Chapter 2 Flashcards
What are the structures in the brain stem?
-medulla oblongata (heart rate, respiration, blood pressure)
-pons (sleep-wake cycle and respiration)
-midbrain (hearing, motor control, alertness)
-reticular formation (alertness in particular)
What is the Thalamus?
-the gateway to the brain
-it receives almost all incoming sensory information before that information reaches the cortex; expect olfactory information
What is the Hypothalamus?
-a brain structure that is involved in the regulation of bodily functions, including body temperature, body rhythms, blood pressure, and blood glucose levels
-it also influences our basic motivated behaviours (aggression, hunger, thirst, sex).
What is the Hippocampus?
-a brain structure that is associated with the formation of new memories
-also memory of arrangements, places, objects
-volume of gray matter found highly correlated with years of experience as a taxi driver (important for navigation)
What is the Amygdala?
-serves a vital role in learning to associate things with emotional responses and in processing emotional information
-special role:
–responding to fear eliciting stimuli
–evaluating facial expressions of emotional significance (strong reaction to fearful face)
–intensification of memories associated with emotional arousal
What affects the learning of behaviour?
-preexisting behavioural tendencies constrain or limit how learning occurs and the extent of learned behavioural change
-much behaviour is elicited:
–bright light causes constriction of the pupils
–respiratory passage irritation leads to sneezing or coughing
–a sudden clap of thunder gets our attention
-the simplest form of elicited behaviour is reflexive behaviour
What are the 2 human spinal orientations?
-the dorsal and ventral aspects of the human spine
–the ventral side of the spinal cord corresponds to the anterior side
–the dorsal side corresponds to the posterior side
What is the nature of elicited behaviour?
-reflex-involves eliciting stimulus and corresponding linked response
-the particular relation between some stimulus and the associated reflex is a consequence of the nervous system organization
What are the 3 different neurons involved in simple reflexes?
- a sensory or afferent neuron
-transmits information to the spinal cord - a motor neuron or efferent neuron
-effects or activates muscles involved in the reflex - an interneuron (one or more) that is an intermediary neuron
-passes information from one neuron (sensory) to
another neuron, such as the motor neuron
What are these 3 neurons responsible for?
-the afferent, interneuron, and the efferent neuron constitute the reflex arc
-because one or more neurons are involved, this is a polysynaptic reflex
-if just two neurons are involved (sensory and motor) it is a monosynaptic reflex (simplest type of reflex)
What are the 3 parts of the polysynaptic pathways in the spinal cord (reflex arc)?
- excitatory pathways, sensory neuron activates motor neurons supplying ipsilateral (same side) flexor muscles, which withdraw the limb from noxious stimuli.
- inhibitory interneurons ensure that the motor neurons supplying antagonist muscles are inactive during the reflex response.
- at the same time, motor neurons supplying contralateral (opposite side) extensor muscles are excited to provide support during withdrawal of the limb
Why do most sensory neurons not pass directly into the brain?
-synpase in the spinal cord
-permits faster reflex actions
-brain receives input while the reflex is being carried out
-brain analyses the information after the reflex action
What are the suckling and rooting reflex?
-innate response due to the stimulation of the face, mouth, or cheek by touching/stroking (the head is turned towards the side of the stimulus).
-brainstem mediated primitive motor reflex also called the frontal release reflex.
What is the respiratory occlusion reflex?
-if a baby’s breathing is inhibited, reflexive actions include:
–head is pulled back
–wiping the face
–or crying if these are not effective
What are the 3 types of motor neurons?
-Upper motor neurons: originate in the cerebral cortex; travel inferiorly to the brain stem or spinal cord; glutamate is the NT
-Lower motor neurons: originate in the spinal cord and innervate glands and muscles; acetylcholine (ACH) is the NT
-Automatic and somatic motor neurons: somatic: alpha, beta, and gamma motor neurons
What are the 4 types of sensory neurons?
-Mechanoreceptors
-Thermoreceptors
-Nociceptors (electromagnetic receptors)
-Chemoreceptors
What are autonomic reflexes?
-autonomic reflexes, largely unconsciously, regulate internal organs smooth muscles and glands
When does the brain mediate a reflexive response?
-reflexes, which are automatic, can be modified by the descending brainstem and cortex pathways
-if you are carrying a kitten and fall, automatic reflexes would normally move to break the fall, but here you do not want to drop the kitten; within 30ms the cortical motor centers would modify the reflexes to allow you to also protect the kitten
What is the process of Puillary light reflex?
-light is flashed near one eye
-impulses reach the brain via the optic nerve
-the response is conveyed to the pupillary musculature (iris muscles)
-pupils contract
What is Modal Action Patterns (MAP)?
-MAP: response sequences typical of a particular species
-many stimuli will elicit different responses from different organisms
–chicks peck a red patch near the tip of the parent’s bill, causing the parent to regurgitate food for them
What is Sign Stimulus?
-specific stimulus that elicits certain response
–when chick peck at their parent’s beak to regurgitate, red spot near the tip is the sign stimulus
What is Supernormal Stimulus?
