Higher brain functions. Magdalena Gibas-Dorna

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1 Higher brain functions Magdalena Gibas-Dorna

Dear Students, Please note that this ppt presentation presents anatomical considerations of brain structures that are associated with higher brain functions The lecture is based on Ganong s

2 Dear Students, Please note that this ppt presentation presents anatomical considerations of brain structures that are associated with higher brain functions The lecture is based on Ganong s Review of medical Physiology Only selected higher brain functions are presented The mark indicates the most important info For more learning please visit:

3 two oval skull includes regions of higher functions Diencephalon Cerebellum Cerebral Hemispheres

4 Diencephalon integrates conscious and unconscious activity Between cerebral hemispheres Mostly thalamus and hypothalamus

Thalamus transmits sensory information and emotional state Nuclei of thalamus: Anterior group limbic system Medial group hypothalamus emotion center to cerebrum frontal lobe Ventral group touch and

5 Thalamus transmits sensory information and emotional state Nuclei of thalamus: Anterior group limbic system Medial group hypothalamus emotion center to cerebrum frontal lobe Ventral group touch and proprioceptive information relayed to cerebral cortex Posterior group optic and auditory information to cerebral cortex Lateral group emotional state feedback from limbic system; integrates with sensory information

6 Limbic system = emotional nervous system Higher mental functions, such as learning and formation of memories Structures of limbic system include: The Hippocampus The Amygdala The Thalamus The Hypothalamus The Fornix and Parahippocampus The Cingulate Gyrus

7 The Hippocampus hippocampus is a major part of the brain involved in declarative memory function transformation (not storage) of short term into long term memory

8 The Amygdala integrative center for emotions, emotional behavior, and motivation mediation and control of such activities and feelings as love, friendship, affection, and expression of mood the center for identification of danger the amygdala is the nucleus responsible for fear

9 The Thalamus anterior nuclear group connects subcortical areas and the cerebral cortex - every sensory system (except olfactory sys) includes a thalamic nucleus receiving sensory signals and sending them to the primary cortical area Regulates sleep and wakefulness; damage to the thalamus can lead to permanent coma Functionally connected to the hipocampus Plays role in episodic memory (events)

10 The Hypothalamus - HOMEOSTASIS body temperature water balance circadian rhythmicity, regulation of endocrine hormonal levels appetite behaviour (eg. sexuality, combativeness, emotions) milk production

11 The Hypothalamus - HOMEOSTASIS Feeding reflexes licking, swallowing, etc. Subconscious skeletal muscle movements facial expressions, sexual movements Autonomic center control medulla oblongata nuclei for cardiovascular, respiration Secretes oxytocin that stimulates smooth muscle of uterus, mammary glands and prostate Regulates body temperature Controls pituitary gland by hormonal secretion pituitary in turn regulates many hormonal endocrine functions Produces emotions/sensations/drives: e.g. thirst, hunger (not really sensations from periphery) Coordinates autonomic response to conscious input thought of fear produces accelerated heart rate, etc.

12 The Fornix and Parahippocampus: important in connecting pathways for the limbic system The Cingulate Gyrus: participates in the emotional reaction to pain and in the regulation of aggressive behavior

13 Pineal gland Regulates Cycles Secretes melatonin which helps regulate circadian and reproductive cycles

14 Cerebellum posture and movement Oval at back of cranial cavity Convoluted surface of neural cortex (like cerebrum) Damage leads to ataxia disturbance of muscular coordination

Cerebrum (processing central for somatic/conscious information) Two cerebral hemispheres separated by longitudinal fissure (sagittal plane) Central sulcus divide (coronal plane) separates

15 Cerebrum (processing central for somatic/conscious information) Two cerebral hemispheres separated by longitudinal fissure (sagittal plane) Central sulcus divide (coronal plane) separates frontal lobe from parietal lobe Horizontal lateral sulcus (in transverse plane) separates frontal lobe from temporal lobe Parietal-occipital sulculs separates parietal lobe from occipital lobe

