Physiology II - (Part 1) Higher Function of the Brain

What is the outer surface of gray matter than contains neuron cell bodies and is highly convoluted? Why is it so highly convoluted?

Cerebral Cortex

-- increases surface area of cortex

What are the "5" lobes of teh brain?

Frontal, parietal, temporal, occipital, insula

What fissure separates the frontal & parietal lobes? Separates parietal & occipital? Separates temporal from parietal/occipital?

Central sulcus

Parieto-occipital fissure

Lateral fissure

What lobe's main function is motor/efferent planning and execution, and is also involved in personality?

Frontal lobe

What lobes main function is sensory & sensory association?

Parietal Lobe

What lobe's main function is associated with vision/processing and has the primary visual cortex in the calcarine sulcus?

Occipital lobe

What lobe's main functions vary, involving sound, face recognition, language processing, emotion, memory, and learning?

Temporal Lobe

What type of the cerebral cortex is made up of 6 distinct layers of neurons? What percent of the cortex does this make up in humans?

Neocortex

-90%

Which layers has cortical neurons that receive signals (main input layer)? What type of cells are in this layer?

Layer 4 (internal granular layer)

Granular cells

Which cortical neurons communicate with other cortical neurons?

Granular cells

Which layer has cortical neurons that send large output fibers (main output layer)? What type of cells are in this layer?

Layer 5 (Internal pyramidal layer)

Pyramidal/Betz

What layer of the cerebral cortex is 3 layers of cells and involved in hippocampal formation? Which is 4-5 layers and involved in the olfactory cortex?

3: Archicortex

4: Paleocortex

What are three main association areas?

1) Prefrontal

2) Parieto-occipital-temporal

3) Limbic

To the posterior of the central sulcus, what type of information is predominant? Anterior to the sulcus?

Sensory information

- ex: somatosensory, proprioception, vision

Motor

- ex: planned motor, premotor

Which association area interprets incoming sensory information, providing meaning behind a stimuli (somatic sensation, visual, auditory, and olfactory)?

Parieto-occipito-temporal

What are 4 subareas of the parieto-occipito-temporal association?

1) spatial coordinates

2) language comprehension (Wernicke's)

3) visual language processing (reading)

4) Naming objects

T/F: Our somatosensory, association areas, and motor cortex are all very similar amongst humans.

FALSE

- Association areas have LOT of variability (based off life experiences)

What provides us with the ability to localize & process our own body parts, sounds, and visual stimuli? What association area is this a part of?

Spatial Coordinates

-- Parieto-occipito-temporal

What area provides us with the ability to comprehend language, and is the most important area for higher intellectual function?

Wernicke's

Why is Wernicke's area the most important area for higher intellectual function?

Majority of our experiences converted to language form

- memory & thoughts

Wernicke's area is located in which hemisphere? Wernicke's area is _____% larger at birth on this side.

Dominant hemisphere

- 95% on left side of people

50% larger on dominant side at birth

Loss/Damage to Wernicke's area results in what?

Fluent/Global Aphasia

What parieto-occipito-temporal association area is in the angular gyrus between the primary visual cortex and Wernicke's, and relay visual information of written words to Wernicke's to allow the ability to read?

Visual Language (Interpretative) Area

What would happen if the visual language (interpretive) area were damaged?

Difficulty interpreting visual language

- BUT, no problems with auditory processing of language

What parieto-occipito-temporal association area interprets both auditory and visual information? Which is learned through auditory input and which through visual input?

Area for naming objects

Names --> auditory

Qualities --> visual

What area has a general association function which integrates sensory information with deeper meaning and can also involve motor output in thought processes, motor planning, and working memory?

Prefrontal Association Area

T/F: The prefrontal association area is more defined that Wernicke's.

FALSE

When there is damage to prefrontal associations, what general deficit occurs? What are the 2 very important specific deficits?

Higher Intellectual Function Deficits

1) Decreased ambition/planning

2) Loss of purpose

Elaboration of thought, the ability to take multiple sources of info and analyze them, and plan a course of action (mentally & physically) is associated with what area?

Prefrontal Association area

The prefrontal association area has extensive communication with what association area?

Parieto-occipito-temporal association area

What part of our memory involved with prefrontal association area keeps track of multiple pieces of information and allows for a deeper understanding, such as making plans possible, altering conscious action, considering consequences, and solving complex problems?

