Postmortem studies are a type of

neurobiological Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developme ...

research, which provides information to researchers and individuals who will have to make medical decisions in the future.Breeze, A. G., Statham, H., Hackett, G. A., Jessop, F. A., & Less, C.C. (2012). Perinatal postmortems: What is important to parents and how do they decide?. Birth: Issues In Perinatal Care, 39(1), 57-64. doi: 10.1111/j.1523-536X.2011.00513.x Postmortem researchers conduct a

longitudinal study A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of ob ...

of the brain of an individual, who has some sort of phenomenological condition (i.e. cannot speak, trouble moving left side of body, Alzheimer's, etc.) that is examined after death. Researchers look at certain lesions in the brain that could have an influence on cognitive or motor functions.Sternberg, R. J., & Sternberg, K. (2012).Cognitive Psychology (6th ed.). Belmont, CA: Wadsworth/Cengage Learning. These irregularities, damage, or other cerebral anomalies observed in the brain are attributed to an individual's pathophysiology and their environmental surroundings.Yehuda, R. (2004). Commentary on 'Brain Environment Interactions: Stress, posttraumatic stress disorder, and the need for a postmortem brain collection': Understanding heterogeneous effects of trauma exposure: Relevance to postmortem studies of PTSD. Psychiatry: Interpersonal And Biological Processes, 67(4), 391-397. doi:10.1521/psyc.67.4.391.5672 Postmortem studies provide a unique opportunity for researchers to study different brain attributes that would be unable to be studied on a living person.McCullumsmith, R. E., & Meador-Woodruff, J. H. (2011). Novel approaches to the study of postmortem brain in psychiatric illness: Old limitations and new challenges. Biological Psychiatry, 69(2), 127-133. doi:10.1016/j.biopsych.2010.09.035 Postmortem studies allow researchers to determine causes and cure for certain diseases and functions. It is critical for researchers to develop hypotheses, in order to discover the characteristics that are meaningful to a particular disorder. The results that the researcher discovers from the study will help the researcher trace the location in the brain to specific behaviors. When tissue from a postmortem study is obtained it is imperative that the researcher ensures the quality is adequate to study. This is specifically important when an individual is researching gene expression (i.e. DNA, RNA, and proteins). Some key ways researchers monitor the quality are by determining the pain level/time of death of the individual, pH of the tissue, refrigeration time and temperature of storage, time until the brain tissue is frozen, and the thawing conditions. As well as finding out specific information about the individual's life such as: age, sex, legal/illegal substance use, and a treatment analysis of the individual.Pidsley, R., & Mill, J. (2011). Epigenetic studies of psychosis: Current findings, methodological approaches, and implications for postmortem research. Biological Psychiatry, 69(2), 146-156. doi:10.1016/j.biopsych.2010.03.029

Background

Postmortem studies have been used to further the understanding of the brain for centuries. Before the time of the

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

, CAT Scan, or

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

it was one of the few ways to study the relation between behavior and the brain.

Broca

Paul Broca Pierre Paul Broca (, also , , ; 28 June 1824 – 9 July 1880) was a French physician, anatomist and anthropologist. He is best known for his research on Broca's area, a region of the frontal lobe that is named after him. Broca's area is involve ...

used postmortem studies to link a specific area of the brain with speech production. His research began when he noticed that a patient with an aphasic stroke had

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

in the left hemisphere of his brain. His research and theory continued over time. The most notable of his research subjects was Tan (named for the only syllable he could utter). Tan had lesions in his brain caused by syphilis. These lesions were determined to cover the area of his brain that was important for speech production. The area of the brain that Broca identified is now known as

Broca's area Broca's area, or the Broca area (, also , ), is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production. Language processing has been linked to Broca's area since Pierr ...

; damage to this section of the brain can lead to

Expressive aphasia Expressive aphasia, also known as Broca's aphasia, is a type of aphasia characterized by partial loss of the ability to produce language ( spoken, manual, or written), although comprehension generally remains intact. A person with expressive apha ...

Wernicke

Karl Wernicke Carl (or Karl) Wernicke (; ; 15 May 1848 – 15 June 1905) was a German physician, anatomist, psychiatrist and neuropathologist. He is known for his influential research into the pathological effects of specific forms of encephalopathy and also ...

also used postmortem studies to link specific areas of the brain with speech production. However his research focused more on patients who could speak, however their speech made little sense and/or had trouble understanding spoken words or sentences. His research in language comprehension and the brain also found it to be localized in the left hemisphere, but in a different section. This area is known as

Wernicke's area Wernicke's area (; ), also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to B ...

; damage to this section can lead to

Receptive aphasia Wernicke's aphasia, also known as receptive aphasia, sensory aphasia or posterior aphasia, is a type of aphasia in which individuals have difficulty understanding written and spoken language. Patients with Wernicke's aphasia demonstrate fluent ...

Benefits

Postmortem studies allows for researchers to give information that is relevant to individuals by explaining the causes of particular diseases and behaviors. This is in hopes that others can avoid some of these experiences in the future. Postmortem studies also improve medical knowledge and help to determine whether changes happen in the brain itself or in the actual disorder. By doing this researchers are then able to help prioritize experimental studies and integrate the studies into animal and cell research. Another benefit to postmortem studies is that researchers have the ability to make a wide range of discoveries, because of the many different techniques used to obtain tissue samples. Postmortem studies are extremely important and unique despite their limitations.Harrison, P. J. (2011). Using our brains: The findings, flaws, and future of postmortem studies of psychiatric disorders. Biological Psychiatry, 69(2), 102-103. doi: 10.1016/j.biopsych.2010.09.009

Limitations

Postmortem brain samples are limited resources, because it is extremely difficult for a researcher to get a hold of an individual's brain. The researchers ask their participants or the families to consent to allowing them to study the loved one's brain, however there has been a falling rates of consent in the last few years. Subsequently, researchers have to use indirect methods to study the locations and processes of the brain. Another limitation to postmortem studies is the continuous funding and the time it takes to conduct a longitudinal study. Postmortem longitudinal studies usually take place at the time of assessment until the time of death about 20–30 years.

References

{{Reflist Research methods Neuroscience Forensic pathology