Chapter 14: The Brain and Cranial Nerves

Reticular Formation

(Medulla oblongata) Gray and white matter with embedded Nuclei. Regulates autonomic functions. Has different centers that regulate breathing, cardiovascular, digestion... - contains Reflex Centers that receive input from cranial nerves/cerebral cortex and then control some of the peripheral systems

Cerebral Peduncles

(Midbrain) Nerve fiber bundles on lateral sides of midbrain. 1. Descending fibers to cerebellum 2. Descending motor command fibers

Primary Somatosensory Cortex

(Parietal Lobe) SENSORY area; post central gyrus.

Head injury to primary motor cortex...?

(Precentral Gyrus) Loss of voluntary movements controlled by the specific regions damaged.

Flocculonodular Lobe

(cerebellum) Lies above roof of fourth ventricle.

Purkinje Cell Layer

(cerebellum) The cerebellar cortex contains these huge, highly branched purkinje cells. They each receive input from up to 200,000 synapses. The Cerebellar nuclei in the arbor vitae relay information to these cells.

Arbor Vitae

(cerebellum) The internal white matter ("tree") inside the cerebellar cortex which connects the cerebellar cortex nuclei with Cerebellar Peduncles. It is where Cerebellar Nuclei are embedded which relay info to Purkinje cells.

Limbic Lobe

(cerebral hemisphere) Consists of the superficial gyri that curve along the corpus callous (connects two cerebral hemispheres). - Cingulate gyrus: superior - Parahippocampal gyrus: inferior portion - Dentate gyrus: posterior portion (includes hippocampus)

Superior colliculus and Inferior colliculus?

"Corpora Quadrigemina" Brainstem--> Midbrain --> Tectum (gray matter) --> Superior Colliculi (2): integrate VISUAL info Infere Colliculi (2): integrate AUDITORY info

Prefrontal Cortex

"Master switch" - Coordinates information relayed from all cortical association areas - Performs abstract intellectual functions (predict consequences of actions)

Vermis of Cerebellum

"worm" a narrow band of cortex separating left and right hemispheres

Primary Motor Cortex

(Frontal Lobe) MOTOR Area; Precentral gyrus; Includes neurons called Pyramidal cells what initiate voluntary motor command

Paraventricular Nucleus

(Hypothalamus) Secretes oxytocin

The Limbic System

Nuclei and tracts along border between cerebrum and diencephalon. Functions: 1. establishes emotional states 2. Links conscious functions of cerebral cortex with autonomic functions of brainstem 3. Facilitates memory storage and retrieval

Left Cerebral Hemisphere

Reading, writing, math Speech and Language (think wernicke and broca areas are on this hemisphere) Decision making

The cortexes of each Cerebral Hemisphere...

Receive somatosensory information (visual and sensory) from and sends motor commands to the OPPOSITE side of the body. *Correspondence between specific function and specific area of the cortex is not precise.

Midbrain

Regulates auditory and visual reflexes and controls alertness. - Tectum: roof of midbrain (Corpora quadregiemina) - Tegmentum: anterior to cerebral aqueduct (red nucleus and substance nigra)

Inferior Olivary Complex

Relay info (from red nucleus, other midbraincenters, and cerebral cortex) to the cerebellum about somatic motor commands. Most of the nuclei create the Olives (prominent olive-shaped bulges along the ventrolateral surface of medulla oblongata).

Which primary brain vesicle is destined to form the cerebellum, pons, and medulla oblongata?

Rhombencephalon (the bottom of the three primary vesicles) Primary vesicles: Prosencephalon, Mesencephalon, Rhombencephalon

Parkinson's Disease

Increased activity of basal nuclei - loss of dopamine (which inhibits the basal ganglia) - causes there to be more muscle tone and contraction so harder to move Treated by giving L-Dopamine (which will cross BBB) Experienced very differently among people.

Diecephalon

Integrates sensory info with motor commands. Includes the Epithalamus, Thalamus, Hypothalamus, Pineal gland

Thalamus

(diencephalon) - Filters and relays sensory information from spinal cord and cranial nerves to the cerebral cortex. - Relays info between basal nuclei and cerebral cortex - Separated into Left and Right by the third ventricle - Contains the Interthalamic Adhesion: a projection of gray matter that extends into the third ventricle on each side

What may the Hypothalamus be stimulated by?

