SENSORRY4PARTYROCKING
This ascending pathway is responsible for carrying sensory information about discriminative touch, vibration, and conscious proprioception from the body. Its first-order neurons are in the dorsal root ganglion , its second-order neurons are in the medulla , and its third-order neurons are in the VPL of the thalamus.
What is the Dorsal Columns-Medial Lemniscus pathway?
These are the two types of excitatory, glutamatergic afferent fibers that carry input to the cerebellum. One type originates from various sources like the spinal cord and pontine nuclei, while the other originates only from the inferior olivary nucleus.
What are mossy fibers and climbing fibers?
This limbic structure is essential for the formation and storage of declarative-type memory. It receives its main input from the entorhinal cortex and projects out via the fornix to the mammillary bodies.
What is the hippocampus?
This type of memory lasts for only seconds to minutes, is limited to about 7 bits of information, and can be maintained through rehearsal.
What is short-term memory?
This pathologic reflex, a classic sign of an upper motor neuron lesion, involves an extensor plantar response when the sole of the foot is stroked.
What is the Babinski Reflex?
This thalamic nucleus receives sensory information for discriminative touch and vibration from the face via the principal trigeminal system and for pain and temperature from the face via the spinal trigeminal system. The cell bodies for the third-order neurons of these pathways are located here.
What is the Ventroposteromedial nucleus of the thalamus?
These inhibitory, GABAergic neurons serve as the main and only output from the cerebellar cortex, projecting to the deep cerebellar nuclei to modulate their activity.
Originally, the Papez circuit proposed the hippocampus coordinated emotional expression. However, the circuit was later modified to show that this structure, not the hippocampus, is what actually coordinates the activity of the hypothalamus with cortical areas for emotional expression.
What is the amygdala?
This reinforcement system, containing the ventral tegmental area and nucleus accumbens, is critical for instrumental learning. Lesioning it can abolish self-stimulation and cause anhedonia.
What is the mesolimbic dopamine system?
This type of lesion is characterized by symmetrical, proximal weakness, normal deep tendon reflexes, and elevated creatine phosphokinase (CPK) and aldolase levels. A muscle biopsy is considered diagnostic.
What is a myopathy (a lesion of the muscle)?
A patient presents with a progressive, fluid-filled cyst in the central canal of their spinal cord. This condition, known as syringomyelia , damages the decussating fibers of the spinothalamic tracts in the ventral white commissure , leading to this specific sensory deficit at the affected spinal levels.
What is a bilateral loss of pain and temperature sensation?
A lesion in the vestibulocerebellar division (the flocculonodular lobe) would produce this sign, which is characterized by repetitive, uncontrolled eye movements, typically toward the side of the lesion.
What is nystagmus?
This is the largest component of the amygdala in humans. It receives sensory input and is responsible for attaching emotional significance to a stimulus before relaying that information to the central nucleus to generate autonomic responses.
What is the basolateral nucleus of the amygdala?
This brain structure, specifically its deep nuclei like the interpositus nucleus, is the critical site for the associative conditioning of basic motor reflexes, such as a conditioned eyeblink. Notably, the hippocampus is not involved in this specific type of learning.
What is the cerebellum?
A patient presents with weakness in their extraocular muscles and other high-use cranial nerves. An EMG shows a decrement in the compound muscle action potential with repetitive stimulation, the cardinal sign of this lesion location.
What is a neuromuscular junction (NMJ) lesion?
Following a spinal cord injury, a patient presents with ipsilateral loss of motor function, proprioception, and vibration below the lesion. The same patient also exhibits a contralateral loss of pain and temperature sensation below the lesion.
What is Brown-Séquard Syndrome?
A patient demonstrates an inability to perform rapidly alternating movements. This deficit points to a lesion in this specific functional division of the cerebellum, which is responsible for planning and executing skilled movements in a precise spatial and temporal sequence.
What is the cerebrocerebellum (lateral zone/hemisphere)?
A patient experiencing seizure activity in the temporal lobe might present with this specific collection of symptoms: a "dreamy state," olfactory or auditory hallucinations, and memory loss.
What are temporal lobe seizures?
This is a loss of memory for events that occurred prior to a brain injury
What is retrograde amnesia?
A patient presents with asymmetric distal weakness accompanied by significant muscle atrophy, hypotonic or "flaccid" weakness, and absent deep tendon reflexes. An EMG would likely show fasciculations.
What are the signs of a Lower Motor Neuron (LMN) lesion?
A patient presents with hoarseness and dysphagia , vertigo and nystagmus , loss of pain and temperature on the ipsilateral side of their face , and loss of pain and temperature on the contralateral side of their body. These symptoms are caused by a stroke affecting the posterior inferior cerebellar artery (PICA).
What is Wallenberg's Syndrome?
This autosomal recessive neurodegenerative disease is caused by a deficiency in the frataxin protein. Pathologically, it is marked by the atrophy of the spinocerebellar tracts and the dentate nucleus, leading to clinical features like progressive gait ataxia, muscle weakness, and absent tendon reflexes.
What is Friedreich's Ataxia?
A bilateral lesion of the amygdala can cause this syndrome, which is identified by a unique combination of tameness, psychic blindness (an inability to recognize the emotional importance of events), and a loss of sexual inhibition.
What is Kluver-Bucy Syndrome?
The famous patient H.M. had a bilateral lesion of his medial temporal lobe and hippocampus. This resulted in a complete inability to form new declarative memories (anterograde amnesia), yet his short-term memory and his ability to learn procedural tasks, like mirror tracing, remained intact.
What is the evidence that declarative long-term memory is a separate system from short-term and procedural memory?
A patient presents with weakness in the muscles of the lower face on one side, but they can still wrinkle their forehead on that same side. This pattern, known as a "central palsy," points to this specific type of lesion.
What is an Upper Motor Neuron (UMN) lesion (affecting the corticobulbar tract)?