Cortex and Mind: Unifying Cognition (Fuster,2003, henceforth Cortex and Mind) begins with thepremise that cognitive neuroscience is in real needof a paradigm shift: “Indeed, despite thespectacular progress of neuroscience, many of usshare the growing sense that we are not gettingcloser to that solution [to the brain-mind problem],but further away from it. The more facts about thebrain that we know, the less we feel we knowabout the cerebral substrate of the mind, whichseems to be disappearing in a downward spiral ofreductionism” (p. vii; parenthetical commentadded). I was optimistic when I read this section:here is one of the world’s foremost neuroscientistswho is going to steer the ship back to where itbelongs (for lack of a better phrase, behaviouralneuroscience perhaps?).

And yet Cortex and Mind flat out rejects anybrain-mind dualism, but concludes thatconsciousness is epiphenomenal and that the mindis a “category of fact”. My more informed reactionwas that this book, as scholarly, comprehensive andcrafted as it is, by a neuroscientist with such ahuge scope of important research and theory underhis belt, is more of the same kind of allencompassing model that seemingly explains agreat deal of brain and behaviour. But, at the endof the day, it seems to fail to really suggest muchin the way of theoretical or pragmatic relevance tohow most neuroscientists go about their business(beyond appropriate praise for several veryinteresting studies in neurophysiology andneuroimaging, which seem to me to belong smackdab in the middle of the old paradigm which needsshifting, according to Cortex and Mind). To besure, it captures some of the pitfalls of modularity(in its strongest Fodorian sense), but I am underthe impression that most neuropsychologists in the21st century have gotten to the same place already.It also takes connectionism on, and highlights someof the best bits while reminding of the limits (forneuroscience at least) of nets that have littlebiological plausibility. Who could (or would)argue?

What is so revolutionary about the following:distributed brain systems develop “on a core oforganized modules of elementary sensory andmotor functions, to which they remain connected”;that they are relational, based on connectivity

between subsystems; that the relational codes canbe diverse or specific, depending on differentcombinations of subsystems; that single neurons ofgroups of neurons play parts in more than onesubsystem; subsystems can have more than onerole, and that “cognitive functions consist offunctional interactions within and between corticalnetworks” (p. Xi).

To be fair this last point seems at leastsomewhat controversial, to philosophers whowould know more than I do about equivalenceclasses (‘consist of’ – what does that mean,exactly?) and to reductionists/behaviourists whomight question the validity of many definitions ofcognition. I am not sure what is really so distinctabout Cortex and Mind, compared to the myriad ofother alternatives written by scientists who bravelyattempt to solve (but never explain away) themind-body problem. I used to joke to my studentsthat this is the fate of radical reductionists later intheir careers, like heretics drawn back to theChurch after decades in the wilderness (i.e., readSperry, 1952 vs. Sperry, 1980. Also see Corballis,1998; Doty, 1998 and others in the same issue onSperry’s later views). This is unfair when appliedto Professor Fuster’s work of course, as he hasbeen grappling with these less reductionistquestions for many decades already (i.e., Fuster,1958). That aside, what does Cortex and Mindcome up with?

Central features of Cortex and Mind are the“cognits” and the overlapping nature of the fivekey functions of the mind: perception, memory,attention, language and intelligence. Cognits areany representation of knowledge in the cortex, andany one of them is defined by its component nodes(which can be more elementary cognits), and,crucially, the interrelations between them, as theyare primarily associative, dynamic entities. (Morecomplex cognits are defined at one stage as havingwider, more extensive networks, although I wasunsure about how the complexity could bequantified independently of network size or span).Primary motor, visual, auditory and somatosensorycortices are the “bases” of motor and sensoryhierarchies, composed of many more elementarycognits, some hard-wired, which Cortex and Mindconsiders as examples of “phyletic memory” (avery interesting idea, as species are shaped by the

Cortex, (2006) 42, 1043-1047

BOOK AND NEW MEDIA REVIEWS

STRETCHING IDEAS ABOUT THE BRAIN THATHAVEN’T CHANGED MY MIND

Review of Joaquín M. Fuster’s Cortex and Mind: Unifying Cognition. ISBN 0-19-514752-9, Oxford: Oxford UniversityPress, 2003, 310 pages. Price: US $55.00, UK £33.50.

