BIO-375 Exam #4

Cognition

Cognition

Mental processes relating to the acquisition, storage, manipulation, and retrieval of information.

• Processing information

Association Cortex

A critical part of the cerebral cortex that is responsible for integrating sensory information and facilitating higher-order cognitive functions.

• Neocortex that isn’t primary motor or primary somatosensory cortex

Parietal Lobe

Which lobe of association cortex is this?

• Important for attending to stimuli and responding

• Motivation leads to more attention

• Multitasking = switching between what you are attending to

Contralateral Neglect Syndrome

A condition where patients fail to attend to, respond to, or perceive stimuli on the side of space opposite a brain lesion

• Damage in right parietal lobe mainly

• Deny presence of stimuli in left visual field

• Right parietal lobe = attending to left and right visual fields

• Left parietal lobe = attending to right visual field only

Temporal Lobe

Which lobe of association cortex is this?

• Recognize specific objects such as faces

  • Present images of faces to monkeys and neurons become active

  • Angle and direction-specific neurons

• Due to activity of populations of associated neurons

Agnosias

Difficulty recognizing, identifying, and naming (able to acknowledge) stimuli

Prosopagnosia

The inability to recognize faces

• Inferior temporal lobe (the case of L.H.)

Frontal Lobe

Which lobe of association cortex is this?

• Planning and decision making

  • Short-range and long-range planning

• Delayed response task

  • Put food in one tray with another tray empty, cover trays, cause delay, monkey chooses tray and if they choose one with food they get the food

  • Cue → Delay → Response

• Personality

  • James Watts & Walker Freeman- used technique of frontal lobotomy for mental illness treatment- disconnect personality/separate connections from frontal lobe to other parts of brain

Memories

Biological process by which the brain encodes, stores, and retrieves information through changes in neural circuits and synaptic connections

• Synaptic plasticity

Synaptic Plasticity

Process of altering the strength of the synapse and making new connections with different neurons.

• Short-Term

• Long-Term

Short-Term Synaptic Plasticity

Synaptic plasticity that occurs within milliseconds to several minutes

• Increase the [Ca²⁺] inside presynaptic neurons alters the amount of neurotransmitter released (increase NT)

  • Retrograde messengers- postsynaptic neuron sends short messages back to presynaptic neuron to alter amount of NT released

Long-Term Synaptic Plasticity

Synaptic plasticity that involves the changes in responsiveness occurring in the postsynaptic neuron

• Long-term Potentiation (LTP)- increases responsiveness

• Long-term Depression (LTD)- decrease responsiveness

Changes are not permanent

Long-Term Potentiation (LTP)

Type of long-term synaptic plasticity that increases the responsiveness occurring in the postsynaptic neuron

• Add receptors to postsynaptic membrane

  • Requires high-frequency AP

• Early Phase

  • Activation of NMDA receptors

    • Increase [Ca²⁺] intracellular

  • Increase number of AMPA

• Late Phase- stabilization

  • Increase gene expression - increase synaptic proteins

  • Cytoskeletal changes → physically larger synapse

  • Astrocytic changes occur - synapse expands → astrocyte expands

Associativity

In reference to long-term potentiation

• A second (low-frequency) neuron sends signal to add more receptors at same time as high frequency AP

Cooperativity

In reference to long-term potentiation

• A bunch of low frequency AP neurons work together to change post-synaptic neuron

Long-Term Depression (LTD)

Type of long-term synaptic plasticity that decreases the responsiveness occurring in the postsynaptic neuron

• Decrease gene expression

• Decrease synapse size

• Decrease number of receptors

Memory Process

Encoding

• Acquisition

• Consolidation (cellular level)

Storage (system consolidation)

• Involves a lot of neurons

• Integration with existing related memories

Retrieval

Atkinson-Shiffrin Memory Model (Tempooral)

Sensory information (immediate)

• Iconic- visual sensory memories

• Echoic- auditory sensory memories

• Haptic- somatosensory memories

Short-term (working) Memory

• Can rehearse to keep it here

• Information can be retrieved from long-term memory

Long-term Memory

• Storage of information from short-term memory

Declarative Memory (Explicit)

Memories that can be described

• Episodic- recollection of events that were experienced

• Semantic- naming or defining somethings

Nondeclarative Memory (Implicit/Procedural)

Memories that involve skills and habits

• Motor skills - ex. riding a bike

• Puzzle solving - ex. solving rubiks cube

• Habituation/priming - superstitions

Memory Model

The working memory is separate from the short-term memory

• Working memory- active processing system that manipulates information

  • Storage and retrieval to/from long-term memory

• Short-term memory - temporary holding of new information

The Story of H.M.

