Phantoms in the Brain | V.S. Ramachandran

Summary of: Phantoms in the Brain: Probing the Mysteries of the Human Mind
By: V.S. Ramachandran

Introduction

Embark on a fascinating journey into the human brain with the book ‘Phantoms in the Brain: Probing the Mysteries of the Human Mind’ by V.S. Ramachandran. Explore the intricate world of neurological disorders and unravel the enigma behind each part of the brain. Understand how the left and right hemispheres are specialized for unique tasks, learn about phantom limb syndrome and its link with our internal body image, and uncover the complex phenomena of perception. This engaging summary simplifies the complex world of neuroscience for those intrigued by the workings of the human brain.

The Brain and Its Wonders

Neurological disorders are the window to understanding each part of the brain. Researchers no longer need to conduct experimental surgery with the advent of technologies such as transcranial magnetic stimulators. Each section of the brain is specialized in distinct tasks, with even asymmetry in the left and right hemispheres. Through these disorders, researchers are afforded the opportunity to understand the brain’s complex functions without causing harm.

The Ghostly Limbs Within

Our internal body image and physical body can be misaligned, causing phantom limbs that persist for years after the loss of the limb. The phantom limb syndrome is caused by the continued signals sent to the area of the brain responsible for controlling the limb even when it’s gone. The brain’s representational map of the body is responsible for the persistence of the ghostly memories of the limbs in phantom-limb syndrome. Phantom-limb syndrome not only affects our limbs but also other phantom appendages such as phantom erections and phantom breasts. Even though the existence of phantom limbs could suggest the existence of immaterial forms, the internal body image is still dependent on our brains, suggesting that it wouldn’t survive the total loss of the body.

One Side Neglect

Hemi-neglect patients exhibit a profound indifference to the left side of the world. Perception involves many different processes – and not all of them are conscious.

Ellen’s family noticed some peculiarities that left them distraught after her return from the hospital. Ellen had hemi-neglect, a syndrome arising from the right parietal lobe’s stroke that causes one to be profoundly indifferent to the left side of the visual field. It isn’t blindness; it’s just an unconscious disregard for those perceptions. The author suggests that perception is the result of numerous unconscious processes that work together, and we still haven’t comprehensively grasped how they work. While we know that the right parietal lobe is crucial to this process, there are around thirty other brain regions involved in it. Regression modeling can provide insight into which areas of the brain are crucial for particular perception phenomena.

Remarkably, research indicates that hemi-neglect patients’ non-dominant brain’s perceptual processes continue to work even though the searchlight mechanism is impaired. These processes are unconscious, meaning that the individual is not aware of them. In simple terms, these patients are unable to see or comprehend new objects in the left field, such as a splash of red on that side, but they still view other aspects of the object subconsciously.

In conclusion, consciousness is not singular, but instead, the byproduct of many different processes working together. This idea is quite intriguing and raises several questions about the nature of human perception.

The Rationality of Delusions

When patients with Capgras syndrome believe their loved ones have been replaced by duplicates, they are not necessarily irrational. From the perspective of their altered reality, their delusions make sense. A neurologist’s task is not to dismiss but to understand what has changed in a patient’s brain that creates this specific delusion. Studies have shown that Capgras patients exhibit no change in their galvanic skin response when they see an image of their mother, which indicates a total lack of response from the limbic system. It’s possible that the emotional response elicited from the limbic system helps the brain identify who we’re looking at. Therefore, when a patient looks at their mother and feels nothing towards her, the brain might conclude that this person is not really their mother, but a copy.

The Neurological Basis for Denial

A case study of patients with anosognosia – the inability to perceive one’s own illness – reveals the neurological origins of denial. Patients with right hemisphere brain damage display a lack of awareness and concern for their paralysis, while those with left hemisphere damage display the opposite tendencies. The connection between neurological damage and psychological problems may provide new avenues for treatment.

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