How Hair Styles..?

Why do we have different types of Hair Shape

The general curls in the hair are determined by its cross sectional shape. If hair is circular in shape then it forms straight hair. If it is flattened and elliptical then it is curly or kinky. The more circular the shaft is , the straighter it is. If the shaft is more elliptical, the hair is curlier or kinkier.

Short Term Memory

Short-Term Memory(STM)


STM is characterized by:

• Capability such that only seven pieces of independent information can be stored
• A brief duration of these items last from 3 to 20 seconds.

How and where Brain stores information

WHERE THE INFORMATION IS STORED IN THE BRAIN

Like hard disc in computers, we have brain to store the information. Mind and memory are stored in it as software. Scientists have done many experiments in finding where exactly this software is stored in brain.

Some of the results are given below :

• Karl Lashley, a behavioral psychologist made different experiments to know about the part of the brain where the memory is stored. In the 1920s, trained rats to find their way through a maze, then made lesions in different parts of the cerebral cortex in an attempt to erase what he called the "engram," or the original memory trace. Lashley failed to find the engram even after placing lesions every possible places in the brain, however the experimental animals are able to solve the maze. He therefore concluded that memories are not stored in any single area of the brain, but are distributed throughout the brain.

• Brenda Milner—proposed that a part of the brain called the hippocampus as being prominent in memory formation. More recently, it was established that the frontal cortex is also involved; current thinking holds that new memories are encoded in the hippocampus and then eventually transferred to the frontal lobes for long-term storage.

Actually the location of a recollection in the brain varies based on how old that recollection is.

Smith and Squire assessed the brain activity associated with the recollection of old and new memories. They functional magnetic resonance imaging (fMRI) to scan 15 patients' brains while they answered 160 questions about news events that took place at different periods of time during the past 30 years. The experiment is quite simple but for it to produce any conclusion is pretty hard tasks, like creating the non visible relation among the memories of different timelines etc., 

Few inferences made:

First, when one is asked to recall any given memory, the brain encodes not only the questions that were asked to cue the retrieval, but also the resulting recollection, so the associated activity could therefore interfere with that which is being assessed.  Second, more recent memories are likely to be richer and more vivid than older ones, so the strength of the fMRI(functional MRI) signal could be related not just to the time at which a recalled event occurred but also to the richness of the participants' recollection of it.

Finally, recalled memories could be strongly associated with their personal life, which make them easier to be remembered.

Smith and Squire therefore designed their experiments so that they could assess the effects  of the age of a memory independently of both the encoding of the test questions and richness of the recollection of the memory. At the beginning of the task, the researchers gave a set of questions and asked the patients whether or not they knew the answer. And about few minutes later the patients were asked three questions about each news event. 

• First, they were asked to recall the question that had been asked about the event (to know how well they had encoded the information). 
• Then, they were asked the answer to that question (to know the accuracy of recall) and, 
• finally, how much they knew about each of the events (to know the richness of each memory).

 In cognitive psychology, there is one memory system, but it is normally divided into three functions for storage (Anderson, 2000): sensory, short-term often called working), and long- term (often called permanent).

Sensory Memory: The sensory memory retains an exact copy of what is seen or heard

(visual and auditory). It only lasts for a few seconds, while some theorize it last only 300

milliseconds. It has unlimited capacity. It is like when you move on the road you see many things may be humans, animals, objects or even the feel you get, they are momentary and they reach the next level(STM) if it catches your interest like a beautiful girl. 

Short-Term Memory (STM) - Selectively few information enters into this stage. STM is most often stored as sounds, especially in recalling words, but may be stored as images. It works basically the same as a computer's RAM (Random Access Memory) in that it provides a working space for short computations and then transfers it to other parts of the memory system or discards it. It is thought to be about seven bits in length, that is, we normally remember seven items. STM is vulnerable to interruption or interference.Read more..

