Rethinking the Emotional Brain, Joseph LeDoux (2014)
We can best learn about emotions by studying animals. LeDoux writes that relying on subjective human reports about their feelings is not the best way to understand emotions, at least not if we’re trying to understand what emotions are shared by humans and animals. Rather, it is more useful to focus “on circuits that instantiate functions that allow organisms to survive and thrive by detecting and responding to challenges and opportunities.” While different animals have some different functions, “there are also core components of these functions that are shared by all mammals.”
We can best learn about emotions by focusing on survival circuits. He sidesteps the basic emotions debate, stating that he disagrees with Lisa Feldman Barrett in some ways but agrees with her claim that there is insufficient evidence that basic emotions “have dedicated neural circuits.” He does not deny that mammalian brains might contain emotional circuits but believes it is more fruitful to think of emotions in terms of survival circuits, the existence of which are not doubted. Survival circuits are systems “that work in concert to sustain life both on a moment to moment basis and over long time scales.” Survival circuits include, “at a minimum, circuits involved in defense, mainte-nance of energy and nutritional supplies, fluid balance, thermoregulation, and reproduction.”
Survival circuits existed in our evolutionary ancestors. “Survival circuits have their ultimate origins in primordial mechanisms that were present in early life forms. This is suggested by the fact that extant single-cell organisms, such as bacteria, have the capacity to retract from harmful chemicals and to accept chemicals that have nutritional value. With the evolution of multicellular, and multisystem, eukaryotic organisms (Metazoa, or what we usually call animals), fundamental survival capacities increase in complexity and sophistication, in large part due to the presence of specialized sensory receptors and motor effectors, and a central nervous system that can coordinate bodily functions and interactions with the environment.”
Survival circuits detect stimuli. “Survival circuits detect key trigger stimuli on the basis of innate programming or past experience” Innate programming refers to “genetically specified synaptic arrangements that are established in early development. Innate evaluative networks make possible species-wide stimulus-response connections that allow organisms to respond to specific stimulus patterns in tried and true ways (i.e., with hard-wired/ innate reactions) that have been honed by natural selection.” Past experience refers to “conditions under which associations are formed between novel stimuli and biologically innately significant events, typically innate triggers. These experience-dependent associations allow meaningless stimuli that occur in conjunction with significant events to acquire the ability to activate the innate response patterns that are genetically wired to innate trigger stimuli.”
The defense system as an example. Different animals are born programmed to detect specific stimuli and have a defense response when detecting these stimuli. Rodents, for example, have a sensitivity for predator odors, and primates have a sensitivity for snakes and spiders. We are not wired to fear other stimuli, but Pavlovian fear conditioning explains that we can be conditioned to fear neutral stimuli (conditioned stimuli) when it is paired with unconditioned stimuli.
Survival-related behaviors in different species are both similar and different. For instance, all mammals have innate programming to escape threat, but different species will escape the threat in different ways. “For example, while most mammals flee on all fours, some use only two legs (humans), others escape by flying (bats), and still others by swimming (whales, seals, and walrus).”
When a survival circuit is activated, two different responses are possible. Some responses are subcortical and can result in automatic appraisal while other responses can led to cognitive appraisals where processing is “deliberate, controlled and often conscious.”
Reinforcers. Both conditioned and unconditioned emotional stimuli can be described as incentives and as reinforcers, as these stimuli “strengthen the probability that an instrumental response will be learned and later performed.” When a tone is paired with food, the tone is (a) a conditioned stimulus that triggers a survival circuit (eating) and (b) a reinforcer that elicits an approach behavior (eating).
When a survival circuit is activated, several parts of the organism are triggered. The following are triggered: arousal responses in the CNS, innate behaviors (possibly), the autonomic nervous system, and hormonal responses. The result of all this is “the establishment of a state in which brain resources are coordinated and monopolized for the purpose of enhancing the organism’s ability to cope with a challenge and/or benefit from opportunities. The organism becomes especially attentive to and sensitive to stimuli relevant to the survival function, memories rel-evant to the survival function are retrieved, and previously learned instrumental responses relevant to the survival function are potentiated . New learning occurs and new explicit memories (via the hip-pocampus and related cortical areas) and implicit memories (memories stored in the survival circuit) are formed . Such states will be referred to here as global organismic states.”
