The Centers for Disease Control and Prevention estimates that as many as 1.7 million people in the United States experience a traumatic brain injury (TBI) each year, over 15% of which are thought to be sports-related. Despite the relatively high prevalence of these injuries, however, it seems we are just beginning to appreciate the true extent of the effects they can have on the brain. Awareness of previously unrecognized consequences to TBI and repeated TBI--along with the realization that........ Read more »
Blennow, K., Hardy, J., & Zetterberg, H. (2012) The Neuropathology and Neurobiology of Traumatic Brain Injury. Neuron, 76(5), 886-899. DOI: 10.1016/j.neuron.2012.11.021
Where is the blood-brain barrier?The blood-brain barrier surrounds most of the blood vessels in the brain. It is a structure that is formed primarily due to the establishment of tight junctions between endothelial cells (i.e. cells that line the walls of blood vessels). There are also several other cells and proteins contributing to the blood-brain barrier complex; for example, processes called astrocytic end-feet extend from astrocytes to surround blood vessels and provide support to the endoth........ Read more »
Ballabh P, Braun A, & Nedergaard M. (2004) The blood-brain barrier: an overview: structure, regulation, and clinical implications. Neurobiology of disease, 16(1), 1-13. PMID: 15207256
There are many examples throughout nature of microorganisms like bacteria, viruses, and parasites influencing the neurobiology and behavior of their hosts. For example, the rabies virus enters the nervous system almost immediately after a bite or scratch and travels to the brain, where it influences neural activity to make aggressive behavior more likely. This, of course, is beneficial for the virus as it increases the probability its infected host will make contact with another susceptible host........ Read more »
Cryan, J., & Dinan, T. (2012) Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 13(10), 701-712. DOI: 10.1038/nrn3346
The term placebo effect describes an improvement in the condition of a patient after being given a placebo--an inert substance (e.g. sugar pill) the patient expects may hold some benefit for him. The placebo effect has long been recognized as an unavoidable aspect of medical treatment. Physicians before the 1950s often took advantage of this knowledge by giving patients treatments like bread pills or injections of water with the understanding that patients had a tendency to feel better when they........ Read more »
Wager, T., & Atlas, L. (2015) The neuroscience of placebo effects: connecting context, learning and health. Nature Reviews Neuroscience, 16(7), 403-418. DOI: 10.1038/nrn3976
Where is the default mode network?The default mode network (sometimes called simply the default network) refers to an interconnected group of brain structures that are hypothesized to be part of a functional system. The default network is a relatively recent concept, and because of this there is not yet a complete consensus on which brain regions should be included in a definition of it. Regardless, some structures that are generally included are the medial prefrontal cortex, posterior cingulate........ Read more »
Buckner RL, Andrews-Hanna JR, & Schacter DL. (2008) The brain's default network: anatomy, function, and relevance to disease. Annals of the New York Academy of Sciences, 1-38. PMID: 18400922
Parkinson's disease (PD) belongs to a group of diseases that are referred to as neurodegenerative because they involve the degeneration and death of neurons. In PD a group of structures called the basal ganglia, which play a role in facilitating movement, are predominantly affected. The substantia nigra, one of the basal ganglia nuclei as well as one of the most dopamine-rich areas in the brain, is severely impacted; by the end stages of the disease patients have often lost 50-70% of the dopamin........ Read more »
de Hemptinne, C., Swann, N., Ostrem, J., Ryapolova-Webb, E., San Luciano, M., Galifianakis, N., & Starr, P. (2015) Therapeutic deep brain stimulation reduces cortical phase-amplitude coupling in Parkinson's disease. Nature Neuroscience, 18(5), 779-786. DOI: 10.1038/nn.3997
Orbitofrontal cortex (in green)
Where is the orbitofrontal cortex?The orbitofrontal cortex is the area of the prefrontal cortex that sits just above the orbits (also known as the eye sockets). It is thus found at the very front of the brain, and has extensive connections with sensory areas as well as limbic system structures involved in emotion and memory.What is the orbitofrontal cortex and what does it do?The orbitofrontal cortex (OFC) is a poorly underst........ Read more »
To those who believe strongly in the scientific method, it really is the only approach to understanding the relationship between two events or variables that allows us to make assertions about such relationships with any confidence. Due to the inherent flaws in human reasoning, our non-scientific conclusions are frequently riddled with bias, misunderstanding, and misattribution. Thus, it seems there is little that can be trusted if it hasn't been scientifically verified.The scientific method, ho........ Read more »
Moncrieff, J. (2009) A Critique of the Dopamine Hypothesis of Schizophrenia and Psychosis. Harvard Review of Psychiatry, 17(3), 214-225. DOI: 10.1080/10673220902979896
Where is the cochlea?
cochlea and cochlea in cross-section. image courtesy of openstax college.
