NEUROFISIOLOGIA E
PATOLOGIA DEI
PROCESSI COGNITIVI:
Il Lobo Temporale
What are we doing with our
brains at this moment?
•
•
•
•
•
•
•
•
•
•
•
’
Feeling your chair
Squirming (moving)
Watching
Listening
Remembering
Paying attention
Writing
Feeling anxious
Feeling hungry
What happens when you ask a question?
Learning
What are we doing with our
brains at this moment?
•
•
•
•
•
•
•
•
•
•
•
’
Feeling your chair
Squirming (moving)
Watching (me, slides, mobile, the lady on the right)
Listening
Remembering
Paying attention
Writing
Feeling anxious
Feeling hungry
What happens when you ask a question?
Learning
Lobi e solchi degli emisferi cerebrali
Localizzazione dell’insula , visibile aprendo la scissura di Silvio ( solco
laterale)
Major lobes – hidden and visible
insula and Sylvian fissure
Insula is responsible for: ‘gut feelings’ like sense of nausea and disgust,
interoception (feeling internal organs), emotional awarness.
Sylvian fissure runs between parietal and temporal lobes horizontaly
towards junction with occipital lobe. It contains supratemporal plane that
hosts primary and secondary auditory cortex and part of Wernicke’s area
for speech comprehension.
6
AREE CORTICALI
MONOMODALI PRIMARIE: sensitive primarie, motoria primaria
MONOMODALI SECONDARIE : sensitive secondarie
motorie secondarie
AREE ETEROMODALI : aree associative frontali, parietali,
temporali
Aree motorie, uditive, somatosensitive, visive , olfattive e associative
negli emisferi di 3 diversi mammiferi.
Si può notare l’enorme aumento nelll’uomo delle
aree associative
Le aree corticali motorie, uditive, somatosensitive, visive , olfattive
sono aree primarie strettamente correlate con il mondo esterno
( sensitivo-motorie)
Nell’uomo le aree associative consentono un elaborazione avanzata degli
stimoli interni/esterni
Vengono divise in unimodali ( es aree 18-19 corteccia visiva)
e eteromodali o multimodali che sono correlate a funzione di
integrazione
AREE ASSOCIATIVE ETEROMODALI
• CORTECCIA PREFRONTALE
• CORTECCIA PARIETALE POSTEROINFERIORE
• CORTECCIA TEMPORALE LATERALE
• GIRO PARAIPPOCAMPALE
• convergenza di tutti gli stimoli dalle aree unimodali
• controllo sistema limbico e centri sottocorticali
LOBO TEMPORALE
giro temporale superiore
giro temporale medio
giro temporale inferiore
giro fusiforme ( occipito-temporale)
Funzioni: integrazione uditiva, linguaggio (porzione posteriore del giro
superiore, area di Wernicke)
funzioni visuospaziali, apprendimento e memoria
External part of the temporal lobe on
a dissected brain Central sulcus limit
between frontal and parietal
lobe and posterior limit of
primary motor area
Post central
sulcus posterior
limit of primary
sensory area in
parietal lobe
With a blue
arrow:
gyrus
With a red
arrow: sulcus
Terminal branch
sylvian fissure
Heschl’s
gyrus
external part of
primary auditive
area
Gyrus supra
marginalis
( parietal lobe)
Wernicke’s
area belongs to
superior temporal
gyrus
Sylvian
fissure-
Superior
temporal
gyrus
Superior
temporal
sulcus
Middle
temporal
gyrus
Inferior
temporal gyrus
Inferior
temporal
sulcus
6
MRI on horizontal plane of the temporal
lobe
Midbrain
Temporal
pole
Amygdaloid
nucleus
Parahippocampal
gyrus
Arbitrary
delineation
between
parahippocampal
gyrus and lingual
gyrus
Lingual
gyrus
Ento
rhinal
sulcus
Collateral
sulcus
The course of the
collateral sulcus
may be interrupted
in some part of its
course
Collateral
sulcus
Fusiform
gyrus
Lingual gyrus and fusiform gyrus belong to the temporo occipital area
20
I sistemi di connessione
Fasci di associazione tra le diverse aree corticali (DTI)
A, arcuate (superior longitudinal) fasciculus; C, cingulum; EC, extreme capsule; F, fornix and stria
terminalis ; H, hippocampus; IL, inferior longitudinal fasciculus; IO, inferior occipitofrontal
fasciculus; P, putamen; SO, superior occipitofrontal fasciculus (combined with the subcallosal
fasciculus adjacent to it); Th, thalamus; U, uncinate fasciculus.
SINDROMI DA DISCONNESSIONE:
INTERRUZIONE DELLE CONNESSIONI
TRA AREE UNIMODALI/ ETEROMODAI DIVERSE
( es.: anomia per i colori)
http://www.nfos.org/degree/opt41/3
Dalle connessioni tra le diverse aree cerebrali nascono reti specifiche.
