Recent technological and scientific advances have fuelled a neuroscientific revolution. Imaging techniques such as those shown above have given us an unprecedented view into the structure and function of our brain.
Phineas Gage is one of the most famous patients in the history of neuroscience. He was 25 years old when he experienced a serious accident at his work place, where a tamping iron was shot through his head - entering under his eye socket at exiting through the top of his head - after an explosive charge went off. The tamping iron was over a metre long, and after exiting Gage’s head landed 25m away.
Initially Gage collapsed and went into minor convlusions, but recovered quickly and was able to speak after a few minutes. He walked with little assistance to an ox-cart and was brought to a nearby physician. Initially the physician did not believe his story because he was in such good condition, but was convinced when:
Mr. G. got up and vomited; the effort of vomiting pressed out about half a teacupful of the brain, which fell upon the floor.
Gage exhibited a number of dramatic behavioural changes following the accident. Harlow, the physician who initially treated Gage, described this change “He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires”. However the surgeon Henry Jacob Bigelow described his condition as improving over the course of recovery, stated he was “quite recovered in faculties of body and mind”. This may have been early evidence of neural plasticity. This recovery was also reported by a physician who knew Gage while he lived in Chile, who described his ability to hold on a full time job as a Concord coach driver, a job that required exceptional social skills.
Gage’s neurological deficits following his traumatic brain injury is thought to have been exaggerated and distorted over the course of history, to the point that he is often portrayed as a ‘psychopath’. Scientific analysis of the historical accounts of Gage’s life following his accident, namely by the psychologist Malcolm Macmillan, find that these distorted accounts are most likely untrue, and that Gage made a very good recovery.
Post-mortem analysis of the Gage case concluded that it was the left frontal lobe that was damaged in the accident, although further neurological damage may have resulted from infection. Combined examination of the Phineas Gage case with the other famous cases of Tan and H.M. have concluded that social behaviour, memory, and language are dependent on the co-ordination of a number of different brain areas rather than a single region.
Neuro chip records brain cell activity at higher resolution
Brain functions are controlled by millions of brain cells. However,
in order to understand how the brain controls functions, such as simple
reflexes or learning and memory, we must be able to record the activity
of large networks and groups of neurons. Conventional methods have
allowed scientists to record the activity of neurons for minutes, but a
new technology, developed by University of Calgary researchers, known as
a bionic hybrid neuro chip, is able to record activity in animal brain
cells for weeks at a much higher resolution. The technological
advancement was published in the journal Scientific Reports.
“These chips are 15 times more sensitive than conventional neuro
chips,” says Naweed Syed, PhD, scientific director of the University of
Calgary, Cumming School of Medicine’s Alberta Children’s Hospital
Research Institute, member of the Hotchkiss Brain Institute and senior
author on the study. “This allows brain cell signals to be amplified
more easily and to see real time recordings of brain cell activity at a
resolution that has never been achieved before.”
The development of this technology will allow researchers to
investigate and understand in greater depth, in animal models, the
origins of neurological diseases and conditions such as epilepsy, as
well as other cognitive functions such as learning and memory.
“Recording this activity over a long period of time allows you to
see changes that occur over time, in the activity itself,” says Pierre
Wijdenes, a PhD student in the Biomedical Engineering Graduate Program
and the study’s first author. “This helps to understand why certain
neurons form connections with each other and why others won’t.”
The cross-faculty team created the chip to mimic the natural
biological contact between brain cells, essentially tricking the brain
cells into believing that they are connecting with other brain cells. As
a result, the cells immediately connect with the chip, thereby allowing
researchers to view and record the two-way communication that would go
on between two normal functioning brain cells.
“We simulated what Mother Nature does in nature and provided brain
cells with an environment where they feel as if they are at home,” says
Syed. “This has allowed us to increase the sensitivity of our readings
and help neurons build a long-term relationship with our electronic
While the chip is currently used to analyze animal brain cells, this
increased resolution and the ability to make long-term recordings is
bringing the technology one step closer to being effective in the
recording of human brain cell activity.
“Human brain cell signals are smaller and therefore require more
sensitive electronic tools to be designed to pick up the signals,” says
Colin Dalton, adjunct professor in the Department of Electrical and
Computer Engineering at the Schulich School of Engineering and a
co-author on this study. Dalton is also the facility manager of the
University of Calgary’s Advanced Micro/nanosystems Integration Facility
(AMIF), where the chips were designed and fabricated.
Researchers hope the technology will one day be used as a tool to
bring personalized therapeutic options to patients facing neurological
A 5 month old girl with alobar holoprosenceohaly. This condition was diagnosed prenatally in utero and understandably resulted in severe enlargement of the child’s head. The child was oriented to sound, able to move all extremities and responded to external stimuli, however the long term prognosis for this condition is poor as it is typically fatal in the neonatal period.
Fear conditioning, simply put, is teaching someone or something to be afraid of a stimulus. When conditioning someone to predict fear you’re associating a sound, object, action, or something of that nature with something already startling to the person(s). This will cause the person (if done correctly) to associate that sound, object, or action with what they’re already afraid of, and thus eliciting a fearful response.
I’ll break this down rectangle by rectangle to make this easier to understand.
First Rectangle: Obviously, when a mouse is on its own with no stimulus there isn’t going to be an effect.
Second Rectangle: In the upper portion of the second rectangle a mouse is introduced to a startling noise, and that elicits fear which eventually dies off. In the lower portion of the second rectangle the mouse is introduced to the same startling noise, but this time with a bell. Obviously the mouse is still going to be fearful of the startling noise, but now that the bell has been associated with the startling noise, the bell will also scare the mouse. This is because its been conditioned to understand that the bell comes with the startling noise, therefore, when the bell is sounded again the mouse fears the bell not because it’s a bell, but because it is an anticipating the startling noise.
Third Rectangle: Whether or not the mouse hears the bell and the sound or just the sound, it’s still conditioned to feel fear from the bell in anticipation of the startling noise. Though if the bell is continuously rang without introducing the startling noise [fear stimulus] the mouse will lose its conditioning and no longer be afraid of the bell being rung.
An even simpler example would be as follows:
Your friend is afraid of clowns, you play the Michael Jackson song thriller and show him a clown (this will elicit fear merely because of the clown), and lastly you play the song again and because a clown appeared last time at the start of the song, your friend will anticipate a clown and become fearful.
Gross pathology specimen illustrating alobar holoprosencephaly The large single ventricle inside a single hemisphere is the hallmark of the alobar form of holoprosencephaly, in which there are no division of hemispheres. This is the most severe form of holoprosencephaly, the majority of children who have this congenital malformation are still born, die soon after birth, or within the first 6 months of life.
60/F with headaches, nausea, and vomiting. Had a BP of 230/110! Weakness on her right side and aphasia(a language disorder that affects a person’s ability to communicate). Image one shows duret hemorrhage
So every year I’ve been writing these lists of 100 things you learn in each year of medical school (Found here). I am incredibly excited this year to bring you my list of 100 Things You Learn in your Third Year of Medical School.
This list contains advice about how to function on the floor, how to study, and how to handle your work-life imbalance. Click through to find such advice as: • Whatever size scrubs you wear will be the least common size to find. Take as many pairs as you can find and stockpile them. • EVERY procedure in OB requires shoe covers. Better to not need them than to have forgotten them • Night shifts only come in two flavors: Insanely busy or so quiet you can not keep your eyes open. • The best residents will notice when you’re sitting around doing nothing and will send you home—the worst residents will forget you’re even there. • Falling asleep at 9pm is nothing to be ashamed of—in fact be proud of it. • Get comfortable with being uncomfortable.