HIGHER CORTICAL FUNCTION

Primary motor cortex function

precentral gyrus, frontal lobe, motor homunculus, initiates voluntary movement to skeletal muscle

Brodmann area 4

primary motor cortex

Primary somatosensory cortex function

postcentral gyrus, parietal lobe, sensory homunculus, receives sensory information about touch, pressure, pain, itch, temperature

Brodmann area 1, 2, 3

primary somatosensory cortex

brodmann area 44, 45

broca’s area in frontal lobe

Brodmann area 22

wernicke’s area

Pathway for pain and temperature

spinothalamic tract (perceived by primary somatosensory cortex)

Prefrontal cortex function

behavior and mental function

judgement

impulse control

personality

decision making

Right parietal lobe function

visuospatial relationships, navigate environment

Pathway for hearing

Sound waves → Cochlea (inner ear) → Auditory nerve (CN VIII) → Synapses at medulla oblongata → Inferior colliculi (midbrain) → Medial geniculate nucleus (thalamus) → Primary auditory cortex

Pathway for speaking

Thought formed in Wernicke’s area → Arcuate Fasciculus sends message to Broca’s area → Broca’s area plans speech → Plan sent to primary cortex → Motor cortex signals cranial nerves to move muscles (larynx, tongue, lips)

number of layers in cerebral cortex

6

Frontal eye field function

controls voluntary eye movement

Somatosensory association cortex function

interprets sensory info (texture, shape, etc.)

Visual areas function

receives (PRIMARY VISUAL CORTEX) and interprets (ASSOCIATION AREA) visual info in occipital lobe

auditory areas function

receives (PRIMARY AUDITORY CORTEX) and interprets (ASSOCIATION AREA) auditory info in temporal lobe

Olfactory cortex

smell, in temporal lobe

Gustatory cortex (+ brodmann area)

taste, in insula

Visceral sensory area

sensation from internal organs

Vestibular cortex

balance and equilibrium in parietal lobe

Posterior association area

aka posterior parietal cortex, integrates different senses,

Limbic system function

emotion and memory

Hemispheric Lateralization definition

• functional asymmetry

• concept that one side (or the other) of brain is specialized for function

Brodmann area 5

somatosensory association cortex

Brodmann area 6

premotor cortex, supplementary motor cortex

Brodmann area 9, 46

dorsolateral prefrontal cortex WITHIN the prefrontal cortex (motor planning)

Brodmann area 10

anterior prefrontal cortex (memory retrieval)

Brodmann area 17

primary visual cortex

Brodmann area 41, 42

primary auditory cortex

Brodmann area 37

occipitotemporal aka fusiform gyrus

Brodmann area 22, 39, 40

Wernicke’s area

Parietal lobe function

somatosensation, visuospatial processing

Temporal lobe function

hearing, smell, memory, language comprehension

Visceral sensation definition

conditions inside body, e.g. hunger, thirst, nausea

Primary areas general function

receive info

Pre areas general function

plan

association areas general function

perceive info

Broca’s area

1. Frontal lobe

2. Motor speech production (coordinates speaking muscles)

Wernicke’s area + location

1. Temporal lobe

2. Language comprehension

Pathway for proprioception

dorsal column-medial lemniscal pathway

Left hemisphere

1. Analytical thought

2. Language

3. Logic

4. Arithmetic

Right hemisphere

1. Visuospatial 

2. Art

3. Facial recognition

4. Intuitive

5. Music appreciation

Corpus callosum

1. Largest commissural tract

2. Information between left and right cerebral hemisphere

3. Object shown to right   

Association areas (4)

1. Prefrontal cortex (anterior) 

2. Posterior parietal cortex (posterior)

3. Limbic 

4. Variational occipitotemporal 

connects sensory and motor areas, and which is thought to be concerned with higher mental activities.

