Biological rhythms, sleep and dreaming

1
COGNITIVE SCIENCE 17 Final review
2
COGNITIVE SCIENCE 17 Final review
3
Biological rhythms (periodic physiological
fluctuations)

• Types of rhythms
• Ultradian (Basic Rest-Activity Cycle) p294
• Circadian (sleep-wake cycle) p319-326
• Infradian (menstrual cycle)
• Circannual (annual breeding cycles)
• All rhythms allow us to time events
• and anticipate change!

4
With Zeitgeber
See p319.
5
Suprachiasmatic nucleus (SCN) is master pacemaker

• Activity in suprachiasmatic nucleus correlates
  with circadian rhythms
• Lesions of suprachiasmatic nucleus abolish
  free-running rhythms
• Isolated suprachiasmatic nucleus continues to
  cycle
• Transplanted suprachiasmatic nucleus imparts
  rhythm of the donor on the host

p 320-324
6
Timing Photoreceptors

• The existence of photoreceptors not specialized
  for visual functioning
• Regulate photoperiodism (sensitivity to length of
  night)
• Entrainment of circadian rhythms
• Melanopsin-containing cells found in monkey
  retinal ganglion cell layer (Provencio et al.,
  2000)
• Most likely comprise the retinohypothalamic tract
• Sensitive to wavelengths in the 484-500 nm (blue
  light)

7
Single Cycle of Sleep
8
Typical Nightly Sleep Stages
9
Troubled Sleep

• Night terrors (pavor nocturnus)
• Nightmares
• Sleep deprivation p301
• Narcolepsy p297-299

10
Night Terrors and Nightmares

• Night Terrors (p299)
• occur within 2 or 3 hours of falling asleep,
  usually during Stage 4
• high arousal- appearance of being terrified
• Nightmares (p295)
• occur towards morning
• during REM sleep

11
What is a BCI?

• Brain-Computer Interface
• Enables communication without movement or motor
  control.
• Some target patients cannot use any interface
  requiring voluntary movement.

12
What is a BCI?
One of the first uses was designed for Locked-in
Syndrome, a condition marked by total
immobilization yet complete consciousness. This
can follow stroke, injury or disease (MS) which
damages the ventral pons. One notable patient,
journalist Jean-Dominique Bauby, dictated his
memoir using a system of blinking his left eye to
chose a letter. The Diving Bell and the
Butterfly.
13
What is a BCI?
Most BCIs translate your brains electrical
activity (EEGs) into messages or commands.
Performing mental tasks produces electrical
activity detectable with electrode caps.
14
What is a BCI?

• BCIs may be
• Non-invasive (usually EEG)
• Invasive
• ECoG (surface of cortex)
• depth recording (in brain)

15
How do EEGs work?

• Newer EEG recording systems
• Require less or no prep time and skill
• Require less or no gel
• Require fewer electrodes
• Are more portable
• Handle artifacts better
• Are wireless
• Are cheaper

Field recording systems from Quasar, Advanced
Brain Monitoring, and Pineda et al (2003).
16
Components

• How do BCIs work?
• General Schematic
• P300 BCI
• Mu BCI
• Other BCIs

17
Components

• All BCIs have at least four components
• Signal Acquisition
• Feature Extraction
• Translation Algorithm
• Operating Environment

The Four BCI Components (Wolpaw et al., 2002
Allison et al., 2007)
18
Selective attention SSVEP
Steady state visual evoked potential (SSVEP)
Herrmann et al, Exp. Brain Research 2001
19
SSVEP
6 Hz
15 Hz
Steady state visual evoked potential (SSVEP) BCI
(Kelly et al., 2005)
20
Emerging User Goals

• Replacing conventional interfaces for disabled
  users in conventional settings. (BOTH for
  communication and rehab).
• Replacing conventional interfaces for
  conventional users in specific settings.
• Supplementing conventional interfaces.

