Uploaded March 2025 | Updated September 2026, 2 weeks ago
Prion diseases, also known as transmissible spongiform encephalopathies, are a group of neurodegenerative diseases that involve the accumulation of an abnormal form of a protein called prion protein into aggregates that are resistant to being broken down by brain enzymes. In this video, I discuss the general characteristics of prion diseases, including the pathophysiology, epidemiology, and prognosis.
đź§ Take your learning further with my free, self-paced Introduction to Neuroscience course featuring my videos, articles, and hundreds of quiz questions: neuroscientificallychallenged.com/course
If you're looking for accessible and entertaining ways to learn more about the brain, check out my books:
📚Your Brain, Explained: What Neuroscience Reveals About Your Brain and its Quirks: amazon.com/Your-Brain-Explained-Neuroscience-Reveals/dp/1473696569
📚Bizarre: The Most Peculiar Cases of Human Behavior and What They Tell Us About How the Brain Works: amazon.com/Bizarre-Peculiar-Cases-Human-Behavior/dp/139980121X
TRANSCRIPT
Prion diseases, also known as transmissible spongiform encephalopathies, are a group of neurodegenerative diseases that involve the accumulation of an abnormal form of a protein called prion protein into aggregates that are resistant to being broken down by brain enzymes.
The formation of these protein aggregates is associated with pathological changes in the nervous system, such as the formation of tiny holes in grey matter, which gives the tissue a sponge-like appearance. There is also a loss of neurons and other signs of brain pathology, which are associated with symptoms that rapidly worsen over time. The symptoms vary depending on the specific prion disease, but include severe cognitive decline and a variety of neurological problems. Prion diseases are incurable and always result in death; there is currently no treatment recognized to be effective in improving someone’s prognosis.
Unlike other infectious agents, the agent that causes prion diseases seems to consist only of an abnormal form of a protein. Hence the term prion, which is an amalgamation of “proteinaceous infectious particle.” The pathogenic form of prion protein seems to be capable of transmitting its pathogenic state to other, previously healthy, proteins. Additionally, pieces of protein aggregates sometimes break off, and the particles can form additional aggregates. In these ways, prion diseases cause the spread of pathology throughout the central nervous system.
Prion diseases are not transmitted like typical infectious diseases. There is no evidence, for example, of them being transmitted through casual contact. Only a very small percentage of cases are due to an acquired infection. Documented cases of acquired infections have occurred through consumption of contaminated meat or accidental transmission through a medical procedure. Approximately 10-15% of prion diseases are inherited and clearly traceable back to a mutation in the prion protein gene, but most cases are sporadic, without a known cause.
REFERENCES
Piñar-Morales R, Barrero-Hernández F, Aliaga-MartĂnez L. Human prion diseases: An overview. Med Clin (Barc). 2023 Jun 23;160(12):554-560. English, Spanish. doi: 10.1016/j.medcli.2023.03.001. Epub 2023 Apr 21. PMID: 37088611.
Zerr I, Ladogana A, Mead S, Hermann P, Forloni G, Appleby BS. Creutzfeldt-Jakob disease and other prion diseases. Nat Rev Dis Primers. 2024 Feb 29;10(1):14. doi: 10.1038/s41572-024-00497-y. PMID: 38424082.
Picture of spongiform degeneration of gray matter from Tulemo on Wikipedia: en.wikipedia.org/wiki/Transmissible_spongiform_encephalopathy#/media/File:Spongiform_degeneration_in_Creutzfeldt-Jakob_disease.jpg
📝 Pass your next test with my 2-minute neuro videos!
My name is Marc, and I want to immerse you in the fascinating world of neuroscience. When I'm not making videos, I'm a university professor at Penn State. I made this channel to help simplify complex topics into easy-to-understand snippets, perfect for students & enthusiasts alike. 📚
I aim to make learning about the brain fun and easy. Whether you're a student seeking to supplement your studies or a curious mind eager to understand the basics of neuroscience, this channel will provide valuable insights and knowledge into the human brain.
