Psychology Commons^™

Superior Colliculus Lesions Lead To Disrupted Responses To Light In Diurnal Grass Rats (Arvicanthis Niloticus), Andrew J. Gall, Alyssa M. Goodwin, Ohanes S. Khacherian, Laura B. Teal

Faculty Publications

The circadian system regulates daily rhythms of physiology and behavior. Although extraordinary advances have been made to elucidate the brain mechanisms underlying the circadian system in nocturnal species, less is known in diurnal species. Recent studies have shown that retinorecipient brain areas such as the intergeniculate leaflet (IGL) and olivary pretectal nucleus (OPT) are critical for the display of normal patterns of daily activity in diurnal grass rats (Arvicanthis niloticus). Specifically, grass rats with IGL and OPT lesions respond to light in similar ways to intact nocturnal animals. Importantly, both the IGL and OPT project to one another …

Properties Of Perceptual Motor After-Effects In Visuo-Spatial Tasks, Ben Kajaste

Electronic Thesis and Dissertation Repository

A series of experiments were conducted with the general theme and aim of exploring some of the yet to be determined properties of perceptual motor processing after-effects in visuo-spatial tasks. Using a variety paradigms, procedures and methods of analysis, numerous factors of interest were manipulated and examined to determine their implications related to how we process, store, make decisions and execute task requirements when presented with both relevant and irrelevant visuo-spatial information.

Experiment 1 investigated how distractor-generated response retrieval occurs; either via ‘inherent’ processing of high association strength links, or the application of task assignment rules (i.e., response selection determinants) …

The Relationship Between Masking And Short-Term Consolidation During Recall From Visual Working Memory, Timothy J. Ricker, Joshua Sandry

Department of Psychology Faculty Scholarship and Creative Works

The presentation of a similar but irrelevant stimulus immediately following presentation of a memory item is called masking. Masking is known to reduce performance on working memory tests. This is the type of memory used to hold information in mind for brief periods of time for use in ongoing cognition. Two approaches to understanding masking effects have been proposed in different literatures. Working memory researchers often assume that the reduction in working memory performance after masking is because masking interferes with a transient sensory representation that is needed to complete consolidation into a working memory state. Researchers focused on the …

Normal Behavioral Responses To Light And Darkness And The Pupillary Light Reflex Are Dependent Upon The Olivary Pretectal Nucleus In The Diurnal Nile Grass Rat, Andrew J. Gall, Ohanes S. Khacherian, Brandi Ledbetter, Sean P. Deats, Megan Luck, Laura Smale, Lily Yan, Antonio A. Nunez

Faculty Publications

The olivary pretectal nucleus (OPT) is a midbrain structure that receives reciprocal bilateral retinal projections, is involved in the pupillary light reflex, and connects reciprocally with the intergeniculate leaflet (IGL), a retinorecipient brain region that mediates behavioral responses to light pulses (i.e., masking) in diurnal Nile grass rats. Here, we lesioned the OPT and evaluated behavioral responses in grass rats to various lighting conditions, as well as their anxiety-like responses to light exposure. While control grass rats remained diurnal, grass rats with OPT lesions exhibited a more night-active pattern under 12h:12h light-dark (LD) conditions. However, when placed in constant darkness, …

The Contribution Of The Pineal Gland On Daily Rhythms And Masking In Diurnal Grass Rats, Arvicanthis Niloticus, Dorela D. Shuboni, Amna A. Agha, Thomas K. H. Groves, Andrew J. Gall

Faculty Publications

Melatonin is a hormone rhythmically secreted at night by the pineal gland in vertebrates. In diurnal mammals, melatonin is present during the inactive phase of the rest/activity cycle, and in primates it directly facilitates sleep and decreases body temperature. However, the role of the pineal gland for the promotion of sleep at night has not yet been studied in non-primate diurnal mammalian species. Here, the authors directly examined the hypothesis that the pineal gland contributes to diurnality in Nile grass rats by decreasing activity and increasing sleep at night, and that this could occur via effects on circadian mechanisms or …

Pure Partial Awareness Or Interaction Between The Mask And The Masked Stimuli?, Jiangong Guo, Jerwen Jou, Qian Cui, Guang Zhao, Shen Tu

Psychological Science Faculty Publications and Presentations

Many studies using masking paradigm have shown that stimuli can be processed unconsciously. However, different researchers put forward different ideas about the mechanisms of the unconscious information processing. For example, one idea is that the unconscious information might be derived from a partial awareness of the masked stimulus. Another idea is that it is derived from a perceptual interaction between a masked stimulus and the masking stimulus. We used a masking paradigm (with a briefly displayed target followed by a mask) and a subjective rating and an objective forced-choice test (with a word and picture version) given after the display …

Suprachiasmatic Nucleus And Subparaventricular Zone Lesions Disrupt Circadian Rhythmicity But Not Light-Induced Masking Behavior In Nile Grass Rats, Andrew J. Gall, Dorela D. Shuboni, Lily Yan, Antonio A. Nunez, Laura Smale

