+Stimulating Neural Activity
Numerous techniques exist for activating neurons in the brain.Electrode stimulationChemical activation through cannulaePhotostimulation: stimulation with light
+ “Two light-sensitive proteins from unicellular organisms have been harnessed to rapidly activate or silence neurons. This optical remote control allows precise, millisecond control of neural circuits.”
ChR2 Ion Channels – photosensitive proteins channel which depolarize the membrane when blue light is presented.
NpHR Ion Transporter – photosensitive protein channel which hyperpolarizes the membrane when yellow light is presented.
+Genetic Methods
Classical and conditional knockouts (KO). Classical KOs - the function of the gene is abolished from a very
early stage of development. Conditional KOs - there is either a temporal restriction (gene
function is abolished at certain premeditated time windows) or a regional restriction (no gene function in certain brain regions)
Transgenics Foreign gene, e.g. human APP, is inserted into the genome
Knockins Specific mutations are introduced in the gene leading to a loss of
activity of the proteins encoded by the targeted gene (although the gene expression per se is not voided as it is in KOs). Classical or conditional
+Assessment of Species-Common Behaviors
Assessment of behaviors displayed by all members of a speciesOpen-field test – general activityColony-intruder paradigm – aggression
and defensive behaviorElevated plus maze – anxietySocial interactionTests of sexual behavior
+Traditional Conditioning Paradigms - Learning
Pavlovian conditioning Pairing an unconditioned stimulus with
a conditioned stimulus Pavlov’s dogs
Copyright © 2006 by Allyn and Bacon
+ Fear Conditioning Protocol
CUE TEST
Tone (CS)
TRAINING
Novel Context (CS) + Tone (CS) + Footshock(US)
Day 1
CONTEXT TEST
Training Context (CS)
Day 2
+Traditional Conditioning Paradigms - Learning
Operant conditioningReinforcement and punishmentSelf-stimulation
Animal works for electrical stimulation
+Seminatural Learning Paradigms
Mimic situations that an animal might encounter in its natural environment
Conditioned taste aversion Pairing something that makes an animal ill
(emetic) with a taste
Radial arm maze tests spatial abilities
Copyright © 2006 by Allyn and Bacon
+Seminatural Learning Paradigms
Morris water maze – tests spatial abilitiesRat must find hidden platform in an opaque pool
Conditioned defensive burying – following a single aversive stimulus delivered from an object, rats will spray bedding at the object Antianxiety drugs decrease the amount of burying
behavior
+
Emotion
Chapter 11
Mind and Brain
+Chapter Overview
Emotions as Response Patterns Fear Anger, Aggression, and Impulse Control
Neural control of aggressive behavior Role of 5-HT Role of vmPFC Hormonal control of aggressive behavior
Communication of Emotions
Feelings of Emotions
+Emotions as Response Patterns
An emotional response consists of 3 types of components: Behavioral
i.e., dog defending its territory might bark, growl attack Autonomic
Mobilization of energy; activity of sympathetic branch of ANS increase while parasympathetic activity decreases
Hormonal Released from the adrenal medulla Epinephrine and NE further increase blood flow to the
muscles Steroid hormones Cause nutrients stored in the muscles to be converted to
glucose
+Amgydala
Small, almond-shaped structure in the medial temporal lobe Adjacent to hippocampus
+Figure 11.1 The Amygdala
Ventromedial Prefrontal cortex
Ventral striatumDorsomedial nucleus of thalamus (projects to prefrontal cortex)
+Emotions as Response Patterns
Fear Amygdala
Lateral Nucleus (LA) – receives sensory information from neocortex, thalamus, and hippocampus and projects to basal, accessory basal, and central nucleus of the amygdala.
Central Nucleus (CN) – receives information from the basal, lateral, and accessory basal nuclei and projects to many brain regions involved in emotional processes.
