NEU 302 1st Edition Exam 2 Study Guide Lectures 5 10 Neuroscience EXAM 2 Lecture 5 The Basal Ganglia Circuitry 1 Basal Ganglia a Structures i Striatum caudate curved structure and Putamen 1 Stripes of grey matter that connect caudate nucleus and putamen 2 Do basically same function ii Globus Pallidus 1 Much paler that the other matter 2 2 pieces a External segment b Internal Segment medial iii Subthalamic Nucleus iv Substantia Nigra 1 In the Mid Brain 2 Dopaminergic Neurons b It is a brake on the nervous system i It modifies what information is getting through ii Main output is to thalamus c Basic Circuitry i Receives input from most of the cortex 1 Mainly the prefrontal cortex ii Output is to the thalamus iii Thalamus then projects back up to the motor cortex iv Funnels info from whole cortex and projects back to M1 d Very important in cognitive and emotional aspects as well as motor aspects e Direct and indirect pathways i Direct 1 Cortex projects ot Caudate and Putamen 2 The Striatum projects to the globus Pallidus internal 3 Thalamus and then back to cortex ii Indirect 1 Cortex to Striatum 2 Striatum projects to external globus Pallidus 3 This then projects to subthalamic nucleus and then back to thalamus 4 From thalamus back to cortex f 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 cortex 3 At this point the thalamus cant excite cortex ii Movement 1 Cortex sends excitatory signal to striatum 2 Inhibits GP 3 GP allows thalamus to be excited and then excite the motor cortex g Indirect Pathway i Caudate nucleus get stimulation from the cortex ii Projects to the external GP iii GP sends inhibition to the subthalamic nucleus iv Subthalamic nucleus then inhibits the inhibition of the internal GP h Substantia Nigra compacta i The black Body neuromelenin ii Has two type of receptors v 1 D1 receptors excite a Increase cyclic AMP b Work through the direct pathway 2 D2 receptors inhibit a Decrease cyclic AMP b Work through the indirect pathway iii The dopamine is influencing the response of both pathways 2 Parkinson s Disease a First known as the shaking palsy b Symptoms i Disturbances in memory retrieval ii Slow movements iii Rigidity iv Emotional and depressive issues v Akinesia 1 Inability to begin a movement vi Shaky c Circuitry 3 Huntington s Disease a Degradation of Caudate Nucleus b Symptoms i Difficulty walking ii Excessive movements iii Difficulty speaking c Starts in 20s or 30s Lecture 6 Association Cortex 1 Mammalian cortex through evolution a Growth in size and importance of the associative areas of the brain b NEOCORTEX i From 20 of brain to 80 2 Everything besides the primary sensory and motor cortex is a part of the Association cortex 3 Laminar Organization a Layer 2 3 communicates with intra cortical areas b Layers 4 and 5 project down to basal ganglia 4 Main differences from sensory and motor a Subcortical Input b Corticocortical Connections 5 Association cortex gets information from cortex not from sensory afferents a Much Higher Level Circuitry 6 Main Parts of Association Cortex a Parietal Lobe i Attention 1 Direct 2 Select ii Covert Attention Experiment 1 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 cued b 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 time c What would be the percentage of correct responses if she always followed the cue i 80 2 Results a Valid cue i 80 of time sees targe b Neutral cue i 50 c Invalid cue i 20 3 Conclusions a Directing your attention changes how fast your mind can process the light stimulus 4 We are able to internal change where we are directing our attention 5 Hemispatial neglect a Lesions on one side of the brain in the parietal lobe b Eyesight is fine but the side of the world opposite to the lesion seems to not exist c Left sides of drawings aren t incorporated or even considered i Don t even realize the left side is missing ii Ignores left side of mental image d Not a sensory problem but a problem of consciousness i Problem with attention e Normally lesion on right hemisphere f Don t even realize they have a disorder g When imagining a scene could remember the left side of the scene but were not attending to them h Subconsciously still process problem side i Conclusion i Left hemisphere only attends to the right visual field ii Right parietal covers all of the visual field LEFT AND RIGHT 1 Only see horrible problems when right parietal has lesion iii Top down Processing 1 Attending to a stimulus enhances neuronal responses in visual cortex b Temporal cortex i Identification ii What Pathway 1 Face Perception a Humans and other social primates readily perceive faces even in inanimate objects b How i Face Cells in the inferior Temporal Cortex of Rhesus Monkey ii Neurons would fire more and more for objects that resembles faces iii Most responsive to Profiles though some cells would respond strongly to straight on faces c Fusiform Face Area i Both sides of the brain but mainly on the right ii Human Face recognition area d Modern Aspect i How do inanimate drawings trigger same signal as real life representations ii 6 specific regions for face recognition 1 Face Patches 2 Almost every cell is here is face selective 3 Different cells code for different aspects of a face a Hair iris mouth etc 4 Patches give different types of face layouts and patches are interconnected e Prosopagnosia i Inability to recognize faces ii Cant carry an image of people in mind iii Cannot recreate faces in mind f To what extent is the ability recognize faces variable i Being bad at recognizing faces c Frontal Cortex i Planning and WORKING MEMORY ii Most complex and has more cortical to cortical connections than any part of the brain iii Phineas Gage 1 Tamping Iron shot through his cheek into eye and into his frontal lobe a Woke up immediately and walked to the doctor 2 Symptoms a Balance between intellectual faculties and animalistic desires is gone b Pipe Dreamer c Rash and reckless decision making 3 His ability to process social cue then allowed him to overcome this disability 4 Died via seizure iv Delayed Response Task 1 Working memory task 2 Food morsel placed in dish in front of monkey then screen covers vision 3 When uncovered monkey goes for