Learning Melodic Expectancy: Musical Predictability in an SRN

Abstract Descriptive models of music cognition propose various principles as underlying melodic expectancy, with some models proposing that these are innate. A simple recurrent network (SRN) was trained on a set of musical sequences to examine the degree to which the principles described by Schellenberg's (1997) two-factor model might be learned through musical exposure. The principle of pitch proximity, but not pitch reversal constrained the model's expectations of tones following melodic fragments. Implications for this model in the area of music perception and sequential modeling are discussed, as are potential extensions of this simple system

Implications of Cognitive Load for Hypothesis Generation and Probability Judgment

We tested the predictions of HyGene (Thomas et al., 2008) that both divided attention at encoding and judgment should affect the degree to which participants’ probability judgments violate the principle of additivity. In two experiments, we showed that divided attention during judgment leads to an increase in subadditivity, suggesting that the comparison process for probability judgments is capacity limited. Contrary to the predictions of HyGene, a third experiment revealed that divided attention during encoding leads to an increase in later probability judgment made under full attention. The effect of divided attention during encoding on judgment was completely mediated by the number of hypotheses participants generated, indicating that limitations in both encoding and recall can cascade into biases in judgments

Volumetric parcellation methodology of the human hypothalamus in neuroimaging: Normative data and sex differences

There is increasing evidence regarding the importance of the hypothalamus for understanding sex differences in relation to neurological, psychiatric, endocrine and sleep disorders. Although different in histology, physiology, connections and function, multiple hypothalamic nuclei subserve non-voluntary functions and are nodal points for the purpose of maintaining homeostasis of the organism. Thus, given the critical importance of hypothalamic nuclei and their key multiple roles in regulating basic functions, it is important to develop the ability to conduct in vivo human studies of anatomic structure, volume, connectivity, and function of hypothalamic regions represented at the level of its nuclei. The goals of the present study were to develop a novel method of semi-automated volumetric parcellation for the human hypothalamus that could be used to investigate clinical conditions using MRI and to demonstrate its applicability. The proposed new method subdivides the hypothalamus into five parcels based on visible anatomic landmarks associated with specific nuclear groupings and was confirmed using two ex vivo hypothalami that were imaged in a 7 T (7 T) scanner and processed histologically. Imaging results were compared with histology from the same brain. Further, the method was applied to 44 healthy adults (26 men; 18 women, comparable on age, handedness, ethnicity, SES) to derive normative volumes and assess sex differences in hypothalamic regions using 1.5 T MRI. Men compared to women had a significantly larger total hypothalamus, relative to cerebrum size, similar for both hemispheres, a difference that was primarily driven by the tuberal region, with the sex effect size being largest in the superior tuberal region and, to a lesser extent, inferior tuberal region. Given the critical role of hypothalamic nuclei in multiple chronic diseases and the importance of sex differences, we argue that the use of the novel methodology presented here will allow for critical investigations of these disorders and further delineation of potential treatments, particularly sex-specific approaches to gene and drug discoveries that involve hypothalamic nuclei

A Behavioral and Computational Integration of Phonological, Short-Term Memory, and Vocabulary Acquisition Processes in Nonword Repetition

Theories of language acquisition propose an early and important role for perceptual processes, but often present these processes as separate from the short-term sequencing processes and long-term linguistic knowledge that also contribute to the development of language. Using nonword repetition as a measure that reflects the interaction of these processes, we present a computational model that integrates all three of these processes into a single system and examine the similarity between the relationship of these three processes found in the model and the relationship found in adolescent humans

A behavioral and computational integration of phonological, short-term memory and vocabulary acquisition processes in nonword repetition

Abstract Theories of language acquisition propose an early and important role for perceptual processes, but often present these processes as separate from the short-term sequencing processes and long-term linguistic knowledge that also contribute to the development of language. Using nonword repetition as a measure that reflects the interaction of these processes, we present a computational model that integrates all three of these processes into a single system and examine the similarity between the relationship of these three processes found in the model and the relationship found in adolescent humans

Sex Differences in Stress Response Circuitry Activation Dependent on Female Hormonal Cycle

Understanding sex differences in stress regulation has important implications for understanding basic physiological differences in the male and female brain and their impact on vulnerability to sex differences in chronic medical disorders associated with stress response circuitry. In this functional magnetic resonance imaging study, we demonstrated that significant sex differences in brain activity in stress response circuitry were dependent on women's menstrual cycle phase. Twelve healthy Caucasian premenopausal women were compared to a group of healthy men from the same population, based on age, ethnicity, education, and right handedness. Subjects were scanned using negative valence/high arousal versus neutral visual stimuli that we demonstrated activated stress response circuitry [amygdala, hypothalamus, hippocampus, brainstem, orbitofrontal cortex (OFC), medial prefrontal cortex (mPFC), and anterior cingulate gyrus (ACG)]. Women were scanned twice based on normal variation in menstrual cycle hormones [i.e., early follicular (EF) compared with late follicular–midcycle (LF/MC) menstrual phases]. Using SPM8b, there were few significant differences in blood oxygenation level-dependent (BOLD) signal changes in men compared to EF women, except ventromedial nucleus (VMN), lateral hypothalamic area (LHA), left amygdala, and ACG. In contrast, men exhibited significantly greater BOLD signal changes compared to LF/MC women on bilateral ACG and OFC, mPFC, LHA, VMN, hippocampus, and periaqueductal gray, with largest effect sizes in mPFC and OFC. Findings suggest that sex differences in stress response circuitry are hormonally regulated via the impact of subcortical brain activity on the cortical control of arousal, and demonstrate that females have been endowed with a natural hormonal capacity to regulate the stress response that differs from males.Athinoula Martinos Center for Biomedical Imaging at Massachusetts General Hospital Collaborative Start-up Awar