(diencephalon) Functions as a control and integrated center. - Sensory info rom the cerebrum, brainstem, spinal cord - Changes in the composition of the CSF and interstitial fluid - Chemical stability in the circulating blood

Epithalamus

(diencephalon) Roof of diencephalon, superior to third ventricle. Interior portion contains Choroid Plexus. Posterior portion includes the Pineal Gland which makes melatonin (important for regulating sleep and reproductive functions)

Thalamic Nuclei

(diencephalon: thalamus) Relay sensory information to basal nuclei and cerebral cortex. 5 Groups: 1. Anterior nuclei: limbic system (emotions) 2. Medial nuclei: awareness of emotional states 3. Ventral nuclei: relay sensory info to cerebral cortex 4. Dorsal Nuclei: - Pulvinar nuclei (sensory) - Lateral Gesticulate body (visual)- send to occipital lobes - Medial Denticulate body (auditory)

Suprachiasmatic Nucleus

(hypothalamus) Regulates circadian rhythm

Supra-Optic Nucleus

(hypothalamus) Secretes ADH- antidiuretic

Drives

(hypothalamus) behavioral drives; Feeding, thirst, satiety centers

Pre-Optic area

(hypothalamus) regulates body temperature

Amygdaloid Body (Amygdala)

(limbic system) Acts as interface between the limbic system, cerebrum, and various sensory systems.

Hippocampus

(limbic system) Portion of the dentate gyrus of limbic lobe. Important in learning, and storage and retrieval of new long term memories.

Anterior nuclei of thalamus

(limbic system) Relay information from mammillary body to cingulate gyrus

Fornix

(limbic system) Tract of white matter that connects hippocampus with hypothalamus

Respiratory Rhythmicity Centers

(medulla oblongata) One of the 2 major reflex centers. It sets pace for respiratory movements. Includes cells that automatically depolarization to keep a basic rhythm (then centers in the Pons regulate it)

Cardiovascular Centers

(medulla oblongata) One of the 2 major reflex centers. The cardiac center regulates heart rate. The vasomotor center regulates blood pressure, controls blood flow (and through peripheral tissues)

Gracile and Cuneate Nuclei

(medulla oblongata: relay stations) For sensory areas of lower and upper limbs. Pass somatic sensory info to Thalamus. Tracts leaving the nuclei cross to OPPOSITE sides of brain at Decussation of Pyramids.

Solitary Nuclei

(medulla oblongata: relay stations) Receive visceral sensory information

Corpora Quadrigemina

(midbrain: Tectum) The two pairs of sensory nuclei. 1. Superior Colliculi- receives Visual inputs (from lateral gesticulate nucleus of thalamus)- controls reflex movements of eyes, head, neck, and trunk in response to visual stimulants. 2. Inferior Colliculi- receives Auditory inputs (from medulla oblongata and pons)- control reflex movements of head, neck, and trunk in response to auditory stimuli.

Red Nucleus

(midbrain: Tegmentum) Contains many blood vessels. Issues subconscious motor commands to upper limb position and background muscle tone.

Substantia Nigra

(midbrain: tegmentum) Pigmented gray matter (melanin); regulated activity in the basal nuclei. *Parkinson's: loss of neuronal activity in the substantial nigra--> loss of muscle tone

Broca's Area

(motor speech area) Speech production. Primarily associated with LEFT cerebral hemisphere like wernicke's area. Regulates patterns of breathing and vocalization. - If damaged; Can understand words but cannot speak. (stroke)

Apneustic and Pneumotaxic Centers

(pons) Control respiration; Adjust the activities of the respiratory rhythmicity centers in the medulla oblongata.

Visual Association area

(sensory association area) - Interprets activity in visual cortex

Somatosensory association cortex

(sensory association area) - Monitors activity in primary somatosensory cortex (recognizes touch)

Auditory association area

(sensory association area) - Monitors auditory cortex

Premotor Cortex

(somatic motor association area) 1. Coordinate learned movements 2. Involved in repetitive movement (involves cerebellum)

What would occur if damage to Basal Nuclei?

*think parkinson's* Difficulty starting voluntary movements, and decreased muscle tone.

What are the functions of the Limbic System?