21
BCI Stroke Rehabilitation
22
BCI Autism Rehabilitation
UCSDnews.ucsd.edu
23
Emotions (Chapter 11)

• Responses of the whole organism, involving...
• physiological arousal (autonomic/hormonal)
• expressive behaviors (behavioral)
• conscious experience (cognitive)

24
Basic Emotions--presumed to be hard wired and
physiologically distinctive
Are Emotions Universal?

• Joy
• Surprise
• Sadness
• Anger
• Disgust
• Fear

Pg 380
25
Expressing Emotion

• Culturally universal expressions

26
James-Lange Theory of Emotion
Pg 390

• Experience of emotion is awareness of
  physiological responses to emotion-arousing
  stimuli

27
Cannon-Bard Theory of Emotion

• Emotion-arousing stimuli simultaneously trigger
• physiological responses
• subjective experience of emotion

28
Schacters Two-Factor Theory of Emotion

• To experience emotion one must
• be physically aroused
• cognitively label the arousal

29
Physical Arousal
30
Arousal and Performance

• Performance peaks at lower levels of arousal for
  difficult tasks, and at higher levels for easy or
  well-learned tasks

31
Amygdala is deep within the most elemental
parts of the brain.
32
Cognition and Emotion

• The brains shortcut for emotions

33
Brain Structures That Mediate Emotion

• Hypothalamus
• Limbic System
• limbic cortex
• amygdala
• Brainstem

34
Hypothalamus

• What does it do?
• Integration of emotional responses
• Forebrain, brain stem, spinal cord
• Sexual response
• Endocrine responses
• neurosecretory
• oxytocin, vasopressin

35
Hypothalamus

• How do we know that it integrates emotions and
  behaviors?
• Ablation studies
• Stimulation studies
• Primary Emotions Fear and Anger

36
Ablation Studies

• Cats
• Remove cerebral hemispheres rage
• Remove hemispheres and hypothalamus no rage

37
Stimulation Studies on Cats

• Lateral hypothalamic stimulation
• rage, attack
• Other areas defensive, fear

38
HypothalamusRoutes of information

• Input from cortex (relatively unprocessed)
• Output to Reticular Formation

39
Brainstem Reticular Formation

• Brainstem web
• 100 cell groups
• Controls
• sleep-wake rhythm
• Arousal
• Attention

40
Limbic System

• Link between higher cortical activity and the
  lower systems that control emotional behavior
• Limbic Lobe
• Deep lying structures
• amygdala
• hippocampus
• mamillary bodies

41
Limbic Lobe

• What is it?
• Cingulate gyrus
• Parahippocampal gyrus
• Where is it?
• Encircles the upper brain stem
• around corpus callosum

42
Limbic System

• What does it do?
• Integrates information from cortical association
  areas
• How do we know this?
• Kluver - Bucy Syndrome

43
Kluver - Bucy Syndrome

• Removal of temporal lobe in animals
• Pre-op
• aggressive, raging
• Post-op
• docile, orally fixated, increased sexual and
  compulsive behaviors

44
Kluver- Bucy Syndrome in Humans

• Severe temporal lobe damage
• tumors, surgery, trauma
• Visual Agnosia
• Apathy/ placidity
• Hyperorality
• Disturbance in sexual function (hypersexuality)
• Dementia, aphasia, amnesia

45
Amygdala

• What is it?
• Nuclear mass
• Where is it?
• Buried in the white matter of the temporal lobe,
  in front of the hippocampus

46
Amygdala What Does It Do?

• Connects to
• olfactory bulb and cortex
• brainstem and hypothalamus
• cortical sensory association areas
• Emotional Association Area

47
Amygdala
Conditioned emotional response Neutral stimulus
can be associated with aversive stimulus,
resulting in same autonomic, behavioral and
hormonal responses.
Pg. 366
48
Amygdala and Learned Emotions

• Learned fear rats and classical conditioning
• Conditioned emotional response
• Abolish fear response
• cut central nucleus from amygdala OR
• infuse NMDA antagonist into amygdala during
  learning

49
Memory
The ability to retain learned information and
knowledge of past events and experiences and to
be able to retrieve that information.
Learn ---- Retain ---- Retrieve
Encoding ---- Maintenance ---- Retrieval

• Organization of experience.what would you do
  without it?