1044 David P. Carey

plasticity of natural selection working on thegenotype). Primary sensory cortices project tosecondary and tertiary sensory regions which thenregions project to polymodal association areaswhich are clearly at “higher” levels, which mayalso interact with “executive” cognits which haveno obvious sensory or motor function, and so on.Fuster argues “discrete neuronal modules ofspecific function have been identified only inprimary sensory and motor cortex” (p. 66).

I have a few concerns about these arguments.First, many regions or cortex that were labeled asassociation areas not so long ago are currentlyrevealing rather specific sensory or motorfunctions, when explored in behaving monkeyswith the right sorts of tasks and stimuli. Forexample, regions of the intraparietal sulcus, severalsynapses removed from the primary visual cortex,seem to have obvious, well-specified roles relatedto saccades and reaching and grasping movements(i.e., Andersen et al., 2004; Astafiev et al., 2003;Galletti et al., 2003). Are these examples ofpolymodal cortex near the top of a hierarchy, asthey may influence motor behaviour directly,without the participation of circuits in prefrontal orpremotor cortex? The Cortex and Mind model isquite flexible, in that neurons may play differentroles in different cognits. So, LIP neurons might beparticipating in one circuit which activates saccadesthrough several later temporal stages (whichsuggests that the LIP cells are acting as membersof classic association cortex, sitting in betweenmotor and sensory cortex), or they may activatesaccadic eye movements more directly, by directconnections to motor units in the superiorcolliculus or even the brainstem (Giolli et al.,2001), in which case LIP is acting as a type ofpremotor cortex. Similarly, “intermediate” parietallobe regions in so-called visual and somatosensoryhierarchies project directly into neurons of thecorticospinal tract (see Geyer et al., 2000 forreferences). How should these neurons in thesesubregions be categorized in a low to high scheme?Because Cortex and Mind makes much of CNSfeedforward and feedback, such flexibility of LIPcircuitry is not unexpected, but it does imply thatthe dynamic nature of any brain system makes“higher” and “lower” rather fluid constructs.

At times in my career I have been uneasy withthe slipperiness of constructs like higher and lowerwhen authors seamlessly switch betweendescriptions of cognitive versus brain processes.For Cortex and Mind, it is finding and defining thescales of brain processes and cognitive processes inthis respect that’s a crucial part of mappingbetween them, so notions of place in a hierarchy(despite acknowledging much processing whichtakes place in parallel) are not trivial. In specificinstances, these constructs are easy enough tooperationalise: low-level vision, in a neurologicalsense, clearly refers to processes that are closer to

the source of the sensory transduction: the dorsallateral geniculate nucleus is a clearly lower visualstructure than, say V4 or V5. But if a dLGNneurons’ activity is modulated by a corticothalamicfiber from V1, does that cell become higher thanthe V1 cell? Is it appropriate to refer to any gatingof dLGN by cortex as feedback per se, in a simplesort of scheme? Or is it feedforward in some sense,depending on the instructional set or motivationalstate of the animal?

Neural descriptors of feedforward and feedbackconnectivity (based on well described patterns ofaxonal termination in different layers of cortex)have led to the “London subway” maps of visualand non-visual cortex by van Essen and colleagues(i.e., Felleman and Van Essen, 1991; see the latestvariants in monkey and human athttp://brainmap.wustl.edu/vanessen.html). Myrecollection is that these neuroscience-basedmapping studies use the idea in strictly anatomicalterms, deduced in areas early enough in the visualsystem to be fairly assured of reliable assignmentof place in a hierarchy (i.e., V1 then V2 then MT,etc., although now that I think of it, what aboutthose direct subcortical projections to MT?) andthat the authors are appropriately cautious inmaking claims about their functional significance(i.e., Lewis and Van Essen, 2000).

