Neuro Wk 5-Basal Ganglia

forming the walls of the longitudinal fissure

the corpus callosum, fornix, and septum pellucidum

the fornix connects the limbic circuitry and plays a key role in cognition and episodic memory recall

the cerebral cortex has layers: archicortex and paleocortex (3 layers) and neocortex (6 layers)

hippocampus, septum, and amygdala

they are important for the emotional aspects of behavior and memory

90%

in six horizontal layers, each differing by its neuronal density and architecture

they run from the cortex to lower parts of the brain and back, extend from one hemisphere to the other, and connect areas within the same hemisphere

several nuclear masses, including the caudate nucleus, putamen, and globus pallidus

near the internal capsule

the control of movements and posture

the cerebral cortex, diencephalon (thalamus and subthalamic nucleus), and substantia nigra (midbrain)

striatum (input) and globus pallidus (output)

caudate nucleus and putamen

the cerebral cortex, thalamus, and substantia nigra

the globus pallidus and substantia nigra

GABA (gamma-aminobutyric acid), which is inhibitory

it is considered part of the output portion of the basal ganglia and is the origin of most efferent fibers that project to other brain regions

helps initiate motor movement by exciting motor cortex neurons through a "double negative" mechanism involving GABA

prevents unwanted motor movements by inhibiting motor cortex activity through GABA signaling

dopamine produced by neurons in the substantia nigra influences striatal neurons, modulating motor pathways

glutamic acid is used to excite pallidal neurons in the globus pallidus

decreased movement (hypokinetic disorders) or increased movement (hyperkinetic disorders)

decreased dopamine production due to cell degeneration in the substantia nigra, leading to issues with motor movement, speech, cognitive-linguistic skills, and mood

levodopa (which increases dopamine synthesis) and deep brain stimulation (targeting the globus pallidus and subthalamic nuclei)

uncontrolled movements of the arms, legs, head, face, and upper body (choreiform movements), cognitive decline, and mood changes

a defective gene on chromosome 4 leading to abnormal brain function

slow, involuntary twisting and writhing movements, often affecting the upper limb and speech muscles, typically caused by a lesion in the globus pallidus

a violent form of dyskinesia characterized by forceful, jerky, and sudden movements of the arms and legs, often caused by a lesion in the subthalamic nucleus

involuntary muscle contractions that cause slow repetitive movements or abnormal postures

repetitive, jerking movements, especially of the face, neck, and tongue, often a side effect of antipsychotic medications

involuntary movements that occur as a side effect of treatment for Parkinson’s Disease

repetitive, sudden twitches, movements, or sounds known as 'tics'

controls basic life functions such as respiration, heart rate, blood pressure, and reflexes like coughing and swallowing, and contains pathways for sensory and motor signals between the brain and body

midbrain, pons, and medulla oblongata

involved in motor movements, auditory and visual processing, and contains cranial nerve nuclei for the oculomotor (CN III) and trochlear nerves (CN IV)

divided into two parts: the dorsal portion (tectum) and the ventral portion (tegmentum)

it consists of the superior and inferior colliculi, responsible for auditory and visual processing

it contains sensory pathways and controls functions like auditory and visual processing through the colliculi

it primarily contains motor pathways and controls functions like movement via the descending fibers in the corticospinal and corticobulbar tracts

part of the visual system, integrates visual and somatosensory input, and helps initiate orienting movements of the eyes and head toward objects in space

part of the auditory system, involved in ascending acoustic projections to the medial geniculate body of the thalamus

a motor pathway originating in the red nucleus of the midbrain, crossing over and descending in the lateral aspect of the spinal cord to control limb movements

relays signals from the forebrain to the cerebellum, and controls functions like sleep, hearing, equilibrium, respiration, swallowing, and facial movements

trigeminal nerve (CN V), abducens nerve (CN VI), facial nerve (CN VII), vestibulocochlear nerve (CN VIII)

the floor of the fourth ventricle, lateral recess, and the superior, middle, and inferior cerebellar peduncles

regulating autonomic nervous system functions such as respiration, heart rate, and vasodilation, and controlling reflexes like coughing, sneezing, and swallowing

glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve (CN XI), hypoglossal nerve (CN XII)

has two parts: an upper open part that forms the fourth ventricle and a lower closed part that continues into the central canal of the spinal cord

prominent longitudinal columns that run along the ventral surface, containing descending fibers from the corticospinal tract

the crossing over of corticospinal fibers (~75-90%) in the medulla, leading to contralateral control of movement

promotes arousal and consciousness, regulates the sleep-wake cycle, and controls visceral and movement functions

they contain sensory pathways (fasciculus gracilis and fasciculus cuneatus) that carry information to the brain

the ventral surface contains motor pathways, like the corticospinal tract, that control movement