Working Memory

What ability do humans have that other animals do not, involving sensory and motor?

Communication

Complex communication requires the coordination between what areas? (5)

1) Primary auditory/visual cortex

2) Wernicke

3) Prefrontal association area

4) Broca's

5) Primary Motor cortex

What association area has a general association function concerned with emotion, motivation, and behavior, providing context for emotion?

Limbic Association Area

What system is the limbic association area a part of? Where does it communicate with?

Part of complex limbic system

- communicates with many areas of cortex and deeper structures of brain

What part of the limbic association area has 2 connected portions involved in communicating with the primary visual cortex (visual - occipital portion) and with limbic system (emotion - temporal portion) to overall relay specific facial visual stimuli to limbic system for emotional meaning?

Area for Recognition of Faces

Damage to the area for recognition of faces can result in what?

Prosopagnosia

T/F: Thoughts result from a pattern of stimulation in many parts of the brain and is not limited to a specific isolated region.

TRUE

What are some ways to improve study habits? (7 --> but don't dwell on this)

- 20-30 min study session

- reward studying

- dedicated study area

- learn actively (recall not recognize)

- good notes

- teach what you learn

- mnemonics (acronyms, coined sayings, image association)

How long does short term memory last? Intermediate term? Long-term?

STM: Few seconds to few minutes

Intermediate: minutes to few weeks

LTM: permanent (structural changes within neurons)

What details does our body struggle with to remember?

Monotonous details; our brain can't possibly remember everything

What is the inhibition of synaptic pathways for inconsequential information?

Habituation

What is the facilitation/enhancement of synaptic pathways for consequential input (pain/plessure)?

Memory Sensitization

Typically, consequential experiences such as what 3 things can be stored for longer?

1) emotional

2) positive

3) negative

What is a conscious memory involving details of important experiences, surroundings, time, causes, meaning, conclusions?

Declarative (Explicit) memory

What type of declarative (explicit) memory involves personal experiences?

Episodic memory

What type of declarative (explicit) memory involves factual information?

Semantic memory

What type of memory is subconscious and involves motor activities, learned skills, hand-eye coordination, and emotional responses?

Reflexive (implicit) memory

What is the conversion of STM to LTM due to the information having repetition, rehearsal, or meaning?

Consolidation

What is the mechanism of STM?

Circuits of reverberating neurons; when cease to be active, we don't remember

What type of memory is eventually lost unless consolidated into LTM through continued activity, importance, & meaning, and lasts several minutes to weeks?

Intermediate Memory

What is the mechanism of Intermediate memory?

Temporary chemical or physical changes at synapses

What allows continued strength of sensory/memory pathway?

Facilitation

What is the loss of signal strength over time for insignificant events?

Habituation

What pathway allows for pre-synaptic facilitation of sensory pathways in intermediate memory, and is required to keep a sensory pathway signal strong?

Facilitator pathway

NOTE: nothing permenant; temporary

What is the progressive closure of Calcium channels at the sensory axon terminal, decreasing NT release and decreasing signal strength?

Molecular Habituation

What is the release of serotonin by the facilitator pathway, causing a cascade, blocking potassium channels (cannot leave cell temporarily), & prolonging the action potential?

Molecular Facilitation

What type of memory is able to last an entire lifetime since they have been consolidated, and can be selectively recalled by conscious mind?

Long-Term Memory

What is the mechanism of LTM? What are 2 ways this mechanism works?

Actual STRUCTURAL changes

1) Increase NT released (vesicles & release sites)

2) Change structure of dendritic spines (increase # receptors & stronger synapses)

NOTE: permanent change

What is the "use it or lose it" principle?

First few years of life are a time where neurons are in ecess and must make connections to other neurons/glands/muscles

- Neurons may even be lost if no connection made

What can negatively affect consolidation? (2)

1) Concussions

2) General anesthesia

What type of memory is when similar information is grouped, new and old information has to be sorted, and new memories are actually processed to be stored in direct association with old memories?

Codified memories

What is the "physical location" for long term memory storage due to it being the destination and most important origin of reward/punishment signals? Where is it located?

Hippocampus

-- located in most medial portion of temporal lobe cortex

What is the classic circuit involving the hippocampus & structures of the limbic system involved in learning, memory, and emotion?