-exaggerated stimulus used to cause extremely vigorous response
–ex: foods with high levels of sugar and fat cause humans to have much higher rates of salivation and craving than normal food
What are the Sequential Organizations of Behaviour?
-Behaviour Sequence
-Appetitive Behaviour
-Consummatory (completion) Behaviour
What is Behaviour Sequence and its components?
-a sequential series of organized effective actions get the organism to its goal
-appetitive behaviour is an early component of behaviour sequence
-consummatory (completion) behaviour is an end component of behaviour sequence (it is species specific)
What is Appetitive Behaviour used for?
-used to bring the organism into contact with the stimuli that will trigger the consummatory behaviour
–appetitive more variable
-how animals forage for food is categorized as general search mode, focal search mode, and food handling and ingestion mode
How does Learning (Pavlov) affect Sequential Organization of Behaviour?
-learning, via Pavlovian or instrumental (operant), can modify the sequential organization of behaviour
What is a study that showed the affect of Habituation?
-study participants were given lemon/lime juice
-participants salivated more when they tasted food they liked
-participants salivated less and hedonic rating declined, when eating the same food over and over unless they were distracted
–habituation effect: becoming accustomed to a stimulus
What some characteristics of Habituation?
-decline in responding that occurs with repeated presentation
-stimulus specific
-related to taste
-obesity may be at least in part a disorder of habituation
-attention is also a factor in habituation
What is Habituation like in infants?
-babies have longer attention spans when staring at more complex/interesting stimuli.
-another visual stimulus, two faces:
–face that the infants were exposed to initially during a “habituation”
–but then during the experiment a new face was introduced next to the original face
-infants spend more time looking at novel face
What is the Startle Response?
-defensive reaction to potential or actual attack
-with repeated startling stimuli, the startle response will progressively diminish, but there will still be a response
-spontaneous recovery: wait for period of time before presenting the startling stimuli again, strartle response returns
-repeated presentations of a stimulus do not always result in both long-term and short-term habituation effects
What is the Sensitization Effect?
-when already aroused the same eliciting stimulus will trigger a much stronger reaction
–ex: being tapped on the shoulder in a store will not elicit much response, but if already aroused from walking in a dark alley at night then being tapped on the shoulder would more likely elicit a strong reaction
What is the Eyeblink Startle Response Study?
-to induce fear, group A subjects told they would receive mild electric shock when a pleasant picture was shown
-group B had shock threat associated with unpleasant but not pleasant pictures
-outcome: group A when presented with threat of shock and pleasant picture had increased fear
-demonstrates how a response can be altered by emotional state
What is the difference between Habituation and Sensitization?
-Habituation: when your mind tunes out certain stimuli so you can focus on other presumably more important stimuli
-Sensitization: when your mind specifically targets stimuli that it deems more important and makes you pay more attention to
-habituation and sensitization can occur with repeated exposures to a stimulus
What are the 3 components of a reflex…
-not all instances of repetitious stimuli response decline are due to habituation
1. a stimulus
2. sensory to motor nerve relay of a signal via an interneuron
3. motor neurons activate muscle response
What is Sensory Adaptation and Response Fatigue?
-sensory adaptation: when the sense organs become temporarily disabled due to stimuli overload
-response fatigue: when sensory receptors won’t receive stimuli because they are fatigued
–fatigue is outside the nervous system
ADD??
What is the Dual-Process Theory of Habituation and Sensitization?
-dual-process theory assumes different types of underlying neural processes are responsible for increases/decreases in responsiveness to stimulation
–where one neural process decreases responsiveness = habituation
–another neural process increases responsiveness = sensitization
Where do Habituation and Sensitization take place (Dual-Process Theory)?
-habituation and sensitization are not mutually exclusive; dual concurrent activation of each
-habituation processes (underlying mechanisms) are assumed to occur in the S-R system and are activated every time eliciting stimuli are produced
-sensitization processes are assumed to occur in the state system, which activates only in presence of arousing stimuli
Can drugs and toxins change NTs action?
-yes, drugs and toxins can alter NTs action:
–agonists enhance the actions of NTs
–antagonists inhibit the actions of NTs
What does the Agonist Mechanism do?
-increasing production of neurotransmitters in presynaptic neuron
-blocking reuptake receptors on presynaptic cell
-mimicking the action of the neurotransmitter on the postsynaptic cell
What does the Antagonist Mechanism do?
-decreasing production of NTs in presynaptic neuron
-facilitating destruction or breakdown of NT
-blocking the postsynaptic receptors, preventing the NT from activating them
What are the Key NTs?
-Acetylcholine (ACh)
-Serotonin (5-hydroxytryptamine, 5-HT)
-Dopamine (dopaminergic neurons, DA)
-Norepinephrine
-Glutamate
-Gamma-aminobutyric Acid (GABA)
What are characteristics of Acetylcholine (Cholinergic neurons)?
-ACh acts on two general families of receptors found in the CNS and PNS: Nicotinic and Muscarinic receptors
-in the PNS, ACh is the NT responsible for signalling the muscles to contract; essential for movement
-in the CNS, ACh is involved in new memory formation in the hippocampus
-nerve gas blocks ACh NT, which impairs breathing
-nicotine impacts ACh system, it can improve memory
What are characteristics of Serotonin (serotonergic neurons)?
