Physiological aspects

This dissertation studies the neural basis of song, a universal human behavior. The relationship of words and melodies in the perception of song at phonological, semantic, melodic, and rhythmic levels of processing was investigated using the fine temporal resolution of Electroencephalography (EEG). The observations reported here may shed light on a ubiquitous human experience and also inform the discussion of whether language and music share neural resources or recruit domain-specific neural mechanisms. Experiment 1 was designed to determine whether words and melody in song are processed interactively or independently. Participants listened to sung words in which the melodies and/or the words were similar or different, and performed a same/different task while attending to the linguistic and musical dimensions in separate blocks of trials. Event-Related Potentials and behavioral data converged in showing interactive processing between the linguistic and musical dimensions of sung words, regardless of the direction of attention. In particular, the N400 component, a well-established marker of semantic processing, was modulated by musical melody. The observation that variations in musical features affect lexico-semantic processing in sung language was a novel finding with implications for shared neural resources between language and music. Experiment 2 was designed to explore the idea that well-aligned text-settings, in which the strong syllables occur on strong beats, capture listeners' attention and help them understand song lyrics. EEG was recorded while participants listened to sung sentences whose linguistic stress patterns were well-aligned, misaligned, or had variable alignment with the musical meter, and performed a lexical decision task on subsequently presented visual targets.

This thesis examined the developmental differences in inhibition and theory-of-mind of 4-8 year olds as a function of the suggested presence of a supernatural agent. All children played four games designed to assess their current level of inhibition and theory-of-mind performance; Children in the experimental condition, only, were also introduced to an invisible Princess Alice and were told that she was watching during the games. Following these measures, all children engaged in a resistance-to-temptation task to determine any differences in inhibition resulting from Princess Alice's suggested presence. I found that children exhibiting a well-developed theory-of-mind were more likely to express belief in Princess Alice than were children lacking this cognitive ability. This research provided support that cognitive maturity, rather than immaturity, may be necessary for children to express belief in novel supernatural agents, and highlighted the importance of context as a mediating factor in children's behavioral inhibition.

In light of exceptionally delayed reproductive senescence exhibited by a 64 year old female chimpanzee (Pan troglodytes) housed in Florida, endocrinal analyses meant to determine the state of her current reproductive viability were conducted. Urine was collected from the study subject for a period of 88 days spaced within an interim of roughly 6 months and the specimens were sent to the Hominoid Reproductive Ecology Laboratory for assessment. Additional data was collected from three control females in order to provide a basis of comparison against the hormonal markers present in the geriatric study animal. Results indicate that the geriatric female does not presently appear to be cycling, but nor does she exhibit signs of complete reproductive cessation. This could signify that Pan troglodytes adheres to a pattern of reproductive aging not necessarily shared by Homo sapiens, which has further implications for the evolutionary trajectory of menopause in the human female.

This study aimed to understand the differences in strength or coordination of brain regions involved in processing faces in the presence of aging and/or progressing neuropathology (Alzheimer's disease). To this end, Experiment 1 evaluated age-related differences in basic face processing and the effects of familiarity in face processing. Overall, face processing in younger (22-35yrs) and older participants (63-83yrs) recruited a broadly distributed network of brain activity, but the distribution of activity varied depending on the age of the individual. The younger population utilized regions of the occipitotemporal, medial frontal and posterior parietal cortices while the older population recruited a concentrated occipitotemporal network. The younger participants were also sensitive to the type of face presented, as Novel faces were associated with greater mean BOLD activity than either the Famous or Relatives faces. Interestingly, Relatives faces were associated with greater mean B OLD activity in more regions of the brain than found in any other analysis in Exp. 1, spanning the inferior frontal, medial temporal and inferior parietal cortices. In contrast, the older adults were not sensitive to the type of face presented, which could reflect a difference in cognitive strategies used by the older population when presented with this type of face stimuli. Experiment 2 evaluated face processing, familiarity in face processing and also emphasized the interactive roles autobiographical processing and memory recency play in processing familiar faces in mature adults (MA; 45-55yrs), older adults (OA; 70-92yrs) and patients suffering from Alzheimer's disease (AD; 70-92yrs).

This study examines whether obesity affects the accuracy of estimating age-at-death as measured by the age-related changes of the pubic symphysis and auricular surfaces. I scored the hip bones of 119 adults of normal body mass and 126 obese adults (total n = 254) using the SucheyBrooks (1990) method for the pubic symphysis and the Buckberry and Chamberlain (2002) method for the auricular surface. Compared to normal weight individuals, obese individuals exhibited greater inaccuracy in age-at-death estimates when aged from the auricular surface, but not the pubic symphysis. However, age was estimated with less precision in obese individuals using both methods. Obese males are more likely to be aged inaccurately than obese females. The pubic symphysis method may be the preferred method when estimating age in obese individuals, especially males, but forensic anthropologists should use caution when assessing age-at-death in obese adults using either method.