In the cognitive domain in this respect, we areclearly not talking about number of synapses awayfrom input or from the final common pathway(output). Instead, high and low refers to theinferred degree of abstraction or complexity ofprocess A versus process B. In vision, for example,the construction of some sort of object primitive isa later process to, for instance, edge extraction, andthe construction of a representation of say, a face,from object primitives is thought to be an evenhigher process still. Consider this example:recognizing a line drawing of a common object oranimal. Such a simple process which is handled soeasily by even very young children with modestvisual experience suggests that this is a relativelyearly process in any hierarchical visual recognitionscheme (or for the coggies in the audience: RTs forrecognizing line drawings must be ridiculouslyshort). But, speaking of the difficulties that somebrain damaged patients have in recognizing them(compared to photographs or even real 3-dimensional objects) Lord Brain (1941) reminds usthat their simplicity is extremely illusory: “Thepatient’s failure to recognize line drawings ofcommon objects, however, draws attention to theimportance of the opposite principle, namely thatrecognition often depends upon abstraction, notonly from the environment, but even from theobject itself. We are so familiar from an early agewith the representation of objects by outlinedrawings that we are apt to forget how abstractsuch symbols are.” (p. 58). Line drawings areactually highly abstract, and in some sense then

recognizing them must involve the “higher”processes rather than lower or intermediate ones,that could be neurologically distinct fromrecognition of other depictions of the same stimuli.I suspect that from a Cortex and Mind perspective,this example isn’t at all ambiguous as such acts ofrecognition would depend upon diffuse semanticnetworks which deal with sematic nets that knowall about cats, dogs, airplanes and Snodgrasstoasters. (And I suspect Professor Fuster will bemost sympathetic to the phrase “recognitiondepends upon abstraction”).

In any case, labeling processes as higher orlower can be tricky. From another domain: If avisually-guided grasp is relatively impervious toillusory contexts such as those seen in theEbbinghaus or Müller-Lyer illusions, does thisfinding suggest that grasping depends on circuitsthat are lower or higher that those responsible forour perception of those illusions? For manyneuropsychologists, I sense that the gut answerwould be lower, when the anatomy in some sensesuggests higher (or perhaps just different). In someinstances knowledge of cortical processing inanatomical terms goes some way in understandingthese perception-action dissociations (Dyde andMilner, 2002). But in other instances, it is unclearthat categorizing some processes as higher andsome as lower will help sort out what is going on.

Hierarchical models have widespread appeal forall kinds of reasons. Many approaches in vision,from psychophysics to neurophysiology, build onthe notions of bottom-up processes from the retinalimage to viewpoint-invariant representations ofobjects. Much fuss has been made about what thevisual primitives are, with candidate schemes suchas Irving Biederman’s geons as one such example.Cortex and Mind reviews fascinating work oninferotemporal cortex (an “intermediate” are ofvisual processing) by Tanaka et al. (1991) on visualresponse properties of single units, and describesthem as “evidence of upward expansion of arepresentation in the cortical hierarchy of visualprocessing areas” (p. 65). These units displayedsome bizarrely specific receptive field properties(for discussion see Tanaka, 1992; 1993). I canremember when the paper first came out (Tanaka etal., 1991); several of my colleagues and I wereastounded by the remarkably specificity of some ofthe neurons for visual feature conjunctions thatseemed, well, unlikely candidates as visualprimitives of anything.

In spite of these quibbles, Cortex and Mindhighlights a number of salient points that will please,instruct and even influence many neuroscientists.The conceptualization of attention is applied asvigorously to action as it is to perception. Effectively,attentional/selective mechanisms are just asimportant for movement as they are for sensation andperception, for example, the inhibition/suppressionof possible responses as well as preparation of the

Book and new media reviews 1045

executed movement (also see Andersen and Buneo,2002; Bestelmeyer and Carey, 2004; Rushworth etal. 1997). Similarly, he notes that bothpsychophysical and cognitive approaches havedismissed the active nature of the perceptual process,as well as action in its own right. I am strangely(given my misgivings about “consciousness”)attracted to the subjectively unintuitive suggestionthat despite phenomenal experience to the contrary,for many perceptual and sensorimotor processes,consciousness is optional. His ideas about thereconstructive nature of many cognitive processesare similar to interesting suggestions about thereconstructive nature of memory under conditionswhere subjective accuracy is thought to be perfectbut clearly is not (e.g., Conway et al., 2004). Vastswathes of neuroscience and cognition are reviewed,topics as diverse as neural development, Piaget,Tourette’s syndrome, event-related potentials,executive function, Hebbian synapses andconnectionism are all represented in Cortex andMind with some aplomb. It’s not a book I wouldnecessarily hand to an undergraduate, but my newPh.D student may find one in her Christmas stockingif I decide she’s up to the challenge of such a broadportrayal of cognitive neuroscience.

