Cognitive & Neuroscience Intro

1. Cognitive & Neuroscience Intro • Themes • cognitive psychology has been guided by an information processing approach to theorizing • this approach attempts to characterize how information is processed from its initial input until its response • this approach continues to be used

2. Cognitive & Neuroscience Intro • Primary measures • Reaction time (RT) • measure the elapsed time from the onset of a stimulus until there is a response to the stimulus • general goal of measuring RT is to make inferences about underlying cognitive processes (which are assumed to take time)

3. Cognitive & Neuroscience Intro • Primary measures • Accuracy • this measure assesses the accuracy of an individual’s performance • Note: accuracy can be broadly (or narrowly) defined • e.g., verbatim versus gist recall

4. Cognitive & Neuroscience Intro • Analogies • channel capacity • early uses: attention/Broadbent • more recent uses: controlled processing • computer analogy • serial sequential processing of information

5. Atkinson-Shiffrin Model (Atkinson & Shiffrin, 1968)

6. Cognitive & Neuroscience Intro • General early assumptions • sequential stages of processing • stages are independent • stages are non-overlapping

7. Cognitive & Neuroscience Intro • New conceptualizations • parallel processing • e.g., typing • hierarchical organization • e.g., typing a word • e.g., grasping an object (prepare index finger thumb apperture as you move arm toward object) • context effects • semantic priming

8. Cognitive & Neuroscience Intro • Cognitive neuroscience intro • neuron is the basic building block of the brain • cell that is specialized for receiving and transmitting a neural impulse • Note: there is enormous variability in the structure of neurons

9. Cognitive & Neuroscience Intro • Development of neurons and glial cells • germinal (or stem) cells of an embryo give rise to two types of nervous system cells: neuroblasts and spongioblasts (blast is an immature cell) • neuroblasts develop into neurons • spongioblasts develop into glial cells • glial cells provide support to neurons

10. Cognitive & Neuroscience Intro • Cognitive neuroscience intro • Major structures of a neuron • input end: dendrites, which accumulate neural stimulation into the neuron itself • cell body or soma: regulates the biological activity of the neuron • axon: a long tube-like structure used to transmit information • axon terminals or terminal arborizations:output end of the neuron, where neural impulses end

11. An illustration of the various structures of the neuron. The lower diagram illustrates a sensory-motor reflex arc

12. Cognitive & Neuroscience Intro • Basic elements of nervous system • how a simple reflex works (e.g., jerking hand away from a hot stove) • receptor cells in hand react to physical stimulus and that triggers a pattern of firing down a sequence of sensory neurons • tracts of sensory neurons pass message along into the spinal cord where it is routed to brain and back into motor neurons • However, at the synapse the message can route directly to the motor neurons

13. Cognitive & Neuroscience Intro • Basic elements of nervous system • motor neurons in spinal cord transmit message back to arm muscles • these terminate at effector cells, which connect directly to muscle fibres and cause the muscles to pull arm away from hot stove • brain route: message is routed up spinal cord to brain (CNS) • note: central nervous system = spinal cord + brain

14. Cognitive & Neuroscience Intro • Basic elements of nervous system • synapse: region where the axon terminals of one neuron and dendrites of another neuron come together • synapses are small gaps between neurons • any single neuron synapses on a large number of other neurons: called divergence (a typical neuron synapses on from 100-15,000 other neurons) • also any single neuron is the destination of many neurons (called convergence)

15. Cognitive & Neuroscience Intro • Basic elements of nervous system • information is transmitted across a synapse chemically by means of a neurotransmitter • a neurotransmitter is released from small buttons or sacs in the axon terminals, which then fit into receptor sites on the dendrites of the next neuron • two types of neurons: inhibitory and excitatory • inhibitory neurons decrease the likelihood of the next neuron from firing; excitatory neurons have the opposite effect

16. Cognitive & Neuroscience Intro • Structure of Nervous System • Nervous system consists of two major parts: central nervous system (CNS) and peripheral nervous system (PNS) • PNS consists of: skeletal nervous system and autonomic nervous system • Skeletal system controls striated (i.e., striped) muscles, which are under voluntary control, and play an important role in motor cognition and simulation

