Major Structures of the Brain.pdf

PHYSIOLOGICAL PSYCHOLOGY Week 3: Major Structures of the Brain Forebrain Prosencephalon (“forward-brain’) KEY DEFINITIONS:...

PHYSIOLOGICAL PSYCHOLOGY Week 3: Major Structures of the Brain Forebrain Prosencephalon (“forward-brain’) KEY DEFINITIONS: Diencephalon Nucleus: Cluster of neurons in the (“between-brain”) Inc. CNS (plural: nuclei) Thalamus and Tracts: Bundle of nerve fibers Hypothalamus (axons) Telencephalon (“end Peduncle: Stem-like connector brain”) Inc. Cerebral Gyrus: Folded part of the cerebral cortex, hippocampus, cortex (plural: gyri) basal ganglia Midbrain Mesencephalon MAJOR DIVISIONS OF THE BRAIN (“middle-brain”) 1. HINDBRAIN Hindbrain Rhombencephalon - Includes the medulla, pons, (“parallelogram-brain”) and cerebellum - Playing crucial roles in basic Metencephalon (“afterbrain”) life functions and motor coordination Myencephalon (“marrow-brain”) 2. MIDBRAIN - Contains Tectum and Tegmentum HINDBRAIN STRUCTURES - Involved in sensory Mylencephalon (Medulla) processing and movement readiness Responsible for basic life support (heart rate, breathing) 3. FOREBRAIN Contains the reticular formation - Divided into the influencing arousal and attention diencephalon (thalamus and hypothalamus) and Divisions of Reticular Formation telencephalon (cerebral cortex and associated Parvocellular Reticular Nuclei structures) (Lateral Zone) – Regulate exhalation Gigantocellular reticular Nuclei (Medial Zone) – Motor Coordination  Raphe Nuclei (Median) – Where and part of the auditory Serotonin (5-HT) is synthesized; system, aiding in the Mood regulation perception of sound) Somatic Motor Control (tone, balance, and posture – during body HINDBRAIN STRUCTURES movements), Also relays eye and ear signals to the cerebellum so that Metencephalon the cerebellum can integrate visual, auditory and motor coordination Pons: Connects various parts of the brain; regulates breathing and MEDULLARY PYRAMIDS sleep (parang tubo) Cerebellum: Coordinates - Bundle of fibers (Pyramid Tracts) voluntary movements and that decussate and continue down balance; integrates sensory input the spinal cord on the contralateral from the inner ear. side PONS Pyramidal Tracts: Lies on each side of the medulla (ventral and anterior). Corticospinal Tract: Movement of muscles of the Along with the medulla, contains the body reticular formation* and the raphe system.* Corticobulbar Tract: Facial Expression, Movement of the ○ *Descending portion: head, swallowing, phonation control motor areas of spinal and movements of the cord tongue. ○ *Ascending portion: sends output to much of the OLIVARY BODIES “Medullary Olives” or cerebral cortex, increased simply “Olives” arousal and attention - Pair of prominent oval structures that ○ *The raphe system also contain the olivary nuclei. sends axons to the forebrain Two parts: Works in conjunction to increase 1. Inferior Olivary Nucleus arousal and readiness of other parts (part of the olivo-cerebellar of the brain. system and is mainly involved in cerebellar Cerebellum motor-learning and function) A structure located in the hindbrain 2. Superior Olivary Nucleus with many deep folds. (considered part of the pons  Is also important for shifting attention FOREBRAIN STRUCTURES between auditory and visual stimuli Diencephalon MIDBRAIN STRUCTURES Thalamus: Acts as a sensory relay station, processing signals Mesencephalon from the body and transmitting Tectum (roof): Superior and them to appropriate cortical regions. inferior colliculi for visual and auditory reflexes. ❖ Massa intermedia – Joins both lobes. On the surface, Tegmentum: Houses cranial we can see the Lamina nerve nuclei and the substantia ❖ Composed of many nigra, important for movement different pairs of nuclei control. which project to the cortex ○ Substantia nigra: gives ❖ Internal Capsule – Fibers rise to the (corticospinal tracts) that dopamine-containing join the telencephalon to pathway facilitating the diencephalon. They readiness for movement carry motor information from the motor cortex Three colorful structures of Tegmentum downward. ★ Periaqueductal Gray = Gray matter Hypothalamus: Regulates autonomic