BIOL4370 Lecture 8 Social Neurobiology Fall 2024 PDF

11/8/2024 SC/BIOL 4370 – 3.0 [Fall 2024] Neurobiology Lecture 8: The Biology of Sociality 1 1 1  11/8/2024 SCHEDULE 2 2...

11/8/2024 SC/BIOL 4370 – 3.0 [Fall 2024] Neurobiology Lecture 8: The Biology of Sociality 1 1 1  11/8/2024 SCHEDULE 2 2 2  11/8/2024 Housekeeping Remember Written Assignment! Due: Last day of class, at Midnight (12:00am) Submission link will be posted on eClass Make sure to submit in Word format Final exam: Saturday, December 14th 7:00pm- 10:00pm Similar format to midterm 3 Hours 100-110+ marks 3 3  11/8/2024 Outline Describe brain networks used during social interactions Understand the biological basis of self- and other representation Explore the neurobiology of autism 4 4 4  11/8/2024 The Social Brain Humans are social creatures Components: Communicating, learning, and Self-awareness “introspection”: teaching are highly adaptive knowledge about oneself behaviors Feedback based on social Facilitates retention and sharing performance of complex information required for survival Mentalizing: infer the mental “Cultural transmission” states of others Cooperation; coordinating Interpret other’s efforts behavior/mindset Ideas of fairness and morality 5 5  11/8/2024 The Social Brain: Origins Grooming in NHPs Promotes social bonding Confers social status within troops Males mostly groom females Releases endorphins (the body’s natural opioids) Requires understanding of reciprocation, competition, status. Safety in numbers: deters predators 6 6  11/8/2024 The Social Brain: Origins Some calculations suggest human brain is best suited to managing ~150 relationships Chimpanzee troops ~100 individuals Eusociality (co-habitation across generations) provides opportunities for division of labor and altruism Beginning of “camps” ~1 million years ago for Homo Erectus 7 7  11/8/2024 Do humans have a unique capacity for social intelligence? Physical domain: Locating a reward, discriminating quantity, causality (tool usage) Social domain: Solving problems by observing solutions Understanding cues indicating object location Selecting communicative gestures Following eye gaze to a target Understanding intent Adapted from Herrmann et al., 2007 8 8 8  11/8/2024 Do humans have a unique capacity for social intelligence? Adapted from Herrmann et al., 2007 9 9 9  11/8/2024 Morality may be “hardwired” in humans 10 10 10  11/8/2024 Social Cognition Networks The relevance of social factors increase in salience and value Complex social cognition now required Judging attractiveness, social status, understanding social norms Need new skills: mentalizing, processing emotional expression, abstraction 11 11 11  11/8/2024 Social Cognition Networks 12 Adapted from Gazzaniga et al., 2019; pg. 570 12 12  11/8/2024 Social Cognition Networks A network is required due to the sheer complexity of social processing Need to monitor “self”, infer other’s mental states, interpret emotional responses, make socially guided decisions, make value judgements Monitor subjective feelings Adapted from Gazzaniga et al., 2019; pg. 570 13 13 13  11/8/2024 Social Cognition Networks Anterior cingulate cortex: motivation, decision making, cost-benefit calculation, conflict and error monitoring Ventromedial prefrontal cortex: self-referential processing, monitoring subjective feelings Posterior cingulate cortex: prediction, planning Medial parietal cortex: Socio-emotional processing, perception Adapted from Gazzaniga et al., 2019; pg. 570 14 14 14  11/8/2024 Maintaining social behavior norms: the frontal lobe Patient M.R. Suffered coup-contrecoup injury during motorcycle accident Extensive damage to orbital frontal cortex (OFC) Performs well on memory, motor and language tests OFC damage resulted in inappropriate social behaviors -hugs strangers -talks about deeply personal topics -rambles on about his hobbies Adapted from Szczepanski and Knight, 2014; Neuron 15 15 15  11/8/2024 The frontal cortex had regions of specialization involved in sociality Adapted from Szczepanski and Knight, 2014; Neuron 16 16 16  11/8/2024 Socialness is malleable and subject to impairment Abuse (physical, sexual and psychological) can impair social development Neglect also impairs social development Particularly damaging during early “critical periods” of postnatal development Corresponding changes in brain circuits supporting sociality Neuropharmacology (Volume 60, Issue 2-3, pp. 397-404). 17 17 17  11/8/2024 Socialness is malleable and subject to impairment Social isolation results in: -changes in prefrontal cortex function -impaired synaptic plasticity -decreased dopamine and increased serotonin signaling -increased aggression, fear and anxiety Neuropharmacology (Volume 60, Issue 2-3, 18 pp. 397-404). 18 18  11/8/2024 Perception of Social Isolation Even perceived isolation is damaging Self-reports of feeling isolated: predictor of depression, reductions in IQ over time, increased risk for Alzheimer’s Disease Even observed when controlling for social group size, social activity, and marital status. Loneliness associated with decreased glucocorticoid receptor sensitivity Increased activity of the Default Mode Network (dorsal lateral prefrontal cortex, anterior cingulate cortex, retrosplenial cortex) 19 19 19  11/8/2024 Socrates: I think, therefore I am How do we develop our self- knowledge? The physical “you”: body awareness The unobservable “you”: thoughts, experiences, traits How do we distinguish ourselves from others? Self-perception processes Which brain regions are engaged? 