17. Cognitive & Neuroscience Intro • Structure of Nervous System • autonomic nervous system governs smooth muscles and some glands • Smooth muscles, found in heart, blood vessels, stomach lining, and intestines, are not usually under voluntary control

18. Cognitive & Neuroscience Intro • Structure of Nervous System • autonomic nervous system plays a key role in emotion and affects memory functioning • Autonomic nervous system is divided into sympathetic and parasympathetic nervous system

19. Cognitive & Neuroscience Intro • Structure of Nervous System • sympathetic nervous system prepares animal to respond more vigorously in an emergency (flight-or-fight response). Some changes: • Increasing heart rate (and delivering more oxygen and nutrients to organs) • Increasing breathing rate (and providing more oxygen) • Dilating pupils (increasing sensitivity to light) • Reducing digestive function

20. Cognitive & Neuroscience Intro • Structure of Nervous System • parasympathetic nervous system counters sympathetic nervous system and dampens the organism’s responses

21. Cognitive & Neuroscience Intro • Cerebral cortex (Overview) • Brain should be thought of as a collection of components that work together • It consists of two halves, which are called the left and right cerebral hemispheres • Hemispheres are connected by a massive collection of nerve fibres called the corpus callosum, as well as several smaller connections

22. Cognitive & Neuroscience Intro • Cerebral cortex (Overview) • Beneath the skull is a membrane covering the brain called the meninges • Beneath that is a network of blood vessels clinging to the surface of the brain • The surface of the brain contains most of the cell bodies of the neurons, which have a gray colour, hence the term gray matter

23. Cognitive & Neuroscience Intro • Cerebral cortex • cortex: consists of 4-6 layers of cells (or gray matter) • the term cortex (bark) refers to any outer layer of cells • conventionally the terms cortex and neocortex are used interchangeably • the cortex is wrinkled in order to increase its area (think of crumpled paper)

24. Cognitive & Neuroscience Intro • Cerebral cortex • Clefts (indentations) in the brain are called fissures if they extend deeply into brain or sulci if they are shallower • A ridge in the cortex is called a gyrus

25. Gyri and sulci. Lateral (A) and medial (B) views of the gyri. Lateral (C) and medial (D) views of the sulci

26. Cognitive & Neuroscience Intro • Subcortical structures • Beneath the cortex are found subcortical structures and at the centre of the brain are a series of cavities, called ventricles • Ventricles are filled with the same fluid that is found in the spinal cord

27. Cognitive & Neuroscience Intro • hemispheres and lobes • cortex consists of two hemispheres separated by the medial longitudinal fissure • each hemisphere is divided into four lobes • frontal lobe (behind forehead) • temporal lobe (underneath temples) • occipital lobe • parietal lobe

29. The location of the frontal, parietal, occipital, and temporal lobes of the brain

30. Cognitive & Neuroscience Intro • Lobes • The cognitive activities are not assigned specifically to one of the lobes and the lobes are involved in several cognitive activities • A rough guide • occipital lobes • – processes visual input from eyes and from memory (visual imagery, some) • Within the occipital lobe specific different regions process different aspects of vision (e.g., motion, color, shape) • if occipital lobes are damaged blindness results

31. Cognitive & Neuroscience Intro • Lobes • temporal lobes • Involved in several functions • Retention of visual memory • Matching visual input to visual memory • Process input from the ears • Posterior region of the left temporal lobe (Wernicke’s area is crucial for comprehending language • Anterior regions of temporal lobes are crucial for processing new memories, deriving meaning, and processing emotion

32. Cognitive & Neuroscience Intro • Lobes • Parietal lobes • Involved in several functions • Its most anterior gyrus, the somatosensory cortex (area S1), represents sensations on different parts of your body with left S1 representing right side of body and vice versa for right S1 • Parietal lobes are also involved in representing space and your relationship to it, and in representing tool knowledge

