Physiological Psychology Exam 3

Motor Unit

motor neuron and all muscle fibers it innervates

Motor unit recruitment

increasing number of contracting motor units to increase overall strength of contraction

functions of the spinal cord

• execution of movement

• more than relay contains complex motor programs

Lateral motor neurons

project to muscles that control fingers and hands

Intermediate motor neurons

project to muscles that control arms and shoulders

Medial motor neurons

project to muscles that control trunk

Symptoms of ALS

• Progressive, fatal neurodegenerative disease caused by degeneration of motor neurons.

• Loss of motor unit innervation leads to weakness or paralysis of muscles.

• atrophy of muscles, due to loss of trophic factors from motor neurons

Lateral corticospinal tract

Cross and descend spinal cord in lateral position. moves limbs and digits on opposite sides of the body

Ventral corticospinal tract

remain on original side and descend spinal cord in ventral position. moves midline trunk muscles on same side of body

Prefrontal cortex

plans movement and complex behaviors

premotor cortex

produces motor sequences appropriate to task

primary motor cortex

executing skilled movements

Functions of the frontal lobe

prefrontal cortex (plans) → premotor cortex (sequences) → motor cortex (executes plans)

Topographical representation in motor cortex

neural spatial representation of body or areas of sensory world perceived by sensory organ

Basal Ganglia Direct Pathway

too much activity leads to overactivity of thalamus and cortex → more movement

Basal Ganglia Indirect pathways

too much activity leads to inhibition of thalamus and cortex → less movement

Cerebellum Homunculus Lateral parts

movements of limbs, hands, feet, digits

Cerebellum Homunculus medial parts

controls face and midline of body

Motor functions of cerebellum

• timing of movements

• maintaining movement accuracy (error correction)

• combines sensory and motor information to predict where objects will be at some future point in time

Stimulated in the hippocampus due to exercise

stimulates growth of new neurons (neurogenesis)

Exercise increases the production of

enhances production of brain-derived neurotrophic factors (BDNF)

Cellular structure’s function heightened due to exercise

promotes synaptic plasticity in the brain and improves strength and efficiency between neurons allowing messages to be sent faster

Underlying nervous system cause of Parkinson’s disease

loss of DA neurons in nigrostriatal pathway

Symptoms of PD

Begins with slowness of movement, stiffness in joints, tremors.

• stage 1: only on one side

• stage 2: spreads to other side

PD Positive Symptoms

inhibited in normal people. resting tremor (pill rolling), muscular rigidity, involuntary movements

PD Negative Symptoms

disorders of posture & balance (retropulsion), disorders of locomotion (small steps, bradykinesia), speech disturbances, akinesia (masked/stiff face)

Basal ganglia circuit dysfunction in PD

Indirect pathways - too much activity leads to inhibition of thalamus and cortex. Hypokinetic symptom - loss of motor ability. Loss of DA neurons in substantia nigra.

Different treatments for PD

surgical, deep brain stimulation of GP or subthalamic nucleus, transplantation, behavioral, pharmacological

Advantages of L-DOPA

Unlike DA, it can cross the blood-brain barrier. Bypasses rate limited factor in DA synthesis

Disadvantages of L-DOPA

Only gives patients a few more good years: doesn’t work as DA neurons continue to die. Large doses: gets converted to DA in periphery (nausea, vomiting). Psychosis.

Underlying nervous system cause of Huntington’s Disease (HD)

Neurodegenerative genetic disorder caused by autosomal dominant mutation of gene

HD basal ganglia direct pathway

Too much activity leads to overactivity of thalamus and cortex. Hyperkinetic symptoms: excessive involuntary movements. Damage to caudate

Symptoms of HD

Chorea (jerky, random, uncontrollable movement), short-term & long-term memory deficits, executive function deficits (impulsivity, abstract thinking, & cognitive flexibility deficits)

Free will

Do what you want & always have a choice

Drive theory

When drive is high → animal engages in particular behavior. When drive is low → behavior ceases

Flush model

Brain stores energy for behavior (in reservoir). Once behavior is started, it continues until all energy is gone. Intensity of behavior depends on how much energy is in reservoir. Separate stores of energy for different behaviors.

Regulatory behaviors

Behavior that is motivated to meet survival needs of animal: controlled by homeostatic mechanisms, involves hypothalamus

Examples of regulatory behaviors

Internal body temperature. Eating and drinking. Salt consumption. Waste elimination.

