Lecture 6: The Diencephalon and Telecephalon PDF

12 APRIL THE FOREBRAIN Lecture 6: The Diencephalon and Telencephalon 1 CONTENTS DIENCEPHALON - Hypothalamus - Thalamus TELENCEPHALON - Cerebral cortex - Basal ganglia - Limbic system 2 THE FOREBRAIN - The mo...

12 APRIL THE FOREBRAIN Lecture 6: The Diencephalon and Telencephalon 1 CONTENTS DIENCEPHALON - Hypothalamus - Thalamus TELENCEPHALON - Cerebral cortex - Basal ganglia - Limbic system 2 THE FOREBRAIN - The most anterior and prominent part of the brain, with two cerebral hemispheres (cerebrum). - Comprises 80% of the human brain 3 DIENCEPHALON 4 HYPOTHALAMUS - Located between pituitary gland and thalamus - Functions: keeps body in homeostasis - Connector to endocrine systems - Hormone regulation - Stress response (trigger cortisol release) - Body temp, thirst, appetite, emotions, sleep cycles, sex drive, childbirth, blood pressure & heart rate, production of digestive juices, balance body uids 5 fl REGIONS OF HYPOTHALAMUS - Temperature regulation: thermosensitive neurons - Feeding: appestat centre 6 THALAMUS - Gateway for channeling sensory information to: - Visual cortex - Auditory cortex - Frontal lobes 7 TELENCEPHALON 8 CEREBRAL CORTEX - Four lobes: - Occipital (visual info) - Frontal (Finer Movement and Speech Production: Broca’s Area) - Temporal (Speech comprehension: Wernicke’s Area) - Parietal (Orientation in Space) 9 FRONTAL LOBES - Largest lobe - Main roles: motor function, planning movements - Also: thinking, feeling, imagining, making decisions - Key Areas - Motor cortex - Frontal Eye Fields - Broca’s speech area - Prefrontal Cortex 10 FRONTAL LOBES: BROCA’S APHASIA - Located in frontal lobe – LEFT hemisphere - Speech production (not comprehension) - Moves muscles for speech - Makes speech clear, uent - Destruction > “expressive” aphasia. - Know what you want to say but cannot express speech - “Broken” speech: stuttering, stop/start 11 fl TEMPORAL LOBES: WERNICKE’S AREA - Located in temporal lobe – LEFT hemisphere. - Speech comprehension (not production) - Destruction > “ uent” aphasia - Fluent, but meaningless speech - Lack of stutters, starts/stops 12 fl BASAL GANGLIA - Collection of nuclei just below the white matter of the cortex - 3 Principal Structures: - Caudate nucleus - Putamen - Globus pallidus - All form a ‘motor loop’ with the motor area in the frontal lobes 13 BASAL GANGLIA: FLUID MOVEMENT - Function: controls goal/voluntary/ uid movement (e.g., choreographed dancing) - The goal of all movement is to be uid and target-orientated - To achieve this: motor and sensory association areas send information to the basal ganglia to execute particular movement - But disorders are common (e.g., Tourette's Syndrome) 14 fl fl LIMBIC SYSTEM - Group of structures between the neocortex and brain stem. - Principal structures: - Amygdala: Emotions, fear etc. - Hippocampus: Memory - CASE STUDY TIME: HENRY MALAISON 15 QUESTIONS? 16