Where are they?
Close-up view of the meninges surrounding the brain.
The term meninges comes from the Greek for "membrane" and refers to the three membranes that surround the brain and spinal cord. The membrane layers (discussed in detail below) from the outside in are the: dura mater, arachnoid mater, and pia mater. Their positioning around the brain can be seen in the image to the right.What are they and what do they do?The brain is s........ Read more »
Where is it?
Thalamus (in red).
The thalamus is a large, symmetrical (meaning there is one in each hemisphere) structure that makes up most of the mass of the diencephalon. A large number of pathways travel through the thalamus, including all of the sensory pathways other than those devoted to olfaction (smell).What is it and what does it do?The thalamus is often described as a relay station. This is because almost all sensory informati........ Read more »
Sherman, S., & Guillery, R. (2002) The role of the thalamus in the flow of information to the cortex. Philosophical Transactions of the Royal Society B: Biological Sciences, 357(1428), 1695-1708. DOI: 10.1098/rstb.2002.1161
Hodgkin and Huxley used the large axons of the giant squid to measure voltage changes during an action potential.
By the late 1930s, researchers had come to understand several important things about the conduction of signals within neurons. For example, they knew that signaling within neurons is electrical in nature (as opposed to signaling between neurons, which is usually chemical), and that it occurs in bursts of activity called action potentials. And th........ Read more »
Schwiening, C. (2012) A brief historical perspective: Hodgkin and Huxley. The Journal of Physiology, 590(11), 2571-2575. DOI: 10.1113/jphysiol.2012.230458
Today, the knowledge that neurons communicate with one another using chemicals known as neurotransmitters is a foundational part of our understanding of brain function. We use our awareness of neurochemical transmission to design drugs, investigate the causes of disease, and improve our comprehension of behavior (e.g. through experimental methods like microdialysis). In the first half of the twentieth century, however, the means by which neurons........ Read more »
In those who are addicted to drugs (or any other substance or behavior), the desire to re-experience the intoxicating effects they initially felt when they used the drug can be overwhelming. It can lead to compulsive drug-seeking, obsessive thinking, and irrational behavior. In addition to these new thought patterns and behaviors, however, addiction is also is associated with a diminished ability to experience pleasure from non-drug rewards. This reduced pleasure is termed........ Read more »
Wilson, S., Delgado, M., McKee, S., Grigson, P., MacLean, R., Nichols, T., & Henry, S. (2014) Weak ventral striatal responses to monetary outcomes predict an unwillingness to resist cigarette smoking. Cognitive, Affective, . DOI: 10.3758/s13415-014-0285-8
Where is it?
Nucleus accumbens represented by a red dot.
The nucleus accumbens is found in an area of the brain called the basal forebrain. There is a nucleus accumbens in each hemisphere; it is situated between the caudate and putamen. The nucleus accumbens is considered part of the basal ganglia and also is the main component of the ventral striatum. The nucleus accumbens itself is separated into two anatomical components: the shell a........ Read more »
Volman, S., Lammel, S., Margolis, E., Kim, Y., Richard, J., Roitman, M., & Lobo, M. (2013) New Insights into the Specificity and Plasticity of Reward and Aversion Encoding in the Mesolimbic System. Journal of Neuroscience, 33(45), 17569-17576. DOI: 10.1523/JNEUROSCI.3250-13.2013
Pierre Paul Broca
In April of 1861, a 51-year old man was transferred to Paul Broca's surgical ward in a hospital in France. The man, whose name was Leborgne, had epilepsy but was near death due to an uncontrolled infection and the resultant gangrene. There was something curious about Leborgne, however: he had extreme difficulty speaking voluntarily. In fact, one of the only sounds he was able to make--unless antagonized, which could prompt him to curse--wa........ Read more »
A few years ago (2010), the journal Nature Methods chose optogenetics as its "method of the year." The fact that optogenetics, in 2010, was already considered a viable approach to studying the brain is impressive in and of itself, considering that all of the seminal work with optogenetics has been done since the year 2000. Because the method is still a relatively recent development, however, it is probably true that the most intriguing work with optogenetics has yet to be........ Read more »
Where is it?
