Brain and Behavior Exam #4 Study GuideLEARNING AND MEMORY- Learning – relatively permanent change in an organism’s behavior as a result of experience- Memory – the ability to recall or recognize previous experienceo Implies a mental representation of the experience is “stored” in neural pathways- Plasticity – the brain’s ability to change as a result of experienceo Changes in neural pathways and synapseso Brain changes throughout life – allows us to modify our behavior to adapt/learno Brain changes that occur as a result of learning: NOT localized to one region of the brain. Can occur anywhere in the brain. Neurons change their structure – response to changing experiences More dendrites = more connections Strengthen/weaken synapse connections Build new synapse connections/circuits Difficult to study directly Observe behavior to gain insight- How it is studiedo It is challenging to get the animal to reveal what it has learnedo Match the species analyzed with a test appropriate for abilities Rats/mice: mazes, swimming pools, lever pressing Birds: singing Monkeys: observe environment, choose objects Humans: paper and pencil tests- Training Modelso Pavlovian Conditioning Classical Conditioning Associate 2 stimuli and give same response to both Unconditioned Stimulus  Unconditioned Response US + Conditioned Stimulus  Un/Conditioned Response CS  CR Example- Air puff (US)  blink (UR)- Tone (CS)  No response- Air puff + Tone  blink (UR)- Tone  blink (CR) {UR & CR eventually become the same}o Operant Conditioning Instrumental Conditioning- Associate actions w/ consequences, which changes the probabilityof the animal repeating the action in the future- How you measure learning in positive reinforcement testso Time to complete task decreases w/ repetition o # of trials required for task to be completed in time frameo Positive stimulus – applies stimuluso Negative stimulus – removes stimuluso Reinforcement – increases frequency of desirable behavioro Punishment – decreases the frequency of undesirable behavior  Positive reinforcement – applies good stimulus, increased behavior Negative reinforcement – removes bad stimulus, increased behavior Positive punishment – applies bad stimulus, decreased behavior  Negative punishment – removes good stimulus, decreased behavioro Conditioned place preference test No preference before trials (left side/right side) Rat receives rewards/punishments on one side only and learns to prefer that side/other sideo Morris Water Maze Assesses spatial learning and memory- Associate the location of the submerged platform with the visual cues distinguishing the regions of water maze- Hippocampus functioningo Radial Arm Maze Subject placed in center of eight-arm radial maze Four randomly chosen arms have food Subject visits and collects food Tests short/long term memory Used to test effects of marijuana (usually short-term memory affected/impaired)o Novel Object Recognition Rats tend to spend more time interacting with a new object than a previously observed object Measure the amount of time spent with Object A (previous) vs. Object B (novel) Tests hippocampal functiono Extinction Subjects can “unlearn” previously learned behaviors Used in drug rehab Gradual decrease of learned behavior over time- Pavlovian:o No US w/ CS- Operant:o No reward or punishment with action - Categories of Memoryo Short-term – sensory, motor, cognitiveo Long-term Explicit – conscious, subjects can retrieve an item from memory and indicate that they know the retrieved memory is correct Implicit – unconscious, subjects demonstrate knowledge (such as a skill, conditioned response, or recalling events on prompting), but can’t explicitly retrieve information Declarative (explicit) [medial temporal lobe, diencephalon]- Episodic – includes a record of event and your role in event. Tulving said it’s a “marvel of nature”. Transforms brain into a timemachine that allows us to dwell on the past and make plans for the future- Semantic – record of facts/meaning/concepts/knowledge Non-declarative (implicit)- Procedural [basal ganglia]- Priming [neocortex] - Simple classical conditioning [amygdala/cerebellum]- Habituation/sensitization [reflex pathways] Encoding- Implicit tasks – passive role- Explicit tasks – active role- Priming – using a stimulus to sensitize the nervous system to a later presentation of the same or a similar stimulus; often used to measure implicit memoryo What makes I & E memory different? The way they store memories Info from each sensory system (visual, auditory, etc) is processed and stored in different neural areas No single place in the brain is the location of learning and memory – every part of the brain can learn **Emotional memory is both conscious and unconscious- Amnesia – partial or total loss of memoryo Retrograde – inability to retrieve memories formed prior to an evento Anterograde – inability to store new memories after an evento Episodic – remember event but not his/her role in ito Impaired explicit memory – (Patient H.M.) medial-temporal lobe damage; no new memories since surgery, but procedural memory intacto Impaired explicit memory – (Patient J.K.) basal ganglia damage due to Parkinson’s disease; impaired ability to perform tasks he’d done all his life- Korsakoff’s Syndromeo Permanent loss of the explicit memory Inability to learn new info (anterograde amnesia) and to retrieve old info (retrograde amnesia)o Caused by diencephalic damage from chronic alcoholism or malnutrition that produces a vitamin B deficiency- Modifying Synapses/Plasticityo Habituation – a repeated stimulus leads to a decrease in the normal responseo Sensitization – a stimulus to one pathway enhances reflex strength in anothero LTP (long-term potentiation) – long-lasting enhancement in signal transmission between two neuronso LTD (long-term depression) – long-lasting reduction in signal transmission between two neuronso Neurogenesis – evidence that neurogenesis (growth of new neurons) does occur in the mammalian brain Olfactory bulb, hippocampal formation, and possibly the neocortex Reason for neurogenesis is still unclearo Raising rats in enriched enclosures is associated with higher: dendrite length, astrocyte