16 Cerebral function in brief Basal nuclei/ganglia (sometimes considered part of midbrain) Deep in hemispheres Subconscious control of skeletal muscle Rhythmic movements overall walking coordination Frontal Lobe (primary motor cortex)-voluntary control of skeletal muscle Parietal lobe (primary sensory cortex) conscious perception from skin touch, pressure, pain Occipital lobe (visual cortex) conscious perception of visual field Temporal lobe (auditory cortex and olfactory cortex) conscious perception of sound and smell All Lobes integration and processing of sensory input to initiate conscious motor output

17 Find a kid

18 Find hidden face

19 Old or young?

20 Selected higher brain functions

21 Learning and Memory Learning ability to alter behavior on the basis of experience eg. learning/studying new language Memory is the retention and storage of that information

22 Learning and Memory memory is ability to remember past experiences You learn a new language by studying it, but you then speak it by using your memory to retrieve the words that you have learned. Memory is the record left by a learning process

23 Two aspects of learning 1. acquisition of a response in presence of a stimulus 2. suppression of responses in its absence

24 Types of memory

Sensory memory is the memory that results from our perceptions automatically and generally disappears in less than a second Short-term memory (STM) depends on the attention paid to the elements of

25 Sensory memory is the memory that results from our perceptions automatically and generally disappears in less than a second Short-term memory (STM) depends on the attention paid to the elements of sensory memory. Short-term memory lets you retain a piece of information for less than a minute and retrieve it during this time (eg. repeating a list of items that has just been read to you, in their original order. In general, you can retain 5 to 9 items in short-term) Long-term memory (LTM) includes both our memory of recent facts, which is often quite fragile, as well as our memory of older facts, which has become more consolidated. Longterm memory consists of three main processes that take place consecutively: encoding, storage, and retrieval (recall) of information.

26 Short term memory vs. working memory STM cognitive system that is used for holding sensory events, movements, and cognitive information, such as digits, words, names, or other items for a brief period of time (Kolb&Wishaw, 2009) dorsolateral part of prefrontal cortex (dlpfc) WM maintenance and controlled manipulation of a limited amount of information before recall (Baddeley, 1992) STM is a critical component of WM dorsolateral part of prefrontal cortex (dlpfc)

27 Encoding = to assign a meaning to the information to be memorized Storage = active process of consolidation that makes memories less vulnerable to being forgotten Retrieval (recall) of memories = involves active mechanisms that make use of encoding indexes (whether voluntary or not )

HIPPOCAMPUS & MEDIAL TEMPORAL LOBE Working memory consists of central executive in the dorsolateral part of prefrontal cortex and verbal system for retaining verbal memories and a

28 HIPPOCAMPUS & MEDIAL TEMPORAL LOBE Working memory consists of central executive in the dorsolateral part of prefrontal cortex and verbal system for retaining verbal memories and a parallel visuospatial system for retaining visual and spatial aspects of objects Prefrontal cortex has a connection with hippocampus and parahippocampal regions of temporal cortex

Memory forms EXPLICIT (DECLERATIVE) memory associated with consciousness dependent on hippocampus and medial temporal lobes IMPLICIT (NONDECLERATIVE)

29 Memory forms EXPLICIT (DECLERATIVE) memory associated with consciousness dependent on hippocampus and medial temporal lobes IMPLICIT (NONDECLERATIVE) memory its retention does not usually involve processing in the hippocampus declarative memories can become nondeclarative once the task is thoroughly learned.

30 DECLARATIVE memory: EPISODIC for events SEMANTIC for facts (words, rules, language) NONDECLARATIVE memory: PROCEDURAL skills and habits once acquired become automatic PRIMING facilitation of recognition of words or objects by prior exposure to them NONASSOCIATIVE LEARNING learning about one stimulus ASSOCIATIVE LEARNING relation of one stimulus to another

31 Forms of long-term memory

32 Forms of long-term memory

Nonassociative learning Habituation neural stimulus repeated many times (it evokes less and less electrical response as it is repeated) - generally neutral, non-noxious

33 Nonassociative learning Habituation neural stimulus repeated many times (it evokes less and less electrical response as it is repeated) - generally neutral, non-noxious stimuli Sensitization - repeated exposure to a stimulus results in increased responding to that stimulus - the stimulus is paired once or several times with a noxious stimulus

Eric Kandel and his collaborators used Aplysia to unravel synaptic mechanisms for short-

34 Research on neural mechanisms has focused on non-associative learning and classical conditioning. Eric Kandel and his collaborators used Aplysia to unravel synaptic mechanisms for short- and long-term habituation, short- and long-term sensitization, and classical conditioning. Eric Kandel won the 2000 Nobel Prize for Physiology and Medicine for this work. Aplysia

35 Habituation in Aplysia

36 Associative learning classical conditioning; Pavlovian conditioning; respondent conditioning A neutral stimulus is paired with a stimulus that reliably elicits a response. Conditioning is indicated when the previously neutral stimulus evokes a response.