• Linguaggio
• Attenzione spaziale
• Funzioni esecutive e comportamento
• Emozioni e memoria
• Riconoscimento di facce e oggetti
Localization of function in the nervous
system: Functional networks
5
major brain systems subserving
cognition and behavior
Left perisylvian language network
Parieto-frontal network for spatial attention
Occipitotemporal network for object/face recognition
Medial temporal/limbic network for learning & memory
Prefrontal network for attention & comportment

Lateralization of functions
(approximate)
• Left-hemisphere:
– Sequential analysis
• Analytical
• Problem solving
– Language and
communication
– Emotional functions
• Recognizing emotions
• Expressing emotions
– Music Competence
• Right-hemisphere:
– Simultaneous analysis
• Synthetic
– Visual-Spatial skills
•
•
•
•
Cognitive maps
Personal space
Facial recognition
Drawing
– Emotional functions
• Perceiving emotions
• Showing emotions
– Music perception
SUONI E LINGUAGGIO
Onward to the Brain!
• Organ of Corti transmits signals
to the cochlear nerve
• Medulla
– Cochlear Nucleus to Superior
Olivary Complex
• Lateral Lemniscus fiber bundle
carries information to the inferior
colliculus
• Proceeds to the Medial
Geniculate Nucleus of the
thalamus and on to the auditory
cortex
http://www.neuroreille.com/promenade/english/ptw/zoom1.htm
Auditory cortex
• In humans primary auditory
cortex is located within Heschl’s
gyrus.
– Heschl’s gyrus corresponds
to Brodmann’s area 41.
• Another important region in
auditory cortex is planum
temporale located posterior to
Heschl’s gyrus.
– Planum temporale is much
larger in the left hemisphere
(up to 10 times) in right
handed individuals.
– It plays important role in
language understanding.
• Posterior to planum temporale is
Broadmann area 22 that Carl
Wernicke associated with
speech comprehension
(Wernicke area).
22
Speech perception
Brain response to: Words
Pseudowords
Reversed speech

Binder and colleagues (1997) studied activation of brain areas to
words, reverse speech and pseudowords and found that Heschl’s
gyrus and the planum temporale were activated similarly for all
stimuli.

This supports the notion of hierarchical processing of sounds with Heschl’s gyrus
representing early sensory analysis.
Speech signals activated larger portion of auditory cortex than non-speech sounds
in posterior superior temporal gyrus and superior temporal sulcus, but there was no
difference in activation between words, pseudowords and reversed speech.

 The conclusion is that these regions do not reflect semantic
processing of the words but reflect phonological processing of the
speech sounds.
23
Functional mapping of auditory processing
The planum temporale (PT) location
close to Wernicke’s area for speech
comprehension, points towards its
role as the site for auditory speech
and language processing.
 However neuroimaging studies of PT
provide evidence that functional role
of PT is not limited to speech.
 PT is a hub for auditory scene
analysis, decoding sensory inputs
and comparing them to memories and
past experiences.
 PT further directs cortical processing
to decode spatial location and
auditory object identification.
 Planum temporale and its major
associations: lateral superior temporal
gyrus (STG), superior temporal sulcus
(STS), middle temporal gyrus (MTG),
 parieto-temporal operculum (PTO),
inferior parietal lobe (IPL).
24

Functional mapping of auditory processing




Auditory objects are
categorized into human
voices, musical instruments,
animal sounds, etc.
Auditory objects are learned
over our lifetime, and
associations are stored in
the memory.
Auditory areas in superior
temporal cortex are activated
both by recognized and
unrecognized sounds.
Recognized sounds also
activate superior temporal
sulcus and middle temporal
gyrus (MTG).
Fig. (c) shows difference between
Activations for recognized sounds
and unrecognized sounds
25
Functional mapping of auditory processing



Binder and colleagues
propose that middle temporal
gyrus (MTG) is the region
that associates sounds and
images.
This is in agreement with
case studies of patients who
suffered from auditory
agnosia (inability to
recognize sounds).
Research results showed
that auditory object
perception is a complex
process and involves
multiple brain regions in both
hemispheres.
Brain activities in auditory
processing – cross sections at
different depth
26
Function source : Palmer & Hall, 2002
• Numerous bilateral regions are
frequency-dependent
• Overlapping
regions
are
sensitive to intensity and to the
temporal changes in sound
• One region is sensitive to the
spatial properties of sound
(R>L)
• Speech also activates these
regions, but neurons are
probably responding to the
complex acoustic properties in
the sound.
•Perceptual attributes may be
important
27
L
L
H
H H
L
L
Right
hemisphere
Slow-rate temporal
pattern in sound
Auditory Cortex
• Tonotopic Organization
– Different frequencies
of sound are mapped to
different regions of the
auditory cortex
– Extends to the level
of the cochlea
Zhou, X. and M. M. Merzenich (2007).
"Intensive training in adults refines A1
representations degraded in an early
postnatal critical period." Proceedings of the
National Academy of Sciences 104(40):
15935-15940.
• Sound intensity and activation
• Loud sounds (90 dB) activated posterior and medial temporal
gyrus (red)
• Soft (70 dB) sounds activated area (yellow) is found most laterally
of TTG
• Medium intensity (82 dB) sounds activated intermediate area
(green). (NeuroImage 2002;17: 710)
29
Auditory agnosia
• A deficit in recognition
Perception
Auditory
input
Acoustical analysis
Representations
“Apperceptive
agnosia”
“Associative
agnosia”
Auditory agnosia is of this type
30
Recognition
• sordità verbale pura ( lesione bitemporale o sinistra,
area 22)
• agnosia acustica ( area acustica secondaria)
What is Language?
