I argue that the rôle for the cerebellar cortex is in the generation of sensory predictions, not motor sequences. This proposal may explain the allometric relationship described in Braitenberg et al.'s target article. I also point out that the parallel beam organisation may have a nontemporal basis.

Shors & Matzel somewhat lightly dismiss the evidence that a process like LTP may underlie the learning-induced increase in neuronal activity in the hippocampus in eyeblink conditioning. I provide some 12 lines of evidence supporting this hypothesis and the further hypothesis that this learning-induced LTP-like hippocampal plasticity can play a critical role in certain aspects of learned behavior.

Clark & Thornton argue that the recoding functions which are used to solve type-2 problems are, at least in part, the ontogenetic products of general-purpose mechanisms. This commentary disputes this and suggests that recoding functions are adaptive specializations.

The locality assumption (LA) seems rather awkward, especially when one considers centres of neuronal specialisation as defined by observed CNS activity. It is clear from electrophysiology that extra-striate functional compartmentalisation (modularity) is rather less well-defined than first thought; neuropsychological assessment attaching significance to varieties of preserved behaviour also reveals that some basic flaws must be inherent in current reasoning supporting LA.

This commentary reinterprets our recent data on the cerebellar contribution to different cognitive functions in light of Braitenberg and coworkers's hypothesis about the sequence-in/sequence-out cerebellar mode of operation in the motor domain. Cerebellar involvement in spatial data processing, procedural learning, verbal fluency, application of grammatical rules, and writing is dependent on sequence processing.

Self-deception is made unnecessarily puzzling by the assumption that it is an intrapersonal analog of ordinary interpersonal deception. In paradigmatic cases, interpersonal deception is intentional and involves some time at which the deceiver disbelieves what the deceived believes. The assumption that self-deception is intentional and that the self-deceiver believes that some proposition is true while also believing that it is false produces interesting conceptual puzzles, but it also produces a fundamentally mistaken view of the dynamics of self-deception. This target article challenges the assumption and presents an alternative view of the nature and etiology of self-deception. Drawing upon empirical studies of cognitive biases, it resolves familiar “paradoxes” about the dynamics of self- deception and the condition of being self-deceived. Conceptually sufficient conditions for self-deception are offered and putative empirical demonstrations of a kind of self-deception in which a subject believes that a proposition is true while also believing that it is false are criticized. Self-deception is neither irresolvably paradoxical nor mysterious, and it is explicable without the assistance of mental exotica. The key to understanding its dynamics is a proper appreciation of our capacity for acquiring and retaining motivationally biased beliefs.

A fundamental assumption in Shors & Matzel's target article is that brain activity can be related to the traditional categories of mentalistic psychology. This has led them to make numerous further assumptions that are contradicted by the available evidence.

There is a distinction between locality and modularity. These two terms have often been used interchangeably in the target article and commentary. Using this distinction we argue in favor of a “weak” modularity. In addition we also argue that both PDP-type networks and box-and-arrow models have their own strengths and pitfalls.

The sequence-in/sequence-out cerebellar machinery is considered from the computational point of view. We outline a learning framework which discriminates short-term from long-term learning and is able to explain single-trial adaptation to unexpected loads.

We agree with Shors & Matzel's general hypothesis that the proposed link between NMDA-dependent LTP and memory is weak. They suggest that NMDA-dependent LTP is important to arousal or attentional processes which influence learning in an anterograde manner. However, current evidence is also consistent with the view that NMDA receptors modulate memory consolidation retroactively, as occurs in several other receptor classes.

Although Farah makes a convincing case against the tenability of the locality assumption, she does not propose alternative research strategies that do not rest on this assumption. It is proposed here that we may profitably exploit individual differences in neuroanatomy and behavior. In combination with the use of adequate genetic methods, this approach – termed microphrenology – does not need a locality assumption.

“Self-deception” usually occurs when a false belief would be more rewarding than an objective belief in the short run, but less rewarding in the long run. Given hyperbolic discounting of delayed events, people will be motivated in their long-range interest to create self-enforcing rules for testing reality, and in their long-range interest to evade these rules. Self-deception, then, resembles interpersonal deception in being an evasion of rules, but differs in being a product of intertemporal conflict.