50
Common Model of Memory Processes
51
Time Course of Memory Processes
52
Memory Processes
53
Memory Processes

• How do memories get from working memory to long
  term memory storage?
• consolidation
• How do we get them back?
• Retrieval
• Indexing

54
Long Term Memory
55
Squires Taxonomy of Memory
Squire Zola, PNAS, 1996
56
Memory Disorders

• Two main types of Amnesia
• Anterograde (forward) Amnesia
• Retrograde (backwards) Amnesia

57
(No Transcript)
58
Memory Disorders

• Anterograde Amnesia
• Problem forming new memories post-injury/operatio
  n
• Korsikoffs Syndrome (chronic alcoholics),
  Alzheimers, patients like H.M. with
  hippocampal/thalamus damage
• Can read, write, converse, remember life until
  damage was done

59
Memory Disorders

• Retrograde Amnesia
• Problem loss of memory for some period before
  brain injury
• ECT and head traumas
• Trace consolidation theory -- memory hasnt had
  time to become firmly established, but... several
  years?
• Sometimes memories do come back gradually

60
Memory Disorders

• What amnesiacs can do
• procedural memory tasks (mirror tracing)
• implicit memory tasks ( _L_P_A_T)
• behavioral conditioning

61
Memory in the Brain

• Other important brain areas and functions
• Pre-frontal cortexretrieval, working memory
• Hippocampus other parts of Thalamus--consolidati
  on
• Amygdala--emotional events, fear conditioning
• Occipital Temporal Lobes
• visual/auditory memories

62
Hippocampus Functions

• Consolidation of STM to LTM
• Spatial and contextual memory
• Episodic memory
• Declarative memory
• Detection of novel stimuli
• Neurogenesis

63
Hippocampus Malfunctions

• Severe anterograde amnesia
• Mild retrograde amnesia
• Problems navigating space
• Seizures
• Early Alzheimers Disease

64
H.M.

• Right now, Im wondering, Have I done or said
  anything amiss? You see, at this moment
  everything looks clear to me, but what happened
  just before? Thats what worries me. Its like
  waking from a dream I just dont remember.
• Every day is alone in itself, whatever
  enjoyment Ive had, and whatever sorrow Ive
  had.

65
(No Transcript)
66
(No Transcript)
67

Spatial Navigation (cont.)
Time as London taxi driver
Volume of hippocampus
68
(No Transcript)
69
Place cells in hippocampus map out the
environment
70
Place cells respond as a function of external cues
71
Activity-Dependent Synaptic Plasticity (cont.)

• Long-term plasticities
• Short-term potentiation/depression
• Long-term potentiation/depression

LTP is a persistent increase in synaptic efficacy
that can be rapidly induced
72
Bliss and Lomo, 1973
73
Glutamate (NT) opens NMDA receptors, IF it has
been recently depolarized Rapid firing makes
this possible. Slow firing make it more
difficult (LTD).
74
Importance of Communication

• Different forms
• Verbal (speech)
• Sign (gestures)
• Writing (symbols)
• Important social behaviors
• Have made cultural evolution possible
• Enabled discoveries to be cumulative
• Knowledge passed from generation to generation

75
Language Acquisition

• Modularity (Chomsky, 1959)
• Is there a language mental organ? Or does it
  arise from more primitive functions?
• Is it unique to humans?
• What causes the difference?
• Evolution of Language
• Gestures were important
• Language and thought
• Are they interrelated? Yes, but dont need
  language to be able to think.
• Universal grammar?
• Enables infants to acquire language in any
  culture, provided its during the language
  critical period

76
Birdsong

• Similar to human languages in sensitive
  (critical) period
• Stages of development (learning)
• Initial exposure to the song of tutor (father)
• Successive approximation of produced song to the
  stored model
• Crystalization of the song in permanent form
• Deafening and distorting studies by Konishi
  changes the nature of the song learned
• Brain damage studies confirm vocal control
  centers view
• Neurogenesis in birds responding to birdsong

77
Human language as unique

• Syntax and productive properties rules
  governing word order and usage.
• Language comprehension is rapid and automatic
• Language production is rapid

78
Language Disorders

• In language disorders
• 90-95 of cases, damage is to the left hemisphere
• 5-10 of cases, to the right hemisphere
• Wada test is used to determine the hemispheric
  dominance
• Sodium amytal is injected to the carotid artery
• First to the left and then to the right

79
(No Transcript)
80
Brain Lateralization

• LH more specialized for the analysis of sequences
  of stimuli that occur quickly but sequentially
  (comprehension and production).
• RH more specialized for the analysis of space and
  geometrical shapes and forms that occur
  simultaneously.
• Involved in organizing a narrative (selecting and
  assembling the elements of what we want to say)
• understanding prosody ( vs. monotone)
• recognizing emotion in the tone of voice
• Understanding jokes

