Biological Bases of Behavior Exam 3

Learning

How one’s experiences changes the brain

Memory

How changes are stored in the brain and how they are reactivated

What are the types of learning?

Perceptual, stimulus-response, motor, and relational

Perceptual Learning

The ability to recognize a stimulus that has been perceived before

What areas of the brain are associated with perceptual learning?

Primary visual cortex, dorsal stream (analyzes where a stimulus is) and posterior cortex or ventral stream (analyzes what a stimulus is) and inferior temporal cortex

What causes prospoagnosia?

This inability to recognize faces is caused by damage to the ventral stream

Stimulus-Response Learning

Being able to perform particular tasks when a specific stimulus is present

Classical/Pavlovian Conditioning

When a neutral stimulus acquires the properties of an important stimulus

Instrumental/Operant Conditioning

When one learns an association between a response and a stimulus

Hebb Rule

When synapses are active around the same postsynaptic neuron fires are strengthened over time (neurons the fire together will wire together)

What brain area is involved in the classical conditioning of fear?

The amygdala; aversive stimulus to conditioned stimulus activate nuclei in amygdala, leading to conditioned emotional responses

What are the four types of instrumental/operant conditioning? Give an example of each.

Negative Reinforcement: A seatbelt buckle beeping stops

Positive Reinforcement: A child gets dessert for cleaning

Negative Punishment: A child’s phone is taken away

Positive Punishment: A person receives a speeding ticket

What areas of the brain are important in instrumental/operant conditioning?

Basal Ganglia (caudate, putamen, and globus pallidus) as well as the primary motor cortex; reinforcement also often involves the mesolimbic pathway (ventral tegmental area to nucleus accumbens (causes an increase in dopamine))

Motor Learning

Learning that allows one to make new motor responses

What is the process that motor learning generally follows?

Stimulus, to perceptual learning, to stimulus-response learning, to motor learning, to a response

Relational Learning

When one learns the relationships between individual stimuli

Long-term Potentiation (LTP)

Long term increase in magnitude of excitability of a particular neural synapse caused by repeated, high-frequency activity of that input - requires the activation of synapses and the depolarization of postsynaptic neurons (occurs in hippocampus)

What types of receptors are involved with long-term potentiation?

NMDA (n-methyl-D-aspartate) receptor and AMPA receptor

NMDA Receptor

Receptor for glutamate (excitatory), allows Ca2+ inward, and is very prevalent in the hippocampus (normally it is blocked by Mg2+ when not activated)

AMPA Receptor

A receptor that is involved in the strengthening of synapses. They are glutamate receptors that control Na+ channels

Long-term Depression (LTD)

long-term decrease in the magnitude of excitability of a neuron to a particular synaptic input (occurs in hippocampus)

Short-Term Memory (STM)

Immediate memory, occurring in hippocampus, for stimuli recently perceived (can store about 7 items at once and info is lost if not rehearsed)

Long-Term Memory (LTM)

Relatively stable memory for more distant past events (“unlimited” capacity, more permanent, and is stored in the respective area of the cortex (ex: visual memory in visual cortex))

Consolidation

Process by which a short-term memory becomes a long-term memory through rehearsal

Explicit/Declarative Long-Term Memory

Conscious memories that can be expressed by declaration

Episodic Memory

A type of Explicit/Declarative Long-Term Memory that involves an episode of events

Sematic Memory

A type of Explicit/Declarative Long-Term Memory that includes the memory of facts

Implicit/Nondeclarative Long-Term Memories

Memories that are expressed by improved performance in a task without conscious cognition

Anterograde Amnesia

Difficulty learning new info, but can remember events from the past (often results from a head injury)

Retrograde Amnesia

Difficulty remembering events from the past, but no difficulty with new information

Who was H.M.?

A man who got a bilateral medial temporal lobectomy for his severe epilepsy, resulting in severe anterograde amnesia and mild retrograde amnesia

Bilateral Medial Temporal Lobectomy

Procedure performed on H.M. that removed hippocampus, amygdala, and adjacent cortex from both hemispheres

What were the good effects of H.M.’s bilateral medial temporal lobectomy?

Generalized seizures vanished, partial seizures lessened, less anti-convulsant drugs were needed, and motor/perceptual/intellectual abilities remained consistent

What were the negative effects of H.M.’s bilateral medial temporal lobectomy?

