Cognitive Neuroscience Commons^™

Constructing A Parameterized Stimuli Space Suitable To Induce Controlled Changes In Human And Machine Perceptual Systems, Andrew Frankel

Dissertations, Theses, and Capstone Projects

Traditional computer vision applications focus on objective tasks, such as object detection, classification, or segmentation. Much of human experience is inherently subjective, such as our personal response to artwork. Individualized experiences are challenging to replicate in a controlled laboratory environment, as those experiences depend on the unique history and internal models of the observer. This work presents a technique to construct a 2-dimensional parameterized stimuli space suitable to induce controlled changes in the perceptual systems of both human and machine observers. Our contributions are threefold:

1. Using a balanced dataset of 8,800 fine art images spanning 11 art movements and 88 …

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Behavioral And Neural Evidence For Perceptual Inference Of Position, Sharif Saleki

Dartmouth College Ph.D Dissertations

Extensive neuroscientific research has advanced our knowledge of the mechanisms involved in the detection and recognition of visual stimuli. However, to guide flexible behavior in a changing world, the brain must also construct stable and coherent perceptual representations from retinal images that are often ambiguous. To resolve ambiguities and uncertainties, the visual system combines its input with other sources of information such as context and prior knowledge to infer the most likely interpretation of a scene. Thus, perception is inherently an inferential process that goes beyond simple detection or recognition of stimuli. Although inference has been studied in many areas …

Target Selection And Enhancement During Attentional Tracking, Marvin R. Maechler

Dartmouth College Ph.D Dissertations

At any waking moment, we are bombarded with more sensory information than we can fully process. Attention is necessary to deal with the dynamic world we live in. One fundamental function of vision and attention is to keep track of moving objects, but what are the targets of attention during tracking?

One of the first theories of attentional tracking predicted that targets would be selected at early processing stages. By employing the double-drift illusion, which dissociates physical and perceived positions of moving objects, we investigated which of these positions is selected for tracking. Contrary to earlier theories and in line …

Examining Metacognitive Access To Low-Level Ensemble Representations, Vladimir Mudragel

Dissertations, Theses, and Capstone Projects

Ensemble perception is a process that allows our sensory systems to rapidly extract summary information about the stimuli in the environment. For example, we are able to get a sense of the average number of items in a group of similar items (Burr & Ross, 2008; Halberda, Sires, & Feigenson, 2006) or the average size of a group of similar shapes of different sizes (Ariely, 2001). It is theorized that the qualitative result of ensemble perception is that it provides a gist impression of the current environment, which then enables attentional processes in the brain to determine which parts of …

The Effects Of Near-Threshold Color Manipulation On Perceptual Decision-Making And Confidence Report, Trevor Caruso

Dissertations, Theses, and Capstone Projects

Confidence measures are sometimes used to index awareness below a participant’s criterion for what counts as being subjectively aware of a stimulus or stimulus property. If confidence ratings index awareness below subjective thresholds, then one might be tempted to use confidence ratings in place of subjective reports of whether a stimulus/stimulus property was “seen” or “unseen”. As such, a dissociation of confidence from performance may be construed as a dissociation of subjective awareness from objective task performance. This methodology has been used as supporting evidence for blindsight in typical observers (Balsdon and Azzopardi 2015; Peters and Lau 2015; Peters et …

Cortical Dynamics Of Language, Kiefer Forseth

Dissertations and Theses (Open Access)

The human capability for fluent speech profoundly directs inter-personal communication and, by extension, self-expression. Language is lost in millions of people each year due to trauma, stroke, neurodegeneration, and neoplasms with devastating impact to social interaction and quality of life. The following investigations were designed to elucidate the neurobiological foundation of speech production, building towards a universal cognitive model of language in the brain. Understanding the dynamical mechanisms supporting cortical network behavior will significantly advance the understanding of how both focal and disconnection injuries yield neurological deficits, informing the development of therapeutic approaches.

Multimodal Computational Modeling Of Visual Object Recognition Deficits But Intact Repetition Priming In Schizophrenia, Pejman Sehatpour, Anahita Bassir Nia, Devin Adair, Zhishun Wang, Heloise M. Debaun, Gail Silipo, Antigona Martinez, Daniel C. Javitt

Publications and Research

The term perceptual closure refers to the neural processes responsible for “filling-in” missing information in the visual image under highly adverse viewing conditions such as fog or camouflage. Here we used a closure task that required the participants to identify barely recognizable fragmented line-drawings of common objects. Patients with schizophrenia have been shown to perform poorly on this task. Following priming, controls and importantly patients can complete the line-drawings at greater levels of fragmentation behaviorally, suggesting an improvement in their ability to performthe task. Closure phenomena have been shown to involve a distributed network of cortical regions, notably the lateral …

Mechanisms Of Value-Biased Prioritization In Fast Sensorimotor Decision Making, Kivilcim Afacan-Seref

Dissertations and Theses

In dynamic environments, split-second sensorimotor decisions must be prioritized according to potential payoffs to maximize overall rewards. The impact of relative value on deliberative perceptual judgments has been examined extensively, but relatively little is known about value-biasing mechanisms in the common situation where physical evidence is strong but the time to act is severely limited. This research examines the behavioral and electrophysiological indices of how value biases split-second perceptual decisions and the possible mechanisms underlying the process. In prominent decision models, a noisy but statistically stationary representation of sensory evidence is integrated over time to an action-triggering bound, and value-biases …

Visual Entrainment Of Perception-Related Neural Oscillations As A Mechanism For Maintaining Rhythmic Temporal Expectations Across A Wide Range Of Frequencies, Michael James Gray

