Symptom Breakdown: Tactile Hallucinations

Suggested Reading

Schizophrenia

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Tactile hallucinations, also known as somatic or visceral hallucinations, are a perception of touch which is not consistent with reality. Tactile hallucinations include the feeling of movement under the skin, such as insects crawling under the skin, as well as the feeling of movement or touching on the surface of the skin (Kathirvel & Mortimer, 2013). These hallucinations have a high co-occurrence with olfactory hallucinations, and are much less common than either auditory or visual hallucinations in those experiencing schizophrenia. Individuals who experience childhood-onset schizophrenia are more likely than mid or late-onset sufferers to experience these hallucinations (Mueser et al., 1990).

Article: Induction Of An Illusory Shadow Person

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Delusions of Control

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In my review of the schizophrenic delusion of control I noted that a reduction in long-range connections between the frontal and posterior regions of the brain, specifically the supplementary motor area, was likely to be the cause for the disconnection between conscious and unconscious decision making with respect to movement. I also made note of the fact that while damage to this area results in a similar phenomenon in people without schizophrenia, the delusional belief that an external force is controlling the sufferers behaviour was unique to individuals who suffer from delusions of control. At the time I was unaware of any explanation for this phenomenon, the feeling that an external force was controlling the individual’s movements, but it is clear that this belief in an often malicious force controlling or interfering with the actions of the individual is a common aspect to many forms of delusion experienced by people with schizophrenia.

Mini-Review: Morphology of Pyramidal Neurons in Schizophrenia

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Mini-Review: Dendritic Spine Density

Background Information for Mini-Reviews

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In the previous mini-review we explored the differences in dendritic spine density of pyramidal neurons in the brains of people with schizophrenia compared to those without schizophrenia. Due to the severity of this dendritic spine deficiency it seemed unlikely that these pyramidal neurons were otherwise unaffected. Having explored this area of research further, it has become clear that not only do the pyramidal neurons of people with schizophrenia present with fewer spines than those without the illness, but these neurons also show deficiencies in soma size, dendrite length, and dendritic branching.

Article: The Role of Human Evolution in the Development of Schizophrenia

Relevant Pre-Reading:

Schizophrenia

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Recently, theories have been circulating about genes related to schizophrenia potentially being selected for during human evolution. While this may explain the prevalence of schizophrenia, with 0.3-0.7% of people developing the illness at some point in their lives, it is probably too simple of a story. The article we discuss below, by Xu et al. (2015), aims to look much more closely at this phenomenon and determine whether or not it is true.

Mini Review: Dendritic Spine Density in the Prefrontal Cortex in Relation to Schizophrenia

Background Information

There is a lot of research which indicates that specific layers of pyramidal neurons are different in the brains of people with schizophrenia. In this post we’re going to be looking specifically at dendritic spine density in these populations, what this tells us about the overall functioning of these neurons, and the knock-on effects this can have on the conscious functioning of individuals.

Article: Pathway Analyses Implicate Glial Cells in Schizophrenia

Relevant Pre-reading
Schizophrenia

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Very briefly, this research tested 10 genetic pathway sets for their association to schizophrenia and bipolar disorder. The pathways dealt with glial cells, mitochondria, and glutamate, each of which has been implicated in the development of schizophrenia. They found a highly significant association between glial cell SNP’s and schizophrenia.

Article: Increased L1 Retrotransposition in the Neuronal Genome in Schizophrenia

Relevant Pre-Reading

Schizophrenia

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As far as the testing and conclusions go; this is clean research. The scientist involved began with a broad hypothesis: “Are L1 retrotransposon numbers greater in people suffering from mental illness?”. Their testing led them to discovering a high number of L1 retrotransposons in the postmortem prefrontal cortexes of people who, in their lives, had suffered from schizophrenia. There was no significant increase in the number of L1 units in the brains of patients who had experienced depression, or bipolar disorder. By allowing the data reveal this trend they began with a strong theoretical base for further experiments. In their follow-up experiments they were able to narrow their scope, focusing on the relationships between the L1 retrotransposon and known genes for schizophrenia, such as 22q11, and then on similarly focused animal models.

If you’re not too intimidated by long academic reports it is well worth a read, but if you’d prefer a quick rundown keep reading.