Read Online The Boy Who Was Raised as a Dog by Bruce Perry - Free Book Online

to the untrained eye, when you know what trauma can do to children, sadly, you begin to see its aftermath everywhere.
    At that time my laboratory was studying neurobiological mechanisms, which I knew were related to resilience and vulnerability to stress. We were examining a curious but very important effect of drugs that stimulate the systems I’d been studying in the brain. These effects are called sensitization and tolerance, and they have profound implications for understanding the human mind and its reaction to trauma.
    In sensitization a pattern of stimulus leads to increased sensitivity to future similar stimulus. This is what is seen in the Vietnam veterans and the rats that were genetically oversensitive to stress or became that way because of early exposure to it. When the brain becomes sensitized, even small stressors can provoke large responses. Tolerance, on the contrary, mutes one’s response to an experience over time. Both factors are important for the functioning of memory: if we didn’t get tolerant to familiar experiences, they would always appear new and potentially overwhelming. The brain would probably run out of storage capacity, like an old computer. Similarly, if we didn’t become increasingly sensitive to certain things, we would not be able to improve how we respond to them.
    Curiously, both effects can be achieved with the same amount of the same drug, but you get completely opposite results if the pattern of drug use is different. For example, if a rat, or a human, is given small, frequent doses of drugs like cocaine or heroin that act on the dopamine and opioid systems, the drugs lose their “strength.” This is part of what happens during addiction: the addict becomes tolerant, and so more of the drug is needed to achieve the same “high.” In contrast, if you give an animal the exact same daily quantity of drug, but in large, infrequent doses, the drug actually “gains” strength. In two weeks a dose that caused a mild reaction on day one can actually cause a profound and prolonged overreaction on
day fourteen. Sensitization to a drug, in some cases, can lead to seizures and even death, a phenomenon that may be responsible for some otherwise inexplicable drug overdoses. Sadly for addicts, their drug craving tends to produce patterns of use that cause tolerance, not sensitization to the “high” that they desire, while simultaneously producing sensitization to certain undesirable effects, like the paranoia associated with cocaine use.
    More importantly, for our purposes, resilience or vulnerability to stress depend upon a person’s neural system’s tolerance or sensitization following earlier experience. These effects can also help further explain the difference between stress and trauma, which is important to understand as we consider children like Tina and Sandy. For example, “use it or lose it” is something we hear at the gym with good reason. Inactive muscle gets weak, while active muscle gets stronger. This principle is referred to as “use-dependence.” Similarly, the more a system in the brain is activated, the more that system will build—or maintain—synaptic connections.
    The changes—memory of sorts—in muscle occur because patterned, repetitive activity sends a signal to muscle cells that “you will be working at this level” so they make the molecular changes required to do that work easily. In order to change the muscle, however, the repetitions must be patterned. Curling twenty-five pounds thirty times in three closely timed sets of ten curls leads to stronger muscle. If you curl twenty-five pounds thirty times at random intervals during the day, however, the signal to the muscle is inconsistent, chaotic and insufficient to cause the muscle cells to become stronger. Without the pattern the very same repetitions and very same total weight will produce a far less effective result. To