-found in the CNS - arousal, mood, sleep - and PNS - regulation of blood pressure
-most anti-depressant drugs act on serotonergic neurons to regulate serotonin neurotransmission
-5-HT dysregulation plays an important role in major depression
-ecstasy in high doses increases serotonin release and anxiety, slows reaction time, is deadly taken with SSRIs
What are the characteristics of Dopamine?
-dopamine dysregulation is associated with several disorders, including Parkinson’s and Schizophrenia
-dopaminergic neurons:
–initiation of movement; habit learning
–motivating effects - DA is a reward NT; food, sex, and drugs release DA
What are the characteristics of Norepinephrine?
-binds to CNS and PNS alpha adrenergic receptors and beta adrenergic receptors
-PNS regulates HR; beta blockers prevent norepinephrine, slows HR, prescribed after heart attach
-CNS important for alertness, attentiveness and mood
What are the characteristics of Glutamate?
-main excitatory NT in the brain and spinal cord
-binds to several CNS and PNS receptors, such as NMDA and AMPA
–these are both important for neuroplasticity; learning memory
–neuroplasticity modification of structure and function in the brain via formation of new synaptic connections involved in learning or recovery from injury
What are the characteristics of Gamma-aminobutyric Acid?
-binds to two main types of receptors called GABAa receptors and GABAb receptors, found in the CNS.
-GABA is the predominant inhibitory NT in the brain and in the spinal cord.
-anxiolytic (anxiety-reducing) and sedative drugs bind to GABA receptors; alcohol also affects GABA receptors
What are second messengers?
-intracellular (within cells) signalling molecules
-released by the cell from exposure to extracellular signalling molecules (the first messengers molecules
What is Cyclic adenosine monophosphate (cAMP)?
-a second messenger involved in intracellular signal transduction
–transferring effects of hormones (adrenaline) into cells
–it is also involved in protein kinase activation
What is Adenylate cyclase?
-accelerates the conversion of adenosine triphosphate (ATP) to cAMP
What is Protein Kinase A (PKA)?
-it is an enzyme
-action is based on levels of cAMP
-regulates sugar and lipid metabolism
-alters K+ channels and reduces out of cell K+ ions, prolongs action potential
What are Kandel’s findings on his work with Aplysia (huge sea slug)?
-a noxious stimulus to the tail enhances synaptic transmission at several connections in the neural circuit of the gill-withdrawal reflex, including sensory and motor neurons and interneurons = sensitization.
-thus, a synapse can participate in more than one type of learning and store more than one type of memory. The neural circuit participates in both habituation and sensitization.
What are the transmitters released by the presynaptic interneuron?
-interneuron seretonin (5-HT) binds to two receptors; one engages a G protein, which increases the activity of adenyl cyclase
-adenyl cyclase converts ATP to cAMP, thereby increasing the level of cAMP in the terminal of the sensory neuron
-the cAMP activates the cAMP-dependent protein kinase A (PKA)
-PKA alters K+ channels reducing the outward flow of K+, prolonging the action potential, augmenting the flow of C+ into the cell
What happens after there is more C+ in the cell?
-the added C+ entering the cell facilitates NT containing vesicle binding to cell terminal wall and release of NT into synaptic cleft
-with repeated stimulation of the sensory neuron, the action potential within the sensory neuron is unchanged, though less NT is released = habituation
-Ca+ channels on cell membrane opened by arrival of the action potential
-but habituation inactivates some of the C+ channels, reducing amount of C+ entering the sensory neuron and hence reducing vesicle binding and release of NT into the synaptic celft
What are emotional reactions and their aftereffects?
-intense emotional reactions are often biphasic: one emotion during the eliciting stimulus; the opposite emotion when the stimulus is terminated
-emotional reactions change with experience: primary reaction becomes weaker and after-reaction becomes stronger
What is the Opponent Process Theory of Motivation?
-based on the premise that neurophysiological mechanisms involved in emotional behaviour serve to maintain emotional stability
-requires: biphasic emotional reactions; weakened primary reactions to repeated stimulations; weakening of primary reaction with repetition accompanied by strengthening of after-reaction
-activated with an emotional shift away from neutral
What happens when an emotionally arousing stimulus is presented?
-stimulus elicits process A (primary process) which elicits process B (opposite reaction):
–first, process A is unopposed and rises to a peak
–process B is then activated but is not sufficiently strong to counteract the primary emotional response (pro. A)
–process A persists during the stimulus but quickly returns to neutral or baseline when the stimulus is withdrawn; however, process B lingers longer
What happens when a familiar stimulus does not elicit a strong emotional response?
-the affective after-reaction tends to be much stronger:
-process B becomes strengthened with repeated use
–process B then becomes activated sooner after stimulus onset
–this allows process B to more effectively counteract the process of a primary emotional response (process A)
According to Opponent process theory, why do people continue taking drugs when their effects are gone?
-to escape from the misery of withdrawal
-extensive drug use results in reduced reward NT and heightened antireward systems
–this provides negative reinforcement (withdrawal pain reduced), contributing to continued use and addiction