Nevertheless, several of the specifics need to bethought through carefully. For example, the Cortexand Mind view of attentional processes is so broadit fascinates and leaves me uneasy at the sametime. Fuster describes attentional processes aslargely unconscious; he is very critical ofcontemporary views that relate attention toconscious processing. For example: “…awarenessof a limited sector of sensorimum or of sensoryperception at a given moment. This narrow conceptof the focus of attention constitutes basically whatcognitive psychology considers selective attention(with obvious redundancy, for all attention isselective).” (p. 148). He relates inhibition toattention, and then describes centre-surroundreceptive fields of geniculate neurons and thestretch reflex as relevant examples. “…attention isinherent in the neural processing of sensory andmotor information for adaptive purposes (Neisser,1976). Nowhere in the central nervous system isthere evidence of a separate structure or group ofstructures dedicated to attention as a separatefunction. Nor is one needed from a biological pointof view. Attention, with its qualities of selectivityof resources and biased competition (Desimone andDuncan, 1995), is identical to specificity in sensoryand motor systems. In the cortical stages of thesesystems, attention is the process of timely andselective activation of cognits to attend to the ever-changing cognitive demands of adaptation to theenvironment” (p. 148-9, citations in Fuster, 2003).I wonder, if attention has to do with selection andinhibition at such “low” as well as such “high”levels, what brain processes can’t be described asattentional in some fashion or another?

Top-down attentional processes, according toCortex and Mind, have nothing to do withconsciousness per se, but Fuster has toacknowledge that instructional set of a monkeybehaving in a physiological study is somehowinvolved in constraining resource allocation. Heargues “…top down attentional control isessentially made up of feedback from highercognits upon lower ones…No specializedcontrolling structures are needed for thatprocessing, because the processing networkscontrol themselves” (p. 152). Working memory isalso described in the same chapter. “The distinctiveproperties of working memory are not those of anew memory in formation, but rather those of acognit, new or old, which is held active in thefocus of attention as required in the processing ofinformation for prospective action” (p. 155). I amleft wondering if Cortex and Mind is really aneobehaviourist sort of model in disguise, or if Iam just missing out the homunculus at the next,undescribed level? What does “held active in thefocus of attention” mean, if not something relatedto the (‘redundantly-named’) selective attention ofthe observer? If the processing limits aren’t yokedto the limited capacity of an observer’s awareness,why filter input at all, given that so many of thecognits can operate in parallel as well as in ahierarchical (or ‘heterarchical’) fashion? And, forthat matter, does output need to be filtered at all?Do rival motor outputs really need to be inhibitedby non-conscious, parallel cognits? For example,fixation neurons exist in several brain regions, butmost notably in the superior colliculus, a structurein some sense very early in the visual hierarchy.Could prefrontal/premotor circuits activate thoseneurons when conditions require it? Certainly. Butin what sense is it necessary to imply that “thatwhat this is” is inhibition of saccadic eyemovements, as opposed to activating fixation? Inwhat sense do we think that motor programs lie insilent competition, requiring active suppression, ina non-conscious parallel set of cognits?

These broader conceptualizations of attention,memory, language, perception and action havesome strengths, nevertheless. Cortex and Mindreminds us of how the neuroplastic changesdependent on experience are essentially bound inwith virtually all processes such as perception,attention and action. For instance: “Perception is anact of classification of objects by those network-like systems of connections formed by priorexperience with those objects” (p. 8). Gestalt ideasnevertheless receive much attention, as does thenotion that some elements of linguistic skill areclearly genetically predetermined in the wiring ofthe relevant cognits. However, in other instancessome of the assertions which certainly have somevalidity are so generalized that they obscure themain arguments. “The complexity [of intelligence]derives from the close personal relationships

1046 David P. Carey

between intelligence and the other four functions –perception, memory, attention and language. Allfour contribute to intelligence, though each onedoes it in a different way and to a varying degree,depending on the individual and the circumstances.The difficult of defining intelligence derives fromthe infinite variety of its manifestations” (p. 213,bracketed phrase added).