We can best learn about emotions by focusing on survival circuits. He sidesteps the basic emotions debate, stating that he disagrees with Lisa Feldman Barrett in some ways but agrees with her claim that there is insufficient evidence that basic emotions “have dedicated neural circuits.” He does not deny that mammalian brains might contain emotional circuits but believes it is more fruitful to think of emotions in terms of survival circuits, the existence of which are not doubted. Survival circuits are systems “that work in concert to sustain life both on a moment to moment basis and over long time scales.” Survival circuits include, “at a minimum, circuits involved in defense, mainte-nance of energy and nutritional supplies, fluid balance, thermoregulation, and reproduction.”
Survival circuits existed in our evolutionary ancestors. “Survival circuits have their ultimate origins in primordial mechanisms that were present in early life forms. This is suggested by the fact that extant single-cell organisms, such as bacteria, have the capacity to retract from harmful chemicals and to accept chemicals that have nutritional value. With the evolution of multicellular, and multisystem, eukaryotic organisms (Metazoa, or what we usually call animals), fundamental survival capacities increase in complexity and sophistication, in large part due to the presence of specialized sensory receptors and motor effectors, and a central nervous system that can coordinate bodily functions and interactions with the environment.”
Survival circuits detect stimuli. “Survival circuits detect key trigger stimuli on the basis of innate programming or past experience” Innate programming refers to “genetically specified synaptic arrangements that are established in early development. Innate evaluative networks make possible species-wide stimulus-response connections that allow organisms to respond to specific stimulus patterns in tried and true ways (i.e., with hard-wired/ innate reactions) that have been honed by natural selection.” Past experience refers to “conditions under which associations are formed between novel stimuli and biologically innately significant events, typically innate triggers. These experience-dependent associations allow meaningless stimuli that occur in conjunction with significant events to acquire the ability to activate the innate response patterns that are genetically wired to innate trigger stimuli.”
The defense system as an example. Different animals are born programmed to detect specific stimuli and have a defense response when detecting these stimuli. Rodents, for example, have a sensitivity for predator odors, and primates have a sensitivity for snakes and spiders. We are not wired to fear other stimuli, but Pavlovian fear conditioning explains that we can be conditioned to fear neutral stimuli (conditioned stimuli) when it is paired with unconditioned stimuli.
Survival-related behaviors in different species are both similar and different. For instance, all mammals have innate programming to escape threat, but different species will escape the threat in different ways. “For example, while most mammals flee on all fours, some use only two legs (humans), others escape by flying (bats), and still others by swimming (whales, seals, and walrus).”
When a survival circuit is activated, two different responses are possible. Some responses are subcortical and can result in automatic appraisal while other responses can led to cognitive appraisals where processing is “deliberate, controlled and often conscious.”
Reinforcers. Both conditioned and unconditioned emotional stimuli can be described as incentives and as reinforcers, as these stimuli “strengthen the probability that an instrumental response will be learned and later performed.” When a tone is paired with food, the tone is (a) a conditioned stimulus that triggers a survival circuit (eating) and (b) a reinforcer that elicits an approach behavior (eating).
When a survival circuit is activated, several parts of the organism are triggered. The following are triggered: arousal responses in the CNS, innate behaviors (possibly), the autonomic nervous system, and hormonal responses. The result of all this is “the establishment of a state in which brain resources are coordinated and monopolized for the purpose of enhancing the organism’s ability to cope with a challenge and/or benefit from opportunities. The organism becomes especially attentive to and sensitive to stimuli relevant to the survival function, memories rel-evant to the survival function are retrieved, and previously learned instrumental responses relevant to the survival function are potentiated . New learning occurs and new explicit memories (via the hip-pocampus and related cortical areas) and implicit memories (memories stored in the survival circuit) are formed . Such states will be referred to here as global organismic states.”
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