20 20 20  11/8/2024 Self-referential processing We recall information better when Self-reference effect processed in relation to our self May depend on enhanced knowledge of self Promotes greater encoding Adapted from Gazzaniga et al., 2019;. Fig. 13.2 21 21 21  11/8/2024 Self-referential processing Medial prefrontal cortex is Degree of MPFC activation engaged during self-referential correlates with recall of processing information related to self 22 Adapted from Gazzaniga et al., 2019;. Fig. 13.3 22 22  11/8/2024 Neural correlates of sense of self What brain regions mediate the “sense of the self”? Direct stimulation of the posterior parietal cortex Stimulation induces sense in patients that they had moved or spoken even though they had not Suggests they stimulated region that generates “sense of self” Adapted from Gazzaniga et al., 2019; pg. 570 23 23 23  11/8/2024 Default mode network in sense of self MPFC demonstrates elevated activity rates “at rest” The DMN consists of: Ventral medial PFC Dorsal medial PFC Posterior cingulate cortex Retrosplenial cortex Temporal parietal junction Inferior parietal lobule Adapted from Gazzaniga et al., 2019. Figure 13.4 24 24 24  11/8/2024 Default mode network in sense of self DMN may mediate cognition related to: Self-referential processing Thinking about future actions Evaluation of current condition Self-reflective thought May prepare us for effective social cognition by anticipating other’s mindsets Shows increased activity when gauging the beliefs and intentions of others Adapted from Gazzaniga et al., 2019. Figure 13.4 25 25 25  11/8/2024 Neural correlates of positive self-perception Majority of us have inflated sense of self 70% of high school students rate themselves as above average in leadership ability 93% or professors think they are above average at their work More than likely to win lottery, less likely to get divorced Anterior cingulate cortex is active during positive self-appraisal Adapted from Gazzaniga et al., 2019. pg. 570 26 26 26  11/8/2024 Neural correlates of positive self-perception Neural activity in relation to judging positive information about self Rate self-descriptions on a variety of traits When traits were positive, correlated with less deactivation of vACC (ventral anterior cingulate cortex) vACC is responsible for focusing attention on positive self-information Adapted from Gazzaniga et al., 2019. Figure 13.6 27 27 27  11/8/2024 Judging our own positive self-perceptions Damage to the orbital frontal cortex impairs our ability to judge the accuracy of our own positive self-perceptions OFC damage patients: exaggerated their own positive self-characteristics Brought up inappropriate subjects; were proud of their performance! When viewing themselves, demonstrated increased embarrassment OFC responsible for spontaneous accurate self-perceptions Patients with OFC damage are aware of social norms but lack insight Adapted from Gazzaniga et al., 2019. Figure 13.7 28 28 28  11/8/2024 Predicting future mental states: the ventral medial prefrontal cortex Imagining our own mental states in novel situations Allows us to predict other’s states of mind in similar scenarios Mental rehearsal of social situations vmPFC simulates other people’s minds Damage here impairs ability to predict our own likes and dislikes Adapted from Gazzaniga et al., 2019. pg. 57029 29 29  11/8/2024 Predicting mental states: the ventral medial prefrontal cortex vmPFC is activated when weighing how much a person would enjoy something now versus in the future Would you take $20 dollars today or $23 next week? Most take $20 now Higher levels of vmPFC activity associated with increased preference for future payout Adapted from Gazzaniga et al., 2019. pg. 57030 30 30  11/8/2024 Embodiment and out-of-body experiences Embodiment = spatial unity between self and body Temporal parietal junction and angular gyrus mediate sense of unity Electrical stimulation of angular gyrus caused feelings of : -sinking into bed -falling from a height -out of body experience = could see their own body in the bed Adapted from Gazzaniga et al., 2019. Figure 13.7 31 31 31  11/8/2024 Embodiment and out-of-body experiences Temporoparietal junction (near angular gyrus) “Imagine a perspective other than your own” TPJ activity increases when self reporting of transforming egocentric locus to other actor Imagined egocentric perspective TPJ also engaged when imagining an out of body experience Adapted from Gazzaniga et al., 2019; pg. 570 32 32 32  11/8/2024 Embodiment and out-of-body experiences Autoscopic hallucination Right temporo-occipital cortex Effects representation of entire body Don’t feel as if they left their own body However, do see a double of themselves in extrapersonal space May be a failure to synergize proprioceptive