Chapter 1.1, 1.3 - 1.5

Cognitive Neuroscience

Study of how the brain enables thought, coined in the late 1970s for describing the growing inquiry around how the physical brains functions can yield the thoughts, ideas and beliefs of the mind

Human brains have been around for

100,000 years in their current form

Primate brain appeared between 23-34 mil years ago, during the

Oligocene epoch which evolved into the larger brains of great apes in the Miocene Epoch about 7-23 million years ago

Human lineage diverged from chimps from

5 -7 million years ago

In early societies when humans began inquiring the motives of other human beings

They anthropomorphized the natural world and believed that it also had thoughts, desires and emotions

Ancient Greeks

• First created the view that we are separate from the world we occupy and believed that the natural world is an object and could be studied scientifically

• Moved to more rational thinking, that the universe followed a structure and could be studied

• Greeks were limited without methodology

• Pre-Socratic Greek philosopher Thales

Pre-Socratic Greek philosopher Thales

Rejected supernatural explanations of phenomena and believed everything had a natural cause (believed in monism)

Monism

The idea that the conscious thinking and cognition is produced by the brain - Cog neuro focuses on this

Dualism

The idea that the brain and the body had material properties whereas the mind is intangible and has a separate origin

Rene Descartes

• Believed in dualism, that the mind did not follow the laws of physics and thought that the two interacted, the mind could influence the body and vice versa

• Believed that the mind and the body interacted in the pineal gland as it is not found bilaterally

19th century physician and scientists

Began to employ modern tradition of the scientific method to understand the brain

Experimental Psychology

Studying the mind by measuring behaviour

Franciscus Donders (1868-1969)

• First to propose the (now common) method of using differences in reaction time to infer differences in cognitive processing

• Suggested the difference between amount of time it took to identify a light and amount of time it took to identify a coloured light was due to the time required to process of identifying the specific colour

Before experimental psychology

Philosophers wondered how the mind obtained knowledge and had 2 schools of thought

Rationalism Definition

All knowledge could be gained through the use of reason alone

Rationalism 

• Truth was gained through intellectual methods and not by sensory perception.  

• Rationalists would determine true beliefs through thinking and reject beliefs that were unsupportable or superstitious 

• Rationalism replaced religion among scientists 

• Supported by Descartes, Baruch Spinoza, Gottfried Leibniz 

Rationalism ≠ Logical thinking

• Rationalism looks at the meaning of life and concerns itself with personal mental states (happiness, self-interest) - each person views these differently 

• Logic relies simply on inductive reasoning (forming a conclusion based on specific past observations and experiences), probabilities et

Empiricism Definition

All knowledge comes from sensory experience & the newborn brain is a blank slate

Empiricism

• When simple ideas & concepts interact with each other, they become associated with one another and form complex ideas

• An individuals accumulative experience determined their mental development

• Supported by John Locke, David Hume, Thomas Hobbes, John Stuart Mill

Hermann Ebbinghaus

• One of the first scientists to study associationism in the late 1800s

• Believed that complex processes like memory could be measured and analyzed – took inspiration from psychophysicists Gustav Fechner and Ernst Heinrich Weber who studied how physical stimuli are connected to our psychological experiences

Edward Thorndike

Studied associations through Law of Effect

Associationism became the

Psychological explanation for behaviour

Behaviourism Definition

All behaviour is shaped by learning

Behaviourism

• John B. Waston popularized this belief & American psychology was dominated by this idea of a blank slate at birth as it reinforced their sense of 'equality' 

• There had already been evidence against this argument by Descartes, Charles Darwin, Immanuel Kart etc. that complexity is built into the human organism 

Wilder Penfield in 1928

Became first neurosurgeon in Montreal

Montreal Procedure

• Wilder Penfield and Herbert Jasper - treated epilepsy where he surgically destroyed areas of the brain that produced the seizures

• Determined areas of interest in the brain by using electrical probes and observed patients reactions – mapped out sensory and motor cortices in the brain – confirmed LoF in the brain (confirmed John H. Jacksons predictions)