+CN Single most important part of the brain for the expression of
emotional responses provoked by aversive stimuli
Threatening stimuli increase neural activity and fos expression
Damage to CN reduces or abolishes a wide range of emotional behaviors and physiological responses
Animals no longer show signs of fear
Act more tamely when handled
Stress hormones are lower
Less likely to develop ulcers or other forms of stress-induced illnesses
Opposite is true with stimulation of CN
+Emotions as Response Patterns Some stimuli automatically activate the CN and
produce fear responses (loud noises)…but learning which stimuli are dangerous is also very important
The most basic form of emotional learning is CER
ear Conditioned Emotional Response – classically conditioned
fear response.
Figure 11.3 Conditioned Responses
+Classical Conditioning
Physical changes responsible for CC occur in LA
Neurons in LA project to CN, projects to hypothalamus, midbrain, pons and medulla
Responsible for behavioral, autonomic, and hormonal components of conditioned emotional response
+Extinction
Repeated presentation of the CS alone (without the aversive stimuli), then the CR eventually disappears
Extinction is not the same as forgetting, new learning
Animal learns that the CS is no longer followed by an aversive stimulus
Expression of CR is inhibited (memory for the association b/w CS and aversive stimuli is not erased)
Inhibition is supplied by the medial prefrontal cortex
+Research with Humans
Amygdala is involved in human emotional responses. Lesions of the amygdala decrease
emotional responses. Lesions interfere with effects of emotions
on memory.
+Lesions of the amygdala
decrease emotional responses.
Bechara et al., (1995) and LaBar et al., (1995) found that people with lesions of the amygdala showed impaired acquisition of a conditioned emotional response (similar to rats)
Angrilli et al., (1996) found that the startle response of a man with right amygdala damage was not augmented by an unpleasant emotion
In both cases the amygdala plays a role in the expression of the fear response
+
Medial prefrontal cortex is involved in extinction of conditioned emotional responses in humans.
+Lesions interfere with effects of emotions on memory.
When people encounter events that produce a strong emotional response, they are more likely to remember that event.
Cahill et al., (1995) studied a patient with bilateral amygdala degeneration (patient SM)
+Lesions interfere with effects of emotions on memory.
Cahill et al., 1995
Told a story about a boy walking with mother on his way to visit his father at work
Showed a series of slides during story
During one part of the story, boy was injured in a traffic accident, and gruesome slides showed his injuries
Normal subjects – remember more details from the emotion-laden part of the story
Patient SM – no increase in memory
+Lesions interfere with effects of emotions on memory.
fMRI studies confirm lesion data
Cahill et al., 1996 Ss (subjects) watch both neutral and emotionally arousing films
(scenes of violent crime), later asked to recall the films fMRI showed increased activity of the right amygdala when the
subjects recalled the emotionally arousing films but not when they recalled the neutral ones
Ss were most likely to recall the emotionally arousing films that produced the highest level of activity in the right amygdala when they were originally viewed
Isenberg et al., (1999) Seeing words that denote threatening situations increases the
activity of the amygdala
Activation in human amygdala…read words, look at pictures
Ratings of emotional intensity of facial expressions by controls and patient S.M.
+Anger, Aggression, and Impulse Control
Aggressive behaviors are species-typical, usually related to reproductive behavior (defending territory) or self-defense
Threat behaviors are more common than actual attack Threat Behavior – stereotypical species-typical behavior warning
another animal that it may be attacked; postures or gestures. Defensive Behavior – species-typical behavior an animal uses to
defend itself against threat of another animal. Submissive Behavior – stereotyped behavior shown by an animal
in response to threat by another animal. Predation – attack of a member of another species; does not
result in same level of arousal Predator not angry with its prey…it’s simply food and must be
killed
+Figure 11.6 Neural Circuitry in Defensive Behavior
Gregg and Siegel, 2001•Series of studies using cats showed that stimulation of the PAG elicited attack and predation•Hypothalamus and amygdala can influence these behaviors through connections with the PAG
+Anger, Aggression, and Impulse Control
Activity of serotonergic (5-HT) synapses inhibits aggression. Destruction of serotonergic axons in the forebrain facilitates
aggressive attack.
