New Brain Pathway Controlling Fear Memories and Behavior Discovered

Researchers at Cold Spring Harbor Laboratory (CSHL) dicovered a new pathway that controls fear memories and behavior in the mouse brain, offering mechanistic insight into how anxiety disorders may arise.

It is known that the amygdala is responsible for processing memory, decision-making, and emotional reactions. This covers fear memories and fear learning. This latest discovery which is published in Nature, extends the understanding further by finding out what are the controlling factors in and of the amygdala.

The researchers note that the processing of fear is stored within a distinct region of the brain. They found neuron circuit (called the PVT and CeL; see image) that controls fear. Disrupting the circuit results in a huge reduction of fear and strengthening it does the opposite. They also note that the chemical messenger used to transmit and control the fear emotion is BDNF, a molecule already associated with anxiety disorders.

The discovery of the neural circuit can be the basis for new therapies for treatment of anxiety disorders.

Brain Response Time Not Dependent on Number of Neurons in Neural Network

Anatomy of a Neuron

Neuroscientists using a supercomputer to run a simulation of a neural network, have noted that the response time of the brain is the same regardless if the number of neurons in the network is 50 or 1,000. The constructed computer simulation of the neural network showed that the simulated neurons responded with the same speed on both models.

Neurons are responsible for transmitting information and signals to and from the brain. These cells are the main component of the nervous system which includes the brain, spinal cord, and peripheral ganglia (relay points and intermediary connections between different neurological structures in the body).

There are around eighty to one hundred billion neurons in the human brain. These are interconnected to each other by around one hundred trillion synapses to form the neural network. This network transmits information through electrical and chemical signals between the body and the brain.

About 15% of the cardiac output, 20% of the body's oxygen, and 25% of the body's glucose utilization are the resource requirements of the neural network to perform efficiently.

The purpose of the study is to explain long standing questions on the neural network such as neural coordination, network behavior, size requirements, and response times (how the neurons are coordinated to trigger a movement at a particular point in time).

The neuroscientists at Vanderbilt University constructed the computer simulation using Vanderbilt's in-house supercomputer at the Advanced Computing Center for Research & Education. Even with the computing power of a supercomputer, the simulation can only model a neural network of up to 1000 neurons.

Increased Brain Perception and Boosted Senses Through Low-intensity Transcranial-focused Ultrasound

William Tyler focusing low intensity ultrasound on brain region responsible for processing tactile sensory inputs.
Credit: Jim Stroup/Virginia Tech

A study conducted at the Virginia Tech Carilion Research Institute showed that low intensity, transcranial-focused ultrasound can increase the brain's sensory perception.

Ultrasound is a sound pressure wave that is at a frequency that is above the hearing range of humans. Ultrasound is used in various common application such as detectors, non-contact sensors, and specially in medical imaging.

Focused ultrasound is a procedure where ultrasound waves are aimed at a specific region of the body. It is a non-invasive technique to stimulate the targeted tissue or organ without disturbing the surrounding area.

In the study, focused ultrasound was sent to the cerebral cortex region to stimulate the median nerve. This area processes brain signals received from the hand. By doing so, scientists discovered that the test subject started to show significant improvements in the sensory perception tests administered to them. They increased their ability to distinguish the frequency of a chain of air puffs as well as note whether one pin or two pins was touching their skin at a very close distance.

This study is a positive step towards developing applications that can use ultrasound as a noninvasive tool for modulating brain activity.

Ankyrin-G and Kinesin-1 Protein Responsible For Movement Mechanics of Neuron's Sodium Ion Channel to Axon

Nerve Impulse

Scientists have discovered how sodium ion channels travel from the neuron to the axon to initiate central nervous communications to and from the brain. They observed that two proteins, Ankyrin-G and Kinesin-1, play an important role in the process. The ankyrin-G protein tethers the sodium ion channel to the axon while kinesin-1 transports it to the axon.

This process is fundamental in moving nerve signals along the central nervous system. These nerve signals, carried by the sodium ion channel, cover information like sense (touch, feel, taste, etc), movement, memory, and thinking. These signals, which are electrical and chemical in nature, do not fire up all at once, it jumps from axon to axon.

The image of a neuron above shows how the nerve impulse travels along the axon which is the long, slender extension of the nerve cell body.

Scientists have long wondered how the mechanics of the movement of the sodium ion channels, the protein responsible for the signals, from the neuron to axon works. These proteins have to be delivered to the axon or else nothing happens.

There are about 80 to 100 billion neurons in the human brain. These are interconnected to each other through synapses in which there are about 100 trillion. The neural network transmits information through electrical and chemical signals.

The Science of Learning: Studying The Role of Inhibitory Neurons in the Brain's Learning Process

Neurologists are looking at how inhibitory neurons in the brain affects the brain during times of critical learning. Neurons are cells that are responsible for processing and transmitting information through electrical and chemical signals to and from the brain.

Twenty percent of the brain's neurons are inhibitory neurons. The remaining are excitatory neurons. Inhibitory neurons are neurons that are likely not to send information to the brain or central nervous system. This process of sending information is called an action potential.

An excitatory neuron is a neuron that is more likely to generate an action potential.

Scientists have discovered that during a person's younger years, when learning is crucial, inhibitory neurons are not as active to allow the brain to receive more information. As the person gets older, these neurons become stronger which slows down the learning process.

Neurohormone Oxytocin Focusing Ability May Have Links To Autism Spectrum Disorder (ASD)

Researchers may have discovered a link between the neurohormone oxytocin and autism. Studies at the NYU Langone Medical Center show that oxytocin help the brain process information by filtering out background signals and increases the strength of desired signals.

From past data, they have noted that people with Autism Spectrum Disorder (ASD) have low levels of oxytocin and that mutations in the oxytocin receptor gene predispose people to autism.

Oxytocin is a neurohypophysial hormone present in mammals and acts primarily as a neuromodulator in the brain. Neuromodulators affect multiple neurons at once and are diffused through large areas of the nervous system.

Oxytocin is usually associated with parenting and social bonding behavior through psychological behaviors such as trust, pair bonding, and empathy.

Brain Waves From 12,000 Brain Neurons Simulated In A Computer

(c) Copyright: EPFL, Blue Brain Project

The Ecole Polytechnique Fédérale de Lausanne (EPFL) Blue Brain Project in Switzerland and the Allen Institute for Brain Science in the United States have built a computer model that simulates 12,000 neurons. This allows the scientists to learn more about brain waves and how neurons work and interact with each other.

The Computer visualization on the left shows the brain waves produced by 100 detailed models of nerve cells. The strength of the signal is represented by the following color scheme: green = weak signal, yellow = medium, red = strong.

Neurons behave differently from how computer chips operate. With computer chips, a steady stream of power is fed through it at a steady rate. Neurons transmit and process information that are sent in spikes.

The Blue Brain Project aims to complete a working computer model of the human brain. Although the project has simulated 12,000 neurons, it is still a far stride from a complete brain which has billions of neurons comprising the nervous system.

Transcranial Random Noise Stimulation (TRNS) Enhances Math Skills and Ability in Brain

Researchers have found that a non-invasive and harmless process known as Transcranial Random Noise Stimulation (TRNS) enhances the brain's ability in math skills and ability for as long as six months.

Transcranial Random Noise Stimulation is a form of brain stimulation where brain functions are modified by using weak electrical current over the scalp using contact electrodes. TRNS is one type of transcranial current stimulation where the stimulation current is varied randomly.

The principle behind this type of brain stimulation is that the electrical fields generated by the electrical currents modulate the activity of brain neurons and can enhance certain brain functions.

TRNS is a relatively new process but recent studies have already shown enhanced brain performance using this technique.