Module 1

Question 1

What is the Darwinian View?

Answer 1

• many animal behaviours are species-specific
• A question then is whether species-specific behaviour is a product of evolution
• Darwin’s hypothesis is that ALL organisms are related and share the same common ancestors
• During the process of natural selection, biological and behavioural traits that help the organisms survive the selective pressure are preserved and passed on to the next generation.
• Speciation, the process in which a species diverge from its common ancestors and develop its own characteristics, then allows species-specific behaviour to emerge.
• So, in studying “why we do what we do?”, it is also important to appreciate that “we do what we do because of who we are” is part of the answer.

Question 2

What does ethology mean?

Answer 2

• Ethology: the scientific and objective study of animal behaviour.
• With a specific focus on behaviour under natural condition

Question 3

What does ethology assume?

Answer 3

• Assumes that behavioural traits, like physical and genetic traits, are evolutionarily adaptive, and hence are selected for

Question 4

What is Anthropomorphism and Anthropodenial?

Answer 4

Anthropomorphism: extending and attributing human characteristics to other animals
Anthropodenial: a priori rejection of shared characteristics between humans and animals
* “A blindness to the human-like characteristics of animals, or the animal- like characteristics of ourselves.”

Question 5

What are examples of anthropomorphism?

Answer 5

• chimps kiss after fights
• cats knead like humans, but not for the same purpose

Question 6

What is the difference between instinct vs learning for behaviour?

Answer 6

• Instincts often are related to biologically essential resources. Robust instinctive behaviour is critical for animal’s survival. The importance of instincts suggests that they are evolutionarily ancient.
• Learning on the other hand allows for flexibility of innate behaviour and acquisition of new behaviour. Itself is a characteristics of living organisms.
• Both instinctive and learned behaviour allows animals to effectively respond to environmental stimuli and to acquire outcomes that promote survival.

Question 7

What is the take-home message of ethology on animal behaviour?

Answer 7

• An animal’s behaviour is a product of its own evolutionary history
• Interpretation of animal behaviour should question its function, causation, development, and
  evolutionary history
• Interpretation of animal behaviour should avoid overanthropomorphism and anthropodenial
• The concept of instinct has a motivational component, and animals are naturally motivated to
  learn under certain conditions.
• Experimental paradigms should be carefully designed with the organism’s natural behaviour
  being taken into consideration

Question 8

What is homeostasis?

Answer 8

the automatic adjustments the body makes to restore stability when there is a departure from the narrow tolerance ranges the body has for temperature, blood sugar concentration, acidity, salt and water balance, and so on

Question 9

What does the homeostatic model argue for behaviour?

Answer 9

• The homeostatic model argues for a regulatory function of motivation
• The internal environment is constantly monitored. Behavioural adjustments are made accordingly to maintain the constancy of the internal environment
• Motivated behaviour is initiated by start signals and terminated by stop signals.

Question 10

What is the peripheral theory for where homeostatic signals come from?

Answer 10

Peripheral theories: signals are generated outside the brain.
* Stomach contraction recorded in human subjects that reported hunger
* But subjects with a gastric bypass still eat normal amounts of food

Question 11

What is the central theory for where homeostatic signals come from (hint: CMS)?

Answer 11

Central theories: signals are generated in the brain.
* Clifford Morgan: central motive states (CMS)
* CMS is specifically defined in terms of the stimuli, e.g., hunger CMS, thirst CMS.
* Activation of certain brain centres and/or pathways triggers a corresponding CMS that
persist for a period. An active CMS predisposes the organism to act in certain ways to
particular stimuli and directly emits certain behaviours.
* Hypothalamus: a key brain region for regulation of appetite, water content,
temperature, sex drive, circadian cycle etc. through the effects of a variety of hormones

Question 12

What are limitations of the homeostatic model?

Answer 12

• Taking eating for example, we don’t just eat when we are starved; we eat to prevent being starved. Also, the model would predict that the longer we wait since our last meal, the more we eat; it’s often not the case.
• Suggesting that other factors are also involved.
• In humans, social factors may play a role.
• Overall, the model is successful at explaining some but not all aspects of motivated behaviour. In more complex settings, other factors likely contribute as well.