Howell et al., 2007 5-HT activity in monkeys (examining 5HIAA in CSF)
High levels of 5-HIAA in CSF – increased 5-HT activity Young male monkeys with the lowest levels of 5-HIAA
showed a pattern of risk-taking behavior, including inappropriate aggression
46% of monkeys with low levels of 5-HIAA died (killed by other monkeys)
Selective breeding of rats and foxes – tame animals (increased levels of 5-HT and 5-HIAA
+Anger, Aggression, and Impulse Control
5-HT also play an inhibitory role in human aggression Decreased 5-HIAA in CSF is associated with aggression and
other forms of antisocial behavior Fluoxetine (Prozac) is a serotonin agonist and decreases
irritability and aggressiveness People with at least 1 short allele for the 5-HT transporter
have higher anxiety and depression Right amygdala of people carrying the short form of the
5-HT transporter gene showed a higher rate of activity during task (looking at faces expressing fear or anger)
+Anger, Aggression, and Impulse Control
Impulsive violence may be consequence of faulty emotional regulation…in frustrating situations we can usually calm ourselves down…probably due to the vmPFC
Ventromedial Prefrontal Cortex (vmPFC) Includes medial orbitofrontal cortex and subgenual
anterior cingulate cortex.
+Figure 11.9 The Location of the Ventromedial Prefrontal Cortex
+Anger, Aggression, and Impulse Control
vmPFC Plays a role in complex analyses of social situations.
Serves as interface between brain mechanisms involved in automatic emotional responses and those involved in the control of complex behaviors
Includes using our emotional reactions to guide our behavior and controlling the occurrence of emotional reactions in various social situations Moral judgments/dilemmas, decision making
+Phineas Gage
+Anger, Aggression, and Impulse Control Hormonal Control of Aggressive Behavior
Aggression in Males In rodents, androgen secretion occurs prenatally,
decreases, and increases again at puberty. Inter-male aggressiveness increases at puberty.
Organizational effects – influence development of an animal’s sex organs and brain Effects are permanent
Activational effects - occur later in life, after the sex organs have developed. ie. Hormones activate the production of sperm
+Figure 11.13 Organizational and Activational Effects of Testosterone on Social Aggression
Early exposure to androgens has an organizational effect that stimulates the development of testosterone-sensitive neural circuits that facilitate male aggression
+Anger, Aggression, and Impulse Control
Effects of androgens on male aggression are mediated by Medial Preoptic Area
Implanting testosterone in the MPA reinstated intermale aggression in castrated male rats.
+
See Figure 10.18 See Figure 3.21
Medial Preoptic Area
+Anger, Aggression, and Impulse Control
Males attack other males, but rarely attack females Discrimination between sexes based on
pheromones Intermale aggression was abolished in mice by
cutting the vomeronasal nerve (input from vomeronasal organ)
+Anger, Aggression, and Impulse Control
Hormonal Control of Aggressive Behavior Aggression in Females Less aggressive than males. Aggression appears to be facilitated by testosterone.
Most rodent fetuses share their mom’s uterus with brothers and sisters – peas in a pod
A female mouse may have 0,1 or 2 brothers adjacent to her
Being next to a male increases blood levels of androgens prenatally
Females located between 2 males had more testosterone in their blood and, when tested as adults, showed increased aggression
+Anger, Aggression, and Impulse Control
Females of some primate species are more likely to engage in fights around the time of ovulation Mostly with males – likely due to increased proximity to
males
Increased fighting before menstruation Females tend to attack other females
+Anger, Aggression, and Impulse Control - human Boys are generally more aggressive than girls
Small, but significant increases in aggressiveness in female twins that shared a uterus with a male, versus another female
Girls with CAH - exposed abnormally high levels of androgens during prenatal development Show increased aggression
Castrated male (heterosexual and homosexual) criminals tend to show less aggression (and sex drive) Lack controls
Athletes that take steroids (including testosterone) tend to be aggressive Difficult to prove – may be that more aggressive people take steroids
+Chapter Overview
Emotions as Response Patterns
Communication of Emotions
Feelings of Emotions
+Basic Emotions
Finite set of universal, basic emotions Darwin (evolved)
Universality of facial expressions
+Emotions & Facial Expressions
Ekman et al., (1960s)
Analyzing hundreds of films and photographs of people experiencing real emotions
Complied an atlas of facial expressions
Dr. Cal Lightman
Emotions and Facial Expression Six primary emotions
SurpriseAngerSadnessDisgust FearHappiness
Naturally occurring expressions are usually variations or combinations of basic ones
+Additional Facial Expressions
Amusement
Contempt
Contentment
Embarrassment
Excitement
Guilt
Pride in achievement
Relief
Satisfaction
Sensory pleasure
Shame
+Universality of Facial Expression
Several studies
People of different cultures make similar facial expression in similar situations
People can correctly identify the emotional significance of facial expressions displayed by people from different cultures
+Isolated New Guinea tribe
Ekman (1971)devised a list of basic emotions to test tribesmen of Papua New Guinea.