33. Cognitive & Neuroscience Intro • Lobes • Frontal lobes • Involved in several functions • Managing sequences of behaviors or mental activities • Major role in producing speech—Broca’s area of left hemisphere • Controlling movements– area M1 (most posterior gyrus of frontal lobes (also called motor strip); this area is immediately adjacent to S1 • Left M1 controls movements by right part of body and vice versa • Frontal lobes also involved in memory retrieval, in planning and reasoning, and in some emotions

34. Cognitive & Neuroscience Intro • Projection maps • constructed by tracing axons from sensory systems into the brain, and by tracing axons from the neocortex into the motor systems of the brain stem and spinal cord

35. Cognitive & Neuroscience Intro • Projection maps • dark areas in figure are primary projection areas. These areas receive input from the sensory systems or project to the spinal motor systems • lightly shaded areas receive projections (input) from the primary projection areas and are called secondary projection areas • unshaded areas are called higher-order association or tertiary areas

36. Cognitive & Neuroscience Intro • Topography of the neocortex • primary projection areas • visual system--occipital lobes • auditory system -- temporal lobes • somatosensory system -- parietal lobes • motor system -- frontal lobes

37. A projection map

38. Subcortical structures

39. Cognitive & Neuroscience Intro • Subcortical areas • thalamus consists of several nuclei; all sensory systems except for smell have relays here on their way to cortex; also different cortical regions communicate with each other via thalamus

40. Cognitive & Neuroscience Intro • Thalamus • consists of two symmetric nuclei at base of cerebral hemispheres superior to hypothalamus • each hemisphere contains half of the thalamus • thalamus receives ascending input (sensory information) and descending input from cerebral hemispheres, particularly from those cortical regions to which it projects • all sensory systems except for smell have relays here on their way to cortex

41. Cognitive & Neuroscience Intro • Thalamus • can be thought of as a complex relay station for sensory and motor systems except for olfaction (smell) • thalamus is thought to play an important role in the classification, integration of information, before sending it to the cortex for further processing

42. Cognitive & Neuroscience Intro • Thalamus • Thalamus also plays an important role in selective attention • Pulvinar nucleus (a nucleus refers to a cluster of cells) is involved in focusing attention

43. Cognitive & Neuroscience Intro • hypothalamus composed of small nuclei; involved in feeding, sexual behaviour, sleeping, temperature regulation, blood pressure, heart rate, etc. • Some of these functions are accomplished by hormones (chemicals that affect various organs) • Hippocampus located at the anterior end of the temporal lobes; it plays a central role in entering new information into memory although it is not where memories are stored; it governs processes that allow memories to be stored

44. Cognitive & Neuroscience Intro • Amygdala (named, from Greek, because of its almond shape) plays an important role in the appreciation of emotion in others and in the expression of our own emotion (esp. fear) • The amygdala can modulate the functioning of the hippocampus; this helps you store vivid memories of highly emotional information • The amygdala and hippocampus along with other structures are part of the limbic system, which used to be thought to regulate emotion

45. Model of the human limbic system and its major structures

46. Cognitive & Neuroscience Intro • Basal ganglia • collection of nuclei lying beneath the anterior regions of the neocortex • include the putamen (shell), the globus pallidus (pale globe), the caudate nucleus (tailed nucleus), and the amygdala (almond). [Note: striatum = putamen + caudate; globus pallidus = pallidum] • caudate nucleus receives projections from all parts of the neocortex and then projects through the putamen and globus pallidus to the thalamus, and then to the motor areas of the cortex

47. Cognitive & Neuroscience Intro • Basal ganglia • basal ganglia also has reciprocal connections to the substantia nigra (black area) • this projection provides dopamine to the basal ganglia; when dopamine is lost a motor disorder called Parkinson’s disease results

48. Cognitive & Neuroscience Intro • Basal ganglia • functions of basal ganglia • involved in motor function--including postural changes, sequencing of movements into a smoothly executed response, and habit learning • Habit learning (e.g., development of routinized activities such as coming to this lecture hall)

49. Relation between the basal ganglia and the cortex. Arrows indicate theoretical projections of the various areas into basal ganglia structures

50. Cognitive & Neuroscience Intro • Brainstem • Includes the pons and medulla and reticular formation • regulates many movements of animals • responds to sensory features of the environment • regulates eating, sleeping, drinking, body temperature