Donald Hebb worked with Penfield

• Believed that the brain explained behaviour

• Learning had a biological basis 

• "Cells that fire together wire together" - Neurons combine into units 

• Brain is active all the time, stimuli only modify ongoing activity 

• Theory was used in design of artificial neural networks 

Brenda Milner

• Developed set of behavioural studies on Penfields patients

• Provided physiological proof of Episodic Memory (memory of events) & procedural memory (memory of performing actions and skills)

• Called founder of neuropsychology

• Discovered frontal lobes role In processing memory and organizing information

Dominance of Behaviourism changed after 1950s

Psychologists began thinking about cognition

Behaviourist George Miller

Changed his belief that psychology should only study behaviour in the 1950s

Miller published "The Magic Number 7, + or – 2"

• Described how much information is stored in short-term memory, around seven items

• Concluded that the brain is an information processor and set into motion the "cognitive revolution"

• Miller came across Noam Chomsky's ideas of syntactic theories of learning language and concluded that associationism could not explain how children learned language, and that the complexity of language was innate and built into the brain

• Wanted to understand the workings of the brain as an integrated whole including the conscious mind produced by it, creating the field cognitive neuroscience

Patricia Goldman-Rakic

• Produced first description of circuitry of prefrontal cortex & how it relates to working memory 

• Discovered that individual cells in the prefrontal cortex are dedicated to specific memory task, such as remembering a face or voice 

• Performed first studies on influence of dopamine on prefrontal cortex 

• Her findings caused a paradigm shift in the understanding of several psychological disorders such as schizophrenia 

Goal of Cog Neuro

Uncover the connections between the mind & brain

Cog Neuro - set of interdependent connections that provide explanations by linking

• Behaviour to cognitive functions 

• Cognitive functions to brain regions 

• Brain regions to one another 

• Cognitive functions to one another 

• Behaviours to one another 

Explanation (scientific term)

The phenomenon to be explained & the statements (explanatory accounts) offered to account for the phenomenon

Ex. Why do we feel wet when it rains?

• Phenomenon – feeling wet when it rains 

• Account is explanatory statement – because water touches our skin 

Deductive-nomological model - 2 features

1) Explanatory account involves a 'law of nature' & 'initial conditions' 

2) Explanatory target deductively follows from laws of nature and initial conditions  

• Phenomenon to be explained must be a logical consequence of the explanatory accounts, which must be true 

• Explanations are statements, not equations & not truths 

1) Explanatory account involves a 'law of nature' & 'initial conditions' 

Natural laws 

• Empirically confirmed regularities – e.g Newtons Laws of Thermodynamics 

• Must have at least 1 law of nature, otherwise invalid 

2) Explanatory target deductively follows from laws of nature and initial conditions  

Ex. a metal that expands when heated --> the "law" is that all metals expand when heated, and the initial conditions is that the object is made of metal and was heated, therefore when the metal is heated it will expand 

Statistical Explanations

• Focuses on how variables are conditionally dependent on one another 

• Does not depend on known laws of nature 

Causal Mechanistic Explanations

• Draw on causal processes & interactions 

• Does not depend on known laws of nature 

  • Ex. do changes in brain structure cause changes in anxiety? 

One way to define a causal explanation is through James Woodwards interventionist account

"C causes E if there is a possible intervention that changes C such that under that intervention, E would change" 

• Ex. if frontal lobe causes higher cognition, if there is an intervention (lobotomy) higher cognition is lost 

Non-Causal Explanations Definition

• Not all explanation have to be causal 

• Non causal explanations also come from logical & statistical relations, defined by negation 

• Explain phenomena without appealing to causes, instead using things like:

  • Laws of nature

  • Mathematical facts

  • Logical or structural constraints

Laws of nature

Symmetry principles, conservation laws

Mathematical facts

Ex. Why a bridge has a certain resonance frequency

Logical or structural constraints

Ex. Why there are no largest prime numbers

Non-Causal Explanations - “negation”

These explanations don’t work by showing how an intervention on C would change E (causal). They work by citing other explanatory structures

Description

• The process of taking measurements and reporting those measurements to characterize the system of interest (answers: what is happening?) 