and tactile information Or conflicting vestibular and visual information Adapted from Gazzaniga et al., 2019. Figure 13.7 33 33 33  11/8/2024 Understanding the mental state of others Key for social cooperation Represents foundation of social Spend 80% of our time cognition interacting 80-90% of our conversations are spent talking about ourselves and others Depends on empathic accuracy; ability to infer other’s thoughts and feelings Total strangers = 20% accuracy Close friends = 30% accuracy Spouses = 30-35% accuracy Adapted from Gil et al., 2012 34 34 34  11/8/2024 Understanding the mental state of others Begins to develop this when we are Represents foundation of social infants cognition Imitative facial expressions behavior at 42 minutes (!) post birth Suggests it is an innate and automatic behavior 4 months old Increased activity in occipital cortex in the gamma range Increased activity in prefrontal cortex in response to direct eye control Processing information about facial expressions Adapted from Gil et al., 2012 35 35 35  11/8/2024 Why start so young? Attachment learning is critical to survival Noradrenergic system drives rapid olfactory learning So you know what Mom smells like Amygdala responses are dampened So pups don’t learn to associate Mom with pain/aversion We are hardwired to form this attachment regardless of quality of care! Adapted from Poeppel et al., 2020. Figure 36 36 36  11/8/2024 Neural correlates of sharing experiences Medial prefrontal cortex activation associated with perception of self and others Activity of ventral MPFC increases for self-perception and for perception of those perceived as similar and current romantic partner Dorsal MPFC is activated for perceptions of those we perceive as dissimilar 37 Adapted from Gazzaniga et al., 2019. Figure 13.14 37 37  11/8/2024 Empathy Same affective state is activated in the observer By peripherally experiencing it, you understand it Triggers somatic and autonomic responses: “embodied simulation” Connection between mirror neuron networks (MPFC, ventrolateral PFC and anterior cingulate gyrus) and amygdala through the insula Adapted from Gazzaniga et al., 2019. Figure 13.14 Adapted from Gazzaniga et al., 2019. Figure 13.16 38 38 38  11/8/2024 Empathy How to study empathy? In humans, disgust can be reliably induced and is easy to recognize Experience and perception of disgust activate anterior insula Adapted from Gazzaniga et al., 2019. Figure 13.16 39 39 39  11/8/2024 Empathy Anterior insula activation correlates with degree of disgust presented Same brain region activated by disgusting smells Electrical stimulation of insula evokes nausea Brain damage here reduces ability to feel or detect disgust in others Mirror neurons here may facilitate detection of disgust expressed by others Adapted from Gazzaniga et al., 2019. Figure 13.16 40 40 40  11/8/2024 Empathy Insula activated when feeling physical pain Also activated when observing others in pain When received a signal indicating a romantic partner is in pain, insula and anterior cingulate activity increased Adapted from Gazzaniga et al., 2019. Figure 13.17 41 41 41  11/8/2024 Empathy Anterior cingulate also activated when feeling physical pain When received a signal indicating a romantic partner is in pain, insula and anterior cingulate activity increases Anterior insula and anterior cingulate cortex encode unpleasantness Adapted from Gazzaniga et al., 2019. Figure 13.17 Adapted from Gazzaniga et al., 2019. Figure 13.18 42 42 42  11/8/2024 43 43 43  11/8/2024 Processing information about self and other Dorsal anterior cingulate cortex is also active when self-specific processing (but not with others) dACC involved in goal- directed activity, self reflection and action monitoring Right medial prefrontal cortex activated during self reflection Left medial prefrontal cortex activated when thinking about others Adapted from Gazzaniga et al., 2019. Figure 13.18 44 44 44  11/8/2024 Forming impressions of others: Dorsal medial prefrontal cortex Listen to stories about a person’s behavior “Started to dance on a table at a party” Must think about internal state of other people Dorsal medial prefrontal cortex activity correlated with self report of evaluation of person’s behavior Adapted from Gazzaniga et al., 2019. Figure 13.22 45 45 45  11/8/2024 Empathy and fairness Play a card game with two others: one plays fair, the other cheats Insula and anterior cingulate cortex were both active when fair person appeared to be in pain, consistent with reported empathy The activity of insula and ACC was not increased in males watching the cheater experience pain Males have more activity in the ventral striatum and nucleus accumbens Actually enjoyed seeing the cheater in pain! 46 Adapted from Gazzaniga et al., 2019. Figure 13.20 46 46  11/8/2024 Empathy and group membership Sports fans watched games and plays in which their favorite team performed well and won or lost (ex. Yankees vs Redsox) Success of a rival team (favored team lost) increased activation of ACC ACC activation correlated with self-reported psychological pain associated with game outcomes Ventral striatal activity was increased