Tagged: hippocampus
The Power of Meditation
When the word meditation comes up, people usually think of Monks or Buddhists first. However, there is a reason they meditate so often; meditation does wonders for your brain, and here is how.
There are two main types of meditation: 1) Focused-attention meditation or ‘Mindful meditation‘ and 2) Open-monitoring meditation. In Mindful meditation, you focus on one specific thing ranging from your breathing, a specific sensation in your body, or a particular object in front of you.The key point is to focus on one thing without consideration to other thoughts or events happening around you. When any distractions occur, you must be quick to recognize it and turn your focus back to your focal point. Open-monitoring meditation is where you pay attention to all the things happening around you but you do not react to them.
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The Elusive Engram: An Experiment in Memory Implantation
The human hippocampus, considered a key area for memory formation. Immunocytochemical staining for calcium-binding proteins is used in this horizontal section to differentiate major areas. Source - http://vida.neurocure.de/research_interests.html
With each passing minute, multitudes of memories surge through our minds as we recollect past experiences and encode new ones. Since the dawn of introspective thought, humans have wondered where such experiences might be encoded, if a physical encoding is even possible [1]. Fast forward to the 20th century and we now have pioneering works from the likes of Carl Lashley, acclaimed for his application of the term "engram" to describe a physical location and mechanism by which a specific memory is encoded, a memory trace so to speak [3]. Lashley's theories have proved highly influential (though his rat lesion methodologies have been criticized [2]), inspiring countless other neuroscientists such as Richard F. Thompson [6] and Howard Eichembaum [7] to embark on the quest to find the engram.
Fast forward to the 21st century and we continue to see groundbreaking work in engram research. A most recent study published in July 2013 titled "Creating a False Memory in the Hippocampus" [5] provides strong evidence for a functional memory engram through a novel memory implantation procedure. The study was conducted by the Susumu Tonegawa's RIKEN-MIT Lab, which seeks to uncover the neural mechanisms underlying learning and memory. In this experiment, Tonegawa's team of neuroscientists were able to implant artificial memories into the brains of mice using optogenetics, a technology in which the activity of specific neurons can be modulated by exposure to certain wavelengths of light. The specific memory manipulated in this study was a conditioned fear response to a mild electrical foot shock.
Temptation: The Effects of Immediate and Delayed Rewards
As we approach the loved holiday season, we also approach the dreaded weight gain that comes along with it. It probably won’t come as a surprise to you that our brain, specifically the hippocampus, plays a role in resisting immediate or delayed temptation.
The hippocampus deals with memory, including recalling past events and imagining them in the future. A study called “A Critical Role for the Hippocampus in the Valuation of Imagined Outcomes” examines healthy people as well as people with Alzheimer’s disease, which impairs memory and is associated with atrophy of the hippocampus. The study looked at “time- dependent” choices having to do with money in addition to “episodic” choices having to do with food, sports, and cultural events.
Don’t Panic! – Mice Aren’t Actually the Smartest
"Man had always assumed that he was more intelligent than dolphins because he had achieved so much — the wheel, New York, wars and so on — whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man — for precisely the same reasons....In fact there was only one species on the planet more intelligent than dolphins, and they spent a lot of their time in behavioural research laboratories running round inside wheels and conducting frighteningly elegant and subtle experiments on man. The fact that once again man completely misinterpreted this relationship was entirely according to these creatures' plans." - Douglas Adams, The Hitchhiker's Guide to the Galaxy
As tempting as it may be to believe the science fiction version of the intelligence rankings, real-life science has spoken and suggests (much to my displeasure) that humans may actually be the highest on the intelligence scale.
A Blacked Out Memory
Social gatherings are often the scene of hippocampal disruptions. (Scene from the movie Twelve)
"White Mike and his father moved after his mother died of breast cancer. It ate her up and most of their money. They can't control the old radiators and its very hot in the spring time. In White Mike's room, old unpacked boxes stick out of the closet so he can see them. Maybe you know how it is, maybe you don't? But sometimes if you can't see what you're finished with its better. White Mike stripped to his shorts and laid down on the floor so he felt a little cooler. That's how it was the first night in his new room and that's how it still is. White Mike is thin and pale like smoke. White Mike has never smoked a cigarette in his life, never had a drink, never sucked down a doobie. He once went three days without sleep as a kind of experiment. That's as close as he's ever gotten to fucked up. White Mike has become a very good drug dealer.
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Spatial Cognition in Philosophy and Neuroscience
In this post, I attempt to present two major metaphysical accounts of space by Kant and Leibniz, then present some recent findings from cognitive neuroscience about the neural basis of spatial cognition in an attempt to understand more about the nature of space and the possible connection of philosophical theories to empirical observations.