Subscribe and join our journey into the mind! đź§
Prion diseases, also known as transmissible spongiform encephalopathies, are a group of neurodegenerative diseases that involve the accumulation of an abnormal form of a protein called prion protein into aggregates that are resistant to being broken down by brain enzymes. In this video, I discuss the general characteristics of prion diseases, including the pathophysiology, epidemiology, and prognosis.
đź§ Take your learning further with my free, self-paced Introduction to Neuroscience course featuring my videos, articles, and hundreds of quiz questions: neuroscientificallychallenged.com/course
If you're looking for accessible and entertaining ways to learn more about the brain, check out my books:
📚Your Brain, Explained: What Neuroscience Reveals About Your Brain and its Quirks: amazon.com/Your-Brain-Explained-Neuroscience-Reveals/dp/1473696569
📚Bizarre: The Most Peculiar Cases of Human Behavior and What They Tell Us About How the Brain Works: amazon.com/Bizarre-Peculiar-Cases-Human-Behavior/dp/139980121X
TRANSCRIPT
Prion diseases, also known as transmissible spongiform encephalopathies, are a group of neurodegenerative diseases that involve the accumulation of an abnormal form of a protein called prion protein into aggregates that are resistant to being broken down by brain enzymes.
The formation of these protein aggregates is associated with pathological changes in the nervous system, such as the formation of tiny holes in grey matter, which gives the tissue a sponge-like appearance. There is also a loss of neurons and other signs of brain pathology, which are associated with symptoms that rapidly worsen over time. The symptoms vary depending on the specific prion disease, but include severe cognitive decline and a variety of neurological problems. Prion diseases are incurable and always result in death; there is currently no treatment recognized to be effective in improving someone’s prognosis.
Unlike other infectious agents, the agent that causes prion diseases seems to consist only of an abnormal form of a protein. Hence the term prion, which is an amalgamation of “proteinaceous infectious particle.” The pathogenic form of prion protein seems to be capable of transmitting its pathogenic state to other, previously healthy, proteins. Additionally, pieces of protein aggregates sometimes break off, and the particles can form additional aggregates. In these ways, prion diseases cause the spread of pathology throughout the central nervous system.
Prion diseases are not transmitted like typical infectious diseases. There is no evidence, for example, of them being transmitted through casual contact. Only a very small percentage of cases are due to an acquired infection. Documented cases of acquired infections have occurred through consumption of contaminated meat or accidental transmission through a medical procedure. Approximately 10-15% of prion diseases are inherited and clearly traceable back to a mutation in the prion protein gene, but most cases are sporadic, without a known cause.
REFERENCES
Piñar-Morales R, Barrero-Hernández F, Aliaga-MartĂnez L. Human prion diseases: An overview. Med Clin (Barc). 2023 Jun 23;160(12):554-560. English, Spanish. doi: 10.1016/j.medcli.2023.03.001. Epub 2023 Apr 21. PMID: 37088611.
Zerr I, Ladogana A, Mead S, Hermann P, Forloni G, Appleby BS. Creutzfeldt-Jakob disease and other prion diseases. Nat Rev Dis Primers. 2024 Feb 29;10(1):14. doi: 10.1038/s41572-024-00497-y. PMID: 38424082.
Picture of spongiform degeneration of gray matter from Tulemo on Wikipedia: en.wikipedia.org/wiki/Transmissible_spongiform_encephalopathy#/media/File:Spongiform_degeneration_in_Creutzfeldt-Jakob_disease.jpg
📝 Pass your next test with my 2-minute neuro videos!
My name is Marc, and I want to immerse you in the fascinating world of neuroscience. When I'm not making videos, I'm a university professor at Penn State. I made this channel to help simplify complex topics into easy-to-understand snippets, perfect for students & enthusiasts alike. 📚
I aim to make learning about the brain fun and easy. Whether you're a student seeking to supplement your studies or a curious mind eager to understand the basics of neuroscience, this channel will provide valuable insights and knowledge into the human brain.