- Establishing emotional states - Linking the conscious, intellectual function of the Cerebrum with the unconscious autonomic functions of the brainstem - Facilitating memory storage and retrieval

The Medulla Oblongata also includes Relay Stations long sensory and motor pathways...

- Gracile and Cuneate Nucleus: nuclei for sensory areas of the lower and upper limbs - Solitary Nuclei: receive visceral sensory information - Inferior Olivary Complex

Functions of Basal Nuclei?

- Subconscious control of skeletal muscle tone - Coordination of learned movements patterns (walking, lifting)

Pons

1. Sensory and motor nuclei of cranial nerves (V, VI, VII, VIII- 5-8). 2. Nuclei involved with Respiration (Apneustic and pneumotaxic centers) 3. Nuclei and tracts that process and relay info sent to/from cerebellum 4. Ascending, Descending, and Transverse pontine fibers

Functions of Hypothalamus

1. Subconscious control of skeletal muscle contractions 2. Control of autonomic function 3. Coordination of activities of the Nervous and Endocrine systems 4. Secretion of: ADH (vasopressin) and Oxytocin 5. Production of Emotions and behavioral drives: feeding, thirst, satiety centers 6. Coordination between voluntary and autonomic functions 7. Regulation of body temp 8. Control of circadian rhythms

Ataxia

A disorder of the cerebellum which causes a disturbance in muscular coordination. Caused by damage from Trauma or Stroke, or Intoxication.

Medulla Oblongata

All communication between brain and spinal cord pass through here. - Center for coordination of complex autonomic reflexes -Control of Visceral Functions - Involved with sensory info for BOTH Visceral and Somatic 3 Groups of Nuclei: 1. Reticular Formation (autonomic nuclei controlling visceral functions) 2. Sensory and motor nuclei of Cranial nerves 3. Relay stations along sensory and motor pathways 2 Major groups of Reflex Centers: 1. Cardiovascular Centers 2. Respiratory Rhythmicity Centers

Cerebellum

An automatic processing and coordinating center for patterns of muscular activity. It has a complex highly convoluted surface composed of gray matter (Cerebellar Cortex) The folia (folds) of the surface are LESS prominent than the folds of the cerebrum. The Primary Fissure separates the anterior and posterior lobes. Functions: 1. Adjust the postural muscles of the body 2. Program and fine-tune movements controlled at the conscious and subconscious levels. [The cerebellum receives proprioceptive (position) information from the spinal cord and monitors all proprioceptive, visual, tactile, balance, and auditory sensations received by the brain.]

Right Cerebral Hemisphere

Analyzes sensory information (touch, smell, sight, taste) Recognition of faces and voice inflections

Integrative Centers

Are in cortical lobes, both in cerebral hemispheres, specialize in processing different types of info - Receive info from association areas - Direct complex motor activities - Perform analytical functions - Analysis

Wernicke's Area

Area of cortex; language comprehension. Primarily associated with LEFT cerebral hemisphere. Receives info from sensory association areas and coordinates access to visual and auditory memories. - Damage to this area; Can speak normal but cannot understand the words

Transverse Pontine Fibers

Axons that link nuclei of pons with opposite cerebellar hemisphere. The middle cerebellar peduncles are connected to the transverse fibers which cross the anterior surface of the pons.

Caudate Nucleus

Basal Nuclei; subconscious adjustment and modification of voluntary motor commands

Lentiform Nucleus

Basal Nuclei; subconscious adjustment and modification of voluntary motor commands Putamen: lateral portion Globus Pallidus: medial portion

Claustrum

Basal Nuclei; thin layer of gray matter close to putamen

The cranial nerves associated with the Pons...

CN V, VI, VII, VIII (5-8); innervate the jaw muscles, anterior surface of face, lateral rectus of eye muscle, and sense organs of internal ear (vestibular and cochlear nuclei)

Commissures of white matter of the cerebrum

Commissures: Interconnect BETWEEN hemispheres -Corpus Callosum -Anterior commissure

Association Areas

Connected to sensory AND motor regions of cortex. Interpret incoming data or coordinate a motor response.