functions: eating, situated around the cerebral drinking, sleep, and sexual aqueduct behavior. Influences the endocrine ○ Mediates the analgesic effect system via the pituitary gland. of opiate drugs ❖ Optic Chiasm – Where ★ Substantia Nigra = Eye-movement, the nerves from the eyes motor planning, reward-seeking, decussate learning, and addiction (mediated by ❖ Mamilliary bodies – the striatum) Spherical nuclei which has a role in recollective ★ Red Nucleus – Vestigial in primate memory brains, = Motor Coordination (crawling in babies and arm Circuit of midline structures that circle swinging in walking) the thalamus: a. Limbic System Involved in emotional regulation and memory; includes structures like: ○ amygdala (fear, emotional memory)  ○ hippocampus (memory The ventricles are four fluid-filled storage) cavities within the brain containing ○ cingulate cortex (emotion cerebrospinal fluid. and behavior modulation). ○ Fornix – Function is not FOREBRAIN STRUCTURES entirely sure but correlates well with Recall Memory Telencephalon (Cerebral Cortex) ○ Septum Pellucidum – The largest part of the human brain, responsible for higher cognitive functions. Anatomical Barrier yet real function remains unclear. - Includes the olfactory Large furrows are called fissures bulb, hypothalamus, Small ones are called sulci; hippocampus, Ridges between fissures and sulci amygdala, and are called gyri. cingulate gyrus of the cerebral cortex Longitudinal fissure – Divides both hemispheres. Inside, cerebral - associated with commissures connect both motivation, emotion, hemispheres. drives and ○ The largest commissure is aggression. the corpus callosum. b. Basal Ganglia divided into two halves Involved in the control of voluntary joined by two bundles of axons motor activity: called the corpus callosum and the ○ Striatum (Caudate and anterior commissure. Putamen): Planning, learning and execution, motor ○ Lobes of the Cerebral preparation, specifying Cortex: amplitudes of movement, 1. Frontal Lobe: and movement sequences. Involved in reasoning, planning, speech ○ Globus Pallidus: Regulates production (Broca’s movements subconsciously. area), and motor functions (precentral c. Canal System gyrus). The central canal is a fluid-filled 2. Parietal Lobe: channel in the center of the spinal Processes sensory cord. information (postcentral gyrus,  superior parietal 2. Angular Gyrus – Receives visual lobule). information 3. Temporal Lobe: Broca’s Area – Speech Production Involved in auditory (ONLY FOUND ON LEFT) processing (Heschl’s gyrus) and language Wernicke’s Area – Language Comprehension (ONLY FOUND ON comprehension LEFT) (Wernicke’s area). Transverse Temporal Gyri of Heschl – 4. Occipital Lobe: Auditory Cortex Processes visual information. Superior Temporal Gyrus – Auditory processing, and social cognition FOREBRAIN STRUCTURES Middle Temporal Gyrus – Language processes Telencephalon (Cerebral Cortex) Inferior Temporal Gyrus – Visual Postcentral gyrus – analyze sensations Perception of the body Fusiform Gyrus – Object and Facial Anterior Paracentral Lobule – recognition Continuation of the precentral gyrus and concerned with somatosensation of distal Fusiform Facial Area – Recognition of limbs Facial Expression. Precentral Gyrus – Motor Function Superior and Inferior Occipital Gyri – Interpretation of visual stimuli Posterior Paracentral Lobule Precuneus – Innervation of the Cuneate Gyrus – Letters and analysis of contralateral lower extremities, and logical events control of defecation and urination. Lingual Gyrus – Recognition of words Gyrus Rectus/Orbital Gyri – Function is unclear and is viewed as primitive Long and Short Gyrus of the Insula – development but is linked with personality Sensation of Taste and Olfaction and hypersexuality with men. Cingulate Gyrus – Emotion and Superior Parietal Lobule – Behavioral Regulation Somatosensory Activity Parahippocampal Gyrus – Memory Inferior Frontal Gyrus – Speech Encoding and Retrieval production Dentate Gyrus – New episodic memory, Inferior Parietal Lobule – Divided into spontaneous exploration of novel Two Parts: environments 1. Supramarginal Gyrus – Integration of sensory information