• Description gained renewed attention in the Renaissance from Robert Boyle 

Explanation Definition

A statement about how or why something is the way it is/ a statement that makes something comprehensible by describing the relevant structure, operation or circumstance 

Explanation

• Can deduce from explanation how system will behave 

• Ex. We could describe how an increase in human neural activity, measured by brain imaging, relates to a cognitive function based on a computational model (mathematical models simulated in computers). That computational model is then explanatory. 

 

Cog Neuro uses description & explanation

In scientific research to formulate new hypothesis

Prediction Definition

Process of anticipating or forecasting the future

Prediction

• A prediction can work without humans knowing why it works, most common in the area of machine learning (AI that involves statistical learning algorithms) 

• Can use machine learning to predict a person's decision-making capacities from a brain scan without knowing exactly which pixels of the brain image drive that prediction or why 

• Also possible to make effective predictions without accurate description 

• Inaccurate descriptions that produce effective predictions --> explanatory fictions 

Description, explanation and prediction

• Can be distinguished from one another, but they are not always independent, they can overlap 

• The right description can explain something 

• Explanations can sometimes make predictions 

• Predictions are sometimes built on explanations & derive power from explanatory models 

Mechanism

A complex system that produces a systems behaviour by the interaction of a number of parts, where the interaction between parts can be characterized by direct, invariant, change-related generalizations

4 basic features of Mechanisms

• A phenomenon 

• Parts 

• Causings 

• Organization 

Examples of Mechanisms

• Ex. car engines have different parts, organized in a particular way that produce different phenomena 

• Mechanism that produces generation of energy is combustion of fuel in the piston, the translation of this power to the drive train involves other subcomponents (transmission, axle etc) 

• With mechanical process in mind, we can define mechanisms as involving details of the causal parts that make up the subsystem of interest (drive train) - details involve a temporal relationship (sequence of events) & mechanism concept focuses on mechanical structures and their associated forces, activities & motions (molecular & physiological processes) 

Focus on mechanisms greatly benefitted Cog. Neuro.

• Ex. spaital memory (storage & retrieval of information needed to plan a route, remember where an object is located or where an event occurred) 

• Involves building a cognitive map constructed by hippocampus (learning & memory which receives info. About world via series of neural connections from sensory system) - causal explanation built on the mechanism concept 

More information about Mechanisms

• Each higher level behaviour (or phenomenon) e.g memory is explained by detailed causal interactions at lower levels of organization (the series of neurons in the pathway from sensory system to hippocampus & underlying molecular processes enabling learning 

• Not all explanations are molecular ones 

• Molecular biology & mechanistic phenomena could never fully explain the mind 

Pathway Definition

Captures a sequence of causal steps, where these steps track the flow of some entity through a system & abstract from significant causal detail as well as emphasize the 'connection' aspect of causal relationships

Pathway 

• Pathway concept is key to cognitive neuroscience.

• As early worked focused on causal relationships, current work focuses on highlighting pathways in circuits & networks

• How do we repeat a word that we hear? 

  • Auditory info interest ear & processed in auditory cortex - info then passed from region to region, arriving at a network for speech production - resulting in a spoken word 

Causal constraint Definition

Cause with several additional features

Causal constraint

• It can limit a phenomenon of interest (e.g the location of connections can limit flow of neural activity).  

• It is separate from or external to the phenomenon it limits; connections are separate from and external to the neural activity.  

• A causal constraint is considered relatively fixed compared to other explanatory factors 

• Structures or guides the phenomenon's outcome, connections structure & guide neural activity 

  • Studies of how structural connectivity constrains activity flow are causal studies & can provide causal explanations for brain dynamics & by extension cognitive processes 

Not all pathways in the brain are structural pathways - but when it is

It can serve as a structuring cause (a cause that structures the realization of some phenomenon, such as neural activity patterns) which can be distinguished from a triggering cause (a cause that triggers a sequence of events that composes a process)

Triggering cause Definition 

Stimulus that triggers or causes a process or sequence of events to occur

Triggering cause Example

Ex. An electrical pulse that is applied to a brain region and gives rise to neural activity pattern structured by patterns of synapses

Each type of cause can feature in a

Causal explanation or a non-causal explanation