Nervous System Part 3: Cerebral Cortex Flashcards
Glistening white material on either side of the thalamus/lateral ventricles.
-Contains myelinated axons coming down out of the Motor regions of the brain.
-Also has fibers that travel up to the Thalamus
-Takes sensory info to cerebral cortex and motor info down from cerebral cortex
Internal Capsule
Separates the Right Hemisphere from the Left Hemisphere of the Brain
Median Longitudinal Fissure
Primary Motor Center.
Located between the Precentral Sulcus and the Central Sulcus.
-Originates most corticospinal tract motor fibers (brain fibers -> cross over at inf. Medulla -> project to end of spinal cord)
-Primarily responsible for Voluntary, Fine digital movement (mostly distal movement - hands/wrists)
Precentral Gyrus
Primary receiving area for (Somesthetic) General Sensation. Located behind the Central Sulcus.
-Relay fibers carrying general sensation project here first.
-Follows Homunculus Pattern
Postcentral Gyrus
Area 312
Postcentral Gyrus
Area 4
Precentral Gyrus
Deep in Median Longitudinal Fissure: Foot, Hip
Around curve: trunk, arm, HAND
Then, FACE, tongue, and Larynx
Motor Homunculus
An area just rostral to the Precentral Gyrus
-Responsible for movement of large proximal muscles.
-Follows homuncular pattern (view picture of Homunculus)
Premotor Cortex
Portion of premotor cortex that allows you to carry out single tasks by memory.
Ex: putting on a coat. Do it naturally.
-Facilitator of motor planning (plan out ahead of time what you’re going to do)
-Guided more by memory than by visual cues
Supplementary Motor Area
Area rostral to the Premotor Cortex/Supplementary Motor Area.
-Portion of the Cerebral Cortex that controls Voluntary extra-occular movement
-Eyes will move together at the same speed in the same direction.
Frontal Eye Field
Rostral to the Frontal Eye Field.
-The executive portion of the brain.
-Measurement of personality, problem solving, emotions/control, reasoning, decision making, memory, and anything unique about a person.
-Tells the rest of the brain what to do.
Prefrontal Area
-Pars Orbitalis: sits right over the orbit
-Pars Triangularis: triangular gyrus with apex pointed down and back
-Pars Opercularis: pothole looking, sits nearest to Precentral Gyrus
Inferior Frontal Gyrus
Pars Triangularis + Pars Opercularis.
-Drives motor speech
-Expressive aphasia: can’t talk
-Dominant on the left side in most people
“Broken Speech”
Broca’s Area
Median Longitudinal Fissure: Toes, feet
Around the curve: hip, neck, arm, wrist, hand (big, but not as big as motor)
Lateral Side: LIPS, face, teeth, jaw, tongue, pharynx
Sensory Homunuculus
Pain and Temperature
Tactile Senses:
-Fine touch (can you tell what you are touching) and pressure
-Stereognosis (can you pick up an object and be able to tell the shape of it without looking)
-2 Point discrimination (can you differentiate between 2 close points)
-Kinesthetic sense (conscious proprioception - can you tell where limbs are at all times)
-Vibration (can you feel vibration when a tuning fork is placed against bone)
General Sensation (Somesthesis)
Lateral Group of Thalamic Nuclei contains 2 Components:
-VPL (Ventral Posterolateral Nucleus)
-VPM (Ventral Posteromedial Nucleus)
Thalamus (General Sensory Nuclei)
Involved with general sensation fibers coming in from the body (trunk, extremities) that project to the relay nucleus of the thalamus.
VPL (Ventral Posterolateral Nucleus)
Involved with general sensation fibers coming off of the face and projecting to relay nucleus of the thalamus
VPM (Ventral Posteromedial Nucleus)
Dorsal to the Postcentral Gyrus
-Contains the General Sensory ASSOCIATION Areas
-Superior Lobule
-Inferior Lobule
-Precuneus
-Interparietal sulcus (separates superior from inferior).
Helps you make decisions and process different types of sensations that come into the brain that are being relayed up via the relay nuclei of the thalamus.
Parietal Lobe
Composed of the Supramarginal Gyrus and the Angular Gyrus
Inferior Parietal Lobule
Provides sensory tactile feedback to guide motor tasks.
-Carrying out a motor task requires sensory input to project into the motor system to tell it what to do.
-Provides texture discrimination input for motor tasks involving sensory feedback.
-Also has Speech comprehension area (Wernicke’s Area).
Supramarginal Gyrus
Processes and integrates speech to understand what someone is telling you
-Supramarginal Gyrus
Wernicke’s Area
Dyspraxia (Ideational or Ideamotor). Problem with interface between sensory and motor. Cannot process the tactile information, so can’t carry out the activity.
Receptive Aphasia (can talk ok, but can’t put words together = word salad)
Disorders of the Supramarginal Gyrus
A form of dyspraxia where you know what you’re supposed to do with an object, but you can’t do whatever it is.
Ex: you have a shirt, but you can’t remember how to put it on properly
Ideamotor