Classical conditioned reflex After the CS and US had been paired a sufficient number of times, the CS produced the response originally evoked only by the

37 Classical conditioned reflex After the CS and US had been paired a sufficient number of times, the CS produced the response originally evoked only by the US. The CS had to precede the US. Meat placed in the mouth = unconditioned stimulus (US) Bell ringing = conditioned stimulus (CS) CS US UR bell meat saliva CR

38 Respondent behavior is a characteristic of classical conditioning that is a reflex in response to the stimulus provided. Operant behavior, when someone acts on the surrounding environment to receive the reward or punishment stimulus, is a defining factor of operant conditioning

Associative learning operant conditioning; instrumental learning a learning procedure whereby the effects of a particular behavior in a particular

39 Associative learning operant conditioning; instrumental learning a learning procedure whereby the effects of a particular behavior in a particular situation increase (reinforce) or decrease (punish) the probability of the behavior operant conditioning reinforces one's actions with reward or punishment

40 Instrumental learning

41 Molecular basis of memory alteration in the strength of selected synaptic connections that involves gene activation and protein synthesis Habituation Sensitization Synaptic plasticity: Long-term potentiation (LTP) Long-term depression (LTD) Change in efficacy of synapse - increasing or decreasing amount of neurotransmitter presynaptically or by increasing or decreasing amount of AMPA receptors (thereby making that synapse more sensitive)

LTP in the hippocampus: A mammalian model for learning typical LTP experiment 1. stimulate neuron A, record PSP from neuron B 2. stimulate neuron A tetanically (e.g. burst of stimuli @ 100 Hz) 3.

42 LTP in the hippocampus: A mammalian model for learning typical LTP experiment 1. stimulate neuron A, record PSP from neuron B 2. stimulate neuron A tetanically (e.g. burst of 100 Hz) 3. record PSP from B w/test pulses at varying intervals 4. PSP augmented for several days or even up to months 5. this augmentation is what is called LTP

43 LTP (long term potentiation) rapidly developing persistent enhancement of the postsynaptic potential response to presynaptic stimulation after a brief period of rapidly repeated stimulation of the presynaptic neuron (increase in Ca ions in postsynaptic neuron)

44 After intense stimulation of the presynaptic neuron, the amplitude of the post-synaptic neuron s response increases. The stimulus applied is generally of short duration (less than 1 second) but high frequency In the postsynaptic neuron, this stimulus causes sufficient depolarization to evacuate the Mg2+ that are blocking the NMDA receptor, thus allowing large numbers of calcium ions to enter the dendrite CREB plays a major role in gene transcription, and its activation leads to the creation of new AMPA receptors that can increase synaptic efficiency still further.

46 LTP in the hippocampus: A mammalian model for learning

CaMKII: Calcium/calmodulin dependent kinase II PKA, PKC: Protein kinase A, C CREB: camp-responsive element-binding protein Low-frequency stimulation results in small increases in [Ca 2+ ] in

49 CaMKII: Calcium/calmodulin dependent kinase II PKA, PKC: Protein kinase A, C CREB: camp-responsive element-binding protein Low-frequency stimulation results in small increases in [Ca 2+ ] in the postsynaptic cell, which in turn results in fewer AMPA channels opening in response to glutamate. This is called low-frequency depression and is a mechanism for weakening synaptic strength.

50 LTD (long term depression) decrease in synaptic strength produced by slower stimulation of presynaptic neurons and is associated with a smaller rise in intracellular Ca2+ than occurs in LTP In the hippocampus, the role of LTD is thought to be to return synapses that have been potentiated by LTP to a normal level so that they will be available to store new information. Elsewhere in the brain, LTD may be actively responsible for the storage of new information, as in the cerebellum

LTD develops when a presynaptic neuron is active at low frequencies (1 to 5 Hz) without the postsynaptic neuron s being subjected to strong depolarization, as it is with LTP.

51 LTD develops when a presynaptic neuron is active at low frequencies (1 to 5 Hz) without the postsynaptic neuron s being subjected to strong depolarization, as it is with LTP. instead of proteins such as CaM kinase II or kinase A being activated, enzymes called phosphatases dephosphorylate AMPA receptors this dephosphorylation of the AMPA receptor would be to reduce the amplitude of the postsynaptic potential to the normal level where it was before LTP. IT is also believed that the number of AMPA receptors decreases during LTD

52 amnesia Anterograde amnesia Amnesia for events that occur after trauma. Retrograde amnesia Amnesia for events that occur just prior to the brain trauma

Confabulation The reporting of memories of events that did not take

53 Korsakoff s syndrome Permanent anterograde amnesia caused by mamillary bodies damage resulting from chronic alcoholism. Confabulation The reporting of memories of events that did not take place without the intention to deceive, seen in people with Korsakoff s syndrome.

54 Alzheimer Disease

protein) and senile plaques (β-amyloid peptides), Mechanism: polypeptides form extracellular aggregates, which

55 SIGNS: loss of short-term memory, which impedes recollection of recent events followed by general loss of cognitive and other brain functions, Cytopathologic hallmarks: intracellular neurofibrillary tangles (tau protein) and senile plaques (β-amyloid peptides), Mechanism: polypeptides form extracellular aggregates, which can stick to AMPA receptors and Ca2+ ion channels, increasing Ca2+ influx. The polypeptides also initiate an inflammatory response

56 Summary

57 SENSES PREFRONTAL CORTEX (working memory) PARAHIPOCAMPAL CORTEX HIPPOCAMPUS SUBICULUM AND ENTORHINAL CORTEX NEOCORTICAL AREAS

58 Speach and language physiology

59 Definitions Language = cognitive behaviour Speach = the means of communication between the two individual or group of individuals (sensory and motor). Spoken or written speach. Is there any difference between language and speach?

60 American Speach-Langue-Hearing Association: Language is made up of socially shared rules that include the following: What words mean How to make new words (e.g., friend, friendly, unfriendly) How to put words together What word combinations are best in what situations ("Would you mind moving your foot?" or "Get off my foot, please!") Speach is the verbal means of communicating: Articulation How speech sounds are made (e.g., children must learn how to produce the "r" sound in order to say "rabbit" instead of "wabbit"). Voice Use of the vocal folds and breathing to produce sound. Fluency The rhythm of speech (e.g., hesitations or stuttering can affect fluency).

61 Language is symbolisation of ideas, ability to convert thought into comprehensive words Speaking Hearing Repeating Reading Writing

62 Two hemispheres specialization related to handedness Dominant hemisphere = Categorical hemisphere sequential-analytic processes (mathematical and scientific skills) reasoning LANGUAGE Lesions produce language disorders Representational hemisphere visuospatial relations (3D awarness) identification of objects by their form and music awarness, art. awarness, face recognition imaginaion Lesions produce astereognosis

64 1. Name the colors which were used for writing the words within 15 sec 2. Representative hemisphere tries to name the colors, but the dominant hemisphere analyses definitions (insists on reading the word)

Corpus callosum transfers information between 2 hemispheres Categorical hemisphere Language In 96% of righthanded individuals left hemisphere is

65 Corpus callosum transfers information between 2 hemispheres Categorical hemisphere Language In 96% of righthanded individuals left hemisphere is dominant In 70% of left-handers the left hemisphere is the categorical one Representational hemisphere: Facial expression, intonation, body language

66 Brain Areas Concerned with Speech / Language Wernicke s area Broca a area Speech articulation area in insular cortex Motor cortex Angular gyrus Aud/Vis/Touch association areas

ASSOCIATION AREAS These areas receive and analyze signals simultaneously from multiple regions of both the motor and sensory cortices as well as from

67 ASSOCIATION AREAS These areas receive and analyze signals simultaneously from multiple regions of both the motor and sensory cortices as well as from sub-cortical structures. The most important association areas are Parieto-occipitotemporal association area Prefrontal association area Limbic association area.

68 PRIMARY, SECONDARY AND ASSOCIATION AREAS

69 PARIETO-OCCIPITOTEMPORAL ASSOCIATION AREAS 1. Analysis of the Spatial Coordinates of the Body. 2. Area for Language Comprehension. 3. Area for Initial Processing of Visual Language (Reading). 4. Area for Naming Objects.

70 Language areas of brain Broca's Area - special region in the frontal cortex; word formation. Located partly in the posterior lateral prefrontal cortex and partly in the premotor area. Wernicke's language comprehension center - in the temporal association cortex

Broca s area (44, 45): anterior speach area Location: 3rd frontal gyrus Detailed and coordinated pattern of vocalization Wernicke s area (22): posterior speach area Location: at the posterior end of

71 Broca s area (44, 45): anterior speach area Location: 3rd frontal gyrus Detailed and coordinated pattern of vocalization Wernicke s area (22): posterior speach area Location: at the posterior end of the uperior temporal gyrus Comprehension of the auditory and visual information Exner s area (6): motor writing centre Location: middle frontal gyrus of categorical hemisphere Exner s area Dejerine s area (39) Location: angular gyrus processes information from the read words that they can be converted into auditory forms of the words in Wernicke s area Dejerine s area

72 Language areas of brain (Dejerine s area)

73 Dejerine s area Path taken by impulses when a subject names a visual object projected on a horizontal section of the human brain

74 Auditory Language Perception

75 Visual Language (Reading) (Dejerine s area)

76 Interesting facts In individuals who learn a second language in adulthood, fmri reveals that the portion of Broca s area concerned with it is adjacent to but separate from the area concerned with the native language How about children?

77 STEPS OF COMMUNICATION Steps of Communications Collection of sensory input: Auditory and visual Integration: hearing and articulation mechanism Motor execution

78 SPEECH PRODUCTION PROPCESS

79 Speach/language disorders

80 APHASIA CATEGORICAL HEMISPHERE APHASIA IS LOSS OF OR DEFECTIVE LANGUAGE it results from damage to the speach centres within left hemisphere Please note that: In aphasia there is on lesion in vision, hearing, or motor areas of brain.

82 Nonfluent aphasia Nonfluent aphasia (motor aphasia) Broca s area Speech is slow, and words are hard to come by

83 Fluent aphasia Fluent aphasia - it was thought to be due to lesions of the arcuate fasciculus connecting Wernicke s and Broca s areas lesions in and around the auditory cortex speech itself is normal and sometimes the patients talk excessively. However, what they say is full of jargon and neologisms that make little sense

84 Fluent or Receptive (Wernicke s Aphasia) Patients with Wernicke s Aphasia usually have great difficulty understanding speech, even though there is no deafness. They may speak fluently, often in long sentences, but the meaning of their sentences is unclear. ( fluent paraphasia ).

85 Conduction Aphasia (form of fluent aphasia) Patients may be able to understand speech as well as produce meaningful speech, but have difficulty repeating a spoken sentence. patients can speak relatively well and have good auditory comprehension but cannot put parts of words together or conjure up words Often associated with damage to the Arcuate Fasciculus, which connects Wernicke s area with frontal pre-motor structures.

86 The Arcuate Fasciculus Big fibre bundle connecting Broca s and Wernicke s Areas

87 Anomic aphasia Location: the angular gyrus in the categorical hemisphere without affecting Wernicke s or Broca s areas there is no difficulty with speech or the understanding of auditory information; instead there is trouble understanding written language or pictures

88 Agnosia Have we met?

89 Agnosia inability to recognize objects by a particular sensory modality even though the sensory modality itself is intact Parietal lobe Unilateral inatension, when lesion is in representational hemisphere (right one)

90 Thank you! Magdalena Gibas-Dorna

Introduction to Physiological Psychology Review

Introduction to Physiological Psychology Review ksweeney@cogsci.ucsd.edu www.cogsci.ucsd.edu/~ksweeney/psy260.html n Learning and Memory n Human Communication n Emotion 1 What is memory? n Working Memory: