If we review the history of practically any place, rare is the place that does not have one or more ghostly apparitions and extrasensory experiences that include the presence of wandering spirits. But why do so many people see ghosts? That is the question that BR Kartheek and his colleagues attempted to answer in an interesting 2013 review published in the ‘ International Journey of Pharmaceutical & Biological Archives ‘.
There are many different diseases whose list of symptoms includes the appearance of visual hallucinations . Some of the best known examples are schizophrenia, Parkinson’s or Alzheimer’s, although there are others that also cause hallucinations such as Creutzfeldt Jacbo disease or bovine spongiform encephalopathy (the well-known ‘mad cow disease’) and dementia due to bodies of Lewy . Some of these diseases cause the perception of percepts to be altered (a term coined by the philosopher Giles Deleuze), the different perceptions that can be had before the same stimulus .
The authors of the work pointed out that the presence of this type of phenomena would have a neural basis , more specifically related to the atrophy of brain areas that are dedicated to visual perception, such as the parietal areas . In other works, such as the one published in ‘ Progress in Neurobiology ‘ in 2014 , a team of Australian researchers highlighted an interesting distinction between different types of hallucinations and their relationship with brain networks of attention . It differentiated between simple visual hallucinations in which attention does not participate in the regulation of the perceptual process , complex visual hallucinations that are related to an alteration in the attention control networks (it would lead to a misinterpretation of ambiguous percepts) and complex visual hallucinations without awareness or feeling , which may be associated with less activity in the dorsal network of attention in which the frontal cerebral cortex and the posterior dorsal parietal cortex are involved.
This knowledge about the phenomenon allows us to eliminate the stigma that the visualization of spirits or ghosts has associated with for a long time and allows us to generate appropriate intervention strategies , such as training in attentional control and inhibition, which can improve this symptom in certain cases. Although it is only the first investigations, the results provided a good knowledge from which to start for new projects that delve further into the subject.
Marisa Fernández, Senior Neuropsychologist, Unobrain.