• Grammar
– Phonetics, morphology, syntax, semantics
•
•
•
•
•
Symbol usage
Ability to represent real-world situations
Ability to articulate something new
Intention to communicate
Duality, productivity, arbitrariness, interchangeability,
specialization, displacement, and cultural
transmission (Linden 1974)
“An infinitely open system of communication”
Rumbaugh, 1977
Schematic representation of the
components that are involved in
spoken and written language
comprehension.
Input can enter via either auditory
(spoken word) or visual (written word)
modalities.
The flow of info is bottom up, from
Perceptual identification to
“higher-level” word and lemma
activation.
Interactive models of language
Understanding would predict top-down
influence to play a role as well.
W. W. Norton
Outline of the theory of
speech production developed by
William Levelt (1999)
Adapted from Levelt, W.J.M., The Architecture of Normal Spoken Language Use, in Blanken, G., Dittman,
J., Grimm, H., Marshall, J.C., and Wallesh, C-W. (Eds.), Linguistic Disorders and Pathologies: An
International Handbook. Berlin: Walter de Gruyter, 1993
Speech Production
Brain areas involved in Language
Wernicke-Geschwind Model
1. Repeating a spoken word
• Arcuate fasciculus is the bridge from the Wernicke’s
area to the Broca’s area
Wernicke-Geschwind Model
2. Repeating a written word
• Angular gyrus is the gateway from visual cortex to Wernicke’s
area
• This is an oversimplification of the issue:
– not all patients show such predicted behavior (Howard, 1997)
Functional neuroimaging of the language
network
One to many, many to one
CJ Price, J Anat 2002
Language function: Using neuroimaging
to test hypotheses
CJ Price, J Anat 2002
Brain Imaging
fMRI:Record during
language tasks
– Activated brain areas
consistent with temporal
and parietal language
areas
– More activity than
expected in nondominant
hemisphere
Generate words
from a category
Silently repeat
a heard sentence
Listen to a story
Slide 42
Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins
A functional MRI protocol for localizing language comprehension in
the human brain
Gary W. Thickbrooma ,*, Michelle L. Byrnesa, David J. Blackerb, Ian T. Morrisc,
a,b,d Frank L. Mastaglia
Brain Research Protocols 10 (2003) 175–180
TONE DECISION TASK
Semantic decision
PET by Damasio’s
• Different areas of left hemisphere (other than
Broca’s and Wernicke’s 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
Wernicke’s area):
– “the man started the car engine and stepped on
the pancake”
– Takes longer to process if grammar is involved
LETTURA
Neural systems for reading
• Converging evidence indicates three important
systems in reading, all primarily in the left hemisphere– Some right hemisphere activation now implicated;
• These include an anterior system and two posterior
systems:
1) anterior system in the left inferior frontal region;
2) dorsal parietotemporal system involving angular
gyrus, supramarginal gyrus and posterior portions of
the superior temporal gyrus;
3) ventral occipitotemporal system involving portions
of the middle temporal gyrus and middle occipital
gyrus
50
Dorsal (Green) and Ventral Pathways (Purple)
Written language neural
pathway
• Visual input transmitted from lateral
geniculate to primary cortex in striate
areas and secondary extrastriate cortex.
• From here 2 streams– Ventral (what): unimodal visual area of
fusiform gyrus (may contain ortho reps of
words)
– Dorsal (where): superior parietal lobule for
spatial aspects of reading.
52
Heteromodal areas
• Wernicke’s including angular gyrus, supramarginal gyrus
– Likely responsible for integration of written & spoken word
forms.
– Wernicke’s is massively connected to inferior temporal
category specific areas for faces animals, tools
– Also with frontal areas for overt speech production
(Broca’s), and reciprocal connections for memory and
manipulating verbal information.
53
Confirmed two systems for reading
• word analysis
– operating on individual units of words such as phonemes,
requiring attentional resources and processing relatively
slowly
• Parietotemporal area
and
• visual word attention
– an obligatory system that does not require attention and
processes very rapidly, on the order of 150 msec after a
word is read; Price et al 1996.
• Occipitotemporal area
• visual word form area appears to respond preferentially to
rapidly presented stimuli (Price et al 1996) and is engaged
even when the word has not been consciously perceived
(Dehaene et al 2001).
