Localization of Function in the Brain & Nervous System

A comprehensive set of Q&A flashcards covering nervous system organization, brain localization of function, language areas, neuron structure, neurotransmission, neurotransmitters, movement, emotion, spinal cord and disease basics.

What are the two main divisions of the nervous system and what do they include?

Central nervous system (CNS): brain and spinal cord. Peripheral nervous system (PNS): all nerves and ganglia outside the brain and spinal cord.

What are the two subdivisions of the Peripheral Nervous System (PNS)?

Somatic nervous system and Autonomic nervous system.

What does the Autonomic Nervous System regulate and what are its two divisions?

Regulates involuntary functions; Parasympathetic (rest and digest) and Sympathetic (fight, flight or freeze).

What are the major lobes of the cerebral cortex and their basic functions?

Frontal: planning, judgment, personality. Temporal: auditory processing, memory. Parietal: somatosensory, spatial processing. Occipital: visual processing.

Which areas are primarily involved in language processing?

Broca’s area (speech production) and Wernicke’s area (comprehension); Geschwind’s territory connects them.

Where is Broca’s aphasia located and what are its features?

Broca’s area in the left hemisphere; nonfluent speech, comprehension largely spared, awareness of deficit.

Where is Wernicke’s aphasia located and what are its features?

Wernicke’s area in the left hemisphere; fluent but meaningless speech, impaired comprehension, reading/writing often affected, lack of awareness.

What is Geschwind’s territory and its role?

Left-hemisphere region important for processing multiple properties of words (sound, visual form, meaning) and for abstract thinking; connects Broca and Wernicke.

What are the key components and functions of a neuron?

Dendrites/soma receive information; axon hillock initiates action potentials; axon transmits; synapse releases neurotransmitters; myelin and nodes of Ranvier speed transmission.

What happens at the presynaptic terminal during neurotransmission?

Action potential arrives; voltage-gated Ca2+ channels open; Ca2+ influx; vesicles fuse with membrane; neurotransmitters released into the synaptic cleft.

What happens at the postsynaptic membrane after neurotransmitter release?

Neurotransmitters bind receptors; can produce EPSP (depolarisation) or IPSP (hyperpolarisation).

What is the threshold for triggering an action potential?

Around −55 mV; if graded potentials reach this threshold, an action potential occurs.

What is the difference between Excitatory Post-Synaptic Potentials (EPSPs) and Inhibitory Post-Synaptic Potentials (IPSPs)?

EPSP depolarises the membrane increasing the likelihood of an AP; IPSP hyperpolarises decreasing the likelihood.

Name the major excitatory and inhibitory neurotransmitters discussed and their general roles.

Glutamate (Glu): major excitatory; GABA: major inhibitory.

What are the CNS and PNS functions of Acetylcholine (ACh)?

CNS: memory formation, attention, arousal; PNS: parasympathetic effects and skeletal muscle contraction; cholinergic dysfunction linked to memory impairment (Alzheimer’s).

Where is dopamine produced and what are its main roles?

Produced in the midbrain (substantia nigra) and hypothalamus; motor planning/execution, reward/motivation; loss linked to Parkinson’s disease.

What are the roles of Serotonin (5-HT)?

Regulates mood, aggression, appetite, sleep-wake cycles; also influences GI tract; effects depend on receptor subtype.

What is Epinephrine’s role in the body?

Hormone and neurotransmitter; sympathetic response: increases heart rate, bronchodilation, glucose production, pupil dilation; involved in stress response.

What is the cerebellum responsible for?

Planning and execution of smooth, coordinated movements; maintains posture; compares brain’s motor intent with actual performance and provides corrections.

What are the basal ganglia and the direct vs indirect pathways?

Basal ganglia regulate initiation/control of movement; direct pathway excites motor cortex to aid movement; indirect pathway inhibits motor cortex to suppress unwanted contractions.

What is the primary motor cortex and how is it organized?

Controls voluntary movements; primarily contralateral; organized as a motor homunculus with regions dedicated to body parts; more use → more cortical representation.

What is the limbic system and its five Fs?

Emotion, behavior, and memory system; the five Fs: Feeding, Fleeing, Fighting, Feeling, Fornicating; components include the thalamus, hypothalamus, hippocampus, amygdala.

What is the role of the thalamus?

Gateway for sensory input; relays information to cortical areas involved in sensory processing.

What is the role of the hypothalamus and the HPA axis?

Regulates hormones and autonomic responses; part of the HPA axis controlling stress response (fight or flight).

What is the role of the prefrontal cortex?

Higher-level cognitive functions: impulse control, planning, decision making, regulation of emotional responses.

What are the hallmark brain changes and symptoms in Parkinson’s disease?

Lewy bodies (α-synuclein) in substantia nigra; reduced dopamine; motor symptoms like tremor, rigidity, bradykinesia; treatment includes Levodopa and sometimes deep brain stimulation.

What is Levodopa and how does it help in Parkinson’s disease?

A dopamine precursor converted to dopamine in the brain; often given with carbidopa to reduce side effects; improves mobility.

What is deep brain stimulation in Parkinson’s disease?

Electrodes implanted in the basal ganglia to reduce involuntary movements and tremor.

What is Alzheimer’s disease and its main pathology?

Dementia with progressive memory loss and cognitive decline; β-amyloid plaques and tau tangles; cholinergic deficits; memory impairment.

What treatment can help mild to moderate Alzheimer’s disease and how does it work?

Cholinesterase inhibitors; increase acetylcholine by blocking its breakdown; may temporarily improve memory; not disease-modifying.

What are the two main types of spinal reflexes?

Monosynaptic (single synapse between sensory and motor neuron) and polysynaptic (involves interneurons and multiple synapses).

What is the basic spinal nerve organization and how many pairs are there?

31 pairs of spinal nerves; dorsal (sensory afferent) roots bring information to the CNS; ventral (motor efferent) roots carry commands from CNS to muscles.

Where is language processing located beyond Broca and Wernicke’s areas?

Geschwind’s territory in the left hemisphere; integrates sound and visual properties of words and supports abstract processing; connects Broca and Wernicke.

What are the visual pathways described as the ‘what’ and ‘where’ pathways?

What pathway (ventral stream) processes object identity (temporal lobe); Where pathway (dorsal stream) processes spatial location (parietal lobe).