chapter 12 Flashcards
- Emotions vs motivation
Emotions: Cognitive interpretations of subjective feelings
Motivation: Behavior that seems purposeful and goal-directed
Neuroanatomy for both:
-Hypothalamus
-Limbic system
-Frontal lobes
- What did B. F. Skinner demonstrate?
-Operant Conditioning
–Reinforcer: In operant conditioning, any
event that strengthens the behavior that
it follows.
-Suggested learning plays a vital role in
behavior
-Posited experience shapes behavior by
pairing stimuli and reinforcers
–Many complex behaviors are learned
–Learning takes place in a brain that has
been selected for evolutionary
adaptations
-The environment does not always change the brain
–Pigeon in a skinner box: A pigeon in a
Skinner box can quickly learn to peck a
disc to receive a bit of food, but it cannot
learn to do it to escape from a mild
electric shock to its feet.
–Brains are not prewired to make every
kind of association
- What does it mean to say a trait is inborn? Do humans demonstrate inborn traits?
Inborn means a trait one is born with. Some human inborn traits are suckling and blinking.
Evolutionary explanation of behavior:
-Innate releasing mechanisms (IRMs)
–Hypothetical mechanism that detects
specific sensory stimuli and directs an
organism to take a particular action
–Activators of inborn adaptive responses
that aid an animal’s survival
-Although IRMs are prewired into the brain, they can be modified with experience
–Spontaneously produced facial
expressions in blind children (same
expressions as sighted people)
–Emphasis on different stimuli in different
cultures
- Regulatory vs nonregulatory behavior? Examples of each.
Regulatory Behaviors:
-Motivated to meet the survival needs of the
animal
-Controlled by homeostatic mechanisms that
include the hypothalamus
Examples:
-Internal body temperature; set point
-Amount of water in body
-Balance of dietary nutrients; salt
consumption
-Blood-sugar levels
-Waste elimination
Nonregulatory Behaviors:
-NOT required to meet the basic survival
needs of the animal; NOT controlled by
homeostatic mechanisms
-Include everything beyond survival needs
-Most involve a variety of forebrain
structures, especially the frontal lobes
Examples:
-Sexual behaviors
-Parental behavior
-Aggressive acts
-Food preference
-Curiosity
-Reading
- How are the hypothalamus and pituitary gland related to each other?
Hypothalamus: Maintains homeostasis by acting on both the endocrine and autonomic systems
The anterior pituitary is connected to the hypothalamus by a system of blood vessels that carry hormones from the hypothalamus to the pituitary.
1. The posterior pituitary receives input from
axons of hypothalamic neurons.
2. Both regions respond to hypothalamic
input by producing hormones that travel in
the bloodstream to stimulate target organs.
-The pituitary consists of distinct anterior and
posterior glands.
-The posterior pituitary is composed of neural
tissue and is essentially a continuation of the
hypothalamus.
Feedback loop:
Hypothalamus –releases hormones–> Anterior Pituitary –Pituitary hormones –> Target Organs – (feedback back to hypothalamus) and/or –> Hormones
- What are chemosignals? What are some examples of ways they motivate behavior?
Chemosignals (chemical signals): Play a central role in motivated and emotional behavior
-Identify group members
-Mark territories
-Identify favorite and forbidden foods
-Form associations among odors, tastes, and emotional events
Odor and taste also play a fundamental role in emotional and motivated behavior biology.
-Chemical disgust
-Social disgust; moral disgust (hygiene disgust)
- How does the hypothalamus know when to stop signaling glands to release hormones?
When certain predetermined blood levels of those hormones are reached, the hypothalamus and/or the pituitary ceases hormone release, thereby turning off the cascade.
Hypothalamus:
-Receives projections from all major nervous
system subdivisions
-Integrate diverse adaptive behavior
-Acts to organize cerebral inputs and produce
feedback loops that regulate cerebral info to
orchestrate homeostasis and motivated
behaviors
-Controls hormone systems that play a
central role in generating behavior
-Electrical stimulation of different nuclei in
hypothalamus produces goal-directed
behaviors in animal studies
–eating
–digging
–displaying fear
–predatory or attack behavior
–reproductive behavior
- How is chemosignaling different between humans and other animals?
Receptors for smell:
Scent interacts with chemical receptors, which are constantly being replaced
-Olfactory receptor neuron lifetime is about 60 days
-The epithelial receptor surface varies widely across species. In humans, this area is estimated to range from 2 to 4 square centimeters; in dogs, it is approximately 18 square centimeters; and in cats, it is about 21 square centimeters.
- How do humans detect smells? How does that information travel to cortex for processing?
