Behavioral Neuro Midterm study guide

Structural divisions: 2

1. Central nervous system (CNS)

2. Peripheral nervous system (PNS)

Central nervous system

Composed of the brain and spinal cord. Responsible for processing, integration, and initiating responses.

peripheral nervous system

includes cranial and spinal nerves

-subdivided into somatic and autonomic systems

somatic system

voluntary control of skeletal muscles

autonomic system

involuntary control of smooth muscle, glands, viscera

divisions: sympathetic and parasympathetic

sympathetic division of autonomic NS

prepares body for emergency situations by increasing heart rate, dilating pupils, etc... (fight, flight, fear)

Parasympathetic System

maintains homeostasis and conserves energy (rest and digest)

Spinal cord function

serves as link between brain and body, mediates reflexes and simple motor functions (not higher cog)

Frontal lobe

Primary motor cortex (Area 4), premotor areas (6-8) for planning and initiation, executive functions, personality, speech (Broca's).

parietal lobe

Primary somatosensory cortex (Areas 3, 1, 2), superior parietal lobule for spatial awareness and constructional tasks.

temporal lobe

Auditory processing (Wernicke's area, Area 22), memory (hippocampus), emotion (amygdala).

occipital lobe

Area 17 (primary visual), Areas 18-19 (visual recognition)

left hemisphere lateralization and specialization

Language, analytical reasoning, sequential processing

right hemisphere lateralization and specialization

Pragmatics, prosody, visual-spatial functions, environmental orientation

Hemispheres lateralization and specialization

Hemispheres are equipotential at birth; specialization emerges by ~2 years

Contralateral organization: each hemisphere controls the opposite side

Topographical representation: specific cortical areas map to specific body regions

Functional networking: specialized yet integrated systems

Sensory-afferent

neuron cell bodies are in dorsal root ganglia (pseudounipolar)

dorsal pathways convey information (touch, proprioception)

dorsal horn processes sensory input.

motor-efferent

Ventral horn contains motor neurons

dermatomes

correspond to skin areas supplied by specific spinal nerves

Neuron structure:

• Dendrites receive signals; axon hillock initiates action potentials; axon terminals release neurotransmitters.

• Myelin (Schwann cells in PNS; oligodendrocytes in CNS) enables saltatory conduction.

• Nodes of Ranvier facilitate action potential propagation.

Electrical properties of neuron

• Resting membrane potential depends on high K⁺ inside and high Na⁺ outside.

• Irritability: ability to respond to a stimulus and generate an impulse.

• Conductivity: ability to transmit impulses.

• Absolute refractory period (~8 ms): neuron cannot refire.

Synaptic transmission

• Exocytosis: vesicles release neurotransmitters into the synaptic cleft.

• Neurotransmitters diffuse and bind to postsynaptic receptors, altering ion channels.

• Postsynaptic binding generates excitatory or inhibitory effects.

• Examples: acetylcholine at neuromuscular junction, receptor issues in myasthenia gravis, demyelination in MS.

Neuroplasticity

brain's ability to reorganize after injury

• Repeated motor/swallowing tasks strengthen synaptic efficacy (Hebbian learning).

• Underlies rehab for dysarthria, dysphagia, aphasia.

Limbic system (3)

amygdala

hippocampus

cingulate gyrus

amygdala

fear and aggression

part of limbic system

hippocampus

memory consolidation

part of limbic system

cingulate gyrus, thalamus, fusiform gyrus

emotion and recognition

part of limbic system

Visual processing pathways (2)

Dorsal-where: spatial location

ventral-what: object and face recognition

tactile agnosia

failure to recognize objects by touch

hemineglect

nondominant inferior parietal lesion

prosopagnosia

face recognition deficits

foramen magnum

transition point from brainstem

(hole in the base of the skull through which the spinal cord passes)

Spinal cord sections (5)

1. cervical

2. thoracic

3. lumbar

4. sacral

5. coccygeal

1. cervical section

slender gray matter and largest amount of white (all ascending/descending fibers pass through)

· Neck area- 12 SN

· Dorsal lemniscal column (gracilis and cuneatus)

· Corticospinal

· Lateral column- spinothalamic and spinocerebellar

2. thoracic

enlarged white matter (more processing

· Torso, chest cavity, lung- 12 SN

· Fasciculus gracilis: discriminative touch from lower body

· Fasciculus cuneatus: discriminative touch from upper body

· Lateral corticospinal tract, Spinothalamic tract, spinocerebellar

3. lumbar

larger dorsal and ventral horn (serves leg movement)

· 5 SN

· Dorsal lemniscal- gracilis- fine touch, proprioception, vibration

· Lateral corticospinal tract- volunt. Info to limbs

· Anterolateral system: spinothalamic and spinocerebellar tracts

conus medullaris

tapered end of spinal cord

cauda equina (horse's tail)

roots of nerves that extend from the end of the spinal cord

filum terminale

thin thread of fibrous tissue at end of conus medullaris, attaches to coccygeal ligament to stabilize

4. sacral

large proportion of gray matter (receive sensory)

· 5 SN

· Fasciculus gracilis- sensation from sacral to midthoracic level

· Lateral corticospinal tract- motor fibers

· Spinothalamic tract- pain, temperature (sensory)

5. coccygeal

1 SN

contralateral vs ipsilateral control

contralateral: opposite side

ipsilateral: same side

broadmann area: 4

primary motor cortex (precentral gyrus)

broadmann area: 44 + 45

broca's area association

associated w/ motor 4 (activate tongue, lips, expressive speech movement)

broadmann area 3,1,2

primary sensory cortex

broadmann area 41 +42

primary auditory cortex

broadmann area 22

wernicke's (superior temporal convolution)

associated w/ auditory 41+ 42 (receptive speech)

Broadmann area 17

primary visual cortex (occipital)

broadmann area 18, 19

occipital lobe

broadmann area 39, 40

39- angular gyrus

parietal lobe: reading, naming, writing

pseudounipolar neurons

a type of sensory neuron that has a single short process extending from its cell body (soma) which quickly splits into a T-shaped junction with two distinct axonal branches

bipolar neuron

a nerve cell that has a single dendrite at one end and a single axon at the other end

multipolar neuron

a neuron with one axon and many dendrites attached to its soma

saltatory conduction

signals travel quickly under myelin between nodes; speed depends on axon diameter and myelination

absolute refractory period

period of unresponsiveness; short but consistent- Na channels reset

exocytosis

release of substances out a cell by the fusion of a vesicle with the membrane.

postsynaptic receptors

The other side of the synapse. The neuron that contains receptors (usually on dendrites) ready to bind to the neurotransmitter released from the presynaptic neuron.

neuroplasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

functional networking

networks of neurons have special functions

topographical organization

location of peripheral sensory neuron maps directly onto specific cells in the cortex