Subscribe and join our journey into the mind! đź§
![2-Minute Neuroscience: Brown-Séquard Syndrome
Brown-Séquard syndrome is a rare neurological condition caused by damage to one side of the spinal cord, a situation referred to as hemisection of the spinal cord. This type of damage results in a distinct pattern of deficits due to the way different nerve tracts travel through the spinal cord. In this video, I describe the neurological deficits in Brown-Séquard syndrome and the reasons behind their characteristic pattern.
đź§ Take your learning further with my free, self-paced Introduction to Neuroscience course featuring my videos, articles, and hundreds of quiz questions: https://neuroscientificallychallenged.com/course
WATCH MORE
https://youtu.be/Ma4i6nH3qMQ?si=uCCpznvT-7lUao4Q
https://youtu.be/nQfRUehU4zQ?si=M4LErRdeEmzjdl7C
https://youtu.be/gcOqv0uzyAQ?si=8kbRL_2ag-41XHCQ
If youre looking for accessible and entertaining ways to learn more about the brain, check out my books:
📚Your Brain, Explained: What Neuroscience Reveals About Your Brain and its Quirks: https://www.amazon.com/Your-Brain-Explained-Neuroscience-Reveals/dp/1473696569/
📚Bizarre: The Most Peculiar Cases of Human Behavior and What They Tell Us About How the Brain Works: https://www.amazon.com/Bizarre-Peculiar-Cases-Human-Behavior/dp/139980121X/
TRANSCRIPT
Brown-Sequard syndrome is a rare neurological condition caused by damage to one side of the spinal cord, a situation referred to as hemisection of the spinal cord. This type of damage results in a distinct pattern of deficits due to the way different nerve tracts travel through the spinal cord.
Brown-Sequard syndrome involves weakness or paralysis below the hemisection on the same side of the body as the damage, because the spinal cord damage affects the corticospinal tract. The corticospinal tract carries movement signals from the brain, and it decussates–or crosses over–in the brainstem before continuing down into the spinal cord. The corticospinal tract on one side of the spinal cord is thus carrying movement signals intended for the same side of the body, so when it is damaged those signals can’t reach that side of the body below the injury, leading to weakness or paralysis on that side.
Damage to one side of the spinal cord would also result in deficits in touch, proprioception, and vibration sense below the hemisection on the same side of the body as the damage. These deficits are caused by damage to the dorsal column, which carries these types of sensations up the spinal cord from the same side of the body. Although the pathway does cross over, this doesn’t occur until it reaches the brainstem, so spinal cord damage to the pathway causes deficits on the same side as the damage.
Brown-sequard syndrome also causes deficits in pain and temperature sensation due to damage to the spinothalamic tract. The spinothalamic tract fibers cross over soon after entering the spinal cord. Thus, the right side of the spinal cord is carrying pain and temperature sensations from the opposite side of the body. Therefore, pain and temperature deficits in Brown-sequard syndrome are experienced on the opposite side of the body below the hemisection.
REFERENCES
Haines DE. Fundamental Neuroscience for Basic and Clinical Applications. 4th ed. Philadelphia, PA: Elsevier; 2013.
Shams S, Davidson CL, Arain A. Brown-Séquard Syndrome. 2024 Feb 27. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 30844162.
Vanderah TW, Gould DJ. Noltes The Human Brain. 8th ed. Philadelphia, PA: Elsevier; 2021.
📝 Pass your next test with my 2-minute neuro videos!
My name is Marc, and I want to immerse you in the fascinating world of neuroscience. When Im not making videos, Im a university professor at Penn State. I made this channel to help simplify complex topics into easy-to-understand snippets, perfect for students & enthusiasts alike. 📚
I aim to make learning about the brain fun and easy. Whether youre a student seeking to supplement your studies or a curious mind eager to understand the basics of neuroscience, this channel will provide valuable insights and knowledge into the human brain.
Subscribe and join our journey into the mind! 🧠2-Minute Neuroscience: Brown-Séquard Syndrome](https://i.ytimg.com/vi/R45w3Y5Js4o/mqdefault.jpg)









