Lecture Exam 3 Flashcards
Temporal Categories of Memory
Immediate memory
Short-term memory
Long-term memory
Forgetting
Immediate Memory
Fractions of a second-seconds
- The routine ability to hold ongoing experiences in mind for fractions of a second.
- The capacity of immediate memory is very large and each sensory modality (visual, verbal, tactile, and so on) appears to have its own memory register
- Example: While making saccadic eye movements, we are continuously getting new ‘snapshots’ of the visible environment.
- Example: Memory of somebody walking across the room just a second ago and knowing they moved to the right.
Short term memory
Seconds-minutes
- The ability to hold and manipulate information in mind for seconds to minutes while it is used to achieve a behavioral goal.
- Example: Searching for the ketchup bottle in the fridge, you know what you are looking for while looking around
- Asking somebody to repeat numbers 475 or use digit span testing (most people can remember approximately 7-9 digits)
Working memory
Seconds-minutes
- A part of short term memory but introduces a manipulation component.
- Example: Not only asking to repeat numbers 475 but to tell you them backwards.
Long term memory
Days-years
- Retaining information in a more permanent form of storage for days, weeks, or years.
- Important/significant information can enter long term memory (from immediate or short-term) by conscious or unconscious rehearsal or practice.
- Example: I remember my 8th birthday party, where you were on 9/11. Highlights importance of emotional salience which promotes consolidation.
Engram
- The physical embodiment of the long-term memory in neuronal machinery
- “Single memory unit”
- Depends on long-term changes in the efficacy of transmission of the relevant synaptic connections, and/or the actual growth and reording of such connections.
- Example: The memory is represented by protein changes, generation of new proteins or AMPA which will improve strength of synaptic connection; this may be where the memory actually can be.
- Example: We know if hippocampus is damaged you lose memory, so the theory is that they have to be localized somewhere.
Consolidation
- Aspect of long term memory which refers to the progressive stabilization of memories following initial encoding of memory “traces”.
- Requires changes in gene expression, protein synthesis and synaptic plasticity (e.g., AMPA cell phosphoralation)
Engram + Consolidation
Both of these topics are ‘controversial’. No evidence for a physical site of memory storage. Memory is not a one-size-fits-all situation.
2 Forms of Long term Memory
- Semantic/Declaritive/ EXPLICIT
- Skill learning/Nondeclaritive/IMPLICIT
Implicit Memory
Nondeclarative; unconscious recollection of previously learned information. This type of memory is typically manifested in an automatic manner, with little conscious effort of the subject.
-Examples: Priming, Procedural (skills and habits), Associative learning (classic and operant conditioning), Nonassociative learning (habituation and senstization).
Explicit Memory
Declarative; deliberate or conscious retrieval of previous experiences as well as conscious recall of factual knowledge about people, places, facts and events.
Examples: Facts (semantic) and Events (episodic).
Brain systems underlying declarative memory acquisition and storage
Reliant on midline diencephalic and medial temporal lobe structures. Hippocampus in particular.
- Papez/Limbic Circuit
- Prefrontal cortex, forebrain, fornix, thalamus, mamillary bodies, amygdala, rhinal cortex, hippocampus, MMT, corpus callosum, temporal lobe.
Posterior hippocampus and spatial navigation
Together with the entorhinal cortex, the hippocampus has specialized cells with receptive fields that specifically respond to spatial location.
Appreciate that there are cells in the posterior hippocampus that respond to SPATIAL LOCATION and have denser connectivity in this range
Example: study where taxi drivers have increased area of posterior hippocampus than controls.
Rodent models of spatial learning
“Place cells” which fire for being in a very specific location. Was proven with the morris water maze task for rodents.
Rats will learn where pedestal is in water to rest. If you remove the pedestal and everything else stays same “place cells” will activate and they will swim immediately to where platform is. If you damage hippocampus there is no memory for were that platform was.
(CA 1, CA2, CA3, DG, FI)
Patient HM (1926-2008)
- Seminal case for understanding why temporal lobe is important for memory.
- HM suffered from severe epilepsy.
- Dr Scoville, a neurosurgeon, localized the seizures to the R and L medial temporal lobes.
