What is a post mortem? How have post mortems been used throughout history? A post mortem examination is a famous technique used to examine the brain and body after death. Psychology has employed post mortem examinations in the past to determine brain function, based on abnormalities present in the patient before their death. Nowadays, more modern techniques, such as functional magnetic resonance imaging (fMRI) can be used, but post mortems still have their place in the field of medicine and psychology.
- We are going to delve into the world of post mortems.
- First, we will establish post mortem examination meaning.
- Then, we will explore the history of post mortem examinations, identifying key strides in post mortem use.
- Finally, we will provide an evaluation of post mortem examinations, discussing the advantages and disadvantages of post mortem examinations in psychology.
Post Mortem Examination Meaning
Post mortem examinations (also referred to as an autopsy) are performed after death and are a technique used to examine the body and brain and potentially identify any abnormalities.
Usually, a coroner (if the death is sudden or suspicious) or a doctor (to learn more about why the death occurred) requests a post mortem. Nowadays, a pathologist is in charge of carrying out the post mortem examination.
Post mortem examinations are useful to find damaged areas in the brain and assign a function to those damaged areas based on how the patient behaved or suffered before their death.
After performing a post mortem on a patient who couldn’t speak and only said the word ‘tan,’ scientists found lesions in his brain’s left hemisphere in the frontal cortex. Therefore, they concluded that language function occurs in that area now known as Broca’s area.
Fig. 1: An illustration of a post mortem of the brain in 1905 for students, Wikimedia Commons.
History of Post Mortem Examinations
Professionals and medical practitioners have performed post mortem examinations throughout history. They have been incredibly valuable in the advancement of knowledge of human anatomy.
Galen of Pergamum was the first Greek physician to use post mortems as a means to connect patients' symptoms they suffered in life with abnormalities found in the body after death (Britannica, 2020).
The study of anatomy progressed throughout the ages using post mortems after connecting abnormalities with symptoms and studying the human body became more accessible.
Particular strides occurred in the 13th century, 1302 (the first forensic investigation using post mortems), the Renaissance period, and the 18th century, where Giovanni Morgagni (the father of modern anatomical pathology) pioneered examining the body and documenting it using the naked eye (Britannica, 2020).
Giovanni Morgagni published "De sedibus et causis morborum per anatomen indagatis", Of the seats and causes of diseases investigated through anatomy, which established the study of anatomical pathology as a credible science.
Since then, post mortems have continued to develop in both procedure, report format, and medical significance.
Fig. 2: De sedibus et causis morborum per anatomen indagatis", Of the seats and causes of diseases investigated through anatomy.
The Procedure of a Post Mortem Examination
In a post mortem, pathologists may examine areas of interest first but tend to vary in how they examine the body and brain, depending on professional preferences.
Typically, they will treat the brain using a chemical fixative or preservative (such as formaldehyde) to make it firm and to preserve it for future investigations.
Treatments help them cut the brain into sections and examine it without it falling apart.
Once a post mortem is performed and completed, the pathologist will give a detailed report of the observed issues to the coroners office, including areas of damage or areas that are out of the norm. The report helps the diagnosis process and helps people understand what could have been the cause of any abnormalities when the patient was alive.
Examples of Post Mortem Examinations in Psychology
A post mortem examination can be helpful in many different areas of psychology when trying to understand the reasons behind a patient’s atypical behaviour.
For instance:
Mackay et al. (1982) found that the brains of patients with schizophrenia in a post mortem examination had an increased amount of dopamine and dopamine receptors compared to a neurotypical person. The study helped researchers understand the role dopamine plays in schizophrenia. Further research helped the development of the dopamine hypothesis.
When examining HM, a famous case cited in psychology, Annese et al. (2014) found that the patient had lesions in his hippocampus. He had suffered from epileptic seizures throughout his life and when he was 27 years old he had brain surgery to help alleviate the symptoms. However, after the surgery, HM couldn’t store new memories or remember previous moments of his life. His language and motor skills weren’t affected, but he couldn’t learn new things or store them in his brain. The discovery of the hippocampus’ lesions thus confirmed its role in the storage and formation of new memories.