Papez Circuit

What is the sequence of the Papez Circuit?

Hippocampus -->

Fornix -->

Mammillary Bodies of Hypothalamus -->

Mammilo-thalamic tract -->

Thalamus -->

Cingulate gyrus of limbic lobe

Why is the fact the hippocampus is involved with reward/punishment important when it comes to LTM storage?

Importance of meaning and emotion behind memory storage

What type of amnesia is due to damage of the hippocampus, where there is a loss of ability to store NEW declarative memories in LTM, but past memories are typically intact?

Anterograde Amnesia

What type of amnesia is due to damage of the hippocampus OR thalamus, where this is a loss of recent memories? What does this imply about the function of the thalamus?

Retrograde amnesia

-- implies thalamus important in retrieval/recall of past memories

95% of people have a dominant _____ hemisphere?

Left

Wernicke's area is 50% larger on which side? Where is Broca's area dominant? Where is hand skills area dominant in 90% of individuals?

Left, Left, and LEFT

The nondominant hemisphere (Right), is important for everything else (ex: music, art, nonverbal communication, visual patterns, spatial relations) except what?

Language

What is the large structure responsible for bidirectional communication between the majority of the cerebral hemispheres?

Corpus Callosum

What are the small structures responsible for communication between the anterior temporal lobes and in the amygdala as part of limbic system (emotional connections)?

Anterior commissures

When a person with a cut corpus callosum is asked to raise their right and left arm, what happens?

Only able to raise right, not left

-- sound/language processed on left side (Wernicke's sent to left motor cortex and right hand raised)

Subconscious mind is controlled by what two areas of the brain?

Reticular formation & limbic system

What is the reticular activating system (RAS)?

series of neurologic circuits in the brain that control the functions of staying awake, paying attention, and sleeping

The RAS receives signals from __________, where orexin will release neurons and activation of the cerebrum can occur.

lateral hypothalamus

Which of the 2 ways of cerebrum activation via Reticular Activating System is direct stimulation of background neuronal activity throughout the brain?

Generalized

Which of the 2 ways of cerebrum activation via Reticular Activating System is activation of neurohormonal systems that facilitate or inhibit specific areas of cerebrum through hormone-like neurotransmitters

Specific

What part of the generalized Reticular Activating System is located in the Pons & Midbrain, and projects to the thalamus where signals distributed widely?

Bulboreticular faciliatory area

What neurotransmitter is used in the Generalized Reticular Activating System? How long does the signal last?

Acetylcholine (ACh)

-- lasts only miliseconds

What type of signals does the Specific Reticular Activating System release? How long does the signal last?

Neurohormonal signals from nuclei of the reticular activation system release several NT (which can be inhibitory or stimulatory)

- Longer lasting (minutes to hours)

What is the only nuclei of the Specific Reticular Activating System is inhibitory?

Nuclei of the raphe (serotonin)

What neurohormonal signals of the Specific Reticular Activating System are stimulatory? Where do they originate? Is their activity diffuse?

Norepinephrine

Originate in locus coeruleus; diffuse area of activity

Acetylcholine

Originate in gigantocellular nucleus

What neurohormonal signals of the Specific Reticular Activating System is inhibitory? Where does it originate? Where does it act on?

Serotonin

- originates in raphe nuclei

- acts on diencephalon and inhibits pain in spinal cord (enkephalins)

What neurohormonal signal of the Specific Reticular Activating System is both inhibitory and stimulatory? Where does it originate? Where does it act on?

Dopamine

- originates in substantia nigra

- acts on Caudate & Putamen of basal nuclei

- stimulatory in hypothalamus & limbic system (emotion & motivation)

Which drug will stimulate brain activity by counteracting adenosine receptors which facilitate sleep, increasing excitability and reducing threshold?

Caffeine

Which drug will inhibit brain activity by decreasing excitability of neurons and increase threshold by making neurons less responsible to excitatory agents?

Anesthetics

What is the sensory function of the Reticular Activating System?

Reticular formation receives incoming info (pain) & sends to thalamus and cortex

T/F: There is a negative feedback loop between the RAS & Cortex.

FALSE

Positive feedback loop

(NOTE: This may help establish memories by activating these back and forth signals)

T/F: Each area of cerebral cortex corresponds to a specific area in the thalamus.

TRUE