- Dr Scovelle actually removed more than just the hippocampus, HM ended up with a bilateral anterior hippocampal, amygdalar and entorhinal cortical resection.
- HM was mostly cured of his epilepsy by his surgery
- However, he suffered profound ANTEROGRADE AMNESIA. Inability to form new episodic memories.
- Brenda Milner discovered that his working memory and procedural memory were intact (examples: could do mirror drawing test, draw a path through a maze, tower of hanoi game)
Where memory likely is “stored”
Evidence for cerebral cortex as the major long-term repository for many aspects of declarative memory.
Association
- Important for storage
- Ability to remember meaningless information is extremely limited. Must ASSOCIATE things with something else or provide meaning/context.
- Mneumonists assign meaning to number strings to remember them beyond typical 7-9 digit span (Ex: Singling the digits of Pi decimels)
Association Research
- Research on depression indicates those with depression will attend to certain negative memories over good or have a different attending pattern. People who are depressed have rumination and bias to remember negative experiences over positive experiences.
- Storage of information is important for association based cues. For example, when HUNGRY subjects have increased ability to recognize a certain food item or non-food item. When people are SATED they recognize food or non-food items at similar level.
Conditioned learning
-Generation of a novel response elicited by repeatedly PAIRING a novel stimulus with a stimulus that normally elicits a response.
Classical conditioning
Conditioned learning.
Innate reflex is modified by associating normal trigger with an unrelated stimulus (e.g., Pavlovs dogs)
Amnesia
Abnormal forgetting or pathological forgetfullness
The inability to learn new information or to retrieve information that has already been acquired
Retrograde Amnesia
Difficulty retrieving memories established prior to precipitating neuropathology
- More typical of the generalized lesions associated with head trauma
- Also affected by neurodegenrative disorders, such as AD
- This tells us that while the hippocampus/midline diencephalic structures form and consolidate declarative memories, they are ultimately stored elsewhere
Anterograde Amnesia
An inability to establish new memories following neurological insult
Agnosia
Inability to recognize stimuli.
Often misinterpreted as memory deficit, but does not result from memory, attention, language problems or unfamiliarity to the stimuli.
Results from dysfunction of one of the sensory modalities: visual, tactile, auditory.
Visual example: when seeing cup, “its red, its smooth” verse when touching the cup “its a mug”
Prospagnosia
Inability to recognize faces .
Phonagnosia
Inability to recognize voices
Korsakoffs
Amnestic disorder caused by thiamine dieficiency associated with prolonged injestion of alcohol.
Mammillary bodies severely degenerated, part of circuit for forming memory
Major symptoms of alcoholic Korsakoff syndrome:
- Anterograde amnesia
- Retrograde amnesia
- amnesia of fixation (loss of immediate memory)
- confabulation
- minimal content in conversation
- lack of insight
- apathy
Example: Potential absence of certain vitamins in diet, B12+ or thiamine deficiency, you cannot produce enough energy for cells to work at level of mammillary bodies OR difficulty with kidneys where these nutrients are ultimately absorbed.
Korsakoff + Thiamine
Thiamine is essential for decarboxylation of pyruvate.
Deficiency during this metabolic process is thought to cause damage to the medial thalamus and mammillary bodies of the posterior hypothalamus as well as generalized cerebral atrophy.
These brain regions are all part of the limbic system, which is heavily involved in emotion and memory.
Anatomy of neocortex
Components of cortical structure 6 LAMINAE (counted from the surface of cortex inward toward white matter) 1. Molecular layer 2. Small pyramidal layer 3. Medium pyramidal layer 4. Granular layer 5. Large pyramidal layer 6. Polymorphic layer
Composition of…
- Molecular layer
- Small pyramidal layer
- Medium pyramidal layer
- Granular layer
- Large pyramidal layer
- Polymorphic layer
- Molecular layer is dendrites and axons
- Small pyramidal layer made of pyramidal cells. Foster cortico-cortical connections (between lobes, areas)
- Medium pyramidal layer made of pyramidal cells and local-axon collaterals. Foster cortico-cortical connections (between lobes, areas)
- Granular layer made of stellate cells and THALAMIC in nature
- Large pyramidal layer made of dendrites and SUBCORTICAL (besides thalamus)
- Polymorphic layer made of descending axons and deep white matter with OUTPUTS TO THALAMUS
Cerebral localization and key principles
Explanations for function:
Localized processes vs distributed networks.