Question 13

What are the two ways the body informs the brain what it needs?

Answer 13

• Through direct innervation
• Through signalling molecules in the extracellular space/circulatory system
  » Instinctive behaviours may be “hard-wired” in the nervous system, but there need to be modulatory signals to increase and decrease the neural circuit/network outputs to initiate, terminate, and modulate the behaviour.

Question 14

What is neuromodulation?

Answer 14

Neuromodulation is a primary way to achieve modulation of neuronal and neural circuit functions, which subsequently alters physiology and behaviour.

Question 15

How can you modify the strength of a synapse?

Answer 15

• Long-term potentiation (LTP) can be induced via activation of glutamate NMDA receptors (Ca+)
• Experimentally, high-frequency tetanic stimulation can be used to induce LTP
• Similarly, long-term depression (LTD) can also be achieved. Thus, one way to modify synaptic strength is through firing action potentials (APs) within the synaptic pathway.

Question 16

What are the problems of increased synapse strength?

Answer 16

Potential problems: firing AP is energetically expensive, structural changes are energetically expensive, induced changes are less reversible

Question 17

What is the difference between neurotransmitter vs neuromodulator vs hormone?

Answer 17

• Neurotransmitter: synaptically transmitted, typically activates ion channels (ionotropic)
• Neuromodulator: synaptically and extra-synaptically transmitted, typically activates G protein-
  coupled receptors (GPCRs; metabotropic)
• Hormones: signalling across systems – sometimes molecules from outside the nervous system
  act on the brain, and sometimes brain-derived molecules act on other systems.

Question 18

What are examples of neuromodulators?

Answer 18

Monoamines: synthesized from amino acids
* Dopamine
* Serotonin
* Norepinephrine/epinephrine (noradrenalin/adrenalin)

Question 19

What are examples of neurohormones?

Answer 19

• (Neuro)peptides: genetically encode, highly diverse
• Insulin
• Oxytocin/vasopressin
• Endorphin
• Fatty acids/lipid molecules: modification of fat and lipid molecules
• Anandamide
• testosterone and estrogen

Question 20

What is co-transmission?

Answer 20

• Neuromodulation is not limited by physical connections
• Co-transmission: multiple chemicals released by the same neuron

Question 21

What is a connectome and intrinsic and extrinsic modulation?

Answer 21

• Connectome: the collection of physical connections (synapses and
  gap junctions) in the nervous system
• Intrinsic modulation – modulatory actions within the modulated circuit
• Extrinsic modulation – modulatory actions coming from outside

Question 22

What are the short-term and long-term effects of neuromodulation?

Answer 22

GPCR activation leads to activation of multiple downstream second messenger pathways, that have various effects on synaptic plasticity.

• Short-term effects:
• Ion channel modification (e.g., AP duration)
• Neurotransmitter releasable pools
• Postsynaptic channel conductance
• Long-term effects:
• Gene expression
• Neuronal morphological changes
• Neuronal health

Question 23

How does neuromodulation add richness to neural dynamics?

Answer 23

• With the extra layers of neuromodulatory connectomes, a nervous system can have even more dynamic changes to have fine-control and coordination of physiological and behavioural changes.
• Neuromodulation comes in different ”flavours”, that are determined by the specific neuromodulatory signalling components involved.
• Feedback/feed forward/opponent process
• The dynamic changes potentially could help organisms accommodate the everchanging environment
• animals depend on the appropriate interpretation of sensory information to make favourable behavioural decisions
• to achieve this, neural circuits underlying innate behaviours (feeding/mating/etc), must possess some intrinsic flexibility to reflect changing internal states
• drosophila offer extensive genetic toolbox to parse the mechanisms of how internal motivational states modify neural circuit function

Question 24

What brain area/hormone increases feeding?

Answer 24

Lateral hypothalamus
Ghrelin/Orexin - hunger hormone

Question 25

What brain area/hormone decreases feeding?

Answer 25

Ventromedial Hypothalamus

Question 26

What chemicals trigger the different taste receptors?

