Somatosensory System
The somatosensory system includes the sensory modalities of touch, pain, temperature, and _________.
What is proprioception?
The decision to initiate a voluntary movement begins in this area of the brain involved in planning and selecting appropriate motor actions.
What is the prefrontal cortex?
This limbic structure plays a central role in consolidating information from short term memory to long term memory, spatial navigation, and linking emotions to memories.
What is the hippocampus?
The cerebellum is divided into three functional zones. The vermis controls axial muscle coordination, the intermediate zone controls limb movements, and the __________ controls complex motor planning and learning.
What are the lateral hemispheres?
The thalamus relays somatosensory information to this part of the cerebral cortex, located in the post-central gyrus.
What is the primary somatosensory cortex (SI)?
The ascending spinal pathway that transmits information about pain and temperature is called the __________ tract.
What is the lateral spinothalamic tract?
The large pyramidal cells located in Layer V of the primary motor cortex are also known as __________ cells and are responsible for initiating voluntary motor commands via the corticospinal tract.
What are Betz cells?
This limbic structure plays a role in fear conditioning, olfactory perception, and attaching emotional significance to stimuli.
What is the amygdala?
The cerebellum controls movement using these two types of control systems: one that adjusts movements during execution and one that uses sensory information to pre-plan movements.
What are feedback and feedforward systems?
The type of pain transmitted quickly by A-delta fibers, characterized by sharp, localized sensations, is called __________ pain.
What is fast pain?
These mechanoreceptors, located in the superficial dermis, respond to skin deformation and are especially sensitive to light touch and vibration.
What are Meissner’s corpuscles?
The corticospinal tract, which facilitates fine motor control, crosses at the pyramidal decussation in the medulla. Approximately what percentage of these fibers decussate to form the lateral corticospinal tract?
What is 85%?
This limbic structure helps drive the body's conscious response to unpleasant experiences, including pain, and plays a role in predicting and processing fear.
What is the cingulate gyrus?
This cerebellar nucleus, located laterally and linked to the lateral zone, plays a critical role in fine motor control and projects to the contralateral red nucleus and corticospinal tract.
What is the dentate nucleus?
This sensory area, located in the parietal lobe and labeled Areas 5 and 7, integrates input from the somatosensory cortex with motor and visual information.
What is the somatosensory association area?
These proprioceptive mechanoreceptors, found at musculotendinous junctions, inhibit muscle contraction when they detect excessive tension, thereby preventing injury.
What are Golgi tendon organs?
This descending brainstem tract, originating from the medial vestibular nucleus, splits bilaterally and descends to control head and neck movements by influencing muscles above the thoracic level (T6 and above).
What is the medial vestibulospinal tract?
These structures, which connect to the hippocampus via the fornix, play a crucial role in recollective memory.
What are the mammillary bodies?
A patient with cerebellar damage who struggles to smoothly reach for objects, often overshooting the target, may have this type of motor deficit.
What is dysmetria?
The dorsal column-medial lemniscus pathway transmits conscious proprioception, discriminative touch, and vibration sense to the brain and includes two fasciculi: the _________ and the _________.
What is the fasciculus cuneatus and fasciculus gracilis?
The sensory afferent neurons responsible for detecting rapid and sustained muscle stretch wrap around intrafusal fibers of the muscle spindle and are known as _________.
What are type Ia (annulospiral) and type II (flower spray) afferents?
These tracts control axial and proximal limb muscles to regulate posture and locomotion. The __________ facilitates flexion, while the __________ facilitates extension.
What is the lateral reticulospinal tract and medial reticulospinal tract?
This pathway connects the hippocampus to other brain regions and is crucial for memory formation and recall, particularly episodic memories.
What is the fornix?
The cerebellar cortex has three layers, including the Purkinje cell layer, which contains large, branching neurons that send __________ signals to the deep cerebellar nuclei.
What are inhibitory signals?
A lesion affecting only one side of the spinal cord, also known as Brown-Séquard syndrome (hemicord), results in the loss of touch and proprioception on the __________ as the lesion and loss of pain and temperature on the __________.
What is the ipsilateral side and contralateral side?