Explanations for dysfunction:
Localized lesions, false localizations, disconnections
Critical principles
1) Anatomic distinctions apply functional distinctions.
2) . Localized damage can have systemic effects
Example: Lesions in one area (occipital lobe or association areas) may have extending consequences as they are not “localized” to the occipital lobe because of vast connections to other regions of cortex.
3) Patterns of connectivity important. Some syndromes reflect loss of processors others reflect disconnection.
Example: If lesion in white matter connection between language and vision regions –> impairs reading ability.
Hemispheric Lateralization
95% R handed language dominance on L side
5% L handed language dominance on R side
Left Dominant Hemisphere
- Complex motor processes
- Language
- Verbal memory
- Arithmetic: sequential and analytical calculating skills
- Musical ability: sequential and analytic skills in trained musicians
- Sense of direction: following a set of written directions in a sequence
Overall, language, sequencing, calculating, complex motor. Think renaissance man/woman who is verbally eloquent, plays piano also does science/math.
Right Non-Dominant Hemisphere
- Gestalt (many things in a scene)
- Visiospatial skills
- Attention to environment (attention to L and R visual fields)
- Arithmetic (estimation, line up columns)
- Emotional significance to events and languae
- Musical ability in untrained musicians
- Sense of direction (spatial orientation)
Overall, intonation, visuospatial skills and attention. Think boat captain on open waters messing around with guitar. Needs basic calculation skills but really good sense of navigation.
Dorsal Stream
Tells us the “where and how”.
Terminates in parietal association cortex.
Functions to incorporate data from other cortical regions with visual information (proprioception, vestibular, auditory).
Key features:
- processes motion
- active for manipulable objects
- integrates spatial location
Dorsal Stream Damage
R hemisphere dorsal pathway lesion causes severe left neglect.
L hemisphere dorsal pathway lesion causes minimal right neglect.
Partial bilateral lesions to both dorsal pathways cause sauvere R neglect.
Hemispatial Neglect
Secondary to lesions of parietal association areas.
Typically, neglect for contralesional LEFT side of space secondary to RIGHT parietal damage.
In health, R parietal cortex attends to L and R visual field while L parietal only attends to R visual field. Therefore, a lesion in R the left cortex only attends to the R visual field so there is no attention from the R cortex to see the L visual field.
Bias to R side of scene, even if the entire scene is within the “central” visual field
Extinction: Only see left side of “central scene” wen right side is hidden/removed.
Sensory hemispatial neglect
Sensory (visual, tactile, auditory): Will ignore visual, tactile or auditory stimulation in contralateral hemispace, even though sensation is intact.
Action/intentional hemispatial neglect
Will perform fewer movements in contralateral hemispace
Egocentric hemispatial neglect
Profound neglect for the contralateral half of the external world and own bodies.
Simultanagnosia
Parietal/dorsal stream deficit.
Impaired ability to perceive parts of visual scene as a whole.
Deficit in visuo-spatial blidning.
Optic ataxia
Parietal/dorsal stream deficit.
Impaired ability to reach for something under visual guidance
Ocular aprxia
Parietal/dorsal stream deficit.
Difficulty voluntarily directing gaze to periphery
Bilants syndrome
Parietal/dorsal stream deficit.
Triad of optic ataxia, ocular apraxia and simultanagnosia.
Bilateral dorsalateral parieto-occipital association cortex lesions.
Often caused by MCA-PCA watershed infarct.
Gerstmann’s Syndrome
Localized to dominant inferor parietal lobe deficit at angular and supramarginal gyrus.
Includes agraphia (cant write), acalculia (cant do simple math), finger agnosia and left-right confusion
Ventral stream
Tells us the “what”
Moves across the temporal lobe. Posterior temporal lobe giving us simple imagery and graduating to more complex/3D images at anterior temporal lobe.
