Sunday, March 10, 2019

Neurobiology of Emotions

Panksepp describes seven, primary process* emotional networks [here primary process refers to basic, evolutionarily determined systems located in deep subcortical brain structures, not to types of thinking] which can be elicited by electrical stimulation to various brain centers; they are Seeking, Rage, Fear, Lust, Care, Panic, and Play. They are evolutionarily determined  --- not from the later evolved cortex --- but from subcortical structures such as the amygdala and from brainstem and vagus, and thus are found in other species. The four pleasurable emotional networks are Seeking, Lust, Care, and Play; Rage, Fear, and Panic are not pleasurable, that is, animals in laboratory experiments will not repeatedly push levers to stimulate these networks.

Seeking, such as looking for food or exploring the world [for the pleasure of exploration] informs motivation and ‘drives’. Rats will repeatedly push levers to stimulate pleasure centers in their brains and then subsequently energetically explore their surroundings. Frustration and anger may be brought on by thwarting Seeking behaviors. [This motivational and arousal system is found in the nucleus accumbens, ventral tegmental area (VTA), the lateral hypothalamus, and periaqueductal gray area (PGA) with diffuse mesocortical and mesolimbic pathways, the latter, particularly dopamine pathways of the brain responsible for cravings and addictions.]

Rage can be elicited in predatory animals by stimulating specific parts of the brain [an attack system; the medial amygdala to bed nucleus of stria terminalis (BNST) to anterior and ventromedial and perifornical hypothalamus to dorsal PAG.] When aggression is predatory --from the Seeking system-- animals will self stimulate by pushing levers, but when it is agitated anger, it is not pleasurable for them and they will not push the lever. This indicates two types of aggression.

Fear of attack by a predator is not the same as fear of separation (panic). [Central and lateral amygdala to medial hypothalamus to dorsal PAG to nucleus reticularis pontine caudalis.] Fear is meant to alert us to dangers, and elicits, via the autonomic nervous system’s sympathetic and parasympathetic circuitry, flight or freeze reactions. This system promotes generalized anxiety, some phobias, and PTSD.

Panic results from separation from the attachment figure. It is different from Fear. The soothing and comfort found with the good enough attachment figure mimics that of opioid receptor stimulation. [Powerful attachment to exogenous opioids is known as addiction.] Oxytocin  -- the attachment [bonding] hormone-- also soothes separation panic. Prolactin,as well, affects attachment. [anterior cingulate/anterior thalamus to BNST/ventral septal to midline and dorsomedial thalamus to dorsal preoptic hypothalmic to dorsal PAG. Panic vocalizations found in certain animals (such as dogs, guinea pigs) originate in the periaqueductal gray area of the brain and the medial thalamus and basal ganglia.] Panksepp posits that depression may be a mechanism to conserve energy by terminating separation distress.

Lust motivates sexual behavior and ensures the survival of the species. [Paraphrasing TS Elliot: Birth, copulation and death are all the facts when you get down to brass tacks.] Freud, in his libido theory, overvalued it as one of the two most important drives. Humans’ cortical centers can override these biological imperatives according to cultural mandates but other animals cannot. [BNST to corticomedial amygdala to preoptic and ventromedial hypothalamus to lateral ventral PAG]

Maternal Care nurtures offspring ensuring the survival of the species. Without it, most mammalian offspring could not survive. As with all the systems, there is variability in its intensity with strength of devotion to the offspring dependent on the mother’s own capacities and resilience. Maternal care and bonding is heightened by oxytocin. It also plays a part in romantic attachment. [Anterior cingulate to BNST to preoptic hypothalamus to VTA to ventral PAG]

Play elicits joy. It is pleasurable and allows for healthy engagement with others. It forges bonds and is the antidote to the pain of separation. Conversely, psychic pain inhibits play. Panksepp even tickled rats and made them chirp (laugh). Rats deprived of social interaction became play hungry (just like those deprived of food would be hungry for food). Decerebrate rats still played! Play in young animals helps them become more socially --and sexually-- competent (in the cortex) adults. Deprived of play, animals may become aggressive. [Human children need time for play, too. Panksepp wonders if overdiagnosis of ADHD comes from play hunger; If there is deprivation of lower brain needs, the upper cortex function is ‘distracted.’]

Traditional psychoanalysis with its emphasis on left brain language centers (narrative, interpretation, insight) of the cortex may nonetheless trickle down to deeper brain structures.
Emotional regulation experienced in the therapeutic context may effect change at subcortical levels and in neuronal networks at the level of dendritic branchings as well as ‘priming’ the soothing and ‘feel good’ neurotransmitters (oxytocin, opioids, dopamine).

*Panksepp refers to secondary process as learning in the basal ganglia to link emotions and perceptions, and tertiary process as learning from experiences in the neocortex which engenders thinking. Ancient feeling states forge memory and knowledge.

Davis, K; Panksepp, J (2018) The Emotional Foundations of Personality: A Neurobiological and Evolutionary Approach.

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