Limbic system parts

1. Cingulate gyrus

2. Hippocampus

3. amygdala

4. Some part of hypothalamus and thalamus

Perception of hemispheres

1. Left FOV (‘fov’ different from eye) perceives info in right brain, vice versa

2. Left brain can name object, but right brain recognizes the object e.g. sees and recognizes I.N (right brain) → ‘that’s the love of my life’ (left brain)

Hippocampus

1. Forms new memories

2. Converts STM to LTM

Cerebellar processing

1. Cerebellum receives info from: 

   1. Premotor cortex - Plans movement

   2. Brainstem nuclei - Info about proprioception, balance

   3. Proprioceptors - Sensory feedback from actual movement

2. Compares intended movement with actual movement 

3. Correction

4. Signal sends to motor cortex (via thalamus) to fine-tune motor command

5. Brainstem nuclei adjusts posture, balance

‘U’ shaped fibers

Short association fibers

Interhemispheric communication

communication between both cerebral hemispheres

working memory definition

1. made in prefrontal cortex (dorsolateral pfc)

2. ‘task associated’ memory, active storage (holds and uses info at same time)

3. seconds to minutes

short term memory

1. lasts for few seconds

2. passive storage—holds information only

3. swift electrical and chemical signals between cells

4. made through long term potentiation

long term memory

1. days, years, lifetime

2. more synaptic connection

corticobulbar tract

head face neck movements through cranial nerves, axons project from cortex and terminate in brainstem

examples of direct pathways

• ALL DIRECT PATHWAYS ARE DESCENDING MOTOR

• corticospinal - DIRECT

• corticobulbar - DIRECT

indirect descending pathway, function, example

• involuntary, automatic movement, coordination, posture, balance

• e.g. reticulospinal, vestibulospinal, rubrospinal

• ‘extrapyrimidal’

• originates from brainstem nuclei

• descending pathways ends with ‘spinal’

direct descending pathway + function

• fine, skilled voluntary movement (limbs, hands, fingers)

• e.g. lateral corticospinal tract

• directly from cerebral cortex to spinal cord with fewer synapses

primary auditory cortex location

• in superior temporal gyrus

• broddmann area 41, 42

• within heschl’s gyrus

projection from (origin), termination, synapsing on (type of neuron at destination that receives the signal): CORTICOSPINAL

1. primary motor cortex

2. ventral horn of spinal cord

3. lower motor neurons

projection from (origin), termination, synapsing on (type of neuron at destination that receives the signal): INDIRECT DESCENDING PATHWAYS: RETICULOSPINAL, VESTIBULOSPINAL

1. brainstem nuclei

2. ventral horn of spinal cord

3. interneurons, lower motor neurons

projection from (origin), termination, synapsing on: SPINOTHALAMIC

1. sensory receptors to spinal cord

2. ventral posterior nucleus in thalamus (axons in thalamus then project to cortex, but the pathway itself ends at thalamus)

3. tertiary sensory neurons

projection from (origin), termination, synapsing on: DORSAL COLUMN-MEDIAL LEMNISCAL

1. sensory receptors to dorsal column

2. ventral posterior nucleus in thalamus

3. tertiary sensory neurons

projection from (origin), termination, synapsing on: CORTICOBULBAR

1. primary motor cortex

2. brainstem at motor cranial nerve nuclei

3. lower motor neurons

where do descending motor tracts terminate?

ventral horn of spinal cord or brainstem nuclei

where do ascending pathways terminate?

thalamus

first order neuron + function, location

1. sensory

2. connects sensory receptor to CNS

3. cell body within DRG

interneuron + function, location

1. connects 2 neurons in CNS

2. only in CNS (scattered)

3. response to sensory input, creates reflexes, integrates info

lower motor neuron + location, synapses with

1. motor

2. ventral horn/brainstem motor nuclei

3. synapses with skeletal muscle fibers

most sensory neurons are what type of neuron

pseudounipolar

tertiary neuron + function, location

1. ascending

2. connects thalamus to specific region of sensory cortex

3. carries sensory info to cortex

4. located in thalamus

second order neuron

1. ascending

2. connects CNS to thalamus

3. found in spinal cord or brainstem (e.g. dorsal horn or nucleus gracilis/cuneatus)

4. **AXONS DECUSSATE TO OTHER SIDE