Answer 26

Sweet: sucrose
Bitter: quinine
Salty: sodium chloride
Sour: citric acid
“Umami”: amino acid (glutamate and aspartate)

Question 27

How does the cafeteria study conflict with the homeostatic model?

Answer 27

• We don’t always eat what we need…
• The homeostatic model would predict that deviation in carbohydrates, ions, fats, proteins etc. should elicit motivated eating behaviour for specific nutrients.
• The cafeteria studies: animals and humans allowed to free-feed with a range of food choices.
• Subjects eat a well-rounded diet when balanced choices are provided
• But shows preference for high-sugar diet among other choices
  Possibilities –> sugar is an energy source that is instant, addictive

Question 28

How does sleep change self-reported motivation?

Answer 28

• Participants were either sleep-deprived or had normal sleep, then asked to report their motivation on several items.
• Sleepiness was associated with motivation to engage in sleep- preparatory behaviour (shut-eyes) in comfortable (bed), safe environment (home, partners).
• Increased sleepiness was associated with decreased motivation for social and physical activities.
• Could we engage in sleep-preparatory behaviour and reduce social/physical activity to help with insomnia?

Question 29

How are hormone levels modulated by anticipation (sexual motivation)

Answer 29

• The anonymous scientist works on a remote island in isolation Monday to - Friday Facial hair length measured daily
• Facial hair length has a 20% increase on Friday (his off day)
• Facial hair growth is controlled by FSH
• Suggests that hormone levels may be modulated by anticipation (presumably sexual motivation)

Question 30

How do certain conditions impact prioritization of behaviours?

Answer 30

• Well-fed male prioritizes sex over food, as for this species, males can only reproduce when they mate.
• Hermaphrodites are less motivated to mate, as they can self-fertilize. They always prioritize food.
• During starvation, males modify the sensory neuron function to prioritize food, as food becomes critical for survival, hence, they are more motivated to feed.
• Different behavioural prioritization reflects different motivational states that are governed by different biological motivators under certain conditions.

Question 31

What is thermoregulatory behaviour?

Answer 31

Most common thermal regulatory behaviour in animals is thermotaxis
* Tax behaviour: locomotion towards or away from along a gradient of the stimuli
* Various stimuli can trigger tax behaviour: sounds (sonotaxis), chemicals (chemotaxis) etc.

Question 32

how biological motivators can be utilized in learning paradigms

Answer 32

1) Food and water restrictions lead to different learning
- In a two-choice discrimination task, water-deprived rats learn the task at a faster rate when water is used as reward.
2) C-elegans thermotas toward preferred temperature
- Temperature preference can be modified by prior experience. Thus, motivated behaviour appears
to be modifiable by experience (learning).

Question 33

What study shows that taste can be modulated by starvation (what are the findings)?

Answer 33

• starvation potentiates sweet GRN synaptic output, while independently suppressing the synaptic output of bitter GRNs
• the direct source of bitter GRN modulation is unknown
• Finding 1: Using GFP reconstitution across synaptic partners (GRASP), novel octopaminergic neurons in the ventrolateral cluster (OA-VL) are found to make contact with the bitter gustatory neurons.
• Finding 2: Starvation changes the electrophysiological (ephys) recordings in OA-VL neurons (less firing)
• Finding 3: Calcium response in bitter GRNs is modulated by OA-VLs in response to starvation (less Ca+ response, meaning bitter GRN not activated)
• Finding 4: Genetically silencing 4 different populations of OA-VL neurons led to a reduction of bitter-induced PER suppression (starved drosophila more likely to eat bitter foods) .
• Finding 5: Bitter taste sensitivity is modulated by OA-VL and potentiated by Oct-Tyr receptor
• Bitterness potentially indicates toxins and is normally avoided by robust bitter response. Starvation suppresses bitter taste sensitivity through changes in octopaminergic/tyraminergic signalling to increase the chance of feeding.
  -

Question 34

What is the take-home message of why starvation changes taste preference?

Answer 34

• Starvation modulates physiology that leads to behavioural changes:
• Increased feeding (motive)
• Towards bitter food (incentive)
• Neuromodulation (in this case, by octopamine and tyramine) plays a key role in changing the nervous system function in response to starvation/satiation, leading to different behavioural states.
• Instinctive behaviour, like feeding and avoiding poisons, is critical for survival and has to be robustly and reliably performed when needed. Instinct has a layer of motivation that selects and energizes appropriate responses to best enhance survival.
• Therefore, instinct may also be modulated by internal and external factors for adaptive purposes.

Question 35

What is the difference between affect, temperament, moods, emotion?

Answer 35

• Affect: a generic term for our feelings
• Temperament: long-term, stable tendencies to having positive or negative affect
• Moods: low-level, persistent, often non-specific affective experience
• Emotions: more intense, more brief, specific reaction towards something
  The three can influence each other.

Question 36

How can emotion be measured

Answer 36

Verbal behaviour:
* self-reported subjective emotional experience can be obtained
* Potential problems with language and biases
Non-verbal behaviour:
* Most can be objectively and directly observed and measured
* Need to be interpreted in the situation
Physiological responses:
* Can be objectively and directly measured
* Must take into consideration other sources of responses (e.g., medical reason)

Question 37

What is the operational definition of emotion?

Answer 37

An emotion is operationally defined by the situation it is observed in and the consequences it produces

Question 38

What did Darwin say about emotions?

Answer 38

the same emotional responses (facial expressions) tend to accompany particular emotions, across human races and cultures, and similar species tend to express emotions similarly.

Question 39

What are the evolutionarily adaptive reasons for us to have emotions:

Answer 39

• Allows us to acts quickly with little cognitive processing
• Prepares the body for the situation
• Influences thoughts and reasoning
• Guide future motivated behaviour
• Communicates with other members in social settings
• Regulates social behaviours

Question 40

How can emotion motivate behaviour based on stimulus?

Answer 40

• A stimulus can produce positive or negative affect and can be presented or removed
• Rewards encourage behaviour (increased motivation)
• Punishers discourage behaviour (decreased motivation to engage/increased motivation to avoid)
• These can play a role in both goal-directed behaviour and learning

Question 41

What is the James-Lang theory of emotion?

Answer 41

• emotional experience is the perception of the response to the situation
• E.g., we see a predator, run first, experience fear later.

Question 42

What is the Canon-Bard theory of emotion and how is it challenged?

Answer 42

• thalamic sensory inputs generate emotional experience and physiological responses independently.
• Challenged by the findings that spinal cord injury patients reported less subjective feelings of anger and fear.

Question 43

What is Schachter’s cognitive labelling theory?

Answer 43

physiological arousal is necessary for emotional experience, the cognitive interpretation of the arousal determines the emotional experience
* Two-factor theory: arousal and cognitive label

Question 44

What was the Capilano suspension bridge experiment and what is the attribution theory?

Answer 44

• Male participants asked to cross the Capilano Suspension Bridge (high arousal) or a small bridge (low arousal).
• An attractive female interviewed them in the middle, and gave them her phone number in a
  flirtatious manner in the end.
• More sexual content in the interview and more likely to call in the high arousal group.
• The attribution theory by Fritz Heider (1958): our natural tendency to make causal attributions of the events we experience.
• Argues that mislabelling/misattribution of the arousal resulted from crossing the bridge (fear) to romantic attraction (love).

Question 45

What is part of the limbic system?

Answer 45

amygdala,
hippocampus,
cingulate cortex,
hypothalamus,
mammillary body, fornix, septum, olfactory bulb/piriform cortex, entorhinal cortex,

Question 46

How is emotion processed in the brain?

Answer 46

The limbic system interacts strongly with the nucleus accumbens (reward processing) and the frontal cortex (cognitive association), which are essential for goal-directed behaviour

Question 47

What are the hemispherical differences in emotion and what is the sword and shield hypothesis?

Answer 47

Both hemispheres participate in emotion processing, but in asymmetrical ways:
* Left hemisphere dominance for positive emotions
* Right hemisphere dominance for negative emotions
Findings potentially obscured by that fact that most participants were right-handed. When handedness is varied, the pattern is reversed accordingly.
- The sword and shield hypothesis: cortical substrates of approach motivation overlap functionally and anatomically with cortical circuits for performing approach actions (sword/dominant hand), and the cortical substrates of avoidance motivation with circuits for performing avoidance actions (shield/non-dominant hand)

the hemispheric laterality of affective motivation depends on the laterality of motor control for the dominant hand (i.e., the “sword hand,” used preferentially to perform approach actions) and the nondominant hand (i.e., the “shield hand,” used preferentially to perform avoidance actions)

Question 48

What are the pleasure centres of the brain?