This study tested the hypotheses that phonological memory contributes to vocabulary and grammatical development in young Spanish-English bilinguals, and that the relation between phonological memory and both vocabulary and grammar is language-specific. Phonological memory skill was the percentage of consonants correctly repeated (PCC) in English, and Spanish Nonword Repetition (NWR) tasks at 22 months. Vocabulary size and grammatical complexity were measured at 25 months using the English and Spanish versions for the MacArthur-Bates Communicative Development Inventories. Nonword repetition accuracy was significantly related to both subsequent vocabulary size and grammatical complexity within and across languages after controlling for the percentage of input in English. The relations were not significantly higher within than between languages. The results suggest that in these young Spanish-English simultaneous bilinguals phonological memory is a language-general ability that contributes to the development of vocabulary and grammar in both English and Spanish.

The purpose of this study was to determine the effect of cadence on time trial performance in novice female cyclists. Ten novice female cyclists volunteered to participate in this study. Participants performed 3 sessions: one VO2 peak and two time trials (TT). Cadence was randomly selected and fixed for each TT (60 or 100 rpm) while power output (PO) was adjusted by the participant, as tolerated. Finish time, HR, blood lactate, PO, VO2, and RPE were measured throughout the time trials. The major finding of this study was the significantly faster (p<0.05) finish time (minutes) during the 60 rpm condition (34:23) versus the 100 rpm condition (37:34). Also the 60 rpm TT resulted in significant (p<0.05) differences for HR (155.9 vs 161.2 bpm), gross efficiency (21.1% vs 17.7%), and PO (147 vs 129 watts). These results indicate that novice female cyclists benefit from adopting a low cadence during an 8k TT.

The purpose of this study was to determine the acute effects of caffeine supplementation on strength and muscular endurance in resistance-trained women. In a randomized manner, 15 women consumed caffeine (6 mg/kg) or placebo (PL) seven days apart. Sixty minutes following supplementation, participants performed a one repetition maximum (1RM) barbell bench press test and repetitions to failure at 60% of 1RM. Heart rate and blood pressure were assessed at rest, 60 minutes post-consumption, and immediately following completion of repetitions to failure. Repeated measures ANOVA indicated a significantly greater bench press maximum with caffeine (p<0.05) (52.9 « 11.1 kg vs. 52.1 « 11.7 kg) with no significant differences between conditions in 60% 1RM repetitions (p=0.81). Systolic blood pressure was significantly greater post-exercise, with caffeine (p<0.05) (116.8 « 5.3 mmHg vs. 112.9 « 4.9 mmHg). Our findings indicate a moderate dose of caffeine may be sufficient for enhancing strength performance in resistance-trained women.

DNA methylation, the addition of a methyl group to the 5' position of DNA cytosines (5mC), is generally associated with transcriptional repression during early embryo formation ; however, in the adult brain, it is dynamically regulated and plays an important role in the formation and maintenance of memory. Very recently, it has been hypothesized that DNA hydroxymethylation, the addition of a hydroxyl group to methylated cytosines (5mC), serves as an intermediate in the DNA demethylation pathway. GIven its recent discovery, the role of DNA hydroxymethylation in memory has not yet been explored. In this study, we developed an immunofluorescent triple labeling protocol in order to begin examining the involvement of 5mC and 5hmC in neurons activated by consolidation of a contextual memory associated with methamphetamine in the brain's reward center, the nucleus accumbens.

Caloric restriction (CR), the reduction of nutrient intake short of malnutrition, extends the lifespan of various organisms and can improve measures of human health. Whether mechanisms of lifespan extension are conserved between humans and model organisms is unknown. In mammals, implementing CR is easily achieved by providing a restricted group with a fraction of the food consumed by an "ad libitum" fed group, which has unlimited food access. Due to the difficulty in directly controlling Drosophila food intake, caloric restriction, performed similarly to the mammalian paradigm, has never been tested in flies. Here, we demonstrate a system that allows measurement of food intake throughout life. This system will be used to measure fly lifespan under caloric restriction analogous to current mammalian studies. Our work will help tease apart the differences between the various caloric and dietary restriction paradigms in Drosophila, strengthening our understanding of how fly models relate to mammalian systems.