He observed that members of an isolated culture could reliably identify the expressions of emotion in photographs of people from unfamiliar cultures They could also ascribe facial expressions to
descriptions of situations.
Ekman concluded that the expressions associated with some emotions were basic or biologically universal to all humans
+Communication of Emotions
Facial Expression of Emotions: Innate Responses Young blind children show similar facial
expressions as normal sighted children.
+Neural Basis of the Communication of Emotions: Recognition Laterality of Emotional Recognition
Right hemisphere is more important for the comprehension of emotion.
Bowers et al., 1991 found that patients with right hemisphere damage had difficulty producing or describing mental images of facial expressions of emotions
George et al., 1996 had Ss listen to some sentences and identify their emotional content. Comprehension of emotion from word meaning
increased the activity of the PFC bilaterally, the left more than the right.
Comprehension of emotion from tone of voice increased the activity of only the right PFC.
+Role of the Amygdala in
Recognition
Important for emotion recognition, especially for facial expressions (of fear). Amygdala lesions impair ability to recognize fear
expression FMRI studies show large increases in amygdala activity
when people view photographs of faces expression fear
Affective Blindsight – ability of a person who cannot see objects in his/her blind field to accurately identify facial expressions of emotion without conscious perception of them.
+Amygdala and Fearful Facial Expressions
Adolphs et al, (2005) Computer software that exposed only parts of either a fearful or
happy facial expression to determine what regions of the face the subjects relied on to discriminate between expressions
Results Control subjects consistently relied on eyes to make decisions
about expression S.M. – did not derive information from the eyes
She did not even look at the eyes of any face, regardless of emotion
+Facial Expressions and the Amygdala
Why the specific problem with fearful expressions?
Most expressions contain other cues that can be used for identification Happiness – smile Fear – increase in size of the white region (sclera) of the
eyes
+Facial Expression and the Amygdala
Amygdala appears to be an integral part of a system that automatically directs visual attention to the eyes when encountering any facial expressions
+Communication of Emotions
Perception of Direction of Gaze Important to know if another’s gaze is directed toward
you or not.
Recognition of the direction of another monkey’s gaze involves neurons in the superior temporal sulcus (Figure 11.22).
fMRI study confirmed monkey data Pelphrey et al., 2003 had people watch an animated
cartoon of a face. When the direction of gaze changed, increased activity was seen in the right STS an
+Communication of Emotions
Role of Imitation in Recognition of Emotional Expressions Mirror neurons – neurons located in the ventral premotor
cortex and inferior parietal lobule that respond when the individual makes a particular movement or sees another individual making that movement
Mirror neuron system is activated when we observe facial movements in others and may provide feedback important for empathy
+Disgust
Anterior insula is essential to both detection and experienced of disgust Imaging data Patient with anterior insula damage
Same area of the anterior insula was activated both when Ss viewed expressions of disgust in others and when they smelled unpleasant odors Additional evidence that the insula is important in disgust Understanding the emotions of others may require stimulating
and thus mildly experiencing emotions ourselves