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Cortical Blindness (Plus Anton-Babinski Syndrome, Blindsight, & Riddoch Syndrome)
Published in Alexander R. Toftness, Incredible Consequences of Brain Injury, 2023
The leading theory for both blindsight and Riddoch syndrome is that there are paths that information from the eyes can take to the parts of the brain that detect features of objects or motion without passing through the part of the brain thought to be responsible for the perceptual experience of “seeing” (Ajina & Bridge, 2017). In these people their primary visual cortex is typically severely damaged, but other connections leading from their eyes into their brain remain intact (Weiskrantz, 1996). Essentially, their brain is still using information from the eyes for things other than typical conscious sight. This leads to a situation where a person is capable of “looking, pointing, detecting and discriminating without seeing” (Cowey & Stoerig, 1991, p. 140). Many connections bring information from the eyes into different places in the brain, and the pattern of surviving connections seems to determine what type of blindsight or Riddoch syndrome develops (Arcaro et al., 2019). This arrangement is similar to disorders of central hearing (see Cortical Deafness).
Hallucinations and Deception
Published in Harold V. Hall, Joseph G. Poirier, Detecting Malingering and Deception, 2020
Harold V. Hall, Joseph G. Poirier
An important consideration in evaluating situations for the potential for malingered hallucinations is multicultural factors (Siddi et al., 2019). Cultural beliefs may influence what is considered normative and usual regarding a perceptual experience. This commentary is not intended in any way to impose value significance to any one cultural percept over another. Cultures vary widely regarding perceived interest in different sports activities (e.g., “football” versus “baseball” versus “soccer” versus “women wrestling,” etc.); cultural/religious beliefs may sanction certain practices where others do not (e.g., “speaking in tongues,” forms of religious “witnessing,” “voodoo,” “witchcraft,” and “witch burning,” etc.). All of these cultural differences may carry different meaning regarding what is considered hallucinatory and what is not.
Valence, bodily (dis)pleasure, and emotion
Published in David Bain, Michael Brady, Jennifer Corns, Philosophy of Suffering, 2019
One natural idea is to use the model of perception. Perceptual experience – be it visual, auditory, etc. – possesses three features that make it an attractive model of valence. First, perceptual experience is intentional. The visual experience of a violet chrysanthemum is about this flower, its colour and shape; the auditory experience of a B flat is about a sound of this tonality. Second, there are good reasons to think that the intentionality of perceptual experience does not depend on the deployment of concepts. One can see a violet chrysanthemum without possessing the concepts of violet or chrysanthemum, as one can hear a B flat without possessing the concepts of this pitch and tonality (e.g. Crane 1992). Third and relatedly, the intentionality of perceptual experience is hardly detachable from its phenomenology: to have a visual experience that is about a violet chrysanthemum is closely related to the way this experience fills one’s stream of consciousness.18
The Effects of Blue-Light Filtering Intraocular Implants on Glare Geometry
Published in Current Eye Research, 2023
Billy R. Hammond, Colin R. Gardner, Lisa Renzi-Hammond
Over the last decade, there has been an effort by both ophthalmic practitioners and vision science researchers to focus on the real-world perceptual experience of patients receiving services. To this end, several qualitative instruments have been developed for the sole purpose of assessing patients’ quality of vision (QoV). As is typical when creating psychometric instruments, the development process involves a literature review, extensive interviews, focus groups, Rasch analysis, testing against objective standards, etc. One useful feature of this type of work is that it identifies the most bothersome issues that patients are experiencing and places them into categories with minimal overlap. For example, McAlinden et al.1 identified ten basic “bothersome” categories: glare, halos, starbursts, hazy vision, blurred vision, distortion, double vision, fluctuation, focusing difficulties, and depth perception. Patients are often given illustrations of these issues as part of their assessment (see, for instance, examples of halos and starbursts/spokes shown in Figure 1).
Yoga and the experience of embodiment: a discussion of possible links
Published in Eating Disorders, 2020
Niva Piran, Dianne Neumark-Sztainer
The current understanding of the construct of embodiment is grounded in the writings of the French phenomenologist Merleau-Ponty (1962). In contrast to Cartesian ontology that viewed the mind and body as distinct, the body as a material object and the mind as a thinking subject (Crossley, 1995), as well as the mind as superior to the body (Bordo, 1993), Merleau-Ponty (1962) proposed that the mind and body were equivalent, intertwined and inseparable (Csordas, 1994; Howe, 2003). Further, he viewed the body not only as sensational but also as sentinel in perceiving, interpreting, and experiencing the world meaningfully (Crossley, 1995). For Merleau-Ponty, therefore, the body is the site of subjectivity, and embodiment refers to the “perceptual experience of engagement of the body in the world.” This interpretive “perceptual experience” is always in relation to a particular location of the body in the world; a dialectical relationship therefore exists between body and culture, and inner and outer, such that the body performs culturally informed practices, and, in turn, shapes culture (Crossley, 1995).
Observing Erotic Videos With Heterosexual Content Induces Different Cerebral Responses in Homosexual and Heterosexual Men
Published in Journal of Homosexuality, 2020
Claudia Amezcua-Gutiérrez, Hernández-González Marisela, Alonso Fernández Guasti, Manuel Alejandro Cruz Aguilar, Miguel Angel Guevara
Some studies have used beta oscillations as an index of visual perception (Piantoni, Kline, & Eagleman, 2010), cognitive and emotional processes (Ray & Cole, 1985), vigilance, arousal, and selective attention to relevant stimuli (Wrobel, 2000), whereas gamma activity has been associated with the integration of features into a coherent percept (Tallon-Baudry, Bertrand, Peronnet, & Pernier, 1998; Zion-Golumbic & Bentin, 2007) and conscious perception of the external world (Huges, 2008), as well as cognitive processing and perceptual experience (Başar-Eroglu et al., 1996; Rieder et al., 2011). As was mentioned in the Introduction, the prevalence of the theta (Başar, 1999) and gamma bands (Başar-Eroglu et al., 1996) in the frontal cortices has been observed during the processing of bimodal sensory stimulation, demonstrating that complex sensory events increase frontal cognitive processing in the theta and gamma range (for a review, see Başar et al., 2001). In this work, we also observed an increased AP of these same bands (theta and gamma) in the prefrontal subregions of the homosexual men during observation of the erotic video with heterosexual content, which confirms the suggestion that they could apply greater cognitive and emotional processing to erotic stimuli. This cognitive processing could involve selective attention (focusing on the man with penile erection more than the woman), cognitive flexibility, and inhibition, which allowed subjects to have different perceptions of the erotic video (i.e., pleasant vs. unpleasant) and, hence, reach different degrees of sexual arousal.