HPA axis activation, proceeding from the hypothalamus to the pituitary gland to the adrenal glands.
The hypothalamic-pituitary-adrenal axis, or HPA axis as it is commonly called, describes the interaction between the hypothalamus, pituitary gland, and adrenal glands. The hypothalamus and pituitary gland are located just above the brainstem, while the adrenal glands are found on top of the kidneys.What is it and what does it........ Read more »
Cajal's depiction of neurons in the cerebellum.
Although many consider him now to be the "father of modern neuroscience," when Santiago Ramon y Cajal (1852-1934) was a boy he dreamed of one day being an artist. His father, who was otherwise very nurturing to Cajal's intellectual development, discouraged the expression of Cajal's artistic aspirations. He saw art as a fruitless endeavor, and he was nothing if not a pragmatist. Nevertheless, Cajal found ways t........ Read more »
López-Muñoz, F., Boya, J., & Alamo, C. (2006) Neuron theory, the cornerstone of neuroscience, on the centenary of the Nobel Prize award to Santiago Ramón y Cajal. Brain Research Bulletin, 70(4-6), 391-405. DOI: 10.1016/j.brainresbull.2006.07.010
Although many within the scientific community believe that pedophilia has its origins in the brain, the neurobiological underpinnings of the disorder are still very unclear. It is hoped, however, that technologies that allow for the observation of brain activity in real-time, like positron-emission tomography (PET) and functional magnetic resonance imaging (fMRI), will provide us with more information about potential abnormalities in the brains of pedophiles (for more abou........ Read more »
Ponseti, J., Granert, O., van Eimeren, T., Jansen, O., Wolff, S., Beier, K., Deuschl, G., Bosinski, H., & Siebner, H. (2014) Human face processing is tuned to sexual age preferences. Biology Letters, 10(5), 20140200-20140200. DOI: 10.1098/rsbl.2014.0200
Although the drug methylenedioxymethamphetamine, better known as MDMA or ecstasy, is often lumped into the category of hallucinogens, it has a unique set of effects that make it very distinct from other drugs in this class. Specifically, along with creating a positive mood state and reducing anxiety, MDMA is known for fostering strong feelings of empathy and compassion.In some ways, MDMA appears to act on the brain in a manner similar to other amphetamines. Specifically, i........ Read more »
Kirkpatrick, M., Lee, R., Wardle, M., Jacob, S., & de Wit, H. (2014) Effects of MDMA and Intranasal Oxytocin on Social and Emotional Processing. Neuropsychopharmacology, 39(7), 1654-1663. DOI: 10.1038/npp.2014.12
The motor cortex (in red)
Neuroscience now views the cerebral cortex as a region of the brain that is essential for sensation, movement, and the heightened level of cognition we associate with humans as compared other animals. In the 1700s, however, many scientists considered the cortex to be a functionally insignificant outer shell of the brain. This corresponds to its original meaning when translated from Latin, which is "bark" (as in tree bark).By the 18........ Read more »
As awareness of obsessive-compulsive disorder (OCD) has grown over the years, so has the degree to which the disorder is misunderstood. For example, one common misperception is that individuals who suffer from OCD all engage in repetitious rituals like hand-washing, repeatedly checking the locks, or flicking the light switch on and off a specific number of times. While some people with OCD do experience ritualistic compulsions, this is not a necessary component of an OCD d........ Read more »
Radua, J., Grau, M., van den Heuvel, O., Thiebaut de Schotten, M., Stein, D., Canales-Rodríguez, E., Catani, M., & Mataix-Cols, D. (2014) Multimodal Voxel-Based Meta-Analysis of White Matter Abnormalities in Obsessive–Compulsive Disorder. Neuropsychopharmacology, 39(7), 1547-1557. DOI: 10.1038/npp.2014.5
People have been eating psychedelic mushrooms since ancient times. There are indications (although they are impossible to verify) that psychedelic mushrooms played an important role in cultures like the Mayan civilizations of South America thousands of years ago. Of course, the use of "magic" mushrooms has continued into modern times. In 1958, Albert Hofmann (the discoverer of LSD) isolated psilocybin as the active hallucinogenic compound in psychedelic mushrooms.Recently,........ Read more »
