Medulla, Pons and Midbrain

Vocabulary flashcards from the lecture on the Medulla, Pons, and Midbrain covering essential terms and definitions related to brain anatomy and physiology.

Medulla Oblongata

The lower half of the brainstem that connects the brain to the spinal cord, controlling vital autonomic functions such as heartbeat and respiration.

Pons

A structure in the brainstem located above the medulla, acting as a bridge between different parts of the nervous system and involved in regulating sleep and arousal.

Midbrain

The uppermost part of the brainstem, responsible for processing visual and auditory information, as well as controlling reflexes such as eye movements.

Ascending fibers

Sensory fibers in white matter carrying information to higher centers

Descending Fibers

Motor fibers in white matter transmitting signals from the brain to lower centers.

Cerebellum

The large, rounded structure located at the back of the brain, responsible for coordination of voluntary movements, balance, and motor learning.

Reticular Formation

A network of neural interconnected nuclei located throughout the brainstem that regulates arousal, sleep-wake cycles, and various autonomic functions.

Raphne System

A collection of nuclei located in the brainstem that produce serotonin and play a key role in regulating mood, arousal, and various other functions.

Locus Coeruleus

A small cluster of nuclei in the brainstem that is the primary source of norepinephrine, involved in arousal, attention, and the stress response.

Area Postrema (CTZ)

A region in the medulla oblongata that detects toxins in the blood and triggers vomiting as a protective mechanism.

Serotonin Systems

Involves: Norcortex, hypothalmus, temporal lobe, basal ganglia, thalamus, raphe nuclei, cerebellum

Primarily involved in mood, sleep-wake cycles, pain perception, and executive function

Norepinephrine Systems

Involves: norcortex, hypothalamus, temporal lobe, locus coeruleus, thalamus, cerebellum

Primarily involves in arousal, attention, and stress response.

Tegmentum

Contains: ventral tegmental area, substantia nigra, and regions involved in motor control and arousal.

Substantia Nigra

characterized by melanin-pigmented neurons, a major source of dopamine projection to basal nucleithat plays a crucial role in movement regulation and coordination. Dysfunction in this area is associated with Parkinson's disease.

Ventreal Tegmental Area

A group of nuclei located in the midbrain, significant for its role in the reward system, motivation, and the release of the neurotransmitter dopamine. It influences mood, arousal, and the perception of pleasure.

Pontomesencephalotegmental area

A region that includes portions of the pons, midbrain, and tegmentum, playing a vital role in regulating arousal, sleep-wake cycles, and attention. It integrates sensory processing and motor control.

Tectum

Includes: Superior and Inferior colliculus

Superior Colliculus 

A paired structure in the midbrain that is involved in visual processing and coordination of eye movements, playing a role in reflexive responses to visual stimuli.

Inferior Colliculus

A paired structure in the midbrain that is essential for auditory processing and plays a critical role in the localization of sounds and the reflexive responses to auditory stimuli.

Reticular Formation

The midbrain portion of the ascending reticular activating system

Periaqueductal Gray 

A region in the midbrain involved in pain modulation and defensive behavior, playing a key role in the processing of fear and anxiety responses.

Dopamine Systems

Involves: Frontal lobe, striatum, substantia nigra, ventral tegmental area

Nigrostriatal pathway

A critical dopamine pathway that connects the substantia nigra to the striatum, involved in the regulation of movement and coordination.

Mesolimbic pathway

A key dopamine pathway that extends from the ventral tegmental area to the limbic system, playing a central role in reward, motivation, and emotion regulation.

Mesocortical Pathway

A dopamine pathway that projects from the ventral tegmental area to the prefrontal cortex, important for cognition, executive function, and emotional regulation.

Tuberoinfundibular pathway

A dopamine pathway that connects the hypothalamus to the pituitary gland, regulating the release of prolactin and involved in endocrine function.

Reticular formation

is primarily facilitated by the nigrostriatal pathway, connecting the substantia nigra to the striatum, and is critical for coordinating voluntary movements.