The cochlea is a coiled structure that resembles a snail shell (cochlea comes from the Greek kochlos, which means "snail"); it is found within the inner ear. It is a small--yet complex--structure (about the size of a pea) that consists of three canals that run parallel to one another: the scala vestibuli, scala media, and scala tympani.What i........ Read more »
If you're looking for an indication of how intricately human physiology is tied to the environment our species evolved in, you need look no further than our circadian clock. For, the internal environment of our body is regulated by 24-hour cycles that closely mirror the time it takes for the earth to rotate once on its axis. Moreover, these cycles are shaped by changes in the external environment (e.g. fluctuating levels of daylight) associated with that rotation. Indeed, this 24-hour cycle regu........ Read more »
LeGates, T., Fernandez, D., & Hattar, S. (2014) Light as a central modulator of circadian rhythms, sleep and affect. Nature Reviews Neuroscience, 15(7), 443-454. DOI: 10.1038/nrn3743
When you consider that so much of our energy and such a large portion of our behavioral repertoire is devoted to ways of ensuring our survival, suicide appears to be perhaps the most inexplicable human behavior. What would make this human machine--which most of the time seems to be resolutely programmed to scratch, claw, and fight to endure through even the most dire situations--so easily decide to give it all up, even when the circumstances may not objectively seem all that desperate? Suicide i........ Read more »
Epilepsy refers to a group of disorders that are characterized by recurrent seizures. It is a relatively common neurological condition, and is considered the most common serious (implying that there is a risk of mortality) brain disorder, affecting around 2.2 million Americans.The seizures associated with epilepsy are not homogenous; they can have a drastically different presentation depending on the patient, the part of the brain the seizure originates in, and how much of the brain the seizure ........ Read more »
Krook-Magnuson, E., & Soltesz, I. (2015) Beyond the hammer and the scalpel: selective circuit control for the epilepsies. Nature Neuroscience, 18(3), 331-338. DOI: 10.1038/nn.3943
Where is the pineal gland?
Pineal gland (in red). Image courtesy of life science databases.
The pineal gland is considered part of the epithalamus, which is one the main structures that makes up the diencephalon. The pineal gland was so named because it has a pine-cone like appearance. Unlike many structures in the brain, the pineal gland is unpaired; in other words, many brain structures like the hippocampus or amygdala are symmetrical........ Read more »
It seems that, of all of the behavioral neuroscience findings that make their way into popular press coverage, those that involve structural changes to the brain are most likely to pique the interest of the public. Perhaps this is because we have a tendency to think of brain function as something that is flexible and constantly changing, and thus alterations in function do not seem as dramatic as alterations in structure, which give the impression of being more permanent.After all, until relativ........ Read more »
Lazar, S., Kerr, C., Wasserman, R., Gray, J., Greve, D., Treadway, M., McGarvey, M., Quinn, B., Dusek, J., Benson, H.... (2005) Meditation experience is associated with increased cortical thickness. NeuroReport, 16(17), 1893-1897. DOI: 10.1097/01.wnr.0000186598.66243.19
In Walden, his masterpiece about noncomformity and simple living, Henry David Thoreau wrote, "Every generation laughs at the old fashions, but follows religiously the new." And while Thoreau was specifically talking about society's capriciousness in embracing new styles of clothing, his quote applies just as well to our preference for one shade of skin color over another. For, while many now consider a medium-dark tan to be both healthier-looking and more attractive than pale skin, only 100 year........ Read more »
Petit, A., Karila, L., Chalmin, F., & Lejoyeux, M. (2014) Phenomenology and psychopathology of excessive indoor tanning. International Journal of Dermatology, 53(6), 664-672. DOI: 10.1111/ijd.12336
Ventricles, image courtesy of bruce blaus via wikimedia commons
Where are the ventricles?The ventricles are four interconnected cavities distributed throughout the brain that produce and contain cerebrospinal fluid (CSF). The two lateral ventricles are C-shaped chambers found in the cerebral hemispheres (one in each hemisphere). They are connected to the third ventricle by an opening called the interventricular foramen. The third ventricle is a very narrow ........ Read more »
Mortazavi, M., Adeeb, N., Griessenauer, C., Sheikh, H., Shahidi, S., Tubbs, R., & Tubbs, R. (2013) The ventricular system of the brain: a comprehensive review of its history, anatomy, histology, embryology, and surgical considerations. Child's Nervous System, 30(1), 19-35. DOI: 10.1007/s00381-013-2321-3
Throughout the 1970s, biochemist Stanley Prusiner was obsessed with trying to find the causative agent for a mysterious group of diseases. The diseases, which included kuru and Creutzfeldt–Jakob disease in humans and scrapie in sheep, were characterized by slowly-developing symptoms and neurodegeneration so severe it eventually caused the brain to take on the appearance of a sponge (due to myriad little holes that developed where grey matter was lost). By the time Prusiner began studying these........ Read more »
Brettschneider, J., Tredici, K., Lee, V., & Trojanowski, J. (2015) Spreading of pathology in neurodegenerative diseases: a focus on human studies. Nature Reviews Neuroscience, 16(2), 109-120. DOI: 10.1038/nrn3887
Where is the reward system?The term reward system refers to a group of structures that are activated by rewarding or reinforcing stimuli (e.g. addictive drugs). When exposed to a rewarding stimulus, the brain responds by increasing release of the neurotransmitter dopamine and thus the structures associated with the reward system are found along the major dopamine pathways in the brain. The mesolimbic dopamine pathway is thought to play a primary role in the reward system. It connects the ventral........ Read more »
When the movie Lucy was released in the summer of 2014, it was quickly followed by a flurry of attention surrounding the idea that we only use 10% of our brains. According to this perspective, around 90% of our neurons lie dormant, all the while teasing us by reminding us that we have only achieved a small fraction of our human potential. In the movie, Scarlet Johansson plays a woman who takes an experimental new drug that makes her capable of using upwards of 90% of her brain. Due to this sudde........ Read more »
Where is the ventral tegmental area?
Ventral tegmental area along with other structures in the brain connected by dopamine pathways.
The ventral tegmental area, or VTA, is in the midbrain, situated adjacent to the substantia nigra. Although it contains several different types of neurons, it is primarily characterized by its dopaminergic neurons, which project from the VTA throughout the brain. The VTA is considered an integral part of a........ Read more »
Kalivas, P. (1993) Neurotransmitter regulation of dopamine neurons in the ventral tegmental area. Brain Research Reviews, 18(1), 75-113. DOI: 10.1016/0165-0173(93)90008-N
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