Hypothalamus

Contains centers involved with emotions and visceral processes that affect the cerebrum and parts of brainstem. Controls variety of autonomic functions and forms link between nervous and endocrine systems. - Mammillary Bodies: control reflex eating movements - Infundibulum: narrow stalk connecting hypothalamus to pituitary gland - Tuber Cinereum: between infundibulum and mammillary bodies, produces hormones that affect pituitary gland

Whats the Primary Function of the Cerebellum?

Coordinates rapid, automatic adjustments that maintain balance and equilibrium.

What cranial nerves of the sensory and motor nuclei are associated with the Medulla Oblongata?

Cranial Nerves VIII, IX, X, XI, XII (8-12); provide motor commands to muscles of pharynx, neck, and back. Also to visceral organs of thoracic and peritoneal cavities. CN VIII carries sensory info from receptors in internal ear. *Relay ASCENDING info from spinal cord to higher centers

What neurotransmitter does the Substantia Nigra nucleus secrete?

Dopamine; it regulates activity in the Basal nuclei (so it is related to Parkinson's) Midbrain: -Tectum (Gray matter): Superior and Inferior Colliculi - Tegmentum: Substantia Nigra and Red Nucleus

Association fibers of the white matter of the cerebrum

Fibers that interconnect areas in the SAME hemisphere. - Arcuate fibers: interconnect gyri - Longitudinal fibers: connect frontal lobe with other lobes

Hemispheric Lateralization

Functional difference between left and right cerebral hemispheres; each performs certain functions that are not ordinarily performed by the opposite hemisphere.

Which nuclei in medulla oblongata are responsible for relaying somatic sensory info to Thalamus?

Gracile and Cuneate Nuclei Medulla Oblongata: - inferior olivary complex - cardiovascular and respiratory rhythmic centers - Gracile and Cuneate nuclei - CN VIII, IX, X, XI, XII - Reticular Formation

What would occur if there was a blockage in the Interventricular Foramen?

Interventricular Foramen are the channels between the Third Ventricle and the Lateral Ventricles. This blockage could cause... - Hydrocephaly: build-up of fluids in the ventricles deep in the brain - Damage to and distortion of brain in adults

Cerebrum

Largest part of brain that controls conscious thought and intellectual functions. Processes somatic sensory and motor info. Made of Gray matter (Cerebral Cortex and basal nuclei) and White matter (deep to cerebral cortex around basal nuclei)

Projection fibers of white matter of cerebrum

Link cerebral cortex to diencephalon, brainstem, cerebellum, and spinal cord (they pass through the diencephalon). - Internal Capsule: all the ascending and descending projection fibers

Basal Nuclei of cerebrum

Masses of gray matter that are embedded in the white matter of cerebrum. Direct subconscious activities. - Caudate nucleus - Lentiform nucleus - Claustrum

Electroencephalogram (EEG)

Measures brain activity by observing the electrical patterns (brain waves)--> the electrical signals at synapses of neurons in brain - Alpha, Beta, Theta, Delta waves

Conscious perception of which sense would be affected by damage to the Temporal Lobes of the Cerebrum?

Olfactory and Auditory; Temporal Lobe: Auditory cortex (hearing), olfactory cortex (smelling), auditory association area Occipital Lobe: VISUAL Cortex, Visual association area Insula: Gustatory Cortex (taste)

Which area of the diencephalon would be involved in the secretion of Oxytocin?

Paraventricular nucleus of the Hypothalamus. Hypothalamus includes... - Paraventricular nucleus - Pre-Optic area: body temp regulation - Autonomic centers - Lateral Tuberal Nuclei: make inhibitory and releasing hormones - Mammillary bodies: feeding reflexes - Suprachiasmatic Nucleus: regulate Circadian rhythms - Supra-Optic Nucleus: produce ADH (antidiuretic)

What secretes Melatonin?

Pineal Gland!! (in diencephalon)

Central sulcus

Separates the Frontal lobe from Parietal lobe. Separates the Motor and Sensory Areas.

Which area acts as a filter for sensory info coming into the sensory cortex?

Thalamus

All structures of Limbic System

Thalamus (anterior nuclei) Hypothalamus (hypothalamic nuclei and mammillary body) Reticular Formation Limbic lobe (3 gyri) Fornix Amygdala Hippocampus

Cerebellar Peduncles

Tracts that link cerebellum with brainstem, cerebrum, and spinal cord leave the cerebellum as... Superior, Middle, and Inferior cerebellar peduncles