Right ventral stream…
Also gives information on range of rhythm, intonation, pitch, rate, and intensity used to convey meaning in language. There are both receptive and expressive prosody.
Right ventral stream
Affective prosody: emotional state
Linguistic prosody: sentence meaning (rising intonation with a question )
Expressive prosody: production
Receptive prosody: comprehending others production
Aprosodia
Lesion to R temporal association area.
Condition in which a person loses their ability to convey or interpret linguistic prosody.
Caused by damage to R hemisphere brain regions homologues to L hemisphere brain regions responsible for language production or reception.
However, literature is mixed because damage to other brain regions can cause this (frontal lobes), and emotional language is distributed throughout the brain.
Agnosia
Lesion to R or L temporal association areal.
Gnosis = knowledge; A = without –> failure to recognize previously familiar stimula
Modality specific (visual, auditory, tactile)
Visual agnosia more common due to bilateral PCA stroke.
May be limited to a particular class of stimuli (e.g., living things, medical equipment) .
Apperceptive Agnosia
Apperceptive agnosia: primary sensory defect (unable to copy or ID)
If visual in visual association cortex (occipital)
If auditory lesion in auditory association cortex (temporal)(
Associative Agnosia
Associative Agnosia: primary problems with identification. Can copy and perceive.
Disconnects sensory cortices from semantic areas.
Typically associated with anterior temporal damage.
Apperceptive vs Associate Agnosia
Apperceptive there is a problem with perceiving the object
Associative you can perceive it, but you cannot associate it. Patients can copy it fine but cant tell you what it is.
Propopagnosia
Lesions to bilateral inferior occipital-temporal cortex (fusiform gyrus) or junction of visual association cortex and temporal lobe. May be congenital .
Inability to recognize faces.
CANNOT: ID individuals, recognize a face, describe the owner of the face, feel familiarity when viewing faces.
Interpreted as intact “generic” recognition with impaired “specific” recognition.
Achromatopsia
Due to V4 lesions or parieto-temporal-occipital cortex.
Cortical color blindness
Can affect quadrant, hemifeld or entire visual field
Colors appear to be in shades of gray
Cannot name, point to or match colors.
Can name colors presented verbally: what color is grasss? green.
Color agnosia
Inability to name “red items” (e.g., strawberry, apple, heart, etc.)
YET can match/differentiate colors when asked.
Akinestopsia
Lesions to V5 or mesio superior temporal area.
Inability to perceive motion, “motion blindness” .
Depending on severity, may see movement as stroboscopic or may not perceive any motion.
Very dangerous functionally. Cannot perceive cars moving.
YET normal spatial acuity, flicker detection, color vision.
Functional specialization of association cortices
Occipitotemporal = pattern/object recognition, color
Parietal = spatial, action/motor, attention
Dorsal (occipito-parietal) Stream
R side damage
Hemineglect to L Simultanagnosia Optic ataxia Ocular apraxia Balints syndrome
Dorsal (occipito-parietal) Stream
L side damage
Agraphia
Acalculia
Finger agnosia
L/R confusion
Ventral (occipito-temporal) Stream
R side damage
Aprosodia
Ventral (occipito-temporal) Stream
L side damage
Agnosia (apperceptive or associative) Prosopagnosia Achromatopsia Color agnosia Akinetopsia
Emotion
No consensus on definitionbut involves 3 key components:
1) Cognitive appraisal
2) Feeling (subjective changes)
3) Action
Reaction to some stimulus that has an effect internally or externally
“An inferred complex sequence of reactions to a stimulus including cognitive evaluations, subjective changes, autonomic and neural arousal, impulses to action, and behavior designed to have an effect upon the stimulus that initiated the complex sequence (i.e., it’s functional).” (Plutchik, 1982)
Ekaman’s emotion research
Basic emotions exist secondary to universal facial expressions.
Pioneered research using facial expressions in cultures across the world and boiled it down to 6 universally recognized emotions.
Joy, contempt, suprise, sadness, anger, disgust, fear
Yet, others propose 7 or more.