54
Due sistemi corticali: dorsale e ventrale
Cellular responses in ventral stream
• V2-V4 especially orientation & color sensitive
– V4 contains color sensitive cells
– some have complex preferred stimuli
• Inferior temporal cortex (IT) is form sensitive
– big receptive fields (up to entire visual field)
– face selective cells in some regions
– others respond best to complex, 3D stimuli (Tanaka)
www.cnbc.cmu.edu/~mgilzen/85219/slides/Week8a.ppt
Effects of lesions to ventral stream
• Animal studies
– Damage to P pathway inputs abolishes color
perception
– Damage to IT impairs discrimination between
objects and identification
• Human patients
– Achromatopsia
• Loss of color perception
• Associated with damage to lingual and fusiform gyri
– Agnosia
• Apperceptive
• Associative
• Prosopagnosia
www.cnbc.cmu.edu/~mgilzen/85219/slides/Week8a.ppt
PERCEZIONE VISIVA
Visual processing streams: Confirmation
of hypotheses using neuroimaging
Ungerleider LG, PNAS 1998
Visual processing: Attention influences
which stream is used
Ungerleider LG, PNAS 1998
Encoding & recall of categoryspecific information
Faces: Fusiform gyrus
Places: Parahippocampal gyrus
Encoding of category-specific information activates
relevant areas of cortex
Polyn SM et al., Science, 2005
Visual object recognition: Faces & places
Kanwisher N, Science, 2006
Fusiform Face Area (FFA)
• functional brain imaging
investigations of the
normal human brain show
that a region in the
fusiform gyrus is not only
activated when subjects
view faces, but is activated
twice as strongly for faces
as for a wide range of nonface stimuli (Kanwisher et
al., 1997)
L’altra faccia della luna
IL LOBO LIMBICO TEMPORALE
Functions of The Limbic System
LOBO LIMBICO
giro del cingolo
giro paraippocampale
giro paraterminale ( lamina terminalis)
giro subcallosale
ippocampo, paraippocampo, uncus
Emozioni, apprendimento , memoria
Medial Temporal Lobe (MTL)
• Hippocampus
• Connected areas
– Entorhinal cortex
– Perirhinal cortex
– Parahippocampal cortex
Bird & Burgess, Nature Reviews Neuroscience 9, 182-1
Function of MTL
• Principally concerned with memory
• Operates with neocortex to establish and maintain long-term
memory
• Ultimately, through a process of consolidation, becomes
independent of long-term memory
MTL
Simons & Spiers (2003) Nature Reviews Neuroscience 4; 637
STRUTTURA DELL’IPPOCAMPO
A: ricostruzione dell’ippocampo e del fornice.
B : struttura del giro dentato e del corno d’Ammone
C, sezione coronale del giro dentato, ippocampo e
subiculum
D, diagramma delle cellule e fibre dell’ippocampo Le
fibre efferenti dall’ippocampo si originano da cellule
piramidali .
La maggior parte delle efferenze originano dal
subiculum.
Il flusso di informazioni proviene maggiormente
dalla corteccia entorinale > giro dentato> cellule
piramidali dell’ippocampo e subiculum> fornice
Nel giro dentato dono presenti cellule staminali.
(B, modified from Duvernoy HM: The human hippocampus: functional anatomy, vascularization
and serial sections with MRI, ed 3, Berlin, 2005, Springer-Verlag. C, modified from Nolte J,
Angevine JB Jr: The human brain in photographs and diagrams, ed 3, St. Louis, 2007, Mosby.)
• CA1 > CA4 = zone del corno d’Ammone ( ippocampo = corno d’Ammone + giro dentato)
• Paraippocampo = subiculum + corteccia entorinale
Settore CA1 del C.Ammone = settore di SOMMER : compostoa da grandi cellule piramidali,
Con metabolismo molto attivo, alta densita di recettori NMDA, estrema sensibillità all’ipossia,
Marcato potenziamento post-sinaptico ( 2 ore per singolo stimolo in arrivo)
 Memoria sinaptica
 Neuroplasticità
 Crisi epilettiche
Connessioni anatomiche dell’ippocampo
Input e out
dell’ippocampo:
è una struttura nervosa
della regione
temporale mediale
Gli input
all’ippocampo:
arrivano tramite
stazioni di
ritrasmissione nelle
corteccie peririnali,
paraippocampali ed
entorinali
Le uscite
dall’ippocampo:
seguono il percorso
opposto. Gli inputoutput sotto-corticali
dell’ippocampo
viaggiano nel fornice
AFFERENZE DELL’IPPOCAMPO:
• corteccia entorinale ( bulbo olfattorio)
• amigdala
• nuclei settali
• ippocampo controlaterale
• locus coerulus
.
(Modified from an illustration in Warwick R, Williams PL: Gray's anatomy, Br ed 35, Philadelphia, 1973, WB Saunders.)
EFFERENZE DELL’IPPOCAMPO
• Fornice ( attraverso il fornice le informazioni provenienti dall’ippocampo
raggiungono i corpi mammilari,il nucleo anteriore e mediodorsale del talamo,
il cingolo)
Papez Circuit (memory)
Fornix
Mammillary bodies
Other hypothalamic nuclei
Septal nuclei
Substantia innominata
(Basal nucleus of Meynert)
Hippocampal Formation
(hippocampus
and dentate gyrus)
Parahippocampal Gyrus
Neocortex
Mammillothalamic
tract
Anterior Thalamic
nuclear group
Cortex of Cingulate Gyrus
The Papez circuit.
The shortcut from the hippocampus directly to the anterior thalamic nucleus,
not part of the circuit as originally proposed, is indicated by a dashed line. A,
anterior thalamic nucleus; CA, hippocampus proper; D, dentate gyrus; MB,
mammillary body.
(Modified from an illustration in Warwick R, Williams PL: Gray's anatomy, Br ed 35, Philadelphia, 1973, WB Saunders.)