Answer 48

MFB, lateral hypothalamus (LH), and VTA.
- VTA received GABAergic and NEergic modulatory inputs
- VTA is highly DAergic and projects to NAcc and PFC
- NAcc endorphin system plays a role in reward (liking)

Question 49

What is the difference between liking vs wanting and which parts of the brain are responsible?

Answer 49

• Behaviour associated with consumption of tasty liquids (liking)
• Animals accept or reject items passively placed in the mouth (liking/not liking)
• Highly stereotyped and displayed in human infants and rats similarly
• With DA depletion in the tegmental area, animals will not work for the reward (not
  wanting), but when passively fed the reward, they still consume it (liking) * Naloxone (opiate antidote) administration eliminates liking behaviour
• Liking appears to be related the endorphin system, whereas wanting appears to be related to the DAergic system

Question 50

What does the amygdala do?

Answer 50

The amygdala is a key brain region that mediates emotional responses to fearful stimuli
* Patient SM: the amygdala lesion led to no fear
* Toxoplasma gondii: infected rats show impaired predator aversion due to altered gene
expressions in the medial amygdala.

Question 51

What are the fear-conditioning pathways?

Answer 51

• The medial geniculate nucleus in the thalamus and the amygdala are required for fear conditioning.

Question 52

What is involved in complex sound fear conditioning?

Answer 52

The auditory cortex is not involved for simple sound auditory fear conditioning, but is involved when complex sounds are used.

Question 53

What is involved in contextual aspect of fear conditioning?

Answer 53

The hippocampus is critical for the contextual aspect of fear conditioning.

Question 54

Which parts of the brain are involved in voluntary and involuntary emotional expression?

Answer 54

• Voluntary emotional expression: pyramidal motor system
• Involuntary emotional expression: extrapyramidal motor system

Question 54

How is the lateral and medial nucleus of the amygdala involved in fear response?

Answer 54

• Lateral nucleus of the amygdala: sensory interface and acquisition of fear learning
• Medial nucleus of the amygdala: behavioural response

Question 55

What plays a role in facial expression recognition?

Answer 55

Fusiform gyrus, the brain region implicated in face recognition plays a role in facial expression recognition.

Question 56

What are the two pathways involved in emotion processing?

Answer 56

• LeDoux (1993): two pathways are involved in emotion processing
• A “long” pathway responsible for cognitive recognition
• A “short” pathway responsible for quick action
• passion vs reason
  Initial action: evolutionarily selected response, quick and robust
  Cognitive appraisal: bring in additional information to resolve conflicts and to rationalize Modified action: best reflects the “decision”

Question 57

What studies show that animals can recognize facial expression?

Answer 57

Dogs can recognize facial expressions of other dogs and humans, and the gazing patterns converge to visual strategies used by humans.

• Human-dog gazing mutually increased oxytocin levels
• Intranasal administration of oxytocin increases preference for smiling human faces in dogs (Oxytocin is thought to be the “love hormone”)
• “Clever Hans” (1900s), a horse that ”can do math”.

Question 58

How can emotion recognition alter motivation in social settings

Answer 58

Emotional expressions indicate one’s intention, and perceived emotions regulate the other’s behaviours.
* e.g., perceived anger likely elicits fear, perceived distress likely elicits sympathy.
Social referencing: infants seek out information from others to clarify the situation then act accordingly.
* Emotional expressions can provide incentives for desired behaviour
* Similar principles of emotional rewards and punishers apply- change our motivation to
engage or to avoid

Question 59

How does pain induce anhedonia like behaviour?