Mele's study of philosophical and psychological theories of self-deception informatively links the conceptual and dynamic aspects of self-deception and explicates it without positing mutually inconsistent beliefs, such as those occurring in two-person deception. It is argued, however, that he does not do full justice to the dissociation characteristic of self-deception and does not sufficiently distinguish self-deception from self-caused deception.

The neurophysiological phenomenon of LTP (long term potentiation) is considered by many to represent an adequate mechanism for acquiring or storing memories in the mammalian brain. In our target article, we reviewed the various arguments put forth in support of the LTP/memory hypothesis. We concluded that these arguments were inconsistent with the purported data base and proposed an alternative interpretation that we suggested was at least as compatible with the available data as the more widely held view. In doing so, we attempted to illustrate that the inadequacy of present experimental designs did not permit us to distinguish between equally viable hypotheses. In the four years since we wrote the first draft of our target article, hundreds of additional studies on LTP have been published and their results have been incorporated into current theories about memory. A diverse group of commentators responded to our target article with their own theories of how memories might be stored in the brain, some of which rely on LTP. Some commentators doubted whether memories can be stored through modifications of synaptic strength. Some assert that it will never be possible to understand the neural mechanisms of memory; still others remain hopeful that we will accomplish some semblance of a resolution, provided we appreciate LTP's role in a subset of seemingly amorphous memory systems. In summary, although it is commonly written that “LTP is a memory storage device,” the divergence of views among the commentators suggests, at least as strongly as our target article, that such conviction is unwarranted and fails to acknowledge both the lack of consensus regarding the role of LTP in memory and the complexity of the phenomenon of memory itself.

This commentary seeks to place Farah's (1994) arguments in the historical context of ideas about mind-brain relationships. It further seeks to draw a conceptual parallel between the issues considered by Farah in her target article and questions which have concerned neuroscientists since the nineteenth century regarding the functional organization of the brain. Specific reference is made to the relationship between use of the concept of “locality” in cognitive neuropsychology and use of the concept of “localization” in neuroscience.

An adequate cerebellar theory should explain the timing and geometry of signal propagation in the molecular layer, hence Braitenberg et al.'s explanation of how parallel fibers may act as delay lines is important. The suggestion that these delay lines may generate control signals that dampen undesirable response modes during movements is merely interesting.

It is worthwhile to search for forms of coding, processing, and learning common to various cortical regions and cognitive functions. Local cortical processors may coordinate their activity by maximizing the transmission of information coherently related to the context in which it occurs, thus forming synchronized population codes. This coordination involves contextual field (CF) connections that link processors within and between cortical regions. The effects of CF connections are distinguished from those mediating receptive field (RF) input; it is shown how CFs can guide both learning and processing without becoming confused with the transmission of RF information. Simulations explore the capabilities of networks built from local processors with both RF and CF connections. Physiological evidence for synchronization, CFs, and plasticity of the RF and CF connections is described. Coordination via CFs is related to perceptual grouping, the effects of context on contrast sensitivity, amblyopia, implicit influences of color in achromotopsia, object and word perception, and the discovery of distal environmental variables and their interactions through self-organization. Cortical computation could thus involve the flexible evaluation of relations between input signals by locally specialized but adaptive processors whose activity is dynamically associated and coordinated within and between regions through specialized contextual connections.

We respond to Farah (1994) by making some general remarks about information encapsulation and locality and asking how these are violated in her computational models. Our point is not that we disagree, but rather that Farah's treatment of the issues is not sufficiently rigorous to allow an evaluation of her claims.

Mele views self-deception as belief sustained by motivationally biased treatment of evidence. This view overlooks something essential, for it does not reckon with the fact that in self-deception the truth is dangerously close at hand and must be repeatedly suppressed. Self-deception is not so much a matter of what one positively believes as what one manages not to think.

The notion that cerebellar cortex geometry may play a unique role in its function is explored by Braitenberg et al. in the form of a new theory about the distribution of cortical activity. The theory makes specific predictions which are not verified by an experimental study of hindlimb movement in the cat.