IPPOCAMPO E MEMORIA
Nel 1957 un paziente di nome H.M. fu trattato chirurgicamente
per epilessia resistente alla terapia farmacologica con asportazione bilaterale
dell’ippocampo e dell’amigdala.
HM soffri da quel momento di un grave disturbo della memoria episodica
Dopo molti anni dall’intervento il paziente fu sottoposto a RM encefalo.
Il suo caso dimostrò in modo conclusivo il ruolo fondamentale della
parte mediale del lobo temporale nella memoria
HM
AMIGDALA
L’amigdala è un insieme di
circa 12 nuclei situati in
prossimità dell’uncus,
vicino alla parte anteriore
dell’ippocampo, e accanto
al corno temporale del
ventricolo laterale .
Origina dalla corteccia
periamigdaloidea , che
forma parte della
superficie del’uncus.
I nuclei dell’amigdala vengono classificati in 3 principali gruppi :
mediale, centrale e basolaterale, ognuno con diverse funzioni.
Nucleo mediale: è connesso con il sistema olfattorio ed è piuttosto
piccolo negli esseri umani.
Nucleo centrale : collegato all’ipotalamo e alla sostanza grigia
periacqueduttale ha funzioni emozionali
Nucleo basolaterale: è il nucleo più grande negli esseri umani, contiene
cellule piramidali ed è strettamente collegato agli altri nuclei
Suddivisione dell’amigdala
nei
principali nuclei
(basolaterale,
centrale e mediale) con le
principali connessioni.
( PH, parahippocampal
gyrus)
Amygdala Connections
Cerebral cortex
Olfactory system
Thalamus
Brainstem reticular formation
Stria
terminalis
Hypothalamus
AMYGDALA
Ventral Amygdalofugal
fibers
Amygdala Inputs
Olfactory
System
Temporal Lobe
(associated with visual,
auditory, tactile senses)
AMYGDALA
Corticomedial Nuclear
Group
Basolateral Nuclear
Group
Central Nucleus
Brainstem (viscerosensory relay
Nuclei: solitary nucleus
and parbrachial nucleus)
Ventral
Amygdalofugal
Fibers
Maggiori input ai nuclei basolaterale(blu), centrale(rosso) e mediale
(verde) dell’amigdala.
Sono evidenziati gli input dalle aree visive , ma simili proiezioni
esistono dalle principali aree unimodali e dalle altre aree limbiche.
B, brainstem (periaqueductal gray, parabrachial nuclei, other nuclei);
Hy, hypothalamus; S, septal nuclei; T, thalamus (multiple nuclei).
(Modified from Warwick R, Williams PL: Gray's anatomy, Br ed 35, Philadelphia, 1973, WB Saunders.)
Principali efferenze dai nuclei dell’amigdala ( blu= basolaterale;rosso=centrale; verde=
mediale)
(1) stria terminalis: verso i nuclei del setto e l’ipotalamo
(2) Via amigdalofugale e Via amigdalofugale ventrale ( ipotalamo e talamo MD)
(3) proiezioni diffuse alla corteccia frontale ventromediale , corteccia insulare, striato
ventrale, aree olfattorie , tronco encefalico .
(4) connessioni dirette con l’ippocampo e il lobo temporale.
(Modified from Warwick R, Williams PL: Gray's anatomy, Br ed 35, Philadelphia, 1973, WB Saunders.)
Riepilogando:
L’amigdala riceve una gran quantità di input :
1. Molti di questi sono semplici e famigliari, riguardando stimoli visivi,
suoni, stimoli tattili, odori e.
Gli stimoli olfattivi raggiungono direttamente il nucleo mediale , dalla
corteccia e bulbo olfattorio ( tratto olfattorio).
Gli altri tipi di stimoli raggiungono il nucleo basolaterale dal talamo e
dalle cortecce unimodali visiva, uditiva, gustativa e somatosensitiva.
2. Un altro tipo di stimolo arriva all’amigdala dall’insula, dal cingolo e dalla
corteccia orbitofrontale ( via amigdalofugale)
3.Infine l’amigdala riceve input viscerali provenienti dall’ipotalamo ( stria
terminalis) e dal tronco encefalico ( grigio periacqueduttale ,
n.parabrachiale)
Le efferenze dall’amigdala raggiungono le stesse aree da cui l’amigdala
riceve degli input
Limbic System and Basal Nuclei
Anterior Cingulate Gyrus
Orbitofrontal Areas (10, 11)
Medial and lateral temporal lobe
Hippocampus
Amygdala
Entorhinal cortex (24)
Ventral Pallidum
Medial Globus Pallidus
Pars Reticularis
(Substantia nigra)
Ventral Striatum
(nucleus accumbens)
Caudate Nucleus
(head)
Ventral Anterior Nucleus
Dorsomedial Nucleus
Functions of the Amygdala
• Relate environmental stimuli to
coordinated behavioral autonomic and
endocrine and motor responses seen in
species-preservation.
• Responses include:
Feeding and drinking
Agnostic (fighting) behavior
Mating and maternal care
Responses to physical or emotional stresses.
La connessione limbica tra amigdala e gangli della base influenza le
decisioni riguardo al movimento e, più in generale, è necessaria per
l’associazione stimolo-ricompensa.
Qualsiasi cosa possa apparire piacevole determina un aumento di
rilascio di dopamina nello striato che si traduce successivamente in
un’azione; avviene il contrario per ciò che consideriamo spiacevole
Neuro-anatomy of hedonic regulation of food intake; reward (or pleasure)
seeking areas of the brain control orexigenic neurons of LHA
L’amigdala, attraverso le sue connessioni , in
particolare con la corteccia frontoventromediale e
l’ipotalamo, svolge un ruolo fondamentale nella vita
emotiva.
Quando l’amigdala di un animale viene stimolata
l’animale si ferma e rimane attento: a ciò può far
seguito una risposta di difesa, rabbia, aggressione, o
di fuga
La stimolazione dell’amigdala nell’uomo evoca più
spesso paura accompagnata dalle reazioni
vegetative corrispondenti .
La distruzione bilaterale dell’amigdala determina un
assenza di paura e di aggressività con mancanza di
reazioni vegetative .
L’assenza congenita dell’amigdala impedisce
l’apprendimento di reazioni comportamentali
complesse in risposta a determinate situazioni
LA PATOLOGIA
Symptoms of Temporal-Lobe Lesions
Pathologies (lesions)
• Voracious appetite
• Increased (perverse) sexual activity
• Docility:
Loss of normal fear/anger response
• Memory loss:
Damage to hippocampus portion:
Cells undergoing calcium-induced changes
associated with memory
Temporal lobectomy
• Brown and Schäfer (1888) reported
behaviour of monkey ‘Tame one’ after
bilateral temporal lobectomy.
• Preop: wild, fierce
• Postop:
– Does not retaliate or escape if slapped,
tame
– Poor memory and intelligence
– Evidence of hearing and seeing, but ‘no
longer clearly understands meaning of
sights, sounds.’
– Does not select raisins from other food in
dish: does not seem to visually recognize
97 items.
Kluver-Bucy Syndrome:
• Results from bilateral destruction of
amygdala.
• Characteristics:
Increase in sexual activity.
Compulsive tendency to place objects in mouth.
Decreased emotionality.
Changes in eating behavior.
Visual agnosia.
Delusional Misidentification
Syndromes
•
3 DMS:
1. Pick [1903] “reduplicative paramnesia”
•
Misidentifies familiar places as replica
2. Capgras Syndrome [1923]
•
Familiar people described as doppelgangers
–
visual but not emotional recognition
3. Frégoli Syndrome [1927]
•
•
DMS are rare
–
–
99
Person misidentified as someone else with totally different
appearance.
Rare enough to be of little clinical importance
Yet, may still reveal how emotions are processed
Hirstein and Ramachandran
[1997]
• H&R postulate that DMS is caused by
disconnection between visual recognition
system and emotional system.
• E.G. Capgras syndrome due to
disconnection between fusiform gyrus
[face area] and amygdala [limbic system]
100
Hudson and Grace
• 71 women suffered lesion to anterior fusiform
gyrus (between face area and amygdala)
– Frégoli Syndrome
• Identified husband as elder sister (who had died 3 years
previously)
• Only visual misidentification (fine on phone)
• Home was ‘replica’ would pack bags to return to ‘real’
home.
• Support for H&R
101
Pain asymbolia
• Patient’s report they can feel pain, but it no
longer hurts.
• Ramachandran (1998): speculates
disconnection of insula from cingulate
(part of limbic system)
– Insula identifies pain
– Cingulate does not receive signal, so
discounts threat
102
I DISTURBI ACUSTICI E DI
LINGUAGGIO
Auditory agnosia source : Griffiths et al. 1999
• Normal brainstem processing
• Midbrain impairment questionable
• Cortical deficit in perception
- Preserved hearing (pure tones)
- Disordered perception of certain sounds :
Speech - word deafness
Music - amusia
Environmental sounds - environmental sound agnosia
104
A case of word deafness source: Ellis & Young, 1988
• Hemphill and Stengel (1940)
“I can hear you dead plain, but I cannot get what you say. The noises are
not quite natural. I can hear but not understand”
- Normal pure tone audiometry
- Fluent speech “no errors of grammar beyond what is common for his
particular dialect and standard of education”
- Normal reading
- Normal writing and spelling
- Poor spoken word repetition
- Gross asymmetry between spoken and written word comprehension
105
Word deafness source : Ellis & Young, 1988
• Associated symptoms
- Some hearing loss (> 20 dB HL)
- Production (Broca’s) aphasia
- Perception of melody
- Perception of environmental sounds
• Lesion site
- Generally large bilateral infarcts
- When unilateral, it’s more often the left hemisphere
- Involves superior temporal lobe (non-primary auditory cortex)
- May or may not involve Heschl’s gyrus (primary auditory cortex)
106
A case of amusia source : Peretz, 1993
Patient CN
• Symptoms
- Unable to recognise even simplest tune
- Unable to sing children’s songs that she had known well
- No deficit in everyday verbal communication
- No deficit in everyday recognition of environmental sounds
• Lesion site
- Bilateral temporal lobe damage
- When unilateral, it’s more often the right hemisphere
107
Amusia source : Peretz, 1993
• Dissociation within
musical perception
- Right injury - Deficit in melody
perception: the variations in pitch
- Left injury - Deficit in rhythm
perception:
the
temporal
organisation of melody over 100s of
milliseconds or seconds time scale
108
Environmental sound agnosia
source : Griffiths et al. 1999
• Deficit rarely occurs in isolation
Environmental sounds contain fewer changes in acoustic structure over time
than an equivalent length segment of speech or music
109
A common deficit? No! source : Peretz, 1993
• Word deafness, amusia and environmental
sound agnosia are distinct
- speech and music can dissociate after brain damage
- music and environmental sounds can dissociate after brain damage
- environmental sound perception can be selectively spared
- recovery can follow different patterns (e.g. environmental sounds, then
music then speech or in the reverse order)
110
A common deficit? Yes! source : Griffiths et al. 1999
• Word deafness, amusia and environmental sound
agnosia probably co-occur
- May not always be report because not all abilities are tested
• All 3 types of sound contain a mixture of acoustic
features
• Deficit in an intermediate level of analysis, which is
rarely tested
- Analysing the spectro-temporal pattern in sound
111
Auditory neglect
source : Pavani et al., 2003
Symptoms
(a) Rightward biases in sound localization
(b) Poor relative judgements for sounds on the contralesional side
(c) Poor elevation judgements for sounds on the contralesional side
Failure to detect contralesional sound, when presented concurrently
Poor allocation of attention to sounds separated in time
112
Auditory neglect
Lesion site – usually right hemisphere
- inferior parietal lobe
- superior temporal gyrus
- temporo-parietal junction
113
source : Pavani et al., 2003
Quadro riassuntivo
Summary: Correlations of symptoms
with areas of lesion
Aphasic Syndrome
Area of Damage
Broca’s
Broca’s area
Wernicke’s
Wernicke’s area
Conduction
SMG, Insula,
Arcuate fasciculus
Transcortical motor
Transcortical sensory
Areas anterior and/or
superior to Broca’s area
Areas posterior and/or
superior to Wernickes a.
Cf. H. Damasio 1998: 43-44
Two different patients with anomia
Inability to retrieve words for
unique entities
Deficit in retrieval of
animal names
(Left temporal lobectomy)
(Damage from stroke)
Two more patients with anomia
Deficit in retrieval of words for
man-made manipulable
objects
(Damage from stroke)
Severe deficit in retrieval of words
for concrete entities
(Herpes simplex encephalitis)
I DISTURBI AGNOSICI
Cerebral Achromatopsia
Ishyhara plates
Color Agnosia
• What causes it?
– Damage to the extrastriate visual cortex, specifically
the V4 area.
– The visual area 4 (V4) is cut off from sending
information to the lingual gyrus, fusiform gyrus and
inferior temporal gyrus.
– Without the ability to send that information to the
“What” pathway of the temporal lobe, the color
cannot be recognized.
Cerebral Achromatopsia
Usually caused by bilateral damage to V4
(lingual and fusiform gyri (occipitotemporal junction))
characterized by an inability to identify or discriminate colour
Usually full field deficit but hemiachromatopsia possible if
damage is unilateral
Still able to perceive form and motion - dissociation with
akinetopsia and visual form agnosias
Achromatopsia is not:
a)
b)
c)
d)
due to peripheral damage (e.g. retina)
due to primary visual area damage
colour agnosia: disorder of colour categorization
colour anomia: disorder of colour naming
Which part of V4?
Damasio et al., (1989b) in Heilman and Rothi (1993)
42 patients.
achromatopsia associated with lesions below
calcarine sulcus that damaged middle third of lingual
gyrus, but not fusiform gyrus
Calcarine sulcus
Lingual Gyrus
Fusiform Gyrus
Prosopagnosia
• Special nature of face processing originates
from reports of patients who are reportedly
unable to recognize familiar faces while
maintaining the ability to recognize objects.
– This impairment is often accompanied by focal
damage to the ventral occipitotemporal and
temporal cortices.
– Reported to process faces similar to objects
(sometimes absence of inversion effects).
Prosopagnosia
Why just faces? What about objects?
 Fusiform gyrus responds to faces
 Parahippocampal gyrus responds to inanimate objects
Double Dissociation- The areas for recognizing faces and
inanimate objects are separate therefore agnosia for objects and
prosopagnosia do not occur together
Face Processing:
Cognitive and Neural Components
Bruce & Young
(1986)
Haxby et al., (2000
Importance of Facial Configuration
• the importance of the overall configuration of
the face can help us understand why face
recognition can be remarkably robust despite
a variety of natural (change in expression,
orientation etc) as well as unnatural (cartoons)
transformations in faces.
Prosopagnosia
• Marotta, Genovese, & Behrmann (2001)
– fMRI of prosopagnosic patient did not show
normal activation of fusiform.
– Did show left hemisphere posterior fusiform
activation, suggesting faces are being processed
featurally.
Fig. 4-18, p. 83
Prosopagnosia
Brain region involved
George et al. (1999).
fMRI study of positive and
reverse contrast faces.
Bilateral fusiform gyri
response to faces
Right fusiform gyrus only
when face became familiar
(Note contrast to Alexia)
Image of Left Fusiform Gyrus (Visual Word Form Area -VWFA)
and Right Fusiform Gyrus (Weiner et al, 2004.)