Answer 59

Decreased excitability of VTA DA neurons caused by GABAergic inhibition
* Less motivated to work for sugar reward (anhedonia-like behaviour) in pain-experiencing animals
* VTA-NAc projections underly the anhedonia-like behaviour
- Increased sucrose concentration (incentives) moderates lowered sucrose consumption (motivated behaviour) (motivation for food did not decrease when animals in pain were given higher sucrose concentration)

Question 60

What is the evidence for body-emotion interaction (phsyical-psychological pain interaction)

Answer 60

• There are likely cross-talks between bodily and emotional response and regulation pathways
• Insula cortex and anterior cingulate cortex respond to bad taste and emotional disgust Pain-killers alleviate psychological pain (DeWall, et al., 2010; Durso et al., 2015)
  Body temperature affects processing of ”cold” and “warm” emotions (Bruno et al., 2017)
  Illustrates the complexity of emotion- involves bodily responses and conscious perception, with possible interactions at multiple levels

Question 61

What can regulate gene expression?

Answer 61

• Promoters regulate the spatial and temporal gene expression patterns.
• We can take advantage of promoters to target specific subsets of neurons.
• e.g., DAergic neurons synthesize DA using tyrosine hydroxylase (TH), an enzyme that is only present in these neurons. Using the TH promoter allows us to manipulate gene expression in DAergic neurons specifically.

Question 62

What is the difference between mutation and polymorphism?

Answer 62

Mutation: changes in the DNA sequence of an organism.
* Can naturally occur during errors in DNA replication during cell division
* Can be induced by exposure to mutagens (X-ray and chemicals) or a viral infection.
* A mutation does not always mean changes in gene functions.
Polymorphism: the presence of two or more variant forms of a specific gene that can occur among different individuals or populations.
* Like mutations, sometimes there are functional differences, sometimes not.
* From an evolutionary perspective, polymorphism increases biodiversity.

Question 63

What are the two approaches to establish the relationship between gene and behaviour?

Answer 63

• Detect the genetic variations in subjects with the known behavioural variations
  » Begin with a disorder, diagnose with the phenotypes, then compare the genotypes between the patient population and healthy cohorts.
  » Can target specific genes (candidate gene approach) or examine the whole genome (GWAS) genome-wide association studies
• Induce the genetic variations in animal models to induce corresponding behavioural variations

Question 64

What are the pros and cons of genetic variation studies on humans?

Answer 64

Pros: start with human diagnosis, discoveries are usually directly relevant and impactful.
Cons: often correlational; hundreds of variations present; multiple genes may contribute to the same phenotypes (redundancy); possible complex genetic interactions involved; expensive.

Question 65

What are the pros and cons of genetic studies on animal models?

Answer 65

• Many advantages of model organisms:
• Invasive techniques possible
• Well-established tools and protocols to manipulate gene expressions
• Short life cycle allows for rapid, large-scale, high-throughput, investigations
• Screen is possible: identify novel genetic factors and drugs
• Screen: test which IVs (e.g., compounds) produce expected results (e.g., alleviation of symptoms) in controlled populations
• Commonly used: mice, zebrafish, Drosophila (flies), C. elegans (worms)
• Drawbacks: not all genes are conserved; differences in biology; no comparable cognitive and behavioural complexity; cannot interrogate the mind.

Question 66

What was the experiment on the foraging behaviour in flies?

Answer 66

• In Drosophila, foraging gene (for) is responsible for the differences between rover and sitter.
• for gene encodes a cGMP-dependent protein kinase (PKG), which adds a phosphate to various
  molecules in cells. It has 4 different promoters that make 21 different products.
• One gene regulates multiple phenotypes (pleiotropy): foraging strategy; food consumption; metabolism; sensory ability; social behaviour; sleep; learning and memory; from larval stages to adulthood.
• for gene regulates expression of other genes: circadian genes, neuropeptide genes etc.
  for gene also shows complex interactions with the environment that together determine the final outcomes, i.e., phenotypes.
  14

Question 67

What are studies of where human-disease associated variants validated in animals?

Answer 67

• C. elegans chemotax to food cues, and the behaviour is altered by autism associated genes
• PTEN is an ASD-associated gene, its homolog in worms is daf-18.
  Human research has identified disease-associated variants (alleles) of PTEN.
  Genetically engineering the disease-associated variant into worms led to behavioural defici