81
Language Disorders

• Paraphasia
• Substitution of a word by a sound, an incorrect
  word (treen instead of train)
• Neologism
• Paraphasia with a completely novel word
  (colloquialism or slang)
• Nonfluent speech
• Talking with considerable effort
• Agraphia
• Impairment in writing
• Alexia
• Disturbances in reading (sparing writing)

82
Three major types of Aphasia

• Brocas aphasia
• Nonfluent speech
• Wernickes aphasia
• Fluent speech but unintelligible
• Global aphasia
• Total loss of language
• Others Conduction, Subcortical, Transcortical
  Motor/Sensory

83
Brain areas involved in Language
84
Brocas AphasiaBrodmann 44, 45

• Lesions in the left inferior frontal region
  (Brocas area), caudate nucleus, thalamus, etc.
• Nonfluent, labored, and hesitant speech
  (articulation)
• Most also lose the ability to name persons or
  subjects (anomia)
• Can utter automatic or overlearned speech
  (hello songs)
• Have difficulty with function (the, in, about) vs
  content words (verbs, nouns, adjectives)
  (agrammatism)
• Comprehension relatively intact
• Most also have partial paralysis of one side of
  the body (hemiplegia) next to motor cortex
• If extensive, not much recovery over time

85
Wernickes AphasiaBrodmann 22, 30

• Lesions in posterior part of the left superior
  temporal gyrus, extending to adjacent parietal
  cortex
• Unable to understand what they read or hear (poor
  comprehension)
• Unaware of their deficit
• Fluent but meaningless speech
• Can use function but not content words
• Contains many paraphasias
• girl-curl, bread-cake
• Syntactical but empty sentences
• Cannot repeat words or sentences
• Usually no partial paralysis

86
Wernicke-Geschwind Model1. Repeating a spoken
word

• Arcuate fasciculus is the bridge from the
  Wernickes area to the Brocas area damage here
  hinders repitition

87
Wernicke-Geschwind Model2. Repeating a written
word

• Angular gyrus is the gateway from visual cortex
  to Wernickes area
• This is an oversimplification of the issue
• not all patients show such predicted behavior
  (Howard, 1997)

88
Sign Languages

• Full-fledged languages, created by hearing-
  impaired people (not by Linguists)
• Dialects, jokes, poems, etc.
• Do not resemble the spoken language of the same
  area (ASL resembles Bantu and Navaho)
• Pinker Nicaraguan Sign Language
• Another evidence of the origins of language
  (gestures)
• Most gestures in ASL are with right-hand, or else
  both hands (left hemisphere dominance)
• Signers with brain damage to similar regions show
  aphasia as well

89
Signer Aphasia

• Young man, both spoken and sign language
• Accident and damage to brain
• Both spoken and sign languages are affected
• Deaf-mute person, sign language
• Stroke and damage to left-side of the brain
• Impairment in sign language
• 3 deaf signers
• Different damages to the brain with different
  impairments to grammar and word production

90
Dyslexia

• Problem in learning to read
• Common in boys and left-handed
• High IQ, so related with language only
• Postmortem observation revealed anomalies in the
  arrangement of cortical cells
• Micropolygyria excessive cortical folding
• Ectopias nests of extra cells in unusual
  location
• Might have occurred in mid-gestation, during cell
  migration period

91
Dyslexia

• Cna yuo raed tihs? Olny 55 plepoe out of 100 can.
     i cdnuolt blveiee taht I cluod aulaclty
  uesdnatnrd waht I was rdanieg. The phaonmneal
  pweor of the hmuan mnid, aoccdrnig to a
  rscheearch at Cmabrigde Uinervtisy, it dseno't
  mtaetr in waht oerdr the ltteres in a wrod are,
  the olny iproamtnt tihng is taht the frsit and
  lsat ltteer be in the rghit pclae. The rset can
  be a taotl mses and you can sitll raed it
  whotuit a pboerlm. Tihs is bcuseae the huamn
  mnid deos not raed ervey lteter by istlef, but
  the wrod as a wlohe. Azanmig huh?
• yaeh and I awlyas tghuhot slpeling was
  ipmorantt!  