He could not consolidate new memories - he had severe anterograde amnesia and mild retrograde amnesia (couldn’t remember two years leading up to surgery)

Digit Scan Test

A test where one is read numbers and must say them back (tests verbal short term memory)

Digit Scan +1

A test where one is read numbers and must say them back. If all digits are correct, 1 number is added (tests verbal short term memory) - normal max for people is 15, H.M. could only remember 8

Block-taping Memory-span

When one observes taps on a sequence of blocks and must repeat the pattern (assesses visual long-term memory (specifical global amnesia (amnesia for all modes of sensation))) - normal is about 5-6, H.M. couldn’t get 6

Mirror-Drawing Task

When one is asked to draw an image in the mirror and errors decrease over days

Rotary-Pursuit Test

Test where one tracks a spot on a revolving wheel (motor abilities for this improve over time)

Incomplete-Pictures Test

When one is showed fragmented drawings and must guess what they are (H.M. couldn’t remember receiving this test, but he got better overtime)

Pavlovian/Classical Conditioning Test

Developing a conditioned response as a form of LTM testing

Was H.M. able to retain any memories?

H.M. learned and retained tasks/tests (implicit memory) even \n though he had no conscious recollection (explicit memory) of taking them

What were the scientific contributions of H.M.?

We learned that memory functions are NOT diffusely and \n equivalently distributed throughout bran, different modes of storage for STM vs. LTM, and there are 2 distinct categories of LTM

Medial Temporal Lobe Amnesia

Amnesia characterized by memory deficits similar to H.M. - hard to form explicit LTM but not implicit LTM

How are explicit memories effected with medial temporal lobe amnesia?

Semantic memories are more intact than episodic memories

Repetition Priming Task

Similar to the incomplete-pictures task, but with verbal elements (shown a list of words and primed to fill in words) - tests implicit memory

Korsakoff’s Syndrome

Amnesia associated with chronic alcoholism and severe thiamine deficiency - symptoms include severe anterograde amnesia, retrograde amnesia later on, and confabulation (unknowingly making up events)

Blackouts

When, after heavy alcohol use, memory is lost only for drinking period because alcohol prevents consolidation

Gray outs

When, after alcohol use, memory is lost only but cues can facilitate recall - issues with retrieval but not impossible

Alzheimer’s Disease Amnesia

Type of dementia associated with memory loss (predementia Alzheimer’s patients show memory deficits greater than medial temporal lobe damage or Korsakoff’s syndrome). People, experience anterograde and retrograde amnesia in explicit memories and will later have STM deficits and problems with some types of implicit memory

Concussion

Temporary disturbance of consciousness produced by a head injury

Posttraumatic Amnesia (PTA)

Amnesia following a blow to the head - often results in some retrograde amnesia, confusion, and anterograde amnesia

Why do we eat?

To supply our body with energy and building blocks

Digestion

Gastrointestinal process of breaking down food and absorbing its constituents

How is energy stored in the body?

Energy is stored as lipids/fats, amino-acids/proteins, and glucose/glycogen

Why is fat the prefered method of storage?

Fat is the most efficient method of storage - there is twice as much energy in fats than in glycogen because it doesn’t attract and hold as much water

Energy Metabolism

Chemical changes that make energy available for use that occurs in 3 phases (cephalic, absorptive, and fasting)

Cephalic Phase

Phase in energy metabolism where one prepares for eating (from sight or smell)

Absorptive Phase

Phase in energy metabolism where energy is absorbed from food and satisfies immediate energy needs

Fasting Phase

Phase in energy metabolism where there is a withdrawal of energy from storage places

Insulin

Highest in cephalic and absorptive phases; triggers glucose use as fuel by body cells, triggers conversion of blood-borne energy to fat/glycogen/protein, and triggers energy storage in adipose cells/livers/muscles

Glucagon

Highest in fasting phase; triggers change of stored energy to useable fuel

Set Point Theory

Theory of hunger that believes that hunger is a response to an energy need and has the goal to maintain energy at a set point - but obesity exists, it goes against evolutionary pressures (energy storage), reductions in blood glucose or body fat do not reliably induce eating, and it does not recognize other external factors

Positive Incentive Theory

A theory of hunger that believes we are drawn to eat by anticipated pleasure. We have evolved to “crave” and when food has a higher positive-incentive value, we eat more; accounts for the impact of external influences

Adaptive Species-Typical Preferences

We have evolved to often crave sweet and fatty foods (high energy) and salty foods (high sodium)

