IBN week 9

What is the primary role of the inferior temporal cortex (ITC) in visual processing?

Recognizing complex shapes and objects

What does shape constancy allow you to do?

Recognize an object despite changes in viewing angle, size, or position

What is visual agnosia?

An inability to recognize objects despite relatively normal basic vision

Prosopagnosia is most closely associated with damage to which brain area?

Fusiform gyrus

Which pathway is most important for identifying objects?

Ventral visual pathway

Which brain area is especially important for visual motion perception?

MT/V5

Motion blindness is most likely associated with damage to which area?

MT/V5

A person with damage to V1 reports seeing nothing but can still guess the direction of a moving object above chance. What is this called?

Blindsight

Which areas help combine sensory information with motor information?

Association cortical areas

Which statement best distinguishes the ventral and dorsal visual pathways?

Ventral processes object identity; dorsal helps process spatial information and guide action

Ian Waterman could move his muscles, but he struggled to move normally after losing what?

Sensory feedback needed to know where his body was

Which statement best describes the hierarchy of motor control?

Higher brain areas influence lower centers, which ultimately control muscles

Which type of muscle controls movement of the body in relation to the environment?

Skeletal muscle

What is a motor unit?

A motor neuron and all the muscle fibers it innervates

Which arrangement supports the finest motor control?

One motor neuron innervates relatively few muscle fibers

Which neurotransmitter is released at the neuromuscular junction?

Acetylcholine (ACh)

What do extrafusal muscle fibers do?

Perform the force-producing work of skeletal muscles

Intrafusal muscle fibers are found inside which structure?

Muscle spindles

What does proprioception tell you?

Where your body parts are and how they are moving

Which receptor detects muscle stretch or length?

Muscle spindle

Which receptor detects muscle tension or force?

Golgi tendon organ

What is the role of gamma motor neurons?

Control the sensitivity of muscle spindles

What is the main function of the corticospinal (pyramidal) tract?

Support fine voluntary movements, especially of the hands and fingers

Why does the left motor cortex generally control the right side of the body?

Most corticospinal axons cross at the medullary pyramids

What is a major role of the extrapyramidal pathways?

Maintaining posture, muscle tone, and coordinated movement

Which tract helps control posture through trunk and leg muscles?

Reticulospinal tract

Which tract uses vestibular information to stabilize the head and adjust posture?

Vestibulospinal tract

Where is the primary motor cortex (M1) located?

Precentral gyrus of the frontal lobe

What does the motor homunculus demonstrate?

The amount of motor cortex devoted to different body parts varies with control demands

Which area is especially involved in movements guided by external cues?

Premotor cortex

Which area is particularly associated with internally generated movement sequences?

Supplementary motor area (SMA)

What is the general pathway of the basal ganglia motor loop?

Cortex → basal ganglia → thalamus → cortex

Which two structures together form the striatum?

Caudate and putamen

What happens in the basal ganglia's basic movement-selection mechanism when the striatum inhibits the globus pallidus output neurons?

The thalamus can be released from inhibition, facilitating selected movements

Which neurotransmitter-producing neurons are lost in Parkinson's disease?

Dopamine neurons in the substantia nigra

Which is a typical symptom of Parkinson's disease?

Tremor at rest, rigidity, and slowed movement

Why can L-DOPA improve symptoms of Parkinson's disease?

It acts as a precursor to dopamine

What is the cerebellum's main role in movement?

Coordinating timing, precision, and error correction

A person has a clumsy gait and poorly timed movements after brain injury. Which structure may be damaged?

Cerebellum

Which cells are the only output neurons of the cerebellar cortex?

Purkinje cells

What is the role of granule cells in the cerebellum?

Their parallel fibers provide input to Purkinje cells

Which comparison between the basal ganglia and cerebellum is most accurate?

Basal ganglia help select and initiate actions; cerebellum fine-tunes timing and accuracy

Which structure sends cerebellar output toward motor cortical areas through the thalamus?

Deep cerebellar nuclei

A person can perform a movement but struggles to start a self-initiated action. Which system is especially relevant?

Basal ganglia

Which statement about M1 neurons is most accurate according to your notes?

They can become active before movement and encode movement-related parameters