Franz Joseph Gall suggested that surface of the head depends on mental skills. He is one of the firsts linking the brain to cognition.

Can modern phrenology be seen as modern cognitive neuroscience?

• Yes:
  • Functional differentiation of the brain
• No:
  • Functions are defined by thorough experimentation
  • Multidisciplinary research
  • Not just size of brain areas

Brodmann was the first to map the cortex based on cell types. More detailed maps followed later.

The structure of the brain has a reason: function.

You can measure brain activity using

• Action potentials (electrophysiology)
• local field potentials (electrophysiology)
• Electromagnetic field at scalp (EEG/MEG)
• Manipulating neural activity (TMS/tDCS)
• Blood oxygenation (fmri)

Brain elements: neurotransmitter & hormones. You can add pharmacology and food supplements.

Brain computation: making models of the brain to improve applications (facebook, google).

Cognitive neuroscience defines steps/networks in information processes by using neuroscientific methods.

EEG (ElectroEncephaloGraphy):

• Measures the differences in voltage across the scalp
• Reflects post-synaptic potentials (PSP): difference in voltage along axons.
• Both inhibitory and excitatory psp
• Reflects local field potential  not a single action potential but a summation of many neurons

When is the measurement good?:

• Mass activity
• Synchronized activity
• Close to the scalp

32-64 electrodes are enough to measure time effects.

Advantages EEG:

• Temporal characteristics
• ERP’s

EEG measures the voltage potentials and MEG measures the magnetic field. MEG is similar to EEG, but better localization and most sensitive to activity originating from sulci.

EEG = relatively cheap, measures more neurons.

MEG = expensive, better localization

EEG & MEG same temporal resolution, MEG better spatial resolution.

So slow waves = low arousal

Fast waves = high arousal

Gamma (32Hz>) = superlearning

Beta (16-31Hz) = processing information, analytical thinking

Alpha (8-15Hz) = Eyes closed or very relaxed

Theta (4-7Hz) = Sleep, REM, dreaming, deep meditation

Delta (<4Hz) = deep dreamless sleep

ADHD = hyperactive, but less cortical arousal

Treating ADHD = increase arousal with medicine

Each frequency reflects a different mental state.

Average ERP’s to cancel out the noise.

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Attention is selective. Selective attention refers to the allocation of processing resources, generally at the expense of resources allocated to other stimuli.

Neuroscientific concept: attention is the manipulation of activity of population of cells that process sensory information.

Advantages of attention:

• Detailed representation of stimuli
• Faster and more accurate response to stimuli
• Better memory of stimuli, better decision-making, etc.

Disadvantage: opposite effect for unattended stimuli.

Arousal is not attention. Arousal modulates all sensory signals  baseline effect

Attention selects and modulates specific sensory signals  selection effect

Two forms of attention:

• Overt attention: you look at what you want to attend
• Covert attention: you attend something that is outside your gaze

Internal manipulation of attention: you decide yourself what you attend. This is endogenous, top-down or controlled attention.

External manipulation of attention: sensory stimulus characteristics decide what you attend. This exogenous, bottom-up, reflexive attention. The sensory area is shaped by experience over years. It responses to most relevant things due to experience.

--> Salience models: models that predict what you attend automatically.

Attentional blindness

• You cannot process everything at the same time: loss of information.
• Can be measured using the change blindness paradigm

Attentional blink

• Try to detect the white target
• As you are busy with target 1, target 2 is missed

Attentional cueing

• Posner’s cueing task
• Recognition of target is better and faster for congruent cue, and worse for the incongruent cue
• Same applies to exogenous cue

Cocktail party

• People prefer one auditory stream of information over another
• Ignoring one stream is called shadowing

Visual search

• Quickly finding an item in a clustered environment

Neural mechanisms are strengthened when attention is given to it.

Question 1 can be answered using EEG: great temporal resolution.

• Also auditory attention: compare ERP to attended vs. unattended stimuli
• BER is unaffected by attention
• P20-50 and N1 are evoked by attention

Attention is necessary for similarity analysis.

Mismatch negativity (MMN): oddball paradigm.

Feature attention: the amplitude is increased for attended stimuli and the sensitivity is narrowed.

--> Attention acts in the brain area that codes the target feature.

• Orientation: V1
• Color in V4
• Motion in MT+
• Faces in FFA
• Pitch/frequency in auditory cortex

Spatial attention: attention to location in a visual field. Could be an auditory source.

Receptive field: area of interest to the neuron. A neuron responds when a stimulus is shown in its receptive field.

Each cell has a receptive field: responses only to a specific

Representations: somehow the world is represented in the mind and the brain.

Churchland & Sejnowski: the defining function of nervous systems is representational.

Stored representations are believed to depend on the configuration of weights between units. In neural terms, these weights are the strength of synaptic connections between neurons.