The left fusiform gyrus
( referred to as the
visual word form area)
is responsible for
word recognition.
The right fusiform gyrus
is (referred to as the
fusiform face area)
responsible for facial
recognition.
What Causes Prosopagnosia?
• Damage to occipitaltemporal regions of the brain
– Specifically the fusiform gyrus of the interior temporal cortex
– The cause of damage can be from head injury, degenerative
diseases (ex. Alzheimer’s and Parkinson’s disease), right
temporal lobe atrophy, encephalitis, or strokes (ex. Posterior
cerebral artery stroke or transient ischemic attack).
• There is also a genetic form of prosopagnosia that can be passed
down from a parent to child. Prosopagnosia can also be the result
of a developmental disorder.
• Evolutionarily facial recognition is important
– There must be an adaptive benefit for facial recognition. Newborns
show great preference for human faces despite their poor visual acuity.
Newborns use eye contact and facial expressions to engage caretakers
to take care of their needs. Socially facial recognition became essential
to survival because it provides self-identity, identity for group
members, and identity for non-group member (could be an enemy?).
LA MEMORIA
Memory and Forgetting
Classificazione dei tipi di memoria.
Memoria
Esplicita
(dichiarativa)
Episodica
Semantica
Implicita
Procedurale
Emotiva
Vegetativa
(condizionamento)
• cos’è una bicicletta
• ieri sono andato in bicicletta
• andare in bicicletta dopo 10 anni
• ho paura della bicicletta ( non so perché)
memoria semantica
memoria episodica
memoria procedurale
memoria emotiva
Brain regions in Learning and Memory
Patient H.M.
• Bilateral temporal lobe resection for treatment of epilepsy.
• Included removal of hippocampus and amygdala from both sides.
• Various etiologies lead to symptoms like H.M.'S, including stroke and herpes
Case of Patient H. M.
• Age 9, knocked over by a bicycle rider,
sustained brain damage
• Age 16, suffered bilateral temporal lobe
seizures which became uncontrollable
– Unable to work and lead a normal life
• Age 27, underwent bilateral removal of
hippocampal formation, amygdala, parts
of multimodal association areas of
temporal cortex (1953)
Consequences of Psychosurgery for H.M.
• Positive
- seizures better controlled
- IQ unaffected; bright
- good long term memory for
events before the surgery
- good command of language
including vocabulary
- remembered his name and job
he held
• Negative
• suffered anterograde amnesia unable to transfer new short-term
memory into long term memory
– unable to retain for more than a
minute new people, places or
objects
– unable to recognize people he met
during surgery including his
neurosurgeons
– took a year to learn his way around
a new house
- suffered retrograde amnesia for
information acquired a few years
before surgery
Patient HM
• Revealed declarative/ nondeclarative distinction
– Declarative memories (explicit memories) involve
conscious recollection of events and information.
• H.M. Lost this ability.
– Nondeclarative memories (implicit memories) involve
ability to acquire and perform new behaviors or
associations.
• H.M. Retained this ability.
– could perform mirror-tracing after training but could not
remember doing the task before
Semantic Dementia (Snowden 1989)
• Semantic memory (Warrington 1975):
• Term applied to the component of long-term
memory which contains the permanent
representation of our knowledge about things
in the world: facts, concepts and words
• Culturally shared, acquired early in life.
Semantic Dementia (Snowden 1989)
• Affects fundamental aspects of language,
memory and object recognition.
Semantic Dementia
• Progressive anomia, not an aphasia, but a loss of
semantic memory.
• Impaired: naming, word comprehension, object
recognition and understanding of concepts.
• characterized by preserved fluency and impaired
language comprehension: “phonologically and
syntactically correct”
Assessement
• Category fluency
• Generation of definitions
– Lion: ” it has little legs and big ears, they sleep a lot, see them in
shops”
• Word-picture matching
• Famous faces test
• Normal episodic memory, normal visuospatial skills
• Nature of error
Semantic-type naming errors:initially within-category,
“elephant” for hippopotamus, then superordinate “dog” for
everything, then “animal”…
• Profound and complete anomia
• Circumlocutions and semantic paraphasias
– semantic paraphasias, in which the wrong word is
produced, one that is usually related to the target (eg,
"pliers" for "hammer").
• In semantic dementia the most contextfree levels of knowledge (constituting
traditional notions of semantic memory)
are most compromised.
• In contrast, patients may retain
knowledge tied to specific experiences
or routines
SD and memory
• Can relate details ( in a rather anomic fashion)
of recent events, but there is impaired recall
of distant life events.
SD
• In most cases, neuroradiological studies reveal
selective damage to the inferolateral temporal
gyri(inferior and middle) of one or both temporal
lobes, with sparing of the hippocampi,
parahippocampal gyri, and subiculum.
• Note: AD: inferior and middle temporal gyri
Semantic dementia patient with severe focal atrophy of the left temporal lobe
see arrow, right-hand side of MRI scan) involving the pole, inferior, and middle
temporal gyri with relative sparing of the hippocampal complex (H) and of
the superior temporal gyrus.
fine
Grazie per l’attenzione