Faculty Publications

The ventral subparaventricular zone (vSPVZ) receives direct retinal input and influences the daily patterning of activity in rodents, making it a likely candidate for the mediation of acute behavioral responses to light (i.e., masking). We performed chemical lesions aimed at the vSPVZ of diurnal grass rats (Arvicanthis niloticus) using N-methyl-D,L-aspartic acid (NMA), a glutamate agonist. Following NMA lesions, we placed grass rats in various lighting conditions (e.g., 12:12 light-dark, constant dark, constant light); presented a series of light pulses at circadian times (CT) 6, 14, 18, and 22; and placed them in a 7-h ultradian cycle to assess behavioral masking. …

Attentional Biases In Processing Emotional Facial Expressions: Effects Of State Anxiety, Trait Anxiety And Awareness, Mark Edwards

Mark Edwards

The effect of state anxiety and trait anxiety on selective attention for threatening, neutral and happy schematic faces was investigated. A student sample was assigned to high trait anxious (HTA) or low trait anxious (LTA) groups using questionnaire scores and state anxiety was manipulated through the threat of electric shock. Stimulus materials were presented both outside (using a backward masking procedure) and within awareness. A novel version of a probe classification task was developed to assess performance when distracting information and the central task were spatially separated. For the masked trials, the LTA group were slower to identify the status …

Intergeniculate Leaflet Lesions Result In Differential Activation Of Brain Regions Following The Presentation Of Photic Stimuli In Nile Grass Rats, Andrew J. Gall, Lily Yan, Laura Smale, Antonio A. Nunez

Faculty Publications

The intergeniculate leaflet (IGL) plays an important role in the entrainment of circadian rhythms and the mediation of acute behavioral responses to light (i.e., masking). Recently, we reported that IGL lesions in diurnal grass rats result in a reversal in masking responses to light as compared to controls. Here, we used Fos as a marker of neural activation to examine the mechanisms by which the IGL may influence this masking effect of light in grass rats. Specifically, we examined the patterns of Fos activation in retinorecipient areas and in brain regions that receive IGL inputs following 1-h light pulses given …

The Masking Effects Of Light On Circadian Activity And Sleep Rhythms In Drosophila Melanogaster, Aaron David Sheppard

Legacy Theses & Dissertations (2009 - 2024)

As organisms evolved, so did mechanisms for synchronizing behavior to the environmental light-dark cycle. Two main mechanisms provide this link: the synchronization of an endogenous circadian oscillator with the exogenous environment (entrainment), and a process called "masking", which functions independently from the circadian clock. Organisms have evolved these endogenous and exogenous mechanisms to adapt to the light-dark cycle of their niches in order to integrate their behavioral and physiological responses with predictable changes in their environments, in this case changes involving the daily light-dark cycle.

"...Bless Her Little Heart!": The Culture Of Honor And Emotion Recognition, Forrest J. Rackham

Electronic Theses and Dissertations

Author's abstract: Some researchers assert that cultural display rules may explain differences in perceiving emotions (Matsumoto, Yoo, & Chung, 2010). The current study examined the display rule of masking within the Southern culture of honor. It was hypothesized that masking within the culture of honor negatively affects emotion perception sensitivity, particularly in the speed and accuracy of recognizing anger. Southern undergraduate students were primed with the culture of honor and then presented with the Emotional Expression Multimorph Task. Participants chose one of the six emotions (i.e., sad, happy, surprise, fear, disgust, or anger). It was hypothesized participants in the masking …

The Influence Of Emotion On Attention : Examining The Processing Of Negative And Positive Emotion Words In The Dot Probe Task, Tina Sutton

Legacy Theses & Dissertations (2009 - 2024)

The influence of emotion on attention has been examined more closely in recent years using a variety of paradigms. Öhman (1993) suggested that participants more readily pay attention to negative information than neutral information. The current work was designed to expand upon these findings by examining both negative and positive emotion word processing in a non-clinical population using the dot probe task. Experiments 1a and 1b examined the supraliminal and subliminal processing of negative and positive emotion words presented in separate blocks. The results revealed that participants responded faster to the probe when it appeared in the same location as …

Predicting The Readability Of Transparent Text, Lauren F. V. Scharff, Albert J. Ahumada Jr.

Faculty Publications

Will a simple global masking model based on image detection be successful at predicting the readability of transparent text? Text readability was measured for two types of transparent text: additive (as occurs in head-up displays) and multiplicative (which occurs in see-through liquid crystal display virtual reality displays). Text contrast and background texture were manipulated. Data from two previous experiments were also included (one using very low contrasts on plain backgrounds, and the other using higher-contrast opaque text on both plain and textured backgrounds). All variables influenced readability in at least an interactive manner. When there were background textures, the global …