Uploaded June 2022 | Updated September 2026, 3 weeks ago
Schizophrenia is a potentially severe psychiatric condition that involves a variety of symptoms. In this video, I discuss the neuroscience of schizophrenia.
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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:
Schizophrenia is a potentially severe psychiatric condition that involves a variety of symptoms. The symptoms of schizophrenia are often categorized as positive, negative, or cognitive. Positive symptoms involve the development of a behavior or thought pattern that isn’t normally present, such as hallucinations and/or delusions. Negative symptoms involve the loss of a normal function, and include lack of motivation, blunted emotion, or difficulty experiencing pleasure. Cognitive symptoms are those that affect someone’s ability to think clearly, and include deficits in attention, memory, and/or concentration.
The neuroscience of schizophrenia has been difficult to sort out, but a great deal of research has focused on neurotransmitter abnormalities at the root of the disorder. Dopamine has received much of this attention, with the general hypothesis being that dopamine activity is too high in certain parts of the brain in schizophrenia. This hypothesis was originally formulated based on the findings that drugs used to treat schizophrenia act to reduce dopamine activity, and drugs that increase dopamine levels (such as amphetamine) can induce behavior that in some ways resembles the psychotic states schizophrenic patients experience. The idea that increased dopamine activity plays a role in schizophrenic symptoms is now supported by a large body of evidence.
However, dopamine irregularities alone do not seem to explain all the symptoms of schizophrenia. Glutamate abnormalities, such as dysfunctional glutamate receptors, also occur in schizophrenia, and these may be capable of accounting for some negative and cognitive symptoms—something that dopamine levels have been less successful in explaining. Additionally, it has been proposed that dysfunction in glutamate systems may precede and lead to the dopamine hyperactivity observed in schizophrenia. While it’s uncertain what causes these neurotransmitter abnormalities to emerge in the first place, it’s generally believed that schizophrenia can be traced back to disruptions in early neural development that occur due to the influence of both genetic and environmental factors.
REFERENCES:
Howes O, McCutcheon R, Stone J. Glutamate and dopamine in schizophrenia: an update for the 21st century. J Psychopharmacol. 2015 Feb;29(2):97-115. doi: 10.1177/0269881114563634. Epub 2015 Jan 13. PMID: 25586400; PMCID: PMC4902122.
Howes OD, Murray RM. Schizophrenia: an integrated sociodevelopmental-cognitive model. Lancet. 2014 May 10;383(9929):1677-1687. doi: 10.1016/S0140-6736(13)62036-X. Epub 2013 Dec 6. PMID: 24315522; PMCID: PMC4127444.
Kahn RS, Sommer IE, Murray RM, Meyer-Lindenberg A, Weinberger DR, Cannon TD, O'Donovan M, Correll CU, Kane JM, van Os J, Insel TR. Schizophrenia. Nat Rev Dis Primers. 2015 Nov 12;1:15067. doi: 10.1038/nrdp.2015.67. PMID: 27189524.
Owen MJ, Sawa A, Mortensen PB. Schizophrenia. Lancet. 2016 Jul 2;388(10039):86-97. doi: 10.1016/S0140-6736(15)01121-6. Epub 2016 Jan 15. PMID: 26777917; PMCID: PMC4940219.
Schizophrenia is a potentially severe psychiatric condition that involves a variety of symptoms. In this video, I discuss the neuroscience of schizophrenia.
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:
Schizophrenia is a potentially severe psychiatric condition that involves a variety of symptoms. The symptoms of schizophrenia are often categorized as positive, negative, or cognitive. Positive symptoms involve the development of a behavior or thought pattern that isn’t normally present, such as hallucinations and/or delusions. Negative symptoms involve the loss of a normal function, and include lack of motivation, blunted emotion, or difficulty experiencing pleasure. Cognitive symptoms are those that affect someone’s ability to think clearly, and include deficits in attention, memory, and/or concentration.
The neuroscience of schizophrenia has been difficult to sort out, but a great deal of research has focused on neurotransmitter abnormalities at the root of the disorder. Dopamine has received much of this attention, with the general hypothesis being that dopamine activity is too high in certain parts of the brain in schizophrenia. This hypothesis was originally formulated based on the findings that drugs used to treat schizophrenia act to reduce dopamine activity, and drugs that increase dopamine levels (such as amphetamine) can induce behavior that in some ways resembles the psychotic states schizophrenic patients experience. The idea that increased dopamine activity plays a role in schizophrenic symptoms is now supported by a large body of evidence.
However, dopamine irregularities alone do not seem to explain all the symptoms of schizophrenia. Glutamate abnormalities, such as dysfunctional glutamate receptors, also occur in schizophrenia, and these may be capable of accounting for some negative and cognitive symptoms—something that dopamine levels have been less successful in explaining. Additionally, it has been proposed that dysfunction in glutamate systems may precede and lead to the dopamine hyperactivity observed in schizophrenia. While it’s uncertain what causes these neurotransmitter abnormalities to emerge in the first place, it’s generally believed that schizophrenia can be traced back to disruptions in early neural development that occur due to the influence of both genetic and environmental factors.
REFERENCES:
Howes O, McCutcheon R, Stone J. Glutamate and dopamine in schizophrenia: an update for the 21st century. J Psychopharmacol. 2015 Feb;29(2):97-115. doi: 10.1177/0269881114563634. Epub 2015 Jan 13. PMID: 25586400; PMCID: PMC4902122.
Howes OD, Murray RM. Schizophrenia: an integrated sociodevelopmental-cognitive model. Lancet. 2014 May 10;383(9929):1677-1687. doi: 10.1016/S0140-6736(13)62036-X. Epub 2013 Dec 6. PMID: 24315522; PMCID: PMC4127444.
Kahn RS, Sommer IE, Murray RM, Meyer-Lindenberg A, Weinberger DR, Cannon TD, O'Donovan M, Correll CU, Kane JM, van Os J, Insel TR. Schizophrenia. Nat Rev Dis Primers. 2015 Nov 12;1:15067. doi: 10.1038/nrdp.2015.67. PMID: 27189524.
Owen MJ, Sawa A, Mortensen PB. Schizophrenia. Lancet. 2016 Jul 2;388(10039):86-97. doi: 10.1016/S0140-6736(15)01121-6. Epub 2016 Jan 15. PMID: 26777917; PMCID: PMC4940219.




![2-Minute Neuroscience: Corneal Reflex
The corneal reflex is a protective reflex that causes both eyes to blink when the cornea of either eye is touched. In this video, I discuss the neural pathways underlying the corneal reflex as well as what types of damage might cause a deficit in the reflex.
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
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:
The corneal reflex is a protective reflex that occurs when the cornea of either eye is touched. When this happens, the corneal reflex causes the eye being touched to blink but it also causes the other eye to blink at the same time. This ensures that both eyes are protected from any foreign objects or irritants in the environment.
The corneal reflex involves sensory fibers in the ophthalmic division of the trigeminal nerve that are activated when the cornea is touched. These fibers synapse on neurons in the spinal trigeminal nucleus, and those spinal trigeminal neurons then project to the facial motor nuclei on both sides of the brainstem and synapse on neurons of the facial nerve. The facial nerve fibers leave the brainstem and travel to the orbicularis oculi muscle, which closes the eyelid. Thus, the reflex arc uses the sensory input being received in one eye to generate a motor signal that causes both eyes to blink simultaneously.
The corneal reflex is used clinically to test the integrity of the trigeminal and facial nerves and related structures, typically by touching the cornea with a piece of cotton. The healthy response to touching one cornea would be that both eyes would blink, but damage to the trigeminal or facial nerves or other related structures may cause a deficit in the reflex. For example, damage to the right trigeminal nerve could cause a corneal touch to the right eye to elicit no response in either eye, since the sensation might not be detected. But damage to the facial nerve on the right side could cause a corneal touch on the right side to elicit a blink in only the left eye, since the touch would be detected but the right facial nerve may be incapable of carrying out the reflex response.
REFERENCES:
Peterson DC, Hamel RN. Corneal Reflex. [Updated 2019 Jun 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534247/
Vanderah TW, Gould DJ. Noltes The Human Brain. 7th ed. Philadelphia, PA: Elsevier; 2016.
Special thanks to Srikar Gade for help with fact-checking the script for this video. 2-Minute Neuroscience: Corneal Reflex](https://i.ytimg.com/vi/siktmT30nCs/mqdefault.jpg)