Componential Approach
Ortony & Turner
Emotions are not basic. Instead, elementary INDEPENDENT components of visceral-autonomic emotions are innate. We learn to construct emotions using components in early social development. The components aren’t bound together internally.
A lot of evidence that emotions are not basic; atomizing of emotions as a mixture of independent components.
Ex: ANGER 1) furrow brow 2) . open teeth 3) compress lips
Social Constructivism
J. Averill
Emotions are social constructs, not basic nor universal. Emotions depend on SOCIETY we are in.
Different societies have untranslatable emotional vocabularies and therefore fillings.
Emotion research is theoretically flawed (lab conditions, cultural differences, lack of familiarity, conflicting variables)
James Lang Theory
Emotion is a response to physiological change in the body (we cry and then feel sad, we smile and then feel happy)
Stimulus –> Reaction –> Emotion
Cannon-bard theory
Emotions are indepent of emotional expression.
Physiological arousal does not always = emotion.
Emotional experience and physiological arousal occur separately and usually simultaneously.
Stimulus -> Emotion -> Reaction
Schachter and Singers Two Factor Theory
Merges Cannon-bard and James-lang.
Physiological arousal can lead to emotion but cognitive appraisal is important.
Same physiological arousal for multiple emotions.
Example: Your heart rate is elevated, your breathing is fast and you feel jittery. Anxiety from test taking or too much coffee or watching an exciting game?
Dimensional Approach
Emotions are organized along three independent dimensions.
Valence (positive/pleasant to negative/unpleasant)
Arousal (low to high)
Movement/Action (movement toward vs movement away) like fight or flight
Quantifying emotions
3 broad response systems
1) Verbal report (mood, subjective interpretation, expression/prosody, discourse analysis)
2) Behavior (facial, face digitizing, electromyogram, MDVP, gestures, whole body)
3) Physiologic activation/arousal (skin conductance/pupils); Central(EEG, startle response, FMRI,PET); Pyschological factors affecting medical condition
The limbic lobe
Cortex forming a ring around corpus callosum. Cingulate gyrus, medial temporal lobe, hippocampus.
The Papez Circuit
Limbic System Concept
Limbic structures including cortex are involved in emotion
Emotional system on the medial wall of the brain linking cortex with thalamus
Evolution of limbic system allows animals to experience and express emotions byond stereotyped brainstem behaviors (simple reactions)
The Papez Circuit
Localizations and Function
Cortex (emotional experience)
Hippocampus (mediates behavioral expression of emotion. example, hyperemotional response secondary to hippocampus changes in patients with rabies)
Anterior thalamus (lesions lead to PBA)
Amygdala: fear, anxiety, apprehension, defensive motivation
Amygdala + Emotion
Connects diffusely throughout brain. BG, cerebellum, thalamus, frontal, brainstem, etc.
Amygdala + Fear
Bilateral amygdalectomy reduces fear and aggression in all animals tested.
Anger, sadness, and disgust may be effected
Electrical stimulation of amygdala -> increased vigilance or attention. Seizures with temporal lobe foci can have fear and panic as auros.
Fearful faces produce greater amygala activity than happy/neutral faces.
SM Case Study
Bilateral amygdal deconstruction.
Inability to recognize fear in facial expressions.
Little experience of negative emotions and much experience of positive emotions.
Little to no personal space.
Learned Fear
Amygdala involved in classic pavlovian responses; can condition fear.
Amygdala involved in fomring memories of emotional events (not just negative ones)
Confirmed by fMRI images and PET
Amygdala and Aggression
Predatory Agression - Attacks -Against different species for food -Few vocalizations; attack head or neck -No activity in sympathetic division of ANS -Medial Ex: Animal stalking pray
Affective aggression - For Show
-Used for show, not kill for food
-High levels of sympathetic activity
-Makes vocalizations; threatening posture
-Central
Ex: Football players threatening one another animalistically before game.
Surgery to reduce Aggession
Amygdaletomy
Psychosurgery (lobotomy) - last resort
Outcomes:
Reduced agressive social behavior
Increased ability to concentrate
Decreased hyperactivity
Temporal Lobectomy: Animals vs Humans
Temporal lobectomy in rhesus monkeys leads to decreased fear and aggression, decreased vocalizations and facial expressions.
