NEU 302 1st EditionExam # 2 Study Guide Lectures: 5-10Neuroscience EXAM 2Lecture 5: The Basal Ganglia Circuitry1. Basal Gangliaa. Structures:i. Striatum (caudate (curved structure) and Putamen)1. Stripes of grey matter that connect caudate nucleus and putamen2. Do basically same functionii. Globus Pallidus1. Much paler that the other matter2. 2 piecesa. External segmentb. Internal Segment (medial)iii. Subthalamic Nucleusiv. Substantia Nigra1. In the Mid Brain2. Dopaminergic Neuronsb. It is a “brake” on the nervous systemi. It modifies what information is getting through ii. Main output is to thalamusc. Basic Circuitryi. Receives input from most of the cortex1. Mainly the prefrontal cortexii. Output is to the thalamus iii. Thalamus then projects back up to the motor cortexiv. Funnels info from whole cortex and projects back to M1d. Very important in cognitive and emotional aspects as well as motor aspectse. Direct and indirect pathwaysi. Direct1. Cortex projects ot Caudate and Putamen 2. The Striatum projects to the globus Pallidus (internal)3. Thalamus and then back to cortexii. Indirect1. Cortex to Striatum2. Striatum projects to external globus Pallidus3. This then projects to subthalamic nucleus and then back to thalamus4. From thalamus back to cortexf. Direct explained:i. At rest:1. Globus Pallidus inhibits thalamus (GABA)2. Thalamus is excitatory to cortex, so inhibition of the thalamus leads to less activity in the motor cortex3. At this point the thalamus cant excite cortexii. Movement:1. Cortex sends excitatory signal to striatum 2. Inhibits GP3. GP allows thalamus to be excited and then excite the motor cortexg. Indirect Pathwayi. Caudate nucleus get stimulation from the cortexii. Projects to the external GPiii. GP sends inhibition to the subthalamic nucleus iv. Subthalamic nucleus then inhibits the inhibition of the internal GPh. Substantia Nigra compacta i. The black Body (neuromelenin)ii. Has two type of receptors v1. D1 receptors: excitea. Increase cyclic AMPb. Work through the direct pathway2. D2 receptors: inhibita. Decrease cyclic AMPb. Work through the indirect pathwayiii. The dopamine is influencing the response of both pathways2. Parkinson’s Diseasea. First known as the shaking palsyb. Symptoms:i. Disturbances in memory retrieval ii. Slow movementsiii. Rigidityiv. Emotional and depressive issuesv. Akinesia1. Inability to begin a movementvi. Shakyc. Circuitry:3. Huntington’s Diseasea. Degradation of Caudate Nucleusb. Symptoms:i. Difficulty walkingii. Excessive movementsiii. Difficulty speakingc. Starts in 20s or 30sLecture 6: Association Cortex1. Mammalian cortex through evolutiona. Growth in size and importance of the associative areas of the brainb. NEOCORTEXi. From 20% of brain to 80%2. Everything besides the primary sensory and motor cortex is a part of the Association cortex3. Laminar Organizationa. Layer 2, 3 communicates with intra cortical areasb. Layers 4 and 5 project down to basal ganglia4. Main differences from sensory and motora. Subcortical Inputb. Corticocortical Connections5. Association cortex gets information from cortex not from sensory afferentsa. Much Higher Level Circuitry6. Main Parts of Association Cortexa. Parietal Lobei. Attention1. Direct2. Selectii. Covert Attention Experiment1. Cue would tell person where light would be a. Cue was only valid 80% of the time, why?i. What is the difference if you are cued to a spot versus not being cuedb. Target was only presented target half of the time, why?i. Made it so person couldn’t cheat and would just press the button all the timec. What would be the percentage of correct responses if she always followed the cue?i. 80%2. Resultsa. Valid cuei. 80% of time sees targeb. Neutral cuei. 50%c. Invalid cuei. 20%3. Conclusionsa. Directing your attention changes how fast your mind can process the light stimulus4. We are able to internal change where we are directing our attention5. Hemispatial neglecta. Lesions on one side of the brain in the parietal lobeb. Eyesight is fine but the side of the world opposite to the lesion seems to not existc. Left sides of drawings aren’t incorporated or even consideredi. Don’t even realize the left side is missing ii. Ignores left side of mental imaged. Not a sensory problem but a problem of consciousnessi. Problem with attentione. Normally lesion on right hemispheref. Don’t even realize they have a disorderg. When imagining a scene could remember the left side of the scene but were not attending to themh. Subconsciously still process problem sidei. Conclusioni. Left hemisphere only attends to the right visual fieldii. Right parietal covers all of the visual field (LEFT AND RIGHT)1. Only see horrible problems when right parietal has lesioniii. Top-down Processing1. Attending to a stimulus enhances neuronal responses in visual cortexb. Temporal cortexi. Identificationii. “What” Pathway1. Face Perceptiona. Humans and other social primates readily perceive faces even ininanimate objectsb. How?i. Face Cells in the inferior Temporal Cortex of Rhesus Monkeyii. Neurons would fire more and more for objects that resembles facesiii. Most responsive to Profiles though some cells would respond strongly to straight on facesc. Fusiform Face Areai. Both sides of the brain but mainly on the rightii. Human Face recognition aread. Modern Aspect:i. How do inanimate drawings trigger same signal as real life representationsii. 6 specific regions for face recognition1. Face Patches2. Almost every cell is here is face selective3. Different cells code for different aspects of a facea. Hair, iris, mouth, etc.4. Patches give different types of face layouts and patches are interconnected e. Prosopagnosiai. Inability to recognize facesii. Cant carry an image of people in mindiii. Cannot recreate faces in mindf. To what extent is the ability recognize faces variable?i. Being “bad” at recognizing facesc. Frontal Cortexi. Planning and WORKING MEMORYii. Most complex and has more cortical to cortical connections than any part of the brainiii. Phineas Gage1. Tamping Iron shot through his cheek, into eye and into his frontal lobea. Woke up immediately and walked to the doctor2. Symptomsa. Balance between intellectual faculties and animalistic desires is goneb. Pipe Dreamerc. Rash and reckless decision making3. His ability to process social cue then allowed him to overcome this disability4. Died via seizureiv. Delayed Response Task1. Working memory task2. Food morsel