Cortex and Mind makes much of the notion ofa Kuhnian paradigm shift as a necessary step in theprogression of cognitive neuroscience. The failuresof the modularity approach are a key focus and theconclusion to be drawn is that coding in thenervous system is sparse and distributed. Otherparisominious explanations (like the non-equivalence of brain and mind) aren’t reallyconsidered in Cortex and Mind. Fair enough, giventhe work’s mandate. To me, mind is a metaphor;it’s linguistic/semantic shorthand for something like“all types of behaviour which aren’t overtly motorand/or aren’t yoked in any obvious way to thespatial and temporal here and now, thoughts,feelings, plans, awareness, memories, images andso on. Many mental constructs are real in that theyare very useful in controlling and predictingbehaviour at a linguistic level of explanation. Butas a neuroscientific reality? Things that can bemeasured, pointed to, indicated by presence orabsence in the brain, in however subtle a fashion?Surely, in many specific instances, cognitiveconcepts can operationally defined. But just likeconstructs such as “awareness” (one that ProfessorFuster is more familiar with than me), any ideawhich has such a broad spectrum utility inlanguage is unlikely to have a simple instantiationin the brain (Fuster might agree), no matter howdiffuse (Fuster probably won’t agree).

Diffuse network approaches in cognition haveappeal for several good reasons (including they areprobably largely appropriate), but one not so goodreason: falsifiability. If a given construct doesn’texist in a neurological sense (i.e. is synonymouswith neural activity of a certain spatial andtemporal structure) it’s hard to disprove the ideathat its distributed nature in the brain makes itillusive. How would you disprove the existence ofan ESP network in the brain, to a real believer inESP? A mischievous example? Perhaps, but if youreplaced the word “intuition” (which has someexplanatory power for behaviour in day-to-dayparlance, at least) for ESP, would the argument beany different? Is there a cognitive neuropsychologyof intuition? If not, why not? There’s now acognitive neuropsychology of humour, after all.

Ultimately the veracity of constructs in anyscientific domain depend upon their predictivevalue. Psychology and cognitive science, sadly,appear to be relatively unproductive disciplineswhen compared to their natural sciencecounterparts such as biology and chemistry(Cooper, 1982). Is this because our subject matter

Book and new media reviews 1047

is multivariate and difficult? I’d be hard pressed todefend such a position to a cosmologist – whosesubject matter is billions of miles (and years)distant. Is it because our subject is relatively new?Depends on what you consider as the origin ofcognitive science/psychology. If we think about thework of Fechner, Wundt, von Helmholtz and othersin the mid to late 19th century as earlypsychology/cognitive science, and remind ourselvesthat Mendel was planting his peas at roughly thesame time, which discipline would you back as ascience with real subject matter (pun, for those ofyou not paying attention anymore)? Psychology orgenetics, 150 years or so later?

There are many examples of real progress incognitive and behavioural neuroscience in the lasttwo decades, but I suspect that many of them canbe thought of as advancing our knowledge ofbrain-behaviour relationships rather than brain-mind relationships (e.g., Salzman and Newsome,1994 almost takes association cortex out of theequation altogether). Yet we cling on to the mindbrain problem with voracious tenacity. Phenomenalexperience has played a large role in establishingthe categories that we use to parse mental eventsand processes (look at the categories in the averagePsychology text, and I can image that philosophersfrom centuries past would feel quite at home).Which is the only reason I can think of that makesscientists continue to cling to the veracity of themind-brain enterprise, with such little obviousprogress to show for it. And, in my opinion,attempts to reconcile mind and matter sufferbecause of the mind side of the equation. Until wetake mind out of matter, never mind.

