Lec 6: Sensory and Motor Systems Flashcards

Vocabulary flashcards covering sensory systems (vision, audition, somatosensation, taste, smell, perception) and motor systems (cortical control, movement lexicon, subcortical structures, and spinal tracts) from Lecture 6.

Sensation

The detection of physical or chemical energy (constancy or changes) in the environment and its transduction into neural codes.

Perception

The conscious, subjective interpretation of sensations by the brain, influenced by past experiences, emotions, and context.

Receptors

Specialized sensory cells that transduce environmental energy into action potentials and locate sensory events via receptive fields.

Rapidly Adapting Receptors

Sensory receptors that detect changes in environmental energy or stimulus state.

Slowly Adapting Receptors

Sensory receptors that detect constancy in environmental energy or stimulus state over time.

Neural Relays

Interconnected pathways of usually 3 to 4 neurons that convey sensory signals, determine motor responses, and allow signal modification or behavior induction before reaching consciousness.

Rods

Photoreceptors on the retina responsible for black-and-white vision.

Cones

Photoreceptors on the retina responsible for color vision, which are most densely concentrated in the fovea.

Fovea

The central region of the retina characterized by a high density of color-detecting cones and a rod-free area.

Geniculostriate Pathway

The major visual pathway responsible for conscious perception of visual information, routing from the retina through the lateral geniculate nucleus (LGN) of the thalamus to the striate cortex.

Tectopulvinar Pathway

An alternate visual pathway routing through the superior colliculus of the midbrain to the pulvinar region of the thalamus and on to temporal and parietal lobes; sufficient to locate and orient to objects.

Basilar Membrane

A structure in the cochlea lined with auditory hair-cell receptors; its narrow, thick base responds to high frequencies and its wide, thin apex responds to low frequencies.

Tonotopic Organization

The spatial arrangement in the primary auditory cortex (A1) and basilar membrane where specific frequencies map to designated physical locations.

Nociception

The somatosensory subsystem responsible for processing pain, temperature, and itch.

Hapsis

The somatosensory subsystem responsible for tactile perception and fine touch.

Proprioception

The somatosensory subsystem that provides perception of the location and movement of body parts.

Vestibular System

The sensory organ system located in the inner ear (comprising semicircular canals and otolith organs) that mediates balance and orientation.

Sensory Homunculus

A anatomical neural map in the primary somatosensory cortex where larger cortical regions correspond to body parts with greater tactile sensitivity.

Gustation

The chemical sense of taste mediated by taste buds on the tongue, capable of detecting sweet, sour, salty, bitter, and umami tastes.

Olfaction

The chemical sense of smell mediated by receptor hair cells, supporting cells, and basal cells located on the olfactory epithelium in the nasal cavity.

Synesthesia

A perceptual condition occurring in approximately $4\%$ of the population in which distinct sensations mix, such as associating colors with letters, numbers, or sounds.

Gate Control Theory of Pain

A model of pain perception proposing that activation of fine-touch and pressure pathways can inhibit or reduce transmission along pain and temperature pathways at interneurons in the spinal cord.

McGurk Effect

A perceptual phenomenon where visual observation of a speaker's lip movements alters the auditory perception of an ambiguous speech sound.

Parietal Cortex (Motor Role)

The neocortical region that receives and integrates sensory information, sends goals, and initiates movement.

Prefrontal Cortex (Motor Role)

The neocortical area responsible for planning movements based on goals, context, and previous experiences.

Premotor Cortex

The cortical region, including the supplementary motor area, responsible for organizing and coordinating complex movement sequences.

Primary Motor Cortex (M1)

The neocortical area responsible for producing elementary or simple movements.

Movement Lexicon

A repertoire of pre-established movement patterns used by the motor system to compose complex behavioral actions.

Pincer Grip

A precise movement pattern using the thumb and index finger to pick up small items, serving as a key motor developmental milestone.

Basal Ganglia

Subcortical structures including the caudate, putamen, and globus pallidus that receive input from the cortex and substantia nigra to modulate movement force.

Hyperkinetic Symptoms

Unwanted involuntary writhing and twitching movements (dyskinesias) resulting from damage to the caudate and putamen, as observed in Huntington disease and Tourette syndrome.

Hypokinetic Symptoms

Difficulties in initiating voluntary movements resulting from the loss of dopamine input from the substantia nigra, characteristic of Parkinson disease.

Flocculus

A small horizontal lobe of the cerebellum that receives input from the vestibular system and regulates balance and eye movements.

Lateral Cerebellar Hemispheres

The outer regions of the cerebellar hemispheres specialized for controlling movements of the limbs and digits.

Corticospinal Tracts

Major efferent motor pathways originating in somatosensory, primary motor, and premotor cortices that descend to the spinal cord to move the limbs, digits, and body.

Corticobulbar Tracts

Effector neural tracts projecting from the motor cortex to the brainstem to control facial movements.

Lateral Corticospinal Tract

The portion of the corticospinal tract that crosses at the pyramidal protrusion to control movement of the limbs and digits.

Anterior Corticospinal Tract

The portion of the corticospinal tract that stays ipsilateral along the spinal cord to control muscles in the trunk and body midline.

Extensor Muscle

A muscle (such as the triceps) that acts to extend a limb away from the trunk of the body.

Flexor Muscle

A muscle (such as the biceps) that acts to flex or draw a limb toward the trunk of the body.