Immanuel Kant’s account of space in his Prolegomena serves as a cornerstone for his thought and comes about in a discussion of the transcendental principles of mathematics that precedes remarks on the possibility of natural science and metaphysics. Kant begins his inquiry concerning the possibility of ‘pure’ mathematics with an appeal to the nature of mathematical knowledge, asserting that it rests upon no empirical basis, and thus is a purely synthetic product of pure reason (§6). He also argues that mathematical knowledge (pure mathematics) has the unique feature of first exhibiting its concepts in a priori intuition which in turn makes judgments in mathematics ‘intuitive’ (§7.281). For Kant, intuition is prior to our sensibility and the activity of reason since the former does not grasp ‘things in themselves,’ but rather only the things that can be perceived by the senses. Thus, what we can perceive is based on the form of our a priori intuition (§9). As such, we are only able to intuit and perceive things in the world within the framework naturally provided by the capabilities and character (literally the under–standing) of our understanding. Kant then takes our intuitions of space (and time) as concepts integral to pure mathematics and as necessary components of our intuition (§10.91). More
Memory 101: Understanding How We Remember
Do you ever wonder how you are able to remember the name of your third-grade teacher, or the skills you use to ride a bike, or even lines from your favorite movie? Well, if you haven't then you should, because it takes the workings of many regions of our brain to combine all the different aspects of one memory into a cohesive unit.
The first step in this complex process deals with our perceptions and senses. Think about the last time you visited the beach. Recall the sound of the wind and birds, the sight of the sun and ocean, the smell of the salt water and the feeling of the hot sand and shells underfoot. Your brain merges all of these different perceptions together, crafting them into the "memory" that we are able to recall.
All of these separate sensations travel to the part of our brain called the hippocampus. Along with the frontal cortex, the hippocampus plays a huge part in our memory system. These two regions decide what is worth remembering and then store this information throughout the brain.
Perception starts the processes leading up to encoding and storage, which takes place through our brains' synapses (or the gaps between neurons). Through these synapses, neurons are able to electrically and chemically transmit information between themselves. When an electric pulse is fired across the gap, it triggers the release of chemical messengers called neurotransmitters.
Here is a clear view of communication between neurons through the releasing of neurotransmitters over the synapse.
From there, the spread of information begins. The neurotransmitters diffuse to neighboring cells and attach to them, forming thousands of links. All of these cells process and organize the information as a network. Similar areas of information are connected and are constantly being reorganized as our brain processes more and more.
Changes are reinforced with use. So let's say you are learning to play a sport. The more you practice, the stronger the rewiring and connections will become, thus allowing the brain to do less work as the initiation of pulses becomes easier with repetitive firing. This is how you get better at a certain task and are able to perform at a higher level without making as many mistakes. But again, because our brain never stops the process of input and output, practice needs to be constant in order to promote strong information retention.
Knowing all of this, it probably comes as no surprise that the most basic function for ensuring proper memory encoding is to pay specific attention to what you are doing. We are exposed to thousands of things in very short amounts of time, so the majority of it is ignored. If we pay more attention to select, specific bits of information, we'll have a higher potential to remember certain things (try it out for yourself in lecture).
Since the actual process has been discussed, we'll go into greater detail about the types of memory we have and how they differ. There are three basic memory types that act as a filter systems for what we find important. This is based on what we need to know and for how long we need to know it.
The first is sensory memory, which is basically ultra-short-term memory. It is based off of input from the five senses and usually lasts a few seconds or so. An example would be looking at a car that passes by and remembering what color it was based on that split second intake. The effect is vaguely lingering, and is forgotten almost instantly.
Short-term memory is the next category. People sometimes refer to it as "the brain's Post-it note". It has the ability to retain around seven items of information for about less than a minute. Some examples would include telephone numbers or even a sentence that you quickly glance over (such as this one). You have to remember what is being said at the beginning to understand the context. Likewise, numbers are usually better remembered, and have longer staying power in the brain, when split up (800-493-2751 instead of 8004932751 for instance).
Repetition and conscious effort to retain information leads to the transformation of short-term memory into long-term memory. By rehearsing information without interference or disturbances, one is better able to remember things and ingrain them into his/her brain. This is a gradual process, but it proves why studying is important! Unlike the other two memory categories, long-term memory has the ability to retain unlimited amounts of information for a seemingly indefinite amount of time.
This diagram shows a more complex view of the major memory types and their subdivisions.
A piece of information must pass from both sensory and short-term memory to successfully be encoded in long-term memory. Failure to do so generally leads to the phenomenon known as "forgetting", something that many of us are all too familiar with ironically enough!
To give a common example of long-term encoding and memory retrieval, consider trying to recall where you have put your keys down. First, you must register where you are putting your keys and attention while putting them down so that you can remember later. Accomplishing all of this helps a memory to be stored, retained, and ready for retrieval when necessary.
Forgetting may deal with distraction, or simply just failure to properly retrieve a memory. That being said, it should be noted that there is no predisposition to having a "good" or a "bad" memories. Most people are good at remembering certain things (numbers, procedures and mechanisms for example) better than others (names, phrases, or even entire plays) and vice versa. It all depends on where you are able to focus your interests and your attention.
Hopefully, you will be able to remember some of this so that you can use your understanding of the complexities of the brain and memory encoding to your advantage. After all, your brain does all the hard work for you! Now you just need to pay attention and focus on what you find important and what you want to remember to best suit your own needs.
How Human Memory Works - Discovery Health
Types of Memory - The Human Memory
How Does Human Memory Work? - USATODAY.com