Post Mortem Examination Report Format
Pathologists write and report the findings of a post mortem to the coroner's office. A post mortem report format includes the examination of the head, neck, facial features, and body of the person. They will also include measurements such as blood content, and tissue specimens (think liver, hair, bile, and brain tissues).
Any specific abnormalities are noted.
Schizophrenic patients often take antipsychotic drugs that affect their neurotransmitter levels, such as dopamine and serotonin. Because of this, when a person with schizophrenia dies, a pathologist needs to take into account any abnormalities with their dopamine and serotonin levels alongside their potential drug level intakes.
If the patient had high dopamine levels in their brain, and we examined their brain tissue, we couldn’t simply conclude that ‘dopamine is the cause of schizophrenia.’ We would have to acknowledge the patient was taking a drug that facilitates dopamine release and inhibition. Otherwise, this would skew our results and conclusions!
Evaluation of Post Mortem Examinations in Psychology
Like in other techniques of studying the brain, there are advantages and disadvantages of post mortem examination in psychology.
Advantages of Post Mortem Examinations in Psychology
First, let's examine the strengths of post mortem examinations.
High spatial resolution (provides detailed examinations): as the post mortem examination allows scientists to dissect and analyse the brain to an extensive degree, it provides a detailed insight into the brain and its structural form. This means the post mortem has a high spatial resolution compared to other techniques. They can examine the brain on an anatomical and neurochemical level, and structures such as the amygdala and hippocampus are accessible. This is not possible with other techniques, such as an EEG.
Deeper understanding: as the studies above demonstrate post mortem examinations have allowed for a deeper understanding of dysfunction in the brain. This provides valuable evidence for different hypotheses and allows researchers to delve deeper into certain areas of the brain. Post mortem examinations act as a guide in some cases and have shone a light on potential brain functional areas, and how lesions affect them.
Functional evidence: researchers have found damage in certain areas of the brain and they have been able to attribute specific functions to those areas as a result. Broca’s and Wernicke’s areas are both great examples. They were discovered at a time when advanced techniques such as the EEG and an fMRI were not available.
Disadvantages of Post Mortem Examinations in Psychology
Now, let's examine the weaknesses of post mortem examinations.
Environmental and life factors: as post mortem examinations can only be done when a person has died, they can’t actively examine the brain during life to provide a diagnosis like other brain-studying techniques.
Causation: a post mortem examination can only show what damage exists in the brain after death, and suggest that the damaged area may be responsible for any pathophysiology the patient experienced during life. It’s not possible to say the damage is the cause; therefore, post mortem examinations are only correlational, not causal.
- Reynolds (1988) found that antipsychotic drug use affected the number of dopamine receptors in the brains of schizophrenic patients. Antipsychotics are common treatments for schizophrenic patients, so someone could conclude from this data that an abnormal amount of dopamine receptors in the brain causes schizophrenia. However, we cannot causally prove the relation between dopamine receptors and schizophrenia here, as it’s difficult to isolate the variables and recognise that there is a correlational link, but no causation.
Ethical issues: a post mortem examination occurs after death, and is incredibly invasive on the body. It isn’t always possible to get informed consent, especially if the person’s psychological state and ability to give consent are severely affected by their disorder. If a person can’t fully understand what they’re agreeing to, it’s hard to gain full consent making the procedure ethically questionable.
Post Mortem Examination - Key takeaways
- A post mortem examination is performed after death to examine the body and brain.
- Broca’s and Wernicke’s areas are both good examples of discoveries made after a post mortem examination.
- Researchers have used post mortem examinations throughout history to investigate different disorders and try to find damaged areas in the brain and body that correlate with the symptoms.
- A post mortem examination has high spatial resolution and can give a deeper understanding of brain abnormalities, to an anatomical and neurochemical degree.
- A post mortem examination cannot provide causal proof, however. Damage to certain areas of the brain doesn’t always mean those areas are functionally responsible for symptoms in life.
References
- Britannica, T. Editors of Encyclopaedia (2020, February 14). autopsy. Encyclopedia Britannica. https://www.britannica.com/topic/autopsy
- Fig. 2: Biblioteca Europea di Informazione e Cultura, Public domain, via Wikimedia Commons
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