This person had debilitating, untreatable seizures, and they removed his inferior-medial temporal lobe

• Got rid of the seizures

• Had severe anterograde amnesia with some retrograde amnesia

• He couldn’t form new declarative/explicit long-term memories, but he could form new non-declarative implicit/procedural long-term memories

Inferior-medial temporal lobe important for creating new long-term memories - two different pathways for declarative vs. non-declarative memories

Learning Strategies

Help strengthen long-term memories

• Repetition

• Distributed practice

• Retrieval-based learning

• Motivation/attention

• Rote (dry memorization) vs. meaningful learning

Association

Give meaningless items a meaningful context

• Ex. create a story using the words

• Increases learning and memory

Motivation

Increases learning and memory

• Ex. Hungry individuals remember images of food better than non-hungry people

Leads to better attentiveness

• More attention=better memory

Aficionados

An expert in something

• Ex. Chess master

• Remembering the movement of chess pieces better during an actual game than if the pieces were randomly moved

• Repetition and experience

Cortical States

Different states of consciousness

• Consciousness- a state of awareness of ‘self’ and the environment while retaining the ability to respond appropriately to stimuli

Sleep

A suspension of consciousness

• EEG measures brainwaves in different locations of the brain the determine levels of cortical activity

• Four stages and REM

Stage 1 (Sleep)

Becoming drowsy and nodding off, decreasing frequency, and increasing the amplitude of brainwaves

Stage 2 (Sleep)

Decreasing the frequency and increasing the amplitude of the brainwaves, sleep spindles (burst in activity of brain waves) occurs

Stage 3 & 4 (sleep)

Slow-wave sleep, delta waves occurring (giant waves in stage 4), deep/restorative sleep/most restful sleep

Sleep Stages 1-4

• Slow rolling eyes

• Decrease HR, BP, respiration, and metabolism

• Decreased muscle tone and movement

REM Sleep

• Increase in HR, BP, metabolism, and respiration

• Rapid eye movements

• Paralysis of large muscle groups

• Twitching of smaller muscles

Circadian Rhythms

The internal clock

• Suprachiasmatic Nucleus - located in the hypothalamus; master of the sleep/wake cycle

• Photoentrainment- organisms internal biological clock synchronizes with external 24-hour light-dark cycle

  • Retinohypothalamic tract

  • Detect light intensity

  • Pineal gland produces melatonin

  • Melanopsin ipRGCs (retinal ganglion cells)- respond directly to light intensity- increase light = increase APs

Reticular Activating System

Active = Awake

• Stimulate a sleeping cat’s brainstem → induce awakening

Cholinergic Nuclei - increase activity during REM sleep and awake

Raphe Nuclei- increase activity when awake (produce serotonin)

Locus Coeruleus - increase activity when awake (produce norepinephrine)

TMN (hypothalamus) - increase activity when awake (produce histamine)

Cholinergic Nuclei

Increase activity during REM sleep and awake

Raphe Nuclei

Increase activity when awake

• produce serotonin

Locus Coeruleus

Increase activity when awake

• produce norepinephrine

TMN (hypothalamus)

Increase activity when awake

• produce histamine

Thalamus

Structure involved in sleep where if you stimulate when awake → induce sleep state

VLPO

As we transition into sleep cells from the _____ inhibit the TMN and the brainstem nuclei

Orexin Neurons

When we are awake, ______ stimulate the TMN and the brainstem nuclei

Reasons for needing sleep

1. Replenish glycogen levels - ATP

2. Cellular growth, maintenance, and repair

3. Conservation of energy/metabolism

4. Decrease free radicals in brain

5. Removal of waste

6. Other

   1. Wound healing

   2. Improved immune system

   3. Memories

Sleep and Memories

When sleeping the brain can

• Consolidate memories

• Stabilize memories- strengthen synapses

• Integrate new memories w/old memories

• Dissect memories- consolidate the important qualities

• Remove minutiae of the day (unnecessary details)

Approx. 6 hours of sleep is required for some aspects

Different stages of sleep influence different memories

• Deep sleep = increase memory

REM Sleep

When during sleep do our vivid and story like dreams mostly occur?

Hypnic Jerk

The rapid jerking with a sensation of falling that wakes you up.