92
Acquired Dyslexia Alexia

• Disorder in adulthood as a result of disease or
  injury
• Deep dyslexia (pays attn. to wholes)
• cow becomes horse cannot read abstract words
• Fails to see small differences (do not read each
  letter)
• Problems with nonsense words (e.g. glab, trisk)
• Surface dyslexia (pays attn. to
  details/phonemes)
• Nonsense words are fine
• Problems with irregularly spelled words (e.g.
  yacht, pint)
• Suggests 2 different systems
• One focused on the meanings of whole words
• The other on the sounds of words

93
PET by Posner and Raichle

• Passive hearing of words activates
• Temporal lobes
• Repeating words activates
• Both motor cortices, the supplemental motor
  cortex, portion of cerebellum, insular cortex
• While reading and repeating
• No activation in Brocas area
• But if semantic association
• All language areas including Brocas area
• Native speaker of Italian and English
• Slightly different regions

94
PET by Damasios

• Different areas of left hemisphere (other than
  Brocas and Wernickes regions) are used to name
  (1) tools, (2) animals, and (3) persons
• Stroke studies support this claim
• Three different regions in temporal lobe are used
• ERP studies support that word meaning are on
  temporal lobe (may originate from Wernickes
  area)
• the man started the car engine and stepped on
  the pancake
• Takes longer to process if grammar is involved

95
(No Transcript)
96
Other studies

• Right ear advantage in dicothic listening
• Due to interhemispheric crossing
• Words in left-hemisphere, Music in right
• Supported by damage and imaging studies
• But perfect-pitch is still on the left
• Asymmetry in planum temporale
• Musicians with perfect-pitch has 2x larger PT
• Evident in newborns, thus suggesting innate basis
  for cerebral specialization for language and
  speech

97
Planum temporale
Used in language and music
98
Schizophrenia is a PSYCHOTIC DISORDER
A severe mental disorder in which thinking and
emotion are so impaired that the individual is
seriously out of contact with reality.
99
Progression of Schizophrenia
Louis Wain
100
Early onset schizophrenia Wave of gray matter
loss - begins in parietal cortex and spreads
forward
101
Schizophrenia Refers to a group of disorders
There is not one essential symptom that must be
present for a diagnosis. Instead, patients
experience different combinations of the main
symptoms of schizophrenia. It is NOT split or
multiple personality disorder.
102
Two Categories of Symptoms in Schizophrenia

• Positive symptoms
• Negative symptoms

103
Positive Symptoms

• Distortions or excesses of normal functioning
• delusions,
• hallucinations,
• disorganized speech,
• thought disturbances,
• motor disturbances
• Positive symptoms are generally more responsive
  to treatment than negative symptoms

104
Delusions

• False beliefs that are firmly and consistently
  held despite disconfirming evidence or logic
• Individuals with mania or delusional depression
  may also experience delusions.
• However, the delusions of patients with
  schizophrenia are often more bizarre (highly
  implausible).

105
Types of Delusions

• Delusions of Grandeur
• Belief that one is a famous or powerful person
  from the past or present
• Delusions of Control
• Belief that some external force is trying to
  take control of ones thoughts (thought
  insertion), body, or behavior

106
Examples of Delusions of ControlBelieving that
thoughts that are not your own have been placed
in your mind by an external sourceA 29-year-old
housewife said, I look out of the window and I
think the garden looks nice and the grass looks
cool, but the thoughts of Eamonn Andrews come
into my mind. There are no other thoughts there,
only his He treats my mind like a screen and
flashes his thoughts on it like you flash a
picture.
107
Examples of Delusions of ControlBelieving that
your behavior is controlled by an external
forceA 29-year-old shorthand typist described
her (simplest) actions as follows When I reach
my hand for the comb it is my hand and arm which
move, and my fingers pick up the pen, but I dont
control them I sit there watching them move, and
they are quite independent, what they do is
nothing to do with me I am just a puppet who is
manipulated by cosmic strings. When the strings
are pulled my body moves and I cannot prevent it.
108
Types of Delusions

• Thought Broadcasting
• Belief that ones thoughts are being broadcast or
  transmitted to others
• Thought Withdrawal
• Belief that ones thoughts are being removed from
  ones mind