Dissertations, Theses, and Capstone Projects

Visual sensitivity fluctuates rhythmically, in-synch with ongoing, EEG-recorded neural oscillations across a wide range of frequencies (~1-25hz). Some recent work has suggested that these perception-related neural oscillations can be entrained by rhythmic visual stimulation. Evidence is also emerging that the entrainment of ongoing oscillations in visual and auditory cortices is involved in rhythmic temporal expectations. In the introduction chapter, I attempt to bridge these bodies of literature and hypothesize that rhythmic visual stimuli automatically entrain ongoing, perception-related neural oscillations and that this mechanism supports the maintenance of rhythmic temporal expectations. Chapters 2 and 3 address this hypothesis from different angles. …

Sensory Perception, Adrian Rodriguez-Contreras

Open Educational Resources

Different types of sensory systems with their functional modalities will be presented. The biological bases for how these functions are generated and modified will then be described. As vision is the principal means of perception, we will focus in this course most on visual processing. Scientific data will be integrated into the lectures, such that students develop critical skills in analyzing data and proposing hypotheses.

The Generalization Of Fear Condition Between Viewed And Imagined Percepts, Lauryn Michelle Burleigh

LSU Master's Theses

Mental images can provoke intense emotional states (Holmes & Matthews, 2010). Imagery and perception have common neural and physiological mechanisms, including activation of the early visual areas (Albers et al., 2013). We tested the prediction that individuals can acquire fear to imagined percepts and if this fear transfers to viewing percepts, using fMRI and self-reported measures to determine participants’ fear. The participants completed a task in which they viewed and imagined two stimuli, and were fear conditioned when imagining the CS+. Participants are only told that mild electrical stimulation will be paired with one of the stimuli, but not which …

Processing Emotional Expression In The Dance Of A Foreign Culture: Gestural Responses Of Germans And Koreans To Ballet And Korean Dance, Zi Hyun Kim, Hedda Lausberg

Journal of Movement Arts Literacy Archive (2013-2019)

Artistic dance differs between cultures with regard to the formal movement repertoire and methods to represent dancer's emotions. The present study explores how differently the spectators perceive the dance scenes of their own and foreign cultures. We showed German and Korean participants sad and happy dance scenes of the French ballet Giselle and Korean dance Sung-Mu. To learn the perceived thoughts and feelings of the participant from the dance scenes, we analyzed the frequency of their hand movements and gestures, which were accompanied by verbal descriptions of the participant's appreciation immediately after observation of the dance stimuli. The videotaped …

Unimanual And Bimanual Haptic Shape Discrimination, Catherine Jane Dowell

Masters Theses & Specialist Projects

In the current study 24 younger adults and 24 older adults haptically discriminated natural 3-D shapes (bell peppers, Capsicum annuum) using unimanual (one hand used to explore two objects) and bimanual (both hands used, but each hand explored separate objects) successive exploration. Haptic exploration using just one hand requires somatosensory processing in only one cerebral hemisphere (the hemisphere contralateral to the hand being used), while bimanual haptic exploration requires somatosensory processing in both hemispheres. Previous studies related to curvature/shape perception have found either an advantage for unimanual exploration over bimanual exploration or no difference between the two conditions. In contrast …

Insects: Still Looking Like Zombies, Christopher S. Hill

Animal Sentience

In arguing that insect brains are capable of sentience, Klein & Barron rely heavily on Bjorn Merker’s claim that activity in the human mid-brain is sufficient for conscious experience. I criticize Merker’s claim by pointing out that the behaviors supported by midbrain activity are much more primitive than the ones that appear to depend on consciousness. I raise a similar objection to Klein & Barron’s contention that insect behaviors are similar to behaviors that manifest consciousness in human beings. The similarity is weak. I also respond to the related view that integrative activity in mid-brain structures is sufficient to explain …

Change Detection In Rhesus Monkeys And Humans, Deepna T. Devkar, Deepna T. Devkar

Dissertations and Theses (Open Access)

Visual working memory (VWM) is the temporary retention of visual information and a key component of cognitive processing. The classical paradigm for studying VWM and its encoding limitations has been change detection. Early work focused on how many items could be stored in VWM, leading to the popular theory that humans could remember no more than 4±1 items. More recently, proposals have suggested that VWM is a noisy, continuous resource distributed across virtually all items in the visual field, resulting in diminished memory quality rather than limited quantity. This debate about the nature of VWM has predominantly been studied with …

The Effects Of Rectal Temperature And Hydration Status On Perceptual Ratings In Dehydrating Males, Ethan A. Talbot

Honors Scholar Theses

Athletes push the limits of what the human body can handle every day. When they exercise in the heat, they can attain dangerous levels of internal temperature and dehydration. Since athletes are sometimes not aware when they are experiencing severe hyperthermia or hypohydration, it is of interest to anyone who exercises in the heat to study whether athletes are consciously aware that they are approaching dangerous physiological limits. This study compares the perceptual values of athletes exercising in the heat to the changes in their internal temperature and hydration status, to see if athletes can reliably predict their heat and …

Perception Of Emotion In Sounded And Imagined Music, Brian L. Lucas, Emery Schubert, Andrea R. Halpern

Faculty Journal Articles

WE STUDIED THE EMOTIONAL RESPONSES BY MUSICIANS to familiar classical music excerpts both when the music was sounded, and when it was imagined.We used continuous response methodology to record response profiles for the dimensions of valence and arousal simultaneously and then on the single dimension of emotionality. The response profiles were compared using cross-correlation analysis, and an analysis of responses to musical feature turning points, which isolate instances of change in musical features thought to influence valence and arousal responses. We found strong similarity between the use of an emotionality arousal scale across the stimuli, regardless of condition (imagined …