Non-REM Parasomnias

Sleep walking, sleep talking, sleep-related eating disorders, night terrors (pavor nocturnus-deep sleep)

REM Parasomnias

Nightmare disorder, sleep paralysis, REM sleep behavior disorder

Insomnia

Sleep deprivation that decreases cognitive abilities and causes the accumulation of sleep debt

• Decreased attention

• Cognitive skills impaired

• Reaction times slowed

• Language skills decreased

Can be fatal - Fatal familial insomnia/sporadic fatal insomnia

Decrease

Sleep needs ___(increase or decrease)___ with age.

Emotions

A complex reaction pattern involving experiential, behavioral, and physiological elements.

Duchenne

This person studied facial expressions of different emotions using electrodes.

• Facial expression is a large unconscious part of our emotions

Dimensional Theory of Emotions

Emotions are very complex

• Arousal level/Activation

• Valence/Positive vs. Negative

1. Volitional (Classic Motor)

2. Emotional Expression

What are the two descending pathways/systems of facial expressions?

Volitional (Classic Motor)

Which descending pathway of facial expression is this?

• Motor cortex

• Pyramidal tracts

• Spinal cord/brainstem

Emotional Expression

Which descending pathway of facial expression is this?

• Anterior Cingulate Gyrus

• Extrapyramidal tracts (reticular formation)

• Spinal cord/Brainstem

James-Lang Theory of Emotion

Theory of emotion that is very linear

• Experience → Physiological response → Emotion

• Stimulus causes a physiological response which illicit an emotion

Cannon-Bard Theory of Emotion

Theory of emotion that separates the emotional response from the physiological response.

• Stimulus → Thalamus → Emotional Response & Physiological Response

Philip Bard

Determined the notion of “sham rage”

• Generated rage through electrical stimulation in cats

• Removal of hypothalamus = no sham rage

  • When hypothalamus kept = sham rage

Walter Hess

Studied behavior in cats by stimulating the hypothalamus via electrodes to produce rage/behavioral changes in the cats.

James Papez

This scientist argued that there were other structures involved in emotion

• Ex. Fornix, hippocampus, and mammillary bodies

• Amygdala

• Orbital and Medial prefrontal cortex

• Cingulate Gyrus

• Hippocampus

What are some of the other structures that were determined to be involved in emotion.

Kluver-Bucy Syndrome

The removal of medial temporal lobes (remove amygdala) leads to the loss of fear and aggression toward people (in animals typically fearful of people)

• Lost control of their emotions

• Hyperactivity and hypersexuality

John Downer

A scientist who severed the corpus callosum and optic chiasm

• Eye without amygdala

  • With the right eye covered, information can’t get to other side of brain with amygdala

  • Respond with lack of fear

Amygdala

This structure is very important for producing fear and aggression.

Post-Traumatic Stress Disorder (PTSD)

A mental health condition triggered by experiencing or witnessing terrifying events like war, abuse, or disasters.

• Very intense sensory experiences

• Synaptic plasticity within amygdala at the heart

The Case of S.M.

This individual had amygdala degeneration and is missing her amygdala’s.

• She has a difficult time recognizing or feeling fear

• Her other emotions remain intact

Language

The symbolic representation involving

• Syntax- symbolic order of words

• Lexicon- vocabulary; meaning of symbols/words

• Grammar- rules; whole structure of a language

• Prosody- emotion or affect

Speech

Structures involved in production of ______

• Lips, tongue, jaw, lungs, larynx

Dysarthria

Dysarthria

A motor speech disorder due to damage to CN X or associated structures in speech production.

• Paralysis or paresis of muscles used in speech production

Arcuate Fasciculus

The tracts that connect Broca’s area and Wernicke’s area.

Broca’s Aphasia

Motor Aphasia/Expressive Aphasia

• Can understand/comprehend language

• Individuals know what they want to say but struggle to produce speech resulting in halting and short sentences

Wernicke’s Aphasia

Receptive Aphasia/Fluent Aphasia

• Can produce speech but it doesn’t make any sense

• Fluent but meaningless speech, poor comprehension, word salad

Conduction Aphasia

A language disorder caused by damage to the arcuate fasciculus and is characterized by fluent speech and good comprehension but difficulty repeating words or phrases.

Lateralization/Split-brain

Sever the connection between the two hemispheres of the brain

• Certain cognitive processes and functions are more dominant in one hemisphere of the brain than the other

• Info from RVF processed in left hemisphere- can be named and described- direct access to language center

• Info from LVF processed in right hemisphere- can’t be named and described- no access to language center

If a split-brain patient had their language center in the left hemisphere, how would they respond to information in both the right and left visual fields?