109
Types of Delusions

• Delusions of Reference
• Belief that all happenings revolve around
  oneself, and/or one is always the center of
  attention
• Delusions of Persecution
• Belief that one is the target of others
  mistreatment, evil plots, and/or murderous intent

110
Hallucinations

• Sensory experiences in the absence of any
  stimulation from the environment
• Any sensory modality may be involved
• auditory (hearing)
• visual (seeing)
• olfactory (smelling)
• tactile (feeling)
• gustatory (tasting)
• Auditory hallucinations are most common

111
Common Auditory Hallucinations in Schizophrenia

• Hearing own thoughts spoken by another voice
• Hearing voices that are arguing
• Hearing voices commenting on ones own behavior

112
Disorganized Speech / Thought Disturbances

• Problems in organizing ideas and speaking so that
  a listener can understand
• Loose Associations (cognitive slippage)
• continual shifting from topic to topic without
  any apparent or logical connection between
  thoughts
• Neologisms
• new, seemingly meaningless words that are formed
  by combining words

113
Disorganized Motor Disturbances

• Extreme activity levels (unusually high or low),
  peculiar body movements or postures (e.g.,
  catatonic schizophrenia), strange gestures and
  grimaces

114
Negative Symptoms

• Behavioral deficits that endure beyond an acute
  episode of schizophrenia
• More negative symptoms are associated with a
  poorer prognosis
• Some negative symptoms might be secondary to
  medications and/or institutionalization

115
Types of Negative Symptoms

• Anhedonia
• inability to feel pleasure lack of interest or
  enjoyment in activities or relationships
• Avolition
• inability or lack of energy to engage in routine
  (e.g., personal hygiene) and/or goal-directed
  (e.g., work, school) activities

116
Types of Negative Symptoms

• Alogia
• lack of meaningful speech, which may take
  several forms, including poverty of speech
  (reduced amount of speech) or poverty of content
  of speech (little information is conveyed vague,
  repetitive)
• Asociality
• impairments in social relationships few
  friends, poor social skills, little interest in
  being with other people

117
Types of Negative Symptoms

• Flat Affect
• No stimulus can elicit an emotional response
• Patient may stare vacantly, with lifeless eyes
  and expressionless face.
• Voice may be toneless.
• Flat affect refers only to outward expression,
  not necessarily internal experience.

118
Genetic Studies

• Twin
• Blood relatives
• Adoption
• High-risk populations (e.g., children of
  schizophrenic parents)
• Calcineurin and short-term memory (Tonegawa, 2003)

119
(No Transcript)
120
Biological Finding

• The Dopamine Hypothesis
• Disturbed functioning in dopamine system (i.e.,
  excess dopamine activity at certain synaptic
  sites)
• Supportive evidence
• Phenothiazines reduce dopamine activity and
  psychotic symptoms are reduced
• L-Dopa and amphetamines increase dopamine
  activity and can produce psychotic symptoms

121
(No Transcript)
122
Problems

• A large minority of people with schizophrenia are
  not responsive to antipsychotic medications
  affecting dopamine.
• Other effective medications (Clozapine) work
  primarily on serotonin, rather than dopamine,
  system.
• Antipsychotic drugs block dopamine receptors
  quickly, but relief from symptoms is not seen for
  weeks.

123

• Enlarged ventricles
• Indicates deterioration or atrophy of brain tissue

124
Problems

• Differences are relatively small compared with
  control groups, and many schizophrenic patients
  fall within normal range.
• Reported in only 6 to 40 percent of schizophrenic
  patients in a variety of studies.
• Also reported in some patients with mood
  disorders.

125
Biological Finding

• Low relative glucose metabolism in frontal areas

126
Problems

• Participants are generally chronic patients on
  heavy neuroleptic medications.
• Some evidence indicates that antipsychotic
  medications influence cerebral blood flow even in
  patients who are currently medication free.

127
Biological Finding

• Cognitive dysfunctions (visual processing,
  attention problems, recall memory problems)

128
Environmental Factors

• Family Characteristics
• Social Class

129
Social Class and Schizophrenia

• Schizophrenia is most common at lower
  socioeconomic status (SES) levels
• Breeder Hypothesis
• stressors associated with low SES increase the
  likelihood that schizophrenia will develop
• Downward Drift Theory
• individuals with schizophrenia drift into low
  SES areas because they cannot function in other
  environments