Olfaction: Is designed to discriminate if info is safe or familiar or to identify a signal from a receptive mate
-Humans lack a vocabulary for olfactory perceptions and differences despite discrimination among thousands of odors
Olfactory epithelium is receptor surface for olfaction:
-Each olfactory receptor cell sends a process
ending in 10 to 20 cilia into a mucous layer,
the olfactory mucosa.
-Chemicals dissolve in the mucosa to interact
with the cilia.
-Activation of metabotropic receptors leads to
an opening of sodium channels and a change
in membrane potential.
Any given odorant stimulates a unique pattern of receptors, and the summed activity or pattern of activity produces our perception of a particular odor
Olfactory Pathways:
Olfactory receptor cells –> Olfactory bulb –> Many olfactory targets (amygdala and pyriform cortex) have no connection through the thalamus –> Orbitofrontal cortex (OFC) (emotional, social, and eating behaviors)
- How do humans detect taste? How is that different than flavor?
Gustation: In humans, clear differences in taste and preferences are apparent
-Supertasters vs nontasters
Children are much more responsive to taste than adults
-By age 20, humans have lost at least an
estimated 50% of their taste receptors
Receptors for Taste:
Each of the five taste receptor types responds to a different chemical component of food
-Sweet, Sour, Salty, Bitter
Fifth is called the umami receptor
-Especially sensitive to glutamate
Taste receptors are grouped into taste buds, each containing several receptor types.
Gustatory stimuli interact with the receptor tips or microvilli. Ion channels open, leading to changes in membrane potential.
- What are the five taste receptor types?
Salt, Sour, Bitter, Sweet, Umami
- What are a few areas of the brain that taste information goes to?
Cranial nerves form the main gustatory nerve called the SOLITARY TRACT.
-Gustatory region in the INSULA is dedicated
to taste.
-PRIMARY SOMATOSENSORY region is
responsive to tactile info (localizing tastes
and textures on tongue)
Gustatory nerve to orbital cortex: Mixture of olfactory and gustatory input gives rise to perception of flavor
Areas in the right orbital cortex mediate pleasantness of tastes, whereas the same region in the left hemisphere mediates unpleasantness of tastes.
Gustatory projections to amygdala and hypothalamus play a role in pleasantness and strength of flavors.
- What are the four primary roles of the hypothalamus? What are more specific examples of behaviors regulated by the hypothalamus?
Feeding, fleeing, fighting, and having sex.
- Regulating the Autonomic Nervous System:
It controls involuntary functions such as
heart rate, blood pressure, digestion, and
respiration. - Controlling the Endocrine System: By
influencing the pituitary gland, it regulates
hormones that affect growth, metabolism,
and reproductive processes. - Maintaining Homeostasis: It helps regulate
body temperature, hunger, thirst, and
circadian rhythms (sleep-wake cycles). - Managing Emotional Responses: It is
involved in emotional responses and
behaviors, linking the nervous system to
the endocrine system
More specific:
Aphagia: Failure to eat; may be due to unwillingness to at or to motor difficulties, especially with swallowing, following lesions to the lateral hypothalamus (electrical stimulation elicits feeding)
Hyperphagia: Disorder in which animals overeats, leading to significant weight gain; observed following lesions to the ventromedial hypothalamus (electrical stimulation inhibits feeding)
- Osmotic vs hypovolemic thirst?
Two kinds of thirsts:
Osmotic Thirst:
-Results from an increased concentration of
chemicals known as solutes in body fluids
-Drink water to restore solute concentrations
Hypovolemic Thirst:
-Results from a loss of overall fluid volume
from the body
-Drink fluids other than water to restore
nutrients
- Organizing vs activating effects of hormones? What role do hormones play in sex differentiation? What role do they play in sexual activity? What role do they play in sexual orientation? Gender identity?
Hormones have two general effects on brain organization:
-Organizing effects: During developmental,
gonadal hormones organize the brain
-Activating effects: In adulthood, they activate
many sex-specific behaviors, such as mating
behaviors
Many behaviors show sex differences
-Female advantage in verbal fluency
-Male advantage in spatial navigation
Sexual Orientation:
-Determined during early development;
impossible to change
-Influenced by genetics and by epigenetic
factors during prenatal brain development
-No solid evidence points to any postnatal
experience directing sexual orientation, not
lifestyle choice or social learning.
-Humans have sex-related differences in the structure of the hypothalamus and amygdala (present from birth).
–Several hypothalamic nuclei are two to
three times larger in males than females.
-Architectural and functional differences in
the hypothalamus may form a basis for the
spectrum of gender identity
–Transgender persons have a different
pattern of cerebral networks mediating
self-body perception from cisgender
individuals
Cognitive Influences on Sexual Behavior:
-In addition to the amygdala and
hypothalamus, the cortex has role in
controlling sexual behavior.
-However, this role is poorly understood.
-Damage to the frontal lobes can result in a
loss of inhibition about sexual behavior or a
loss of libido (sexual interest).