Kraehenmann, R., Preller, K., Scheidegger, M., Pokorny, T., Bosch, O., Seifritz, E., & Vollenweider, F. (2014) Psilocybin-Induced Decrease in Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers. Biological Psychiatry. DOI: 10.1016/j.biopsych.2014.04.010
By the middle of the 20th century, biologists had become aware of a unique type of communication occurring among insects. The communication involved the secretion of substances that were similar to hormones in some ways, but also very different. While hormones are secreted into the bloodstream to elicit some reaction in the body, these substances exit the body and are used to elicit a reaction in a conspecific (another organism of the same species). They were given the nam........ Read more »
Zhou, W., Yang, X., Chen, K., Cai, P., He, S., & Jiang, Y. (2014) Chemosensory Communication of Gender through Two Human Steroids in a Sexually Dimorphic Manner. Current Biology. DOI: 10.1016/j.cub.2014.03.035
Parkinson's disease (PD) is the second most prevalent neurodegenerative disease in the world (the first most prevalent being Alzheimer's disease), affecting upwards of 7 million people. The characteristic symptoms of the disease include bradykinesia (slow movement), rigidity, tremor, and postural instability. The appearance of these symptoms corresponds with neurodegeneration, or the death of neurons, which occurs predominantly in a collection of nuclei in the brain called the basal ganglia.The ........ Read more »
Cebrián C, Zucca FA, Mauri P, Steinbeck JA, Studer L, Scherzer CR, Kanter E, Budhu S, Mandelbaum J, Vonsattel JP.... (2014) MHC-I expression renders catecholaminergic neurons susceptible to T-cell-mediated degeneration. Nature communications, 3633. PMID: 24736453
I can understand the eagerness with which science writers jump on stories that deal with new findings about autism spectrum disorders (ASDs). After all, the mystery surrounding the rapid increase in ASD rates over the past 20 years (see right) has made any ASD-related study that may offer some clues inherently interesting. Because people are anxiously awaiting some explanation of this medical enigma, it seems like science writers almost have an obligation to discuss new findings concerning the c........ Read more »
Rebecca A. Harrington, Li-Ching Lee, Rosa M. Crum, Andrew W. Zimmerman, Irva Hertz-Picciotto. (2014) Prenatal SSRI Use and Offspring With Autism Spectrum Disorder or Developmental Delay. PEDIATRICS. DOI: 10.1542/peds.2013-3406d
Late last week the French National Centre for Scientific Research (CNRS - the acronym is based on the French translation) put out a press release describing a study conducted through a collaboration between several of its researchers and scientists from The University of Strasbourg. CNRS is a large (30,000+ employees), government-run research institution in France. It is the largest research organization in Europe, and is responsible for about 1/2 of the French scientific papers published annual........ Read more »
Mathis, C., Savier, E., Bott, J., Clesse, D., Bevins, N., Sage-Ciocca, D., Geiger, K., Gillet, A., Laux-Biehlmann, A., Goumon, Y.... (2014) Defective response inhibition and collicular noradrenaline enrichment in mice with duplicated retinotopic map in the superior colliculus. Brain Structure and Function. DOI: 10.1007/s00429-014-0745-5
The brain development of a fetus is really an amazing thing. The first sign of an incipient nervous system emerges during the third week of development; it is simply a thickened layer of tissue called the neural plate. After about 5 more days, the neural plate has formed an indentation called the neural groove, and the sides of the neural groove have curled up and begun to fuse together (see pic to the right). This will form the neural tube, which will eventually become the brain and spinal cord........ Read more »
Hashimoto-Torii, K., Torii, M., Fujimoto, M., Nakai, A., El Fatimy, R., Mezger, V., Ju, M., Ishii, S., Chao, S., Brennand, K.... (2014) Roles of Heat Shock Factor 1 in Neuronal Response to Fetal Environmental Risks and Its Relevance to Brain Disorders. Neuron. DOI: 10.1016/j.neuron.2014.03.002
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