when “hated” team lost (schadenfreude) 47 Adapted from Gazzaniga et al., 2019. Figure 13.21 47 47  11/8/2024 Using social knowledge to make decisions Knowing the rules of social engagement still requires ongoing decisions about how to apply those rules When to hug versus when to shake hands Damage to the ventral medial prefrontal cortex severely impairs social decision making May be impairment in evaluating the values of options or the reward value Used patients with frontotemporal lobar degeneration to study this Patients with FTLD demonstrate socially inappropriate behaviors and make crass comments Adapted from Gazzaniga et al., 2019. Figure 13.32 48 48 48  11/8/2024 Using social knowledge to make decisions When judging social situations with various levels of social impropriety Rolling through a stop light versus cutting in line Rate on scale of 1 to 5 FTLD patients judged negative scenarios as more acceptable relative to controls Correlated with decreased activity in the vmPFC Below: orange = control; blue = FTLD patients Adapted from Gazzaniga et al., 2019. Figure 13.32 49 49 49  11/8/2024 Neural correlates of morality Moral “organ” of the brain may represent value of actions and outcomes Insula appears to represent subjective value and aversiveness of moral transgressions Amygdala distinguishes between intentional and accidental harm within 200ms! Temporoparietal junction most sensitive to attempted harms Encodes information about perpetrators intentions If you stimulate the TPJ get “no harm, no foul” response TPJ helps suppress amygdala response to unintentional transgressions Moral Dilemmas: trolley dilemma DLPFC (totalitarian) and mPFC, TPJ and parietal cortex (personal) 50 50 50  11/8/2024 51 51 51  11/8/2024 Receiving Social Support and mental health Social cues may act as a buffer against social stressors The perception of social support is key Reduces cortisol levels Reminders of social support decreased hypothalamic activity associate with threat There is a “safety signal circuit” vmPFC activity increases when receiving social support vmPFC inhibits amygdala to limit threat responding Also inhibits insula and anterior cingulate cortex (unpleasantness circuit) Adapted from Gazzaniga et al., 2019. pg. 570 52 52  11/8/2024 Providing Social Support and mental health Providing support generates Opioids detectable physiological responses Released in response to supportive Reduces depression symptoms social interactions Lowers BP and heart rate Reduce pain and threat response Predicts lower mortality at 5 years Reduce activity of HPA and SNS Fewer negative symptoms in cancer May contribute to parental behavior survivors Reduced amygdala activity Block opioid signaling enhances fear Activates reward regions of the brain acquisition and prevents fear including septum and VTA forgetting Adapted from Gazzaniga et al., 2019. pg. 570 53 53  11/8/2024 History of Autism Spectrum Disorder (ASD) ASD was first observed by psychiatrist Leo Kanner in 1943 He was studying a group of infants Coined the term “early infantile autism” in his paper published in 1943. Kanner witnessed children who were “socially aloof”, were mute or had abnormal speech and resistant to change in routine. He noted how alert and intelligent these children appeared. 54 54  11/8/2024 Characteristics of Autism Neurodevelopmental disorder Impaired social interactions Preference for isolation Impaired communication Restricted interests Presents before age 3 More prevalent in males Associated with impaired cognitive function Comorbid with epilepsy, sleep disorders, GI complications 55 55  11/8/2024 56 56 56  11/8/2024 Autism and the Default mode network DMN associated with social, emotion and introspective processing When neurotypicals indulge in non-self referential thinking, the MPFC (part of the DMN) is less active No change in activation from resting to engaged focus with ASD fMRI measures suggest that the DMN is always off in ASD Some with ASD state “never thought about inner experience” Some report “only images, no thoughts” in resting state Gazzaniga, 604 57 57  11/8/2024 Neuropathology of Autism Delayed brain development 20% of cases present with macrocephaly May be transient-typically observed from years 2-4 Neurons in hippocampus, cortex present with “immature spines” Suggests developmental delay as these spines are normally observed early in development Could be spine overproduction or lack of “pruning” that creates network imbalances Philips et al., 2015 58 58  11/8/2024 Brain regions affected in Autism Social development: Orbital frontal cortex Anterior cingulate cortex (involved in empathy) Posterior parietal cortex (involved in attention, self- referential processing) Communication Broca’s area (inferior frontal gyrus; IFG) Supplementary motor area (SMA; movement regulation) Basal ganglia (voluntary movement) Amaral et al., 2008 59 59  11/8/2024 Brain regions affected in Autism Repetitive behavior: Orbital frontal cortex (decision making) Anterior cingulate cortex (involved in emotional regulation) Basal ganglia (habit learning) Thalamus (sensory weigh station) Amaral et al., 2008 60 60  11/8/2024 SCHEDULE 61 61 61