Oliver Sacks in the book published by Adelphi in 2009 - almost autobiographical - The mind's eye highlights its own perceptual disturbance: prosopagnosia. Nonetheless, it is the inability to recognize people's faces and sometimes even everyday objects or places, in the most serious cases. This inability is a real cerebral cortical limit:the face - or objects or places - are not "seen" by the affected patient, but they see an eye or a nose, because they are totally unable to associate these elements with a complete face and, subsequently , recognized. It could be said that they see a lump and nothing more, due to the associative deficit.
First of all, it is a real disease:the diagnosis it must be performed by a neurologist, therefore a surgeon specializing in treating anatomical problems of the brain as well as operating the telencephalon . The telencephalon is the correct anatomical term that would replace the more common "brain", as this is made up of different areas and tissues, as well as specialized and diverse sections - bulb, midbrain, medulla, cerebellum. In the telencephalon, the medial temporal lobe undergoes an impairment, such as a systemic ablation. The synapses between neurons they are destroyed, the tissue dies, there is only a cellular compound that is no longer functional. Therefore we speak of physiology. Neurons need nourishment to function and in this area every type of adjuvant cell decays ( astrocytes , for example) and in addition to this the neurotransmitters stop arriving in this area. It has been written sociological:prosopoagnosia, as we will see later, involves an entire circuit of doctors, specialists, family members of the patient as well as discomfort with the real world.
We now come to the steps of history for the affirmation of this disease as a non-psychiatric but a psychological disease.
In the seventeenth century The first studies were made, but the general idea was this:the soul could not stay in a piece of meat, the brain. Descartes he was a pioneer in the opposite direction:he proposed a first dualism, as is known, between mind and body. Doctors of the time were almost enthusiastic about studying the effects of stroke , injuries cerebral - trauma of war or work and so on. At that time it was suspected of the existence of a link between brain and mental functions.
Franz Joseph Gall , a German doctor of the twenty-eighth century, therefore proposed that mental functions originated from the brain, not from the soul or the heart or the liver, but from the telencephalon. Gall's theory was to believe that the brain was divided into 27 organs , each responsible for a moral or mental faculty. This ran into ethical-religious problems:the soul could not be segregated in an organ. Moral faculties are what neuroscientists today call perceptual functions , the cognitive faculties and moral traits :knowing how to distinguish colors, do calculations, have musical aptitudes, logical reasoning, linguistic skills, sociability, behavioral characteristics such as anger, joy, shyness and so on. This, however, cost Gall exile:he took refuge in France. Here he met Jean-Pierre Flourens (1794-1867) :he performed the experiments on the brains of pigeons starting from the assumptions of Gall. He divided the small organs into sections looking for correlations, without obtaining any feedback. Obviously at the time the ablations they were complicated to perform on such small beings. But the Frenchman's sentence was only one:"the brain secretes thoughts as the liver secretes bile".
After a very long silence that lasted until the end of the 1860s, the figure of Paul Broca (1824-1880) emerges . These studied patients with expressive aphasia - their faces did not give emotional signals, they were paralyzed in the same neutral expression - showing that they had limited damage to the left frontal lobe, therefore behind the left eye. In 1865 Broca stated that "we talk to our left hemisphere". Therefore, in spite of the previous beliefs and validated by Flourens, the brain was not a homogeneous and equipotent organ to the liver, a simple organ without any "superior" faculty :cognitive abilities resided there. In particular, the cognitive faculty of visual recognition, among many others.
In 1947 Joachim Bodamer (1910-1995) - German neurologist - described three patients. They not only recognized faces and to understand who they were in front of, they used gimmicks such as clothing, hair styling, voice, all distinctive traits of a person - but never as much as the face.
In 1955 Christopher Pallis (1923-2005) - English neurologist - publishes a new study:some patients did not even recognize the colors, the places where they were born or lived. However, the deficit was also linked to the visual field , which has a correlate in the brain, namely the lower face of the cortex occipitotemporal ( after the ears and towards the nape of the neck, in vulgar language). It is a different and distinct area from the one studied by Broca and studies open to even more specific agnosies. Other studies followed, performed on deceased patients, during their autopsies. Later, thanks to computed tomography , a sort of brain scanner, and magnetic resonance imaging tests could be performed in vivo , analyzing the responses of patients and without harming them. It was Dominic Fflychte to give a name to this area: the fusiform area for facial recognition. In short, a specific brain lobe was responsible for recognizing faces and if injured - stroke, tumors, infections - could give this problem: prosopoagnosia .
Christof Koch (1956, -) and colleagues noted increased activity of the medial temporal lobe ( therefore once again of that area of gray matter that is located approximately behind the ears).
But what are the effects of this injury?
Oliver Sacks offers several examples. An individual stops recognizing faces, therefore also himself in the mirror or loved ones in photography. But what if it all happened to a neuroscientist or… to Sacks? Here, the disease did not spare even those who had studied it for so long. Oliver Sacks wrote The Mind's Eye also to be able to narrate personal experience in the face of prosopagnosia. It masterfully illustrates how failing to recognize people feels awkward, does not feel at ease in crowded environments because even with the expedient of observing details - hairstyles, dresses, jewelry, gowns, bags - socializing is complicated. Imagine a loved one who suddenly no longer recognizes your face:it would mean that among many people your boyfriend or girlfriend, your best friend or neighbor would become a stranger. Your wife or husband of strangers in the house, even in the knowledge that you have a husband or wife or children. If it gets worse, you could find yourself in front of your home without even knowing that it is your home and so on.
How can a patient react in such conditions? He can get help by asking politely to wear a name tag on his clothes, explain what the difficulties are.
The problem of acceptance is twofold:understanding that your brain is not working well and making others understand that you are not crazy, but that you have a brain injury and therefore you cannot do otherwise. There are no cures other than training in recognition through the mimicry of people, their way of walking or their voice. How complicated is it all! If two people are dressed alike:how to tell them apart if they don't talk?
There are so many social and ethical dilemmas. The patients involved are about 2% in the United States, which means that it is not such an unusual, albeit rare, disease. Sacks met a Chinese who also said that in China he had no difficulty, while with Westerners, yes, because they are all the same. It may seem funny, but the hometown is influential in these pathologies, especially as regards the social sphere. Now there are also several websites or books or even TV shows - like Perception - who treat or talk about this disease, this deficit. There are also listening centers or community help centers, to ensure that the patient does not feel insane. Otherwise:he is well aware of his condition.
ANNA MARIA VANTINI
READING LIST:
- Valentina Moro, Barbara Filippi, Brain plasticity , SEID, Florence, 2009
- Oliver Sacks, The Mind's Eye , Adelphi, Milan, 2011
- Aleksandr Lurija, A lost and found world , Adelphi, Milan, 2015
- Berti, Neuropsychology of Consciousness , Bollati Boringhieri, Turin, 2010
- Purves et al., Cognitive neuroscience , Zanichelli, Turin, 2014