David P. Carey

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ASTAFIEV SV, SHULMAN GL, STANLEY CM, SNYDER AZ, VAN ESSENDC and CORBETTA M. Functional organization of humanintraparietal and frontal cortex for attending, looking and

pointing. Journal of Neuroscience, 23: 4689-4699, 2003.BESTELMEYER PEG and CAREY DP. Processing biases towards the

preferred hand: Valid and invalid cueing of left- versus right-hand movements. Neuropsychologia, 42: 1162-1167, 2004.

BRAIN WR. Visual object-agnosia with special reference to gestalttheory. Brain, 64: 43-62, 1941.

CONWAY MA, SINGER JA and TAGINI A. The self andautobiographical memory: Correspondence and coherence.Social Cognition, 22: 491-529, 2004.

COOPER RM. The passing of psychology. Canadian Psychology,23: 264-267, 1982.

CORBALLIS MC. Sperry and the age of aquarius: Science, valuesand the split brain. Neuropsychologia, 36: 1083-1087, 1998.

DESIMONE R and DUNCAN J. Neural mechanisms of selective visualattention. Annual Review of Neuroscience, 18: 193-222, 1995.

DYDE RT and MILNER AD. Two illusions of perceived orientation:one fools all of the people some of the time, but the otherfools all of the people all of the time. Experimental BrainResearch, 144: 518-527, 2002.

DOTY RW. The five mysteries of the mind and their consequences.Neuropsychologia, 36: 1069-1076, 1998.

FELLMAN D and VAN ESSEN D. Distributed hierarchical processingin the primate cerebral cortex. Cerebral Cortex, 1: 1-47, 1991.

FUSTER JM. Effects of stimulation of brain stem on tachistiscopicperception. Science, 127: 150, 1958.

GALLETTI C, KUTZ DF, GAMBERINI M, BREVEGLIERI R and FATTORIP. Role of the medial parieto-occipital cortex in the control ofreaching and grasping movements. Experimental BrainResearch, 153: 158-170, 2003.

GEYER S, MATELLI M, LUPPINO G and ZILLES K. Functionalneuroanatomy of the primate isocortical motor system.Anatomy and Embryology, 202: 443-474, 2000.

GIOLLI RA, GREGORY KM, SUZUKI DA, BLANKS RI, LUI F andBETELAK KF. Cortical and subcortical afferents to the nucleusreticularis tegmenti pntis and basla pontine nuclei in themacaque monkey. Visual Neuroscience, 18: 725-740, 2001.

LEWIS JW and VAN ESSEN DC. Mapping of architectonicsubdivisions in the macaque monkey, with emphasis onpaerito-occipital cortex. Journal of Comparative Neurology,428: 79-111, 2000.

NEISSER U. Cognition and Reality: Principles and Implications ofCognitive Psychology. New York: WH Freeman, 1976.

RUSHWORTH MFS, NIXON PD, RENOWDEN S, WADE DT andPASSINGHAM RE. The left parietal cortex and motor attention.Neuropsychologia, 35: 1261-1273, 1997.

SALZMAN CD and NEWSOME WT. Neural mechanisms for forminga perceptual decision. Science, 264: 231-237, 1994.

SPERRY RW. Neurology and the mind-brain problem. AmericanScientist, 40, 291-312, 1952. Reprinted in ROBINSON TE (Ed),Behavioral Approaches to Brain Research. Oxford UniversityPress, New York, 1983.

SPERRY RW. Mind-brain interaction: Mentalism, yes; dualism, no.Neuroscience, 5: 195-206, 1980.

TANAKA K, SAITO H, FUKADA Y and MORIYA M. Coding visualimages of objects in the inferotemporal cortex of the macaquemonkey. Journal of Neurophysiology, 66: 170-189, 1991.

TANAKA K. Inferotemporal cortex and higher visual functions.Current Opinion in Neurobiology, 2: 502-505, 1992.

TANAKA K. Neuronal mechanisms of object recognition. Science,262: 685-688, 1993.

David P. Carey, Vision Research Laboratories, School of Pschology, University ofAberdeen, Aberdeen, Scotland AB24 2UB.e-mail: d.carey@abdn.ac.uk WWW: http://www.abdn.ac.uk/~psy180/dept/