Nonregulatory behaviors

Behaviors that are unnecessary to meet basic survival needs of animal. Not controlled by homeostatic mechanisms. Most involve frontal cortex more than hypothalamus. Strongly influenced by external stimuli. Sensory system involvement.

Examples of nonregulatory behaviors

Sex. Parenting. Reading. Curiosity

Lateral region

Contains nuclei & nerve tracts that connect lower brain stem to forebrain

Medial forebrain bundle

Tracy that connects structures in brainstem with various parts of limbic system

Posterior pituitary gland

Neurons in the hypothalamus make peptides & send them down axons to here (neural tissue, continuation of hypothalamus). If neurons becomes active → stored peptides are released & picked up by capillaries.

Anterior pituitary gland

Glandular tissue that synthesizes various hormones: hypothalamus controls release via releasing hormones. Cand either stimulate or inhibit release of hormone

Role of posterior hypothalamus in hormones

Magnocellular cells: two neurohormones (oxytocin and Vasopressin [ADH])

Oxytocin

In posterior hypothalamus. Lactation, suppress hypothalamic function: large amount released during childbirth. Controls breast milk production.

Vasopressin (ADH)

In posterior hormone. Regulate blood volume & salt concentration

Role of anterior hypothalamus in hormone

Communication between kidneys & brain x parvocellular cells

Anterior hormone stress response

Periventricular hypothalamus secretes corticotropin - release hormone (CRH) into portal circulation. Adrenocorticotropic hormone (ACTH) released into circulation. ACTH stimulates cortisol release from adrenal cortex

Feedback loops

Controls amount of hormone released

Role of lateral hypothalamus in eating

Damage: led to aphagia. Failure to eat: may be due to unwillingness to eat or motor difficulties (especially swallowing). Stimulation: elicits eating.

Role of ventromedial hypothalamus in eating

Damage: led to hyperphagia. Disorder in which animals overeat leading to significant weight gain. Stimulation: inhibits feeding

Learned taste aversion

Associations are made as long as illness & taste are paired in time: food doesn’t cause illness for association to be made

Ventromedial Hypothalamus role is sexual behavior

controls lordosis. damage abolishes lordosis

Preoptic area of medial hypothalamus role in sexual behavior

• controls copulation in males

• damage disrupts mating

• stimulation activates mating

• not involved in sexual motivation

• damage does not prevent interest in females

Amygdala role in sexual behavior

controls sexual motivation in males and possibly females

Nap time to gain the benefits of neuroplasticity

20 minutes

Benefits of sleep for rehabilitation

restores synaptic plasticity: healing injuries, growth hormone, cortisol levels, addiction recovery

The brain structure that regulates “the four F’s” (fighting, fleeing, feeding, and f-ing) is the

hypothalamus

Olds and Milner (1954) discovered that rats would work very hard to obtain

electrical stimulation of the brain

Regarding sexual behavior, damage to the amygdala

decreases sexual motivation in males

Lesions of which of the following structures would lead to aphagia, or a failure to eat

lateral hypothalamus

The ___ pituitary gland mediates _____

posterior; salt concentration

Regarding nonregulatory behaviors all the following are true except:

they are controlled by homeostatic mechanisms

Most neurons in the mesolimbic system use the neurotransmitter (NT)

dopamine (DA)

Human body temperature of 98.6 is an example of

a set point in homeostasis.

Ventromedial hypothalamus-lesioned rats show

hyperphagia

Which of the following occur in response to physiological deficits and disappear when needs are met

drive states

An organism’s ability to make physiological adjustments to achieve equilibrium is known as

homeostasis

Taste aversions are a type of classical conditioning. The fact that people and animals can develop taste aversions even though sickness may occur long after eating indicates that

there is a biological tendency to associate sickness with any food eaten earlier

Karen has been diagnosed with a tumor in the vicinity of her ventromedial hypothalamus. Which of the following symptoms has Karen MOST likely experienced as a result of her condition

she has experienced a sudden, large weight gain

The result of activity in the hypothalamus-pituitary-adrenal (HPA) axis is

increases in release of cortisol

Which of the following structures is NOT one of the ones that helps the body cope with stress

Hippocampus

Which of the following is NOT considered a regulatory behavior

sex

According to drive theory, when a drive is _____, and animal will engage in a particular behavior and when the drive becomes ____, the behavior ceases.

high; low

In adult females, high levels of estrogen is associated with one more dendritic spines on neurons in the

hippocampus

The hypothalamus regulates hormone-related activity by acting on the

pituitary gland

Some of the most powerful reinforcement effects are obtained through electrical stimulation of the

medial forebrain bundle