Temporal lobectomy in humans (secondary to encephalitis, stroke, Co2 poisining, dementia) leads to symptoms of Kluver Bucy syndrome. Likely related to destruction of amygdala
Kluver Bucy Syndrome
Hyperorality, compulsive eating, hypersexuality, visual agnosia, docility/flattened emotions.
Ventral striatum (Nucleus Accumbens) + Emotion
Involved in pleasure, euphoria, reward circuitry.
Reward center of brain. Things we find enjoyable and all the surrounding emotions go through NA.
Stimulation of NA during DBS surgery for OCD treatment associated with laughter, smiling and intense feelings of pleasure/euphoria.
Septal Regions + Emotion
In basal forebrain you have septal nuclei. If you have lesion in this part of brain you wind up with aggression, rage. If this region is stimulated you get reward-seeking behavior.
Caveats with the Limbic System Concept
Difficulties with the single emotion system concept (in other words - the brain is not simple)
- Diverse emotions (many and mixed)
- Many structures involved in emotion (not 1:1 relationship between structure and function)
- Utility of a single, discrete emotion network (i.e., limbic system) is questionable
Brain structures mediating emotion
limbic system including limbic cortex and amygdala
Hypothalamus
Brainstem
Hypothalamus + Emotion
Deep brain structure made up of a number of nuclei (19 million neurons, 1/7th of a teaspoon)
Hypothalmus is located in base of forebrain, behind optic chiasm, forms part of the walls of 3rd ventricle, continous with infindibulum
Integrates emotional resposnes from forebrain, brainstem, spinal cord.
Sexual responses
Endocrine responses (neurosecretory, oxytocin, vasopressin)
Ablation Studies of Hypothalmus
Give evidence for role of hypothalmus in integrating emotions/behaviors.
In cats if you remove cortex and leave hypothalmus there is rage.
In cats if you remove hemispheres and hypothalamus, no rage.
The Hypothalmus and Aggression
Flynn 1960
Predatory (goal-oriented) agression elicited by stimulating LATERAL hypothalmus.
Elicited affective (reactive/hostile) agression by stimulation to MEDIAL hypothalamus
Neural components of agression beyond the amygdala
Periaquiductal gray (pain and agression), OFC, prefrontal cortex, hypothalmus, cingulate cortex.
Hypothalamus: Routes of information
Input from broad cortex (relatively unprocessed) straight to cortex and significant output to brainstem.
Brainstem + Emotion + Serotonin
Neurotransmitter serotonin.
Sertonergic raphe neurons in brainstem project to the hypothalmus and limbic structures via the medial forebrain bundle. Then spread diffusely throughout cortex.
Rx Example: Drug PCPA blocks serotonin synthesis results in increased aggression. Used to treat depression.
Example: Decreased serotonin turn-over (metabolism) results in increased aggression in rodents.
Cortex + Emotions
Cortex plays role in emotion regulation, interpretation and expression of emotional signals (facial expression, gestures, semantics, prosody)
Insula + Emotions
Insula particularly involved in emotion of disgust.
Connects to much of the rest of the brain. Plays significant role in emotional awareness (“feeling” emotion) and pain regulation.
Orbitofrontal damage + Emotion
Orbitofrontal damage and dysregulation often interpreted as personality changes.
Involved with impulsivity, irritability, disinhibition, overly friendly behavior, hypersexuality, risk taking, emotional lability, mood changes (depression and mania)
Medial frontal/AAC damage + Emotion
Medial frontal/AAC damage and dysregulation associated with poor motivation, flattened emotions, poor initiative, apathy, slowed behavior and thought.
Dorsolateral prefrontal damage + Emotion
Dorsolateral prefrontal damage/dysregulation associated with executive function deficits that can influence emotion regulation and judgement.
3 General Hypotheses for Emotion and teh Brain
1) R hemisphere is dominant for emotion
2) R hemisphere is automatic as compared to controlled L hemisphere
3) Laterality for mood exists. Positive/approach in left hemisphere with negative/withdrawal in right hemisphere.