Long-Term Memory - This is something like a permanent storage. Information is stored on the basis of meaning and importance. There is more to this. Read more..

Tags: Short Term Memory, Log term memory, How brain store the information, brain, memory, chunking, improve memory, improve memory power, Experiments on rats, lesion

Long Term Memory

Check some related posts:

• Short Term Memory
• How information is stored in brain

Long-Term Memory (LTM)


The knowledge we store in LTM affects our perceptions of the world, and influences what information in the environment we attend to. LTM gives the framework and we develop with more knowledge. It takes the priority over the STM and other memories, that is where people make their decisions. The limit of LTM is not known.

Schemas are mental models of the world. Information in LTM is stored in interrelated networks of these schemas. These, in turn, form intricate knowledge structures. Related schemas are linked together and loading one schema retrieves all the related schemas. This is how we recall relevant knowledge when similar information is presented. These schemas guide us by diverting our attention to relevant information and allow us to ignore the rest.

Since LTM storage is organized into schemas, instructional designers activate existing schemas and present it in a structured and interesting manner. This can be done in a many ways, including graphic organizers, movies, etc.


LTM also has a strong influence on perception through top-down processing - our prior knowledge affects how we perceive sensory information. We interpret an experience by the expectations and satisfaction attained. We develop bias from this. Also, most optical illusions take advantage of this fact.
An important factor for retention of learned information in LTM is rehearsal that provides transfer of learning.



Tags:Brain, Long term memory, short term memory, how brain store information,

Hair and its life-cycle

Hair Stucture

         Hair is composed of strong structural protein called keratin. This is the same kind of protein that makes up the nails and the outer layer of skin.

Each follicle of hair consists of 3 layers: 

1. It is the central part of the hair, made up of large loosely connected cells which contain Keratin . (Sometimes the medulla is not continuous in a hair.)

2. The middle layer known as the cortex. The cortex provides strength and both the color and the texture of hair.

3. The outermost layer is known as the cuticle. The cuticle is thin and colorless and is also meant for protection of cortex.

Structure of the hair root

Hair root is enclosed within hair follicle, under the skin. At the base of the hair follicle is the dermal papilla. The dermal papilla is feed by the bloodstream which carries nourishment to produce new hair.



Hair Growth Cycle


Hair on the scalp grows about .3-.4 mm/day or about 6 inches per year. Unlike other mammals, hair growth and loss is random and not seasonal or cyclic. At any given time, a random number of hairs will be in various stages of growth and shedding. There are three stages of hair growth:
catagen, telogen, and anagen.

Anagen - Growth Phase
Anagen is the active phase of the hair. The cells in the root of the hair are dividing rapidly. A new hair is formed and pushes the club hair up the follicle and eventually out. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active phase of growth for 2-6 years. Some people have difficulty growing their hair beyond a certain length because they have a short active phase of growth. On the other hand, people with very long hair have a long active phase of growth. The hair on the arms, legs, eyelashes, and eyebrows have a very short active growth phase of about 30-45 days explaining why they are so much shorter than scalp hair.


catagen phase - Transition phase
At the end of the anagen hair is a catagen phase lasts about a week or two during the catagen phase the hair follicle shrinks to about 1 / 6 of normal length. The lower part is destroyed and the dermal papilla breaks, leaving the root.




Telogen Phase - Resting phase
The resting phase follows the catagen phase and normally lasts about 5-6 weeks.Meanwhile, the hair does not grow but remains attached to the follicle while the dermal papilla remains in a resting phase below. Approximately 10-15 percent of all hairs are in this phase at once.
At the end of the telogen phase, hair follicles in the anagen phase again. The dermal papilla and base of the follicle to meet and a new hair begins to form. If the old hair has not yet fallen the new hair pushes the old one on the growth and the cycle begins again.



Tags: Hair images, hair, hair life cycle, hair stages, hair follicles, hair fall,Anagen Phase, Catagen Phase, Telogen Phase.