Ascending Reticular Activating System (ARAS)

A network of neurons in the brainstem that regulates arousal, consciousness, and sleep-wake transitions through its connections to the thalamus and cortex.

Descending reticulospinal tract 

A pathway that carries motor commands from the reticular formation to the spinal cord, influencing posture and locomotion.

Tectospinal tract

A neural pathway that originates in the midbrain and coordinates head and eye movements in response to visual stimuli, facilitating reflexive actions. (extrapyramidal)

corticospinal tract

A major pathway that transmits motor commands from the cerebral cortex to the spinal cord, controlling voluntary movements. (pyramidal)

rubrospinal tract

A neural pathway that originates in the red nucleus of the midbrain and influences voluntary motor control, particularly for flexor muscles.

vestibulospinal tract

A neural pathway that originates in the vestibular nuclei and helps maintain balance and posture by influencing extensor muscle tone.

Olives

Proprioceptive infro from SC to cerebellum which plays a crucial role in motor coordination and balance

Inferior Cerebellar Peduncle

A structure connecting the medulla oblongata to the cerebellum, it facilitates communication between the spinal cord and cerebellum, playing a key role in balance and coordination.

Middle cerebellar peduncle 

A structure that connects the pons to the cerebellum, facilitating the transfer of information from the cerebral cortex to the cerebellum for motor control and coordination.

Superior cerebellar peduncle

A structure connecting the midbrain to the cerebellum, it transmits information from the cerebellum to the red nucleus and thalamus, aiding in motor coordination and planning.

What structure is brain stem responsible for speel

pons, which regulates sleep and arousal.

decusssation of the pyramids

A crossing of motor fibers in the medulla oblongata where many fibers from the cerebral cortex cross to the opposite side of the body, crucial for voluntary motor control.

decussation of medial lemnisci

A crossing of sensory fibers in the medulla oblongata that conveys somatosensory information to the thalamus, playing an essential role in sensory perception.

spinal trigeminal tract

A pathway that carries sensory information from the face to the brainstem, specifically processing pain and temperature sensations.

dorsal column-medial lemniscus 

A sensory pathway responsible for transmitting fine touch, vibration, and proprioceptive information from the body to the brainstem and then to the thalamus.

corticospinal tract

A major motor pathway that originates in the cerebral cortex and descends through the brainstem to control voluntary movements of the body by innervating spinal motor neurons.

corticobular tract

A motor pathway that connects the cerebral cortex to motor nuclei in the brainstem, controlling muscles of the face and neck.

rubrospinal tract

A descending motor pathway that originates in the red nucleus of the midbrain and contributes to the control of voluntary movements, particularly of the upper limbs.

reticulospinal tarct

A descending motor pathway originating in the reticular formation of the brainstem that plays a crucial role in regulating patterns of movement and maintaining posture and muscle tone.

vestibulospinal tract 

A descending motor pathway originating from the vestibular nuclei in the brainstem, responsible for maintaining balance and coordinating head and eye movements.

tectospinal tract

A descending motor pathway that originates in the superior colliculus of the midbrain, involved in reflexive head movements in response to visual stimuli.

spinothalamic tract 

A sensory pathway that transmits pain, temperature, and crude touch sensations from the body to the thalamus, playing a critical role in pain perception and sensory awareness.

spinal trigeminal tract 

A sensory pathway that transmits sensory information from the face, including pain and temperature, to the thalamus, playing a crucial role in facial sensation.

medial medullary syndrome

A condition resulting from occlusion of the anterior spinal artery, leading to contralateral hemiplegia, loss of proprioception, and sensory deficits on the opposite side of the body.

Lateral medullary syndrome

ipsilateral facial pain and tempurare loss, contralateral limb pain and temperature loss.

Lateral medullary syndrome

involves CN 5, 8, 9, and 10

medial medullary syndrome

involves CN 12

locked-in syndrome

bilateral lesions of the ventral roots, typically due to basilar artery occlusion. Loss of all motor except oculomotor and trochlear. Loss of trigeminal nerve

Weber Syndrome

characterized by contralateral hemiparesis and ipsilateral oculomotor nerve palsy, resulting from midbrain infarction.