Adaptive Species-Typical Aversions

We have evolved to generally dislike bitterness because it’s associated with toxins

Learned Preferences and Aversions

Preferences and aversions that are learned rather than being natural (ex: rat likely to prefer food that smells like other rats because they have learned its likely safe)

Premeal Hunger

The tendency to get hungry at mealtime - when a meal is expected, the body enters cephalic phase due to classical conditioning

Satiety

Being full - signals include food in gut and glucose in blood

Appetizer Effects

Small amounts of food before a meal may increase hunger

Serving Size

Larger serving sizes often mean more will be consumed

Social Influences

More food is consumed when eating with others

Sensory-Specific Satiety

Number of different tastes available at each meal alters intake (varied food items often means food is more palatable, meaning an increase in consumption)

Pros and Cons of Sensory-Specific Satiety

It encourages us to crave/try new things and keep a balanced diet, but unhealthy foods that taste really good often aren’t effected by this - you don’t stop craving them

What areas of the brain are involved with satiety?

The ventromedial hypothalamus (bilateral lesions of this area produce hyperphagia and extreme obesity in rats)

What areas of the brain are involved in hunger?

The later hypothalamus (bilateral lesions of this area produce aphagia - animals will stop eating and can cause motor issues)

Peptides

Made in the hypothalamus, these chains of amino acids function as hormones and neurotransmitters for satiety and hunger

Satiety Peptides (decrease appetite)

Cholecystokinin (CCK), -MSH, Somatostatin, and Leptin

Hunger Peptides (increase appetite)

Neuropeptide Y, Galanin, Orexin-A, Ghrelin

CCK

A peptide, that if injected into rats, caused the consumption of smaller mealsL

Leptin

A peptide that is produced by adipocytes (fat cells) and inhibits feeding via CNS receptors

NPY

A peptide widely distributed throughout the CNS, promotes feeding via CNS receptors, and injections of this into the paraventricular nucleus of the hypothalamus increase eating

Serotonin (5-HT)

Acts as an agonist and decreases appetite when increased levels are present in the synaptic cleft (reduces intake even among palatable foods)

What are the issues with serotonin agonist drigs?

While they help in short term by decreasing cravings, meal size, and snacking, they have been linked to cardiovascular (heart) issues

Prader-Willi Syndrome

A syndrome caused by an accidental chromosomal replication on chromosome 15 from dad - causes people to have an insatiable hunger and slow metabolism (without treatment, patients will become severely obese and often die in early adulthood)

Obesity

Over consumption

Why do some people become obese?

Energy input differences- cravings for unhealthy food, family/cultural norms, and large cephalic-phase

Energy output differences- exercise, different basal metabolic rates, diet-induced thermogenesis (ability to burn fat) and NEAT (nonexercise activity thermogenesis)

Anorexia Nervosa

Voluntary self-starvation (undercondumtion disorder) - sufferers often have a distorted body image, are affluent young females and have some other mental illness; starvation typically increases positive incentive for food, but people with this illness do not have that same reaction - small portions are better for anorexics to not throw the body out of homeostasis

Bulimia Nervosa

Voluntary binging and purging (undercondumtion disorder) - sufferers often have a distorted body image, are affluent young females and have some other mental illness;

How is genetic sex determined?

It is determined by sex chromosomes - XX for female and XY for male

MAMAWAWA

Men are men and women are women assumption - outdated

Hormones

Chemicals produced by glands and released into the blood - 3 types: Amino acid derivatives, peptides and proteins, and steroids (most important for sex development and behavior)

Neuroendocrine System

Made up of nerves and gland cells; It makes hormones and releases them into the bloodstream - includes the pituitary gland, the parathyroid glands and the inner layer of the adrenal gland (adrenal medulla)

Gonad

An organ that produces gametes; a testis or ovary

What hormones do testes and ovaries produce?

Both produce androgen (ex: testosterone), estrogen (ex: estradiol), and progestins(ex: progesterone) at differing levels

Wolffian System

Potential to develop into seminal ducts and vas deferens (male)

Mullerian system

Potential to develop into uterus, vagina, and fallopian tubes

How is gender determines?

Gender is determined by the presence of hormones secreted by testes - anti-mullerin hormone (defeminizing) and androgens (masculinizing) if there are testes

Embryotic Stage

Contains structures for both male and female sexual organs, and around late 2nd/earth 3rd month, one wins

Organizational

Hormones influencing the development of sex organs and brain differentiation