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Why folks coming off stimulants have panic attacks

After conditioning rats to associate a specific sound (think of it as their Jaws music) with an aversive experience (a mild footshock), the team then began the extinction process. As expected, when the sound was played many times without the footshock, rats stopped behaving as if they were afraid of the sound. However, when VTA dopamine neurons were silenced just after playing the sound -- exactly when the rats expected their feet to be shocked -- they could not unlearn the fear response. This showed that without VTA dopamine activity at that specific time, the mental link between the sound and the shock could not be removed.

The Neuroscientific Case for Facing Your Fears – The Atlantic – Medium

When someone encounters a new experience — say, a terrifying rabbit — groups of neurons in their brain fire together, the connections between them become stronger, and molecules accumulate at the places where neurons meet. Many scientists believe that these preserved patterns of strengthened connections are the literal stuff of memories — the physical representations of the things we remember. These connected neuron groups are called engrams. When people bring up old memories, the engram neurons fire up again. They also enter a brief period of instability, when the molecules that preserved the connections between them disappear and must be remade. This process, known as reconsolidation, means that humans are partly reconstructing our memories every time they bring them to mind. And it means that the act of recollection creates a window of time in which memories can be updated, and fears can be unlearned.

The memory part of the brain may also hold clues for anxiety and depression | University of Toronto Scarborough - News and Events

Ito says this finding is important because the conventional thinking is that these areas, along with another part called the dentate gyrus, form a circuit through which information flow occurs in one direction. Information processed by the dentate gyrus gets passed along to the CA3, and then on to CA1. In other words, the CA1 and CA3 should carry out the same function because they’re both part of the same information processing circuit. “But that’s not the case, the CA1 and CA3 in the ventral hippocampus seem to do very opposite things in relation to conflict processing,” says Ito. “It’s this strange bi-directional or oppositional effect, and that goes against traditional thinking of how information processing takes place in this part of the brain,” she says.  Because of its possible role in basic motivational behaviour, it may also offer important insights into a range of mental health illnesses. Addiction, for example, could be linked to deficits of approach motivation. Anxiety and depression on the other hand could be linked to avoidance behaviours, all of which could manifest itself in this part of the brain.

Scientists uncover brain circuits behind putting up a fight or freezing in place: Study may provide clues to disorders including anxiety and phobias -- ScienceDaily

Dr. Huberman's group also discovered that the vMT sends information primarily to two brain areas: the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC). These circuits turned out to be critical in determining how the mice reacted to a visual threat. Turning on the circuit that projected to the BLA caused more freezing responses, while activating the mPFC circuit increased tail shaking responses.

Researchers Find Fear and Courage Switches in Brain - Neuroscience News

Human brains harbor a structure equivalent to the vMT, Huberman said. He speculated that in people with phobias, constant anxiety or PTSD, malfunctioning circuitry or traumatic episodes may prevent vMT signaling from dropping off with repeated exposure to a stress-inducing situation. In other experiments, his group is now exploring the efficacy of techniques, such as deep breathing and relaxation of visual fixation, in adjusting the arousal states of people suffering from these problems. The thinking is that reducing vMT signaling in such individuals, or altering the balance of signaling strength from their human equivalents of the xiphoid nucleus and nucleus reuniens may increase their flexibility in coping with stress.

Animal study connects fear behavior, rhythmic breathing, brain smell center -- ScienceDaily

Other groups have observed that the amygdala and prelimbic prefrontal cortex, which govern learning and memory, emotion, and decision-making, were electrically active during "freezing," at an average of 4 Hz. Moberly observed that freeze behavior, breathing rate, and electrical activity of these brain regions were coordinated literally on the same wavelength.