority Youth: An Analysis of Same‐ Versus Cross‐Race Matches1

Despite the growth of youth mentoring programs in recent years, key questions remain regarding the relative importance of making matches on the basis of shared racial background. Both sides of the argument regarding racial matching are presented, followed by a comparison of the effects of same‐ vs. cross‐race matches involving minority youth (N= 476). Minority adolescents were less likely to report initiating alcohol when placed in cross‐race matches. In addition, minority boys in same‐race matches reported smaller decrements in scholastic competence and self‐worth than did minority boys in cross‐race matches. Minority girls in same‐race matches reported smaller decrements in school value and self‐worth than did minority girls in cross‐race matches. Youth, parent, and caseworker impressions of the 2 relationship types largely converged, but the few impressions that differed tended to favor cross‐race matches. The methodological limitations and implications of this study are discussed.     

Guest Editorial: Who's Afraid of Life After Death?

The evidence for an afterlife is sufficiently strong and compelling that an unbiased person ought to conclude that materialism is a false theory. Yet the academy refuses to examine the evidence, and clings to materialism as if it were a priori true, instead of a posteriori false. I suggest several explanations for the monumental failure of curiosity on the part of academia. First, there is deep confusion between the concepts of evidence and proof. Second, materialism functions as a powerful paradigm that structures the shape of scientific explanations, but is not itself open to question. The third explanation is intellectual arrogance, as the possible existence of disembodied intelligence threatens the materialistic belief that the educated human brain is the highest form of intelligence in existence. Finally, there is a social taboo against belief in an afterlife, as our whole way of life is predicated on materialism and might collapse if near-death experiences, particularly the life review, were accepted as fact.