Some memory functions are intact in amnesic patients.

• The declarative memory is impaired --> specific events
• Procedural memory often intact --> skills

Non-declarative (implicit) memory: memory without awareness. Skill learning, priming, classical conditioning.

Priming tests consist of:

• Free recall
• Cued recall
• Completion

Classical conditioning: before conditioning, the animal responds to the US, but not to the CS. At this stage, this is called the unconditioned response or UCR. During the conditioning the CS and the US are paired repeatedly. Conditioning leads to a conditioned response.

Delay vs trace conditioning in amnesic patients

• Delay: involve procedural memory, is not impaired in amnesic patients
• Trace: declarative memory; awareness, is impaired in amnesic patients

Anterograde amnesia: amnesia for events after the trauma

Retrograde amnesia: amnesia for events before trauma

Hebb: there is simultaneous activity in two neurons.

Changes in the effectiveness of synaptic transmission take place as a result of simultaneous pre- and postsynaptic activity.

There are two research strategies for neurobiology of learning and memory:

1. Top-down: presupposing a certain principle
2. Bottom-up: no presuppositions about the mechanism, but attempts at localization.

Top-down approach of LTP (long term potentiation) and memory.

• LTP: single stimulation of perforant path fibres to dentate gyrus results in an EPSP.
• After a brief tetanus (high frequent pulse; 250 Hz) the characteristics of the EPSP have changed.

NMDA receptor: neurotransmitter can bind to this. But there is a (Magnesium) block. This can be removed by depolarizing the cell. So it requires two simultaneous events: 1. Depolarization 2. Glutamate in the cleft.

Bottom-up approach: imprinting. The formation of early social preference for the mother or another stimulus.

Memory formation involved structural changes in the connections between neurons. Such structural changes involve protein synthesis.

Conclusions:

• Brain damage (MTL) causes amnesia
• Lead to distinction between different kinds of memory, incl. declarative memory and procedural memory
• A number of different brain structures are involved in human memory
• There are top-down and bottom-up approaches
• Bottom-up has the best prospects for localization of the neural substrate for memory
• Memory formation involves structural changes at the level of the synapse

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Emotion has a signaling function, for example for a threat to integrity.

Emotions trigger adaptive responses. From evolutionary perspective: we use it for responses that are adaptive.

Emotions are universal, the basic emotions are: happiness, surprise, fear, anger, disgust and sadness.

• Primary reinforcers: satisfy for example hunger, thirst and safety
• Secondary reinforcers: money, social recognition

3 biosystems from evolutionary perspective:

1. Reptilian brain: life support system, reflexive behavior
2. Paleomammalian: motivation / emotion
3. Neomammalian: higher level control

Limbic system = the emotional brain.

ANS controls the involuntary muscles.

When you encounter a threat, your autonomic nervous system responds:

• Sympathetic: fight / flight
• Parasympathetic: rest & digest

Hormones: HPA-axis. Releases glucocorticoids, which regulates stress.

Fear response: LeDoux model. The amygdala is the important structure. He proposed there are different routes, a fast route and a slow route.

The information enters the BLA (basolateral) amygdala. Then projections are sent to the central amygdala, from where the projections run to the (hypo)thalamus.

‘Emotion’ areas of PFC:

• Anterior cingulate cortex (ACC)
• Subgenual subdivision of ACC (vmPFC)
• Orbitofrontal cortex

Amygdala is involved in fear conditioning.

The CS will elict conditioned (fear) response:

• Yes, with intact amygdala + startle
• With skin conductance: only if learning takes place

The ACC and the anterior insula are consistently activated in response to threat.

In a study, no constant amygdala activation was found during fear. Why?

• FMRI resolution too low (amygdala contains different, quite small areas)
• FMRI time course (typically modelled as same response to each trial, whereas conditioning is a learning process that develops over time)
• Human fear conditioning is only mild threat

A fearful expression will slow down the reaction time in a stroop task. Also when the face is masked and the face is no longer recognizable.

There is no amygdala activation when the attention to the fearful stimulus was explicitely directed away.

There is no anatomical evidence for the fast route of LeDoux. There is however some evidence, such as affective blindsight, binocular rivalry.

Evidence that non-attended or unconsciously processed information can activate amygdala does not necessarily mean that this information has been processed (exclusively) through subcortical channels.

There should also be focus on networks, not only on isolated brain areas. Such as the salience network.

Summary:

• Emotion is an important driver of behavior
• There are several levels of neural system involved in
  
  • Generating emotional response
  • Learning adaptive responses
  • Interactions between emotion and cognition
  • Responses are regulated through mutual connectivity

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Phonology: the study of the abstract sound patterns of a particular language, usually according to some system of rules.

Syntax: the rules for arranging items into their possible permissible combinations in a language.

Semantics: the analysis of the meaning of a language.

Language is a system of discrete infinity. There is a finite number of elements, but unbounded use of those elements.

Human language is grounded on a particular computational mechanism, realized neurally. Each expression is assigned an interpretation at two interfaces.

There is a sensitive period for learning a 2^nd language:

Language wars:

• Language involves Universal Grammer
• Language acquisition is usage-based through statistical learning.

Language has a hierarchical structure.

Aphasia: an impairment in language understanding and/or production that is caused by brain injury.

Damage to Broca’s area and Wernicke’s area is different and expresses itself differently. The damage is always on the left side of the brain, because language is lateralized.

Late 20^th century view:

• Broca’s area: syntax
• Wernicke’s area: lexicon

Contemporary view:

There are two networks; in the frontal and temporal lobes. They interact all the time. There are interactions through dorsal and to ventral pathways.

Neural mechanisms for syntax and hierarchical structures

• Assembly of hierarchical structures involves Broca’s area
• Complex sentence proceeding involves VA 44 and STC via their dorsal connection
• STC supports integration of syntactic and semantic information to achieve sentence interpretation
• STS-PMC connection is present at birth and supports auditory-based phonological learning, but NOT complex syntax

Newborn’s Wernicke’s area is not yet connected to Broca’s area. But it is connected to the premotor cortex.

So there is a sensory-to-motor mapping system. And there is a dorsal system (syntax, hierarchical structures) and ventral system (processing of semantic information.

Ability to imitate sounds is necessary for language in humans. Not in monkeys.

Convergence: different species have come up with similar solutions for similar problems.

2 month old infants: the brain responds more to the sound of the mother than a stranger (is related to memory).

FOXP2 gene mutation causes aphasia to develop. Other animals can have this mutation as well. It is however not a language gene, because:

• Genes make proteins, not behavior
• FOXP2 affects other genes
• Whatever effect it has is in combination with numerous other genes
• Mutation has multiple effects, not only on speech.

Conclusions:

• Language is not the same ass peech or communication
• Language is a computational system, in the mind
• Broca’s & Wernicke’s area / aphasia
• Language is lateralized neurally
• It involved complex interactions between frontal and temporal networks
• Language likely evolved very recently, only in

Utility: psychological value assigned to an outcome.

Prospect theory

• Prospect: option whose future rewards and probabilities are known or can be estimated.
• It is a descriptive theory: it describes what people will choose instead of should do.
• It differs from the expected-utility theory in two ways:
  
  • Reference dependence: current state is a reference point
    
    • Reference point
    • Diminished sensitivity
    • Loss aversion
  • Probability weighting: subjective perception of probabilities
    
    • Possibility effect: a chance is better than no chance
    • Certainty effect: no risk is better than some risk

Primary reinforcer: rewards that have a direct benefit for fitness

Secondary reinforcer: neutral outcome that has been turned into a positive one

Substantial nigra and ventral tegmental area are the dopamine nuclei.

In rats, the dopaminergic system was removed, and the rats still liked certain tastes. This indicates wanting instead of liking: motivation to pursue a reward.

Nucleus accumbens: activated by wide range of motivationally relevant stimuli. Reinforcement of a desirable association.

DA neurons signal changes in information:

Reward prediction error (RPE): the actual outcome differs from what was expected.

Actor-critic models: the brain has 2 systems

1. Critic: evaluation, are rewards better or worse than expected?  ventral striatum (RPE)
2. Actor: updates values of potential courses of action  dorsal striatum

Damage to reward pathways:

• Motor: Parkinson’s, Huntington’s
• Psychiatric: schizophrenia, depression, ADHD

Pathological gamblers’ brains ‘learn’ from near-misses. Males 14-22 years old, prefrontal cortex not fully developed yet.

Salience can lead to dopaminergic increase.

Uncertainty: psychological state of having a lack of information.

Risk: decision has multiple potential outcomes with known probabilities

Brain regions risk taking:

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Ambiguity: probabilities of the outcomes cannot be known. OFC and PFC are involved.

Dual system: two separate processes

• Kahneman:
  • System 1: fast, parallel, automatic, context-dependent
  • System 2: slower, serial, controlled, evidence-based

Social stimuli are rewarding. How rewarding depends on the social relationship.

Two theories:

1. Motivated by internal, reinforcing reward signals
2. Required social cognition to recognize another individual’s needs

Parietal cortex: social cognition

mPFC: thinking about other people’s mental states

Game theory studies how decisions are made in complex situations.

• Prisoner’s dilemma
• Ultimatum game
• Trust game

Altruistic punishment: censuring people who violate social norms.

Currency signal: neurons tracking subjective value, regardless of category.

Drift-diffusion models: assume that decision making is a random drift from neural states towards thresholds for action.

Modality-indepenent value signals: