by vox_mundi » Thu 09 Aug 2018, 12:02:20
Neuroscientists Get At the Roots of Pessimism$this->bbcode_second_pass_quote('', '[')b]... Graybiel's laboratory has previously identified a neural circuit that underlies a specific kind of decision-making known as approach-avoidance conflict. These types of decisions, which require weighing options with both positive and negative elements, tend to provoke a great deal of anxiety. Her lab has also shown that chronic stress dramatically affects this kind of decision-making: More stress usually leads animals to choose high-risk, high-payoff options.
In the new study, the researchers wanted to see if they could reproduce an effect that is often seen in people with depression, anxiety, or obsessive-compulsive disorder. These patients tend to engage in ritualistic behaviors designed to combat negative thoughts, and to place more weight on the potential negative outcome of a given situation. This kind of negative thinking, the researchers suspected, could influence approach-avoidance decision-making.
To test this hypothesis, the researchers stimulated the caudate nucleus, a brain region linked to emotional decision-making, with a small electrical current as animals were offered a reward (juice) paired with an unpleasant stimulus (a puff of air to the face). In each trial, the ratio of reward to aversive stimuli was different, and the animals could choose whether to accept or not.
This kind of decision-making requires cost-benefit analysis. If the reward is high enough to balance out the puff of air, the animals will choose to accept it, but when that ratio is too low, they reject it. When the researchers stimulated the caudate nucleus, the cost-benefit calculation became skewed, and the animals began to avoid combinations that they previously would have accepted. This continued even after the stimulation ended, and could also be seen the following day, after which point it gradually disappeared.
This result suggests that the animals began to devalue the reward that they previously wanted, and focused more on the cost of the aversive stimulus. "This state we've mimicked has an overestimation of cost relative to benefit," Graybiel says.
The caudate nucleus has within it regions that are connected with the limbic system, which regulates mood, and it sends input to motor areas of the brain as well as dopamine-producing regions. Graybiel and Amemori believe that the abnormal activity seen in the caudate nucleus in this study could be somehow disrupting dopamine activity.
The researchers also found that brainwave activity in the caudate nucleus was altered when decision-making patterns changed. This change, discovered by Amemori, is in the beta frequency and might serve as a biomarker to monitor whether animals or patients respond to drug treatment, Graybiel says.
"
There must be many circuits involved," she says. "
But apparently we are so delicately balanced that just throwing the system off a little bit can rapidly change behavior."
Pessimism may be redirected ... Binaural Beats and How they Work?$this->bbcode_second_pass_quote('', '[')b]
Research has shown that brain waves will mimic the observed frequency and alter mood when a person listens to binaural beats.
https://knowingneurons.com/2017/12/21/binaural-beats/ Researchers believe these changes occur because the binaural beats activate specific systems within the brain. An electroencephalogram (EEG) that recorded the electrical brain activity of people listening to binaural beats showed that the effect on a person's body varied according to the frequency pattern used.
... Beta waves in particular are the dominant brainwave pattern during waking hours; our cognitive function frequency runs between 12 and 38 Hz.The rule of thumb is the more complex the cognitive process, the higher the frequency. When we are engaged in complex problem solving, it’s the beta wave.
The beta state is also the underlying frequency to states of anxiety and high-level stress, often referred to as the “fight or flight state, a state when the body rapidly produces a lot of energy in order to cope with threats to survival.This occurs in the higher end of the beta scale, and is the reason why you don’t often find recordings produced using frequencies over 25hz – because extensive exposure to such frequencies can trigger the release of stress hormones and symptoms such as a rapid heart beat and faster breathing.
At the lower end of the beta scale, however, we are able to produce recordings that stimulate the brain and trigger positive benefits such as improved learning ability, increased physical energy and general higher awareness and sharpness.
https://en.wikipedia.org/wiki/Brainwave_entrainment https://en.wikipedia.org/wiki/Beta_wave A 2015 review of the available literature summarized several studies on the effect of binaural beats on memory, creativity, attention, anxiety, mood and vigilance. The authors concluded that for most of these applications, findings are either contradictory or only supported by a single study.
The only consistent finding was that several studies reported that binaural beat stimulation reduces anxiety levels.