efferent neurons

study less study smart

I decided to share my notes taken from this amazing 1 hour Youtube lecture by Marty Lobdell. i really liked him and his tips, i think they are super effective and cover a lot of situations! i highly recommend it!!!!! wow

but here are the tips and examples Marty mentions, so if you don’t have the time to go through the full hour, you can just scroll down. hope this helps somebody!

  • Break your study time in chunks with breaks
    • most students lose focus at 25 minutes
    • it’s a mistake to keep going once you do, since you won’t actually learn anything and you’ll hate every minute of it
    • so when you start losing focus take a 5 minute break
    • do something nice like talking to someone or listening to music
    • it’s something you practice so with time you’ll be able to work for more time without losing focus
    • in the end of the study session have a big reward you look forward to
  • Create a study area
    • environment highly affects the way you act. Bedrooms are for sleeping, kitchens for eating: you’ll feel sleepy in your bedroom and hungry in the kitchen. So if you have a study area, it’ll be easier to start studying and staying focused.
    • study in a specific room like an office or school library if you can
    • if you have to study in your bedroom use a specific object you only use for studying: a lamp/desk. Make it a no-distraction, away from your bed, blank walls area.
  •  The more active the learning, the better
    • 80% active learning 20% passive
    • ask yourself: is it a concept or a fact?
    • learning a concept: understand/grasp/know it
      • put it into your own words
      • really think about the meaning of it
      • relate it with something you already know
      • teach somebody else. Recapitulate what you’ve learned. Talk out loud even if you don’t have anyone to teach - talk alone. Or at anyone that listens.
    • learning a fact: memorize it
      • use mnemonics
        • Acronyms (e.g. colours of the rainbow RoyGBiv – red orange yellow green blue indigo violet)
        •  Coined sayings - anything popular or sayings you’ve heard since you were a child.
        • Interacting images – work even better if they’re weird. Creative associations make you never forget specific details. (e.g. 1 gram of fat has 9 calories: picture a fat cat – each cat has 9 lives)
      • any time 2 things are highly similar but not the same you will get maximal interference!! USE mnemonics!! (e.g. afferent vs efferent neurons: SAME - Sensory Afferent Motor Efferent)
  • Be a part of  study groups
    • others can help you in ways you never thought before
  • Recognizing VS remembering
    • never confuse the two
    • while reviewing a chapter you may recognize concepts but not actually know them
    • and when you get to the test you won’t be able to remember any of it
    • so quiz yourself without looking at it
    • or stop in a page of your notes/textbook and ask yourself what is the concept immediately after and before it
  • Get your REM Sleep 
    • get ~8 hours so you don’t undo your studying
    • this is how your brain stores permanent memories
    • without it you’re ability to remember seriously decreases
    • most people don’t even begin to take the advice but it’s simple: sleep better. Do better.
  • There’s 162 hours in a week. There is time.
    • reflect on what you are doing with your time and what activities you have to prioritize to succed as a student
  • Taking notes is vital.
    • right after the class take 5 minutes to expand everything you’ve jotted down, give it depth.
    • NOT hours later. You won’t remember half the things you wrote down.
  • Ask your questions to class mates and teachers.
    • teachers want you to succeed and it’s more than ok to ask your question in the teacher’s office or in the next class
  • How to use a textbook: SQ3R technique
    • Survey Question Read Recite Review
      • Survey: skim through the entire chapter in a couple of minutes.
      • Raise questions: e.g. what is osmosis? What is this graphic about? What is a prototype?
      • it causes you to look for answers and you’ll find the information better once you actually study it after. If you intend to find something you learn it better.
  • Start studying for tests early.
    • don’t undo yourself. You should only be reviewing the days before the test. don’t leave it till the last minute!

(don’t just scroll through this!!!! really think about these methods and how you can actually implement them so you can benefit from them!!! these actually work but only if you put them into practice boo good luck!)

Signal replicas make a flexible sensor

When a jogger sets out on his evening run, the active movements of his arms and legs are accompanied by involuntary changes in the position of the head relative to the rest of the body. Yet the jogger does not experience feelings of dizziness like those induced in the passive riders of a rollercoaster, who have no control over the abrupt dips and swoops to which they are exposed. The reason for the difference lies in the vestibular organ (VO) located in the inner ear, which controls balance and posture. The VO senses ongoing self-motion and ensures that, while running, the jogger unconsciously compensates for the accompanying changes in the orientation of the head. The capacity to adapt and respond appropriately to both slight and substantial displacements of the head in turn implies that the sensory hair cells in the inner ear can react to widely varying stimulus intensities.

(Image caption: Fluorescence image showing two nerves (stained in red and green), which are responsible for transmitting information from the hair cells to the brain and from neurons (small green dots) that alter hair cell sensitivity, respectively)

In collaboration with Dr. John Simmers at the Centre national de la recherche scientifique (CNRS) at the University of Bordeaux, neurobiologists Dr. Boris Chagnaud, Roberto Banchi and Professor Hans Straka at LMU’s Department of Biology II, have now shown, for the first time, how this feat is achieved. Their findings reveal that cells in the spinal cord which generate the rhythmic patterns of neural and muscle activity required for locomotion also adaptively alter the sensitivity of the hair cells in the VO, enabling them to respond appropriately to the broad range of incoming signal amplitudes. The results are reported in the online journal “Nature Communications”. As Boris Chagnaud points out, “we are not really aware of what movement actually involves because our balance organs react immediately to alterations in posture and head position. The hair cells, which detect the resulting changes in fluid flow in the semicircular canals in the inner ear, enable us to keep our balance without any conscious effort.”

Using tadpoles as an experimental model system, the researchers investigated how the hair cells manage to sense both low- and high-amplitude movements and produce the signals that control the appropriate compensatory response. The tadpole’s balance organs operate on the same principle as the bilateral VOs in humans, and the nerve circuits responsible for communication between the hair cells and the motor neurons in the spinal cord are organized in essentially identical ways.

The role of replicate signals

When a tadpole initiates a voluntary movement, e.g., begins to swim by moving its tail from side to side, nerve cells in the spinal cord send copies of the motor commands to so-called efferent neurons in the brainstem that project to the hair cells in the inner ear. “The effect of this signal is to reduce the sensitivity of the hair cells,” says Chagnaud. By dampening the intrinsic sensitivity of the hair cells, the input from the spinal cord effectively adapts the VO’s dynamic range. This process enables the balance organ to maintain responsiveness to high-amplitude “afferent” stimuli from the periphery, and thus to modulate the head movements that accompany propulsive swimming.

Hence the whole adaptation process is controlled by neurons in the spinal cord, which transmit signals to the VO via nerve cells located in the brainstem just before the muscles carry out the next locomotory behavior. These signals thus notify the VO in advance about the temporal form of the impending movement. “This feedforward principle is crucial, because it prepares the hair cells to react appropriately to the next movement,” Chagnaud explains. “The direct impact of input from the spinal cord on the sensitivity of sensory nerve cells in the balance organ demonstrates the importance of interactions between sensory and motor systems, and it underlines the significance of the interplay between different components of the central nervous system – in this case, the spinal cord and the brainstem. Here, evolution has not only come up with an elegant means of anticipating the effects of locomotion on the body but also of compensating for them in an adaptive fashion.”

The LMU group now intends to study whether all the hair cells in the inner ear also respond to efferent information emanating from the spinal cord or whether the VO possess